[Formulajones]

As Jay is trying to explain, and as I mentioned earlier, You absolutely cannot just rely on math figures that are supplied by cam manufactures, timing chain manufactures etc.....and just toss it together expecting it to be correct.

What ever figures you're coming up with from the cam manufacture and what ever the timing set says, you can throw that out the window, none of it matters.

All that matters is what that degree wheel and dial indicator on that intake lobe tells you. 9 times out of 10 you're going to find that the ICL is not exactly what it's thought to be. There are variances and tolerances that aren't 100% when it comes to those keyways on the crank and camshaft, and also with the timing set both on the cam gear and crank gear. Even if one or the other, or both, are off a couple thou you're going to find bigger changes on that degree wheel that won't match what your cam card says or what you've been told it should be. And every time you move that crank gear to advance or retard the cam, you'll have to check it again, because what you think you moved it, I can almost guarantee you'll find it was much more or much less than what it should have been.

It's a tedious process, it's not as simple as reading a piece of paper and just lining up dots, "IF" you want to do it correctly.

Honestly I would have been more concerned with the bottom end issues that have been pointed out than I would have been with the camshaft.

[TRADERMIKE 2012]

Originally Posted by 400 Lemans

It's a good thing you are going to take it back apart and check it with your degree wheel. I think you are going to find out that you are at 104 degrees advanced and not the 108 that you're looking for.

Well, here are the new numbers for you:

(1) Advance key is at 8 degrees at the Crank and 4 degrees at the Cam. 113.5 Ic/l (1.5 + 4 = 5.5 advance),
113.5 - 5.5 = 108 degrees advance, hypothetical.

(2) Post # 299 has a math error, sorry late at night

(3) We set the Degree Wheel back up to the Engine Crank. We set the Dial indicator on the #1 cyl. @ TDC on the compression stroke.

(4) At .050", after passing to .100" and back to .050" on each of our tests we came up with these degree results:

109, 109.5, 110, 113, 115, 116, 113, 111.5, 110.5, 111.5, 111.5, 111.5, END.

(5) Supposition: The numbers range from 109 to 116, that is 8 different degree numbers. The question is: "could one surmise this is due to Dwell?"

(6) Supposition: Since 112 degrees is in the middle " is this the true TDC now, with the advance we added?"

(7) Note: 112 degrees just happens to be the "041" Cams Intake lobe centerline from the factory.

(8) Is my new ICL now 112 @ 0.050"?

(9) Note: We are using the .050" position on both sides of the Intake Lobes Cam lift to find the new Ic/l after an 8-degree key is used on the Crank Gear, this is 4 degrees at the Cam!

[TRADERMIKE 2012]

Here is the way to degree a cam:

How to Degree A Cam
The following is the method of degreeing a cam that Lunati Cams recommends. The first step in degreeing a Cam is to obtain a few items that should be a part of every serious engine builder’s tool chest. These items are:

A large Degree Wheel, such as LUNATI CAMS P/N 80000
A Dial Indicator & Magnetic Base Stand, such as LUNATI CAMS P/N 80012
A Steel Deck Strap Kit, such as LUNATI CAMS P/N 80013
All of the above is available as LUNATI CAMS DEGREE WHEEL KIT, P/N 80001
Some suitable pointer (made from coat hanger wire, paper clip, etc.) rigidly attached to the block
Step 1
1. The first step is to install your new camshaft and line up the stock timing marks.

2 To begin the actual degreeing procedure, the degree wheel should be attached to the front of the crankshaft. A pointer of some type such as a piece of wire should be secured to the front of the engine. The engine should be capable of turning in either direction. Use a crank socket or other suitable tool to rotate the engine. At this point you will leave the wheel somewhat loose.

Step 2
Step 3
3 Rotate the crankshaft until the number one piston is at approximately Top Dead Center and align the pointer with TDC on the degree wheel. Tighten the wheel.

4 The next step is to find the true Top Dead Center (TDC). The most accurate method is to secure a flat strap (1-1/2 x 1) that will bridge the bore (with the heads removed). A Steel Deck Strap Kit is included in the Lunati Degree Wheel Kit, or is available separately (P/N 80013). (If the heads are on the engine, another method of finding TDC is necessary. This method uses an old, discarded spark plug. Remove the porcelain and use a tap, 3/8" 24NF, to cut threads through the plug. Insert a Bolt so that it will protrude through the plug approximately one inch. Remove the rocker arms and push-rods so the valves will not be bent.

Step 4
Step 5
5 Rotate the engine clockwise until the piston contacts the stop. At this point you should mark the degree wheel.

6 Next, rotate the engine counterclockwise until the piston contacts the stop again. Make another mark on the degree wheel. If the degree wheel is properly located, the marks will be an equal number of degrees on both sides of TDC. If not, the degree wheel will have to be relocated. For example, if you come up with 34 degrees on one side and 30 degrees on the other side, the wheel will have to be rotated 2 degrees to compensate for the misalignment. After the wheel has been relocated, the piston should hit the stop the same number of degrees on either side of TDC. After TDC has been found, remove the piston stop to allow complete engine rotation.

Step 6
Step 7
7 Install the lifter in the number one intake lifter bore. Use a mechanical lifter for flat tappet grinds and a roller tappet if the cam is a roller grind. The indicator must be positioned securely above the lifter. The stem from the dial indicator should be aligned with the lifter as close as possible. Misalignment will cause an improper reading. Rotate the engine at least two revolutions. Make sure the dial indicator is working freely and the lifter is not sticking or binding in the bore, and that you have adequate indicator travel. Rotate the engine clockwise until the lifter is on the heel, or base circle of the cam lobe (minimum lift). Zero the dial indicator.

8 Rotate the engine in clockwise direction until a 0.050" reading is reached.

Step 8
Step 9
9 Rotate the engine in clockwise direction until a 0.050" reading is reached. View the degree wheel at this time. This point is 0.050" of lift on the opening side of the intake lobe before top dead center.

10 Compare the reading on the degree wheel with the "IN OPENS" specification on the cam card. If it does not match, your cam is either retarded or advanced. For example, if the degree wheel reading at 0.050" comes up 10 degrees before top dead center (BTDC), and your P/N 00010 cam card lists the 0.050" intake opening at 8 degrees, your cam is 2 degrees advanced. If the degree wheel reads less than 8 degrees, your cam is retarded. If either is the case, proceed to step 11. If it matches, your cam is installed as designed.

Step 10
Step 11
11 So, what do you do if your 0.050" opening lift point doesn’t match the cam card (or you want to set your cam timing to something other than the cam card specifications)? There are several methods to adjust the valve timing:

Degree bushings can be used on the cam sprocket to offset the cam locating pin.
3- or 9- keyway timing chain sets have additional keyways cut into them to index the crank sprocket.
After you have adjusted your cam using one of the previous methods, go back to step 10.



The Racer's Company. Since the 1960s, Lunati has manufactured engine components of the highest quality using cutting-edge technology. Every single product we sell undergoes extensive testing and analysis to ensure the end result is a superior product that can withstand demanding race conditions.

[TRADERMIKE 2012]

Here are a few links that I used to degree my Cam:

https://youtu.be/cAlw9RpTZ4I

https://youtu.be/wzKtaDke22k

https://youtu.be/57gfBu8uc6k

https://youtu.be/Prj0GUZ7nes

https://youtu.be/n_9rUXYxAY0

Camshaft Math Camshaft Math to Design Competitive Performance Engines

JANUARY 24, 2015 BY MUSCLE CAR DIY

Camshafts are a subject that all car guys love to talk about, and those who listen tend to roll their eyes at the staggering number of terms and numbers. There’s lift and duration, overlap and lobe centers, lobe separation angles and so on, and all of them have numbers attached. Most enthusiasts have a basic understanding of the cam, lifter, pushrod, rocker arm, and valve relationship, but keeping all the numbers straight is often intimidating. This chapter looks at the basic calculations relating to camshafts and valvetrain components and how you can use them to equip and tune your particular combination for top performance.

This Tech Tip is From the Full Book, PERFORMANCE AUTOMOTIVE ENGINE MATH. For a comprehensive guide on this entire subject, you can visit this link:
LEARN MORE ABOUT THIS BOOK HERE


SHARE THIS ARTICLE: Please feel free to share this article on Facebook, in Forums, or with any Clubs you participate in. You can copy and paste this link to share: https://musclecardiy.com/performance...mance-engines/


1
a) A. Exhaust Valve Opens – Power Stroke B. Intake Valve Opens – Exhaust Stroke C. Exhaust Valve Closes – Intake Stroke D. Intake Valve Closes – Compression Stroke b) The basic cam lobe shape is an eccentric with the lifter riding on the base circle. As the cam rotates, the lifter moves up the flank of the lobe and over the top to open the valve. (Courtesy Comp Cams)


Lobe Centers
Imagine a line passing from the center of the cam directly through the highest point on the cam lobe. This is the geometric centerline of that particular lobe. To avoid confusion when comparing cams, remember that the lobe center angle is measured between the centerlines of the intake and corresponding exhaust lobes, while lobe centerline is the angle measured between the center of the lobe and TDC. The lobe center angle is fixed and cannot be changed after the cam is ground. The lobe centerline can be altered by advancing or retarding the cam. When you do this, you are effectively moving the intake lobe centerline closer to or farther from TDC.


2
This illustration tells you everything you need to know about camshaft operation. In addition to lift duration and overlap, it also indicates the intake and exhaust centerlines, lobe separation angle, and the location of timing events relative to the four cycles. Note that 0.050-inch tappet lift equals 0.050 times the rocker ratio to indicate valve lift at the checking point. (Courtesy Comp Cams)


In terms of engine performance, the lobe center angle is significant. A larger angle yields less valve overlap (the period when both valves are open at the same time). This permits the cylinder to begin building pressure sooner and that boosts low-speed torque. Decreasing the angle creates greater overlap and moves the torque curve higher in the RPM range, effectively narrowing the engine’s powerband. For most street applications always select a cam that builds as much torque as possible. Generally, you want valve events that produce a wider lobe center angle, decreasing valve overlap. One of the advantages of the new high-velocity street roller profiles is that you maintain good idle quality by using wider 112- to 115-degree lobe centerlines, but you also have a high-RPM boost with more aggressive lobe profiles (increasing effective duration). The result is a broad torque curve ideal for street use.


Muscle Car B
Supercharged or turbocharged applications should avoid cams with excessive overlap because the pressurized intake system already provides effective cylinder filling and forced exhaust scavenging. In these applications, long overlap can be detrimental because some of the intake charge can be blown right through the engine without being burned. For the average street and strip enthusiast, all of these factors are taken care of by the cam manufacturer. Their vast experience lets them provide you with a Cam that they know will work for your application.


Understanding Cam Specs

For the purpose of this discussion, I will speak in terms of opening and closing valve events. Intake opening (IO) and exhaust opening (EO) represent the intake and exhaust opening points in crankshaft degrees. Intake closing (IC) and exhaust closing (EC) are the intake and exhaust closing events. Cam cards publish these points based on the manufacturer’s chosen reference points: typically, 0.006 inch for advertised duration and 0.050 inch for a universal checking reference based on an agreed amount of lobe lift where reasonable flow is initiated. The following formula is used to calculate intake and exhaust duration. It applies to any lift as long as your cam card specifies opening and closing figures for a particular lift value.


3
The camshaft timing card included with your cam provides the essential specifications for installing your cam correctly. It includes lobe lift, net valve lift, timing points at the advertised duration, duration at 0.050-inch lift, lobe separation angle, and the installed intake centerline. Some cards also include overlap and valve-spring specs. Most manufacturers now publish all their standard cam cards online for your convenience.


Duration at Specified Lift = opening point + 180 degrees + closing point
For example, a COMP Cams XE274H-10 hydraulic cam lists the following opening and closing points for a checking lift of 0.006 inch:

IO = 31-degrees BTDC IC = 63-degrees ABDC
EO = 77-degrees BBDC EC = 29-degrees ATDC

Hence,

Intake Duration = 31 + 180 + 63 = 274 degrees at 0.006-inch lift
Exhaust Duration = 77 + 180 + 29 = 286 degrees at 0.006-inch lift

From this you can calculate the intake and exhaust centerlines. To find the intake lobe centerline, divide the intake duration by two and subtract the indicated intake opening point as shown in our example with the Comp Cam, XE274 example.

Intake Centerline = (duration ÷ 2) – IO
Intake Centerline = (274 ÷ 2) – 31 = 106 degrees

Sometimes you find a very mild or stock cam where the IO occurs after TDC (ATDC). In this case just add the IO figure to one half of the duration.

On the exhaust side the formula is similar, but instead of subtracting the intake opening point, subtract the exhaust closing point.

Exhaust Centerline = (calculated duration ÷ 2) – EC Exhaust Centerline = (286 ÷ 2) – 29 = 114 degrees Once you know this it’s easy to calculate the lobe separation angle (LSA) which is the difference between the two centerlines. Simply add the calculated centerlines together and divide them by 2.

Lobe Separation Angle = (intake centerline + exhaust centerline) ÷ 2
LSA = (106 degrees + 114 degrees) ÷ 2 = 110 degrees

If a cam is ground “straight up,” both centerlines are the same and the LSA is one half of their sum. More commonly you find that cam companies grind their street cams 4 degrees advanced to help boost low-speed torque on longer-duration cams. You can see this in the Comp XE274 example where the intake centerline is 106 degrees, but the LSA is 110 or 4 degrees advanced. Note that 110 degrees is exactly halfway between 106 and 114 degrees. This practice moves the IC event 4 degrees ahead, which tends to diminish top end power in favor of more low-speed grunt for street engines. One other point to note is the use of parenthesis around some timing points. This notation indicates that the cam actually closes the valve after TDC instead of before, even though the card indicates BTDC. You only find this on short-duration cams, but it is important to note if you’re making calculations with a small cam.



Calculating Valve Lift
The net valve lift is a function of camshaft lobe lift and rocker arm ratio. Lobe lift (sometimes called cam rise) is the height of the eccentric portion of the cam lobe above the base circle. The rocker arm transfers the motion of the valve lifter riding on the cam lobe to the valve and increases the lobe lift by the amount of the rocker ratio, which is typically 1.5 to 1.7:1. It provides a convenient means of increasing valve lift without a space or packaging penalty. This is very evident in a pushrod engine where the valvetrain is compact and easily packaged compared to the complication and excessive size required for single and double overhead cam arrangements.


4
The Cam Analyzer from Performance Trends uses hand measured cam profiles or computerized file formats such as Cam Doctor and Cam Pro Plus to provide detailed camshaft lobe evaluation for use in performance simulations.


5
Cam Analyzer uses its motorized unit to rotate the cam so the profiler can read the lobe.


6
Cam Analyzer generates its own cam card for your reference files.


7
Degreeing the cam requires accurately locating TDC with a degree wheel and pointer, and a dial indicator set up to read lifter travel as you rotate the engine.


Net valve lift differs according to the type of lifter. To accommodate thermal expansion, clearance is built into the system in the form of clearance ramps and valve lash for mechanical (solid) lifter cams. The valve lash clearance must be subtracted from the total valve lift to obtain the net valve lift for this type of cam.

Mechanical Lifter Cam Net Lift = (lobe lift x rocker ratio) – valve lash
Example: For a Lobe Lift of 0.300 inch and a 1.5:1 rocker ratio with a 0.022-inch valve lash:
Net Lift = (0.300 x 1.5) – 0.022 = 0.428 inch

A hydraulic camshaft automatically adjusts for thermal expansion via lifter preload against an internal hydraulic plunger. No clearance is necessary and these lifters are typically adjusted with a specified amount of preload or a preferred degree of turn from zero lash; usually one-quarter to one-half turn down. In this case the net valve lift is based on the lobe lift and the rocker ratio alone.

Net Lift = lobe lift x rocker ratio
Net Lift = 0.300 x 1.5 = 0.450 inch

Mechanical (solid) cams are typically smaller than their hydraulic counterparts due to loss of lift attributable to valve lash. But mechanical cams, unlike hydraulic cams, can be tuned somewhat by altering valve lash. Tightening the lash adds lift and starts the valve event sooner, effectively mimicking a larger cam. To accommodate various tuning changes, this is often limited to either the intake valves or the exhaust valves and sometimes only on the end cylinders to accommodate variations in runner length. A racer might tighten the lash on the exhaust side to increase the exhaust event if he feels that the engine is exhaust limited. Or he might tighten the lash on the outer four corner cylinders to compensate for the longer intake runners on those cylinders. That’s equivalent to running a bigger Cam on those cylinders.

You may recall from Chapter 8 that sometimes you can affect dual torque peaks and a broader torque curve by running different-size (c/s area) primary pipes on alternating cylinders in the firing order. This is a fine-tuning measure, but in some cases, you can combine this with valve lash adjustments on selected cylinders to further tune the torque output at different speeds. In theory this is predictable, but in practice it often requires dyno verification to quantify gains.

Valve lash changes should be limited to a maximum of 0.004 inch, and consideration should be given to the known valve-to-piston clearance before going too far on the exhaust side. These tuning measures can net small gains, but the correct combination can effectively broaden a torque curve with surprisingly good results. This may be just enough to give you some added leverage on the competition without having to make major engine modifications.



Finding TDC
Locating TDC accurately is absolutely essential to proper camshaft installation. Exact TDC is the timing basis for all camshaft timing events. The method for locating it varies according to the engine’s state of assembly. Whatever that is, a temporary piston stop is used to stop the piston at some arbitrary distance before and after TDC.


8
A cam checking kit like this one from Comp Cams provides all the necessary measuring tools to successfully degree your high-performance camshaft.


For fully assembled engines that are not already equipped with an accurately set TDC indicator, a threaded piston stop can be installed in the spark plug hole of the number-1 cylinder. Note that on most V-8 engines, the number-1 cylinder is almost always the farthest one forward in the V configuration. Paired rod and piston assemblies on each crank throw dictate that one is always offset farther forward than its counterpart. Study the front of the block to see which of the front cylinders is farther forward. That will be number-1.

If the degree process is being performed during engine assembly, it is best to do it with only the number-1 piston and rod assembly installed on the crankshaft. Rotating the engine to degree the cam is much easier this way. In this case, a flat bar piston stop is bolted to the block deck surface above the number one piston. This type of piston stop has a center bolt that can be adjusted to stop the piston at any desired point below TDC.

Begin by installing the degree wheel on the crank snout, or the balancer if it is already installed.
Before installing the piston stop, rotate the engine until the piston top visually appears to be at TDC. You should be able to see this through the spark plug hole on an assembled engine. It doesn’t have to be exact—just close.
Install a temporary wire pointer and adjust it so the tip is close to the graduated marks on the degree wheel.
Adjust the degree wheel so the pointer indicates TDC (0 degrees) and snug it lightly.
Rotate the engine counterclockwise approximately one-half turn and install the piston stop.
Tighten it securely so it won’t move when the piston contacts it.
Slowly rotate the engine clockwise until the piston contacts the piston stop.
in degrees before top dead center (BTDC). Record that number and then rotate the engine in the opposite direction (counterclockwise) until it completes a revolution and contacts the piston again.

Record the reading on the degree wheel and note that it indicates degrees after top dead center (ATDC).
If your calibrated eyeball is very accurate, the recorded numbers indicate the same number of degrees on either side of TDC and the pointer reads zero with the piston stop removed and the piston brought to the top. In practice, most of us aren’t that accurate, so we have to locate TDC based on a common reference point on either side of TDC. That’s the piston stop. The reason you can’t accurately locate TDC visually is because the piston experiences a brief period of dwell (stationary) at the top of its stroke as the rod angle transitions from one side to the other. The piston is stopped at this point and you have to split the dwell point exactly to find true TDC.

Since the piston stop does not move, it represents a fixed reference point before and after TDC. True TDC is found by splitting the difference between the degree wheel readings.

For example, let’s say your recorded numbers are 34-degrees BTDC and 30-degrees ATDC. The exact number will depend on the depth of your piston stop in the cylinder bore, but it is all relative. TDC is halfway between the recorded readings. Loosen the degree wheel and rotate the degree wheel only until the pointer reads 32-degrees. Lock down the degree wheel and make sure not to touch or move the pointer from this point forward. Check your work by rotating the engine back and forth to the piston stop in both directions. The pointer reading should be the same in both directions (32 degrees in our example). If it is not the same, repeat the steps until the pointer indicates the exact same number of degrees before and after TDC. Once it does, remove the piston stop and degree the cam with confidence that you are locating your timing events based on exact TDC.



Degreeing the Cam
There are two methods for degreeing a camshaft. One compares the opening and closing points of the intake valve to see if they match the manufacturer’s specs on the cam card. The other method locates the intake lobe centerline relative to TDC. Both methods are successful, but the intake centerline method does not verify the intake opening and closing points according to the cam card. Both methods are described below, but the intake opening and closing method is recommended for initial setup. Then you can check your work with the intake centerline method. In either case you need an accurate means of reading lifter travel.


9
Most degree wheels are precise if you are careful about locating the position of the pointer. You can degree accurately with all of them, but many tuners prefer the larger-diameter professional degree wheel.


10
The professional degree wheel offers larger spacing between degree increments for more precise positioning and it can be used to turn the engine by hand if only the number-1 piston is installed.


I prefer the cam checking tool available from Jegs, Summit, and many other suppliers, but successful results can be obtained using a solid lifter or a modified hydraulic lifter with the internal plunger reversed to give the dial indicator plunger a flat surface to bear against. You can also locate the plunger against the edge of the lifter. Make sure that the contact is stable and that the direction of the indicator travel is parallel to lifter travel. Then adjust the dial indicator to ensure that it has enough available range to read total intake lifter travel for the number-1 cylinder.



Intake Opening Method
Install the cam with the timing marks correctly aligned for your engine. Set up your dial indicator and check lifter, or the cam checking tool in the number-1 intake lifter hole as described above. Zero the dial indicator and rotate the engine in the normal direction of rotation for several revolutions to verify that the dial indicator reads full lifter travel and returns to zero each time. You can take this opportunity to verify that lifter travel matches the indicated lobe lift on the cam card. If the lifter does not return to zero on the base circle, determine the cause and correct before continuing.


11
Good degree wheels are marked to indicate a range where valve events normally occur. If you’re measuring an event that occurs outside that range, it is probably incorrect and you should recheck your work.


12
A cam checking tool reads lifter motion directly without the need for dial indicator spindle extensions. It can only be used with the cylinder heads off the engine, but it is the most accurate method.


13
You can read net valve lift and duration with the valvetrain installed by checking it at the retainer. This method incorporates the rocker ratio and any clearance lash to yield an accurate indication of true valve motion.


Once you’re satisfied, begin with the lifter on the base circle and slowly rotate the engine clockwise until the indicator shows 0.050-inch lifter travel. Note the reading on the degree wheel. It should match the intake opening point (IO) indicated on the cam card for 0.050-inch lift. Continue rotating the engine through full lifter travel and down the other side of the lobe until you reach 0.050- inch lift before the intake closing point.

Since you know the lobe lift and the recommended closing point from the cam card, you should be able to anticipate the closing point as you rotate the engine. If you miss it, simply back up about 60 degrees to compensate for timing chain slack and approach the 0.050-inch closing point again. Compare it to the cam card and then continue rotating to verify that the lifter returns to zero again.

Your readings should show the intake opening and closing points and the total lifter travel or lobe lift. If the intake opening event doesn’t match the cam card, you will have to advance or retard the cam to bring it into spec. For example, if your cam is supposed to open the intake valve at 36-degrees BTDC and close at 70-degrees ATDC (at 0.050-inch lift), but your measurements show that it is opening 34-degrees BTDC and closing 72-degrees ATDC, the cam is retarded. The valve event is occurring later than the recommended spec. If it were to open at 38-degrees BTDC and close at 68-degrees ATDC it would be 2-degrees advanced because the valve event is occurring 2 degrees earlier than specified.


Muscle Car B
In either case it is easy to correct using offset cam bushings or a crank gear with multiple keyways. Both allow you to adjust the position of the cam and then recheck it for compliance with the cam card specs. Note that they can also be used to reposition the cam if you deliberately choose to advance the cam to promote low-end torque or retard the cam for a little more top end power.

If your degree results are plus or minus 1 degree of your published specs, consider leaving the engine as assembled because it is entirely possible that the small degree wheel you are probably using is not that accurate. Larger-diameter degree wheels space the degree marks farther apart and, therefore, have a greater chance of improved accuracy.

You can check the accuracy of your wheel by placing it on a large sheet of paper and marking the four 90-degree positions of the wheel. Then move the wheel to various positions and check to see that each 90-degree mark is an equal number of degrees from 90. You may well find that your wheel is not completely accurate. This is why fussing over less than 2 degrees (unless for example, the cam is retarded 2 degrees and you want 2 degrees advanced) may not be worth the effort.



Intake Centerline Method
The intake centerline method finds the location of the intake lobe centerline relative to TDC. The recommended intake centerline is indicated on the cam card and when correct, it should yield the specified intake opening and closing points when you degree the cam. Finding the centerline is easy.

Rotate the engine clockwise until you find the maximum lobe lift, then zero the indicator. Now rotate backward about 0.100 to 0.150-inch to compensate for timing chain slack. Then rotate clockwise until you reach 0.050 inch. This is 0.050 inch before max lift.

Note the reading on the degree wheel. Then continue over the nose of the cam until you reach 0.050 inch again. This is the 0.050 inch after max lift. Note the degree wheel reading again. Now add the two readings together and divide by 2 to find the center line. It should match the cam card.

For example, if your numbers are 80 and 132:
(80 + 132) ÷ 2 = 106-degree centerline

The cam card indicates the correct installed intake centerline. If it calls for 106 degrees and you come up with 108 degrees, the cam is early and you have to retard it 2 degrees to bring it into spec. If you get 104 degrees the cam is retarded and you have to advance it 2 degrees to correct it. If you have degreed the cam with the intake centerline method, go back and check to see if the intake opening and closing points match those indicated on the cam card. If incorrect, determine the direction of error and reposition the cam accordingly.



Calculating Valve Overlap
Overlap is the number of degrees where both valves are off their seats at the same time. It is a combination of the intake opening event and the exhaust closing event. Adding these two points together yields valve overlap.

Valve Overlap = IO + EC

For example, a cam with an intake opening point of 29-degrees BTDC and an exhaust closing point of 23-degrees ATDC has a valve overlap of 52 degrees.

29 degrees + 23 degrees = 52 degrees overlap

Written by John Baechtel and Posted with Permission of Car Tech Books ,

[PAUL K]

Originally Posted by TRADERMIKE 2012

Here are a few links that I used to degree my Cam:

https://youtu.be/cAlw9RpTZ4I

https://youtu.be/wzKtaDke22k

https://youtu.be/57gfBu8uc6k

https://youtu.be/Prj0GUZ7nes

https://youtu.be/n_9rUXYxAY0

Camshaft Math Camshaft Math to Design Competitive Performance Engines

JANUARY 24, 2015 BY MUSCLE CAR DIY

Camshafts are a subject that all car guys love to talk about, and those who listen tend to roll their eyes at the staggering number of terms and numbers. There’s lift and duration, overlap and lobe centers, lobe separation angles and so on, and all of them have numbers attached. Most enthusiasts have a basic understanding of the cam, lifter, pushrod, rocker arm, and valve relationship, but keeping all the numbers straight is often intimidating. This chapter looks at the basic calculations relating to camshafts and valvetrain components and how you can use them to equip and tune your particular combination for top performance.

This Tech Tip is From the Full Book, PERFORMANCE AUTOMOTIVE ENGINE MATH. For a comprehensive guide on this entire subject, you can visit this link:
LEARN MORE ABOUT THIS BOOK HERE


SHARE THIS ARTICLE: Please feel free to share this article on Facebook, in Forums, or with any Clubs you participate in. You can copy and paste this link to share: https://musclecardiy.com/performance...mance-engines/


1
a) A. Exhaust Valve Opens – Power Stroke B. Intake Valve Opens – Exhaust Stroke C. Exhaust Valve Closes – Intake Stroke D. Intake Valve Closes – Compression Stroke b) The basic cam lobe shape is an eccentric with the lifter riding on the base circle. As the cam rotates, the lifter moves up the flank of the lobe and over the top to open the valve. (Courtesy Comp Cams)


Lobe Centers
Imagine a line passing from the center of the cam directly through the highest point on the cam lobe. This is the geometric centerline of that particular lobe. To avoid confusion when comparing cams, remember that the lobe center angle is measured between the centerlines of the intake and corresponding exhaust lobes, while lobe centerline is the angle measured between the center of the lobe and TDC. The lobe center angle is fixed and cannot be changed after the cam is ground. The lobe centerline can be altered by advancing or retarding the cam. When you do this, you are effectively moving the intake lobe centerline closer to or farther from TDC.


2
This illustration tells you everything you need to know about camshaft operation. In addition to lift duration and overlap, it also indicates the intake and exhaust centerlines, lobe separation angle, and the location of timing events relative to the four cycles. Note that 0.050-inch tappet lift equals 0.050 times the rocker ratio to indicate valve lift at the checking point. (Courtesy Comp Cams)


In terms of engine performance, the lobe center angle is significant. A larger angle yields less valve overlap (the period when both valves are open at the same time). This permits the cylinder to begin building pressure sooner and that boosts low-speed torque. Decreasing the angle creates greater overlap and moves the torque curve higher in the RPM range, effectively narrowing the engine’s powerband. For most street applications always select a cam that builds as much torque as possible. Generally, you want valve events that produce a wider lobe center angle, decreasing valve overlap. One of the advantages of the new high-velocity street roller profiles is that you maintain good idle quality by using wider 112- to 115-degree lobe centerlines, but you also have a high-RPM boost with more aggressive lobe profiles (increasing effective duration). The result is a broad torque curve ideal for street use.


Muscle Car B
Supercharged or turbocharged applications should avoid cams with excessive overlap because the pressurized intake system already provides effective cylinder filling and forced exhaust scavenging. In these applications, long overlap can be detrimental because some of the intake charge can be blown right through the engine without being burned. For the average street and strip enthusiast, all of these factors are taken care of by the cam manufacturer. Their vast experience lets them provide you with a Cam that they know will work for your application.


Understanding Cam Specs

For the purpose of this discussion, I will speak in terms of opening and closing valve events. Intake opening (IO) and exhaust opening (EO) represent the intake and exhaust opening points in crankshaft degrees. Intake closing (IC) and exhaust closing (EC) are the intake and exhaust closing events. Cam cards publish these points based on the manufacturer’s chosen reference points: typically, 0.006 inch for advertised duration and 0.050 inch for a universal checking reference based on an agreed amount of lobe lift where reasonable flow is initiated. The following formula is used to calculate intake and exhaust duration. It applies to any lift as long as your cam card specifies opening and closing figures for a particular lift value.


3
The camshaft timing card included with your cam provides the essential specifications for installing your cam correctly. It includes lobe lift, net valve lift, timing points at the advertised duration, duration at 0.050-inch lift, lobe separation angle, and the installed intake centerline. Some cards also include overlap and valve-spring specs. Most manufacturers now publish all their standard cam cards online for your convenience.


Duration at Specified Lift = opening point + 180 degrees + closing point
For example, a COMP Cams XE274H-10 hydraulic cam lists the following opening and closing points for a checking lift of 0.006 inch:

IO = 31-degrees BTDC IC = 63-degrees ABDC
EO = 77-degrees BBDC EC = 29-degrees ATDC

Hence,

Intake Duration = 31 + 180 + 63 = 274 degrees at 0.006-inch lift
Exhaust Duration = 77 + 180 + 29 = 286 degrees at 0.006-inch lift

From this you can calculate the intake and exhaust centerlines. To find the intake lobe centerline, divide the intake duration by two and subtract the indicated intake opening point as shown in our example with the Comp Cam, XE274 example.

Intake Centerline = (duration ÷ 2) – IO
Intake Centerline = (274 ÷ 2) – 31 = 106 degrees

Sometimes you find a very mild or stock cam where the IO occurs after TDC (ATDC). In this case just add the IO figure to one half of the duration.

On the exhaust side the formula is similar, but instead of subtracting the intake opening point, subtract the exhaust closing point.

Exhaust Centerline = (calculated duration ÷ 2) – EC Exhaust Centerline = (286 ÷ 2) – 29 = 114 degrees Once you know this it’s easy to calculate the lobe separation angle (LSA) which is the difference between the two centerlines. Simply add the calculated centerlines together and divide them by 2.

Lobe Separation Angle = (intake centerline + exhaust centerline) ÷ 2
LSA = (106 degrees + 114 degrees) ÷ 2 = 110 degrees

If a cam is ground “straight up,” both centerlines are the same and the LSA is one half of their sum. More commonly you find that cam companies grind their street cams 4 degrees advanced to help boost low-speed torque on longer-duration cams. You can see this in the Comp XE274 example where the intake centerline is 106 degrees, but the LSA is 110 or 4 degrees advanced. Note that 110 degrees is exactly halfway between 106 and 114 degrees. This practice moves the IC event 4 degrees ahead, which tends to diminish top end power in favor of more low-speed grunt for street engines. One other point to note is the use of parenthesis around some timing points. This notation indicates that the cam actually closes the valve after TDC instead of before, even though the card indicates BTDC. You only find this on short-duration cams, but it is important to note if you’re making calculations with a small cam.



Calculating Valve Lift
The net valve lift is a function of camshaft lobe lift and rocker arm ratio. Lobe lift (sometimes called cam rise) is the height of the eccentric portion of the cam lobe above the base circle. The rocker arm transfers the motion of the valve lifter riding on the cam lobe to the valve and increases the lobe lift by the amount of the rocker ratio, which is typically 1.5 to 1.7:1. It provides a convenient means of increasing valve lift without a space or packaging penalty. This is very evident in a pushrod engine where the valvetrain is compact and easily packaged compared to the complication and excessive size required for single and double overhead cam arrangements.


4
The Cam Analyzer from Performance Trends uses hand measured cam profiles or computerized file formats such as Cam Doctor and Cam Pro Plus to provide detailed camshaft lobe evaluation for use in performance simulations.


5
Cam Analyzer uses its motorized unit to rotate the cam so the profiler can read the lobe.


6
Cam Analyzer generates its own cam card for your reference files.


7
Degreeing the cam requires accurately locating TDC with a degree wheel and pointer, and a dial indicator set up to read lifter travel as you rotate the engine.


Net valve lift differs according to the type of lifter. To accommodate thermal expansion, clearance is built into the system in the form of clearance ramps and valve lash for mechanical (solid) lifter cams. The valve lash clearance must be subtracted from the total valve lift to obtain the net valve lift for this type of cam.

Mechanical Lifter Cam Net Lift = (lobe lift x rocker ratio) – valve lash
Example: For a Lobe Lift of 0.300 inch and a 1.5:1 rocker ratio with a 0.022-inch valve lash:
Net Lift = (0.300 x 1.5) – 0.022 = 0.428 inch

A hydraulic camshaft automatically adjusts for thermal expansion via lifter preload against an internal hydraulic plunger. No clearance is necessary and these lifters are typically adjusted with a specified amount of preload or a preferred degree of turn from zero lash; usually one-quarter to one-half turn down. In this case the net valve lift is based on the lobe lift and the rocker ratio alone.

Net Lift = lobe lift x rocker ratio
Net Lift = 0.300 x 1.5 = 0.450 inch

Mechanical (solid) cams are typically smaller than their hydraulic counterparts due to loss of lift attributable to valve lash. But mechanical cams, unlike hydraulic cams, can be tuned somewhat by altering valve lash. Tightening the lash adds lift and starts the valve event sooner, effectively mimicking a larger cam. To accommodate various tuning changes, this is often limited to either the intake valves or the exhaust valves and sometimes only on the end cylinders to accommodate variations in runner length. A racer might tighten the lash on the exhaust side to increase the exhaust event if he feels that the engine is exhaust limited. Or he might tighten the lash on the outer four corner cylinders to compensate for the longer intake runners on those cylinders. That’s equivalent to running a bigger Cam on those cylinders.

You may recall from Chapter 8 that sometimes you can affect dual torque peaks and a broader torque curve by running different-size (c/s area) primary pipes on alternating cylinders in the firing order. This is a fine-tuning measure, but in some cases, you can combine this with valve lash adjustments on selected cylinders to further tune the torque output at different speeds. In theory this is predictable, but in practice it often requires dyno verification to quantify gains.

Valve lash changes should be limited to a maximum of 0.004 inch, and consideration should be given to the known valve-to-piston clearance before going too far on the exhaust side. These tuning measures can net small gains, but the correct combination can effectively broaden a torque curve with surprisingly good results. This may be just enough to give you some added leverage on the competition without having to make major engine modifications.



Finding TDC
Locating TDC accurately is absolutely essential to proper camshaft installation. Exact TDC is the timing basis for all camshaft timing events. The method for locating it varies according to the engine’s state of assembly. Whatever that is, a temporary piston stop is used to stop the piston at some arbitrary distance before and after TDC.


8
A cam checking kit like this one from Comp Cams provides all the necessary measuring tools to successfully degree your high-performance camshaft.


For fully assembled engines that are not already equipped with an accurately set TDC indicator, a threaded piston stop can be installed in the spark plug hole of the number-1 cylinder. Note that on most V-8 engines, the number-1 cylinder is almost always the farthest one forward in the V configuration. Paired rod and piston assemblies on each crank throw dictate that one is always offset farther forward than its counterpart. Study the front of the block to see which of the front cylinders is farther forward. That will be number-1.

If the degree process is being performed during engine assembly, it is best to do it with only the number-1 piston and rod assembly installed on the crankshaft. Rotating the engine to degree the cam is much easier this way. In this case, a flat bar piston stop is bolted to the block deck surface above the number one piston. This type of piston stop has a center bolt that can be adjusted to stop the piston at any desired point below TDC.

Begin by installing the degree wheel on the crank snout, or the balancer if it is already installed.
Before installing the piston stop, rotate the engine until the piston top visually appears to be at TDC. You should be able to see this through the spark plug hole on an assembled engine. It doesn’t have to be exact—just close.
Install a temporary wire pointer and adjust it so the tip is close to the graduated marks on the degree wheel.
Adjust the degree wheel so the pointer indicates TDC (0 degrees) and snug it lightly.
Rotate the engine counterclockwise approximately one-half turn and install the piston stop.
Tighten it securely so it won’t move when the piston contacts it.
Slowly rotate the engine clockwise until the piston contacts the piston stop.
in degrees before top dead center (BTDC). Record that number and then rotate the engine in the opposite direction (counterclockwise) until it completes a revolution and contacts the piston again.

Record the reading on the degree wheel and note that it indicates degrees after top dead center (ATDC).
If your calibrated eyeball is very accurate, the recorded numbers indicate the same number of degrees on either side of TDC and the pointer reads zero with the piston stop removed and the piston brought to the top. In practice, most of us aren’t that accurate, so we have to locate TDC based on a common reference point on either side of TDC. That’s the piston stop. The reason you can’t accurately locate TDC visually is because the piston experiences a brief period of dwell (stationary) at the top of its stroke as the rod angle transitions from one side to the other. The piston is stopped at this point and you have to split the dwell point exactly to find true TDC.

Since the piston stop does not move, it represents a fixed reference point before and after TDC. True TDC is found by splitting the difference between the degree wheel readings.

For example, let’s say your recorded numbers are 34-degrees BTDC and 30-degrees ATDC. The exact number will depend on the depth of your piston stop in the cylinder bore, but it is all relative. TDC is halfway between the recorded readings. Loosen the degree wheel and rotate the degree wheel only until the pointer reads 32-degrees. Lock down the degree wheel and make sure not to touch or move the pointer from this point forward. Check your work by rotating the engine back and forth to the piston stop in both directions. The pointer reading should be the same in both directions (32 degrees in our example). If it is not the same, repeat the steps until the pointer indicates the exact same number of degrees before and after TDC. Once it does, remove the piston stop and degree the cam with confidence that you are locating your timing events based on exact TDC.



Degreeing the Cam
There are two methods for degreeing a camshaft. One compares the opening and closing points of the intake valve to see if they match the manufacturer’s specs on the cam card. The other method locates the intake lobe centerline relative to TDC. Both methods are successful, but the intake centerline method does not verify the intake opening and closing points according to the cam card. Both methods are described below, but the intake opening and closing method is recommended for initial setup. Then you can check your work with the intake centerline method. In either case you need an accurate means of reading lifter travel.


9
Most degree wheels are precise if you are careful about locating the position of the pointer. You can degree accurately with all of them, but many tuners prefer the larger-diameter professional degree wheel.


10
The professional degree wheel offers larger spacing between degree increments for more precise positioning and it can be used to turn the engine by hand if only the number-1 piston is installed.


I prefer the cam checking tool available from Jegs, Summit, and many other suppliers, but successful results can be obtained using a solid lifter or a modified hydraulic lifter with the internal plunger reversed to give the dial indicator plunger a flat surface to bear against. You can also locate the plunger against the edge of the lifter. Make sure that the contact is stable and that the direction of the indicator travel is parallel to lifter travel. Then adjust the dial indicator to ensure that it has enough available range to read total intake lifter travel for the number-1 cylinder.



Intake Opening Method
Install the cam with the timing marks correctly aligned for your engine. Set up your dial indicator and check lifter, or the cam checking tool in the number-1 intake lifter hole as described above. Zero the dial indicator and rotate the engine in the normal direction of rotation for several revolutions to verify that the dial indicator reads full lifter travel and returns to zero each time. You can take this opportunity to verify that lifter travel matches the indicated lobe lift on the cam card. If the lifter does not return to zero on the base circle, determine the cause and correct before continuing.


11
Good degree wheels are marked to indicate a range where valve events normally occur. If you’re measuring an event that occurs outside that range, it is probably incorrect and you should recheck your work.


12
A cam checking tool reads lifter motion directly without the need for dial indicator spindle extensions. It can only be used with the cylinder heads off the engine, but it is the most accurate method.


13
You can read net valve lift and duration with the valvetrain installed by checking it at the retainer. This method incorporates the rocker ratio and any clearance lash to yield an accurate indication of true valve motion.


Once you’re satisfied, begin with the lifter on the base circle and slowly rotate the engine clockwise until the indicator shows 0.050-inch lifter travel. Note the reading on the degree wheel. It should match the intake opening point (IO) indicated on the cam card for 0.050-inch lift. Continue rotating the engine through full lifter travel and down the other side of the lobe until you reach 0.050- inch lift before the intake closing point.

Since you know the lobe lift and the recommended closing point from the cam card, you should be able to anticipate the closing point as you rotate the engine. If you miss it, simply back up about 60 degrees to compensate for timing chain slack and approach the 0.050-inch closing point again. Compare it to the cam card and then continue rotating to verify that the lifter returns to zero again.

Your readings should show the intake opening and closing points and the total lifter travel or lobe lift. If the intake opening event doesn’t match the cam card, you will have to advance or retard the cam to bring it into spec. For example, if your cam is supposed to open the intake valve at 36-degrees BTDC and close at 70-degrees ATDC (at 0.050-inch lift), but your measurements show that it is opening 34-degrees BTDC and closing 72-degrees ATDC, the cam is retarded. The valve event is occurring later than the recommended spec. If it were to open at 38-degrees BTDC and close at 68-degrees ATDC it would be 2-degrees advanced because the valve event is occurring 2 degrees earlier than specified.


Muscle Car B
In either case it is easy to correct using offset cam bushings or a crank gear with multiple keyways. Both allow you to adjust the position of the cam and then recheck it for compliance with the cam card specs. Note that they can also be used to reposition the cam if you deliberately choose to advance the cam to promote low-end torque or retard the cam for a little more top end power.

If your degree results are plus or minus 1 degree of your published specs, consider leaving the engine as assembled because it is entirely possible that the small degree wheel you are probably using is not that accurate. Larger-diameter degree wheels space the degree marks farther apart and, therefore, have a greater chance of improved accuracy.

You can check the accuracy of your wheel by placing it on a large sheet of paper and marking the four 90-degree positions of the wheel. Then move the wheel to various positions and check to see that each 90-degree mark is an equal number of degrees from 90. You may well find that your wheel is not completely accurate. This is why fussing over less than 2 degrees (unless for example, the cam is retarded 2 degrees and you want 2 degrees advanced) may not be worth the effort.



Intake Centerline Method
The intake centerline method finds the location of the intake lobe centerline relative to TDC. The recommended intake centerline is indicated on the cam card and when correct, it should yield the specified intake opening and closing points when you degree the cam. Finding the centerline is easy.

Rotate the engine clockwise until you find the maximum lobe lift, then zero the indicator. Now rotate backward about 0.100 to 0.150-inch to compensate for timing chain slack. Then rotate clockwise until you reach 0.050 inch. This is 0.050 inch before max lift.

Note the reading on the degree wheel. Then continue over the nose of the cam until you reach 0.050 inch again. This is the 0.050 inch after max lift. Note the degree wheel reading again. Now add the two readings together and divide by 2 to find the center line. It should match the cam card.

For example, if your numbers are 80 and 132:
(80 + 132) ÷ 2 = 106-degree centerline

The cam card indicates the correct installed intake centerline. If it calls for 106 degrees and you come up with 108 degrees, the cam is early and you have to retard it 2 degrees to bring it into spec. If you get 104 degrees the cam is retarded and you have to advance it 2 degrees to correct it. If you have degreed the cam with the intake centerline method, go back and check to see if the intake opening and closing points match those indicated on the cam card. If incorrect, determine the direction of error and reposition the cam accordingly.



Calculating Valve Overlap
Overlap is the number of degrees where both valves are off their seats at the same time. It is a combination of the intake opening event and the exhaust closing event. Adding these two points together yields valve overlap.

Valve Overlap = IO + EC

For example, a cam with an intake opening point of 29-degrees BTDC and an exhaust closing point of 23-degrees ATDC has a valve overlap of 52 degrees.

29 degrees + 23 degrees = 52 degrees overlap

Written by John Baechtel and Posted with Permission of Car Tech Books ,

That's a really long post.

[tom s]

WAY TOO long!Tom

[Cliff R]

+2

Degreeing a cam isn't overly complicated, but does involve EXACT precision, like most other things involved with engine building.

I didn't bother reading all the info above, but folks doing should should make sure that determining ICL is NOT the same as finding the degrees BTDC of the #1 intake lobe at .050" tappet lift. Here I do both, ICL first, then degrees BTDC to verify the work and how accurately the cam is ground. In theory if you nail down ICL then the intake open point @ .050" should be where the cam card is telling us.

PS: I probably would have read more of the info, but I've been busy devoting the last few days to pulling down every engine I own and turning at least 7 of the 8 rods around so the pistons face the WRONG direction!..........

[P@blo]

Originally Posted by Cliff R

+2

Degreeing a cam isn't overly complicated, but does involve EXACT precision, like most other things involved with engine building.

I didn't bother reading all the info above, but folks doing should should make sure that determining ICL is NOT the same as finding the degrees BTDC of the #1 intake lobe at .050" tappet lift. Here I do both, ICL first, then degrees BTDC to verify the work and how accurately the cam is ground. In theory if you nail down ICL then the intake open point @ .050" should be where the cam card is telling us.

PS: I probably would have read more of the info, but I've been busy devoting the last few days to pulling down every engine I own and turning at least 7 of the 8 rods around so the face the WRONG direction!..........

You are a fast learner Cliff. I called my machinist and requested the same work be done on my junk and he hung up on me. Maybe Mike can provide the racer guy who built his engine as he clearly knows what he is doing...

These threads seesaw back and forth from asking for help to trying to alter reality. Really drags things out but I am more to blame for keeping reading these type of threads. Seems like we have multiple Zcode400s on the forums these days.

[Formulajones]

Originally Posted by PAUL K

That's a really long post.

LOL I was thinking the same thing when you quoted it, I was like "oh chit it's on here again"

[Stan Weiss]

Yes to long for me to read. lol

Before you can degree a cam you need to find TDC. Please explain how you did this?

Stan

[PAUL K]

Originally Posted by Formulajones

LOL I was thinking the same thing when you quoted it, I was like "oh chit it's on here again"

I didn't want an confusion as to which post I was referring to.

[Formulajones]

Originally Posted by PAUL K

I didn't want an confusion as to which post I was referring to.

...

[Jay S]

I would have replied sooner but my phone ran out of battery trying to scroll thru that one post.

[Jay S]

Twelve different degree readings with a difference of about 8* is not called dwell. It is called incompetence.

Keep trying. Eventually you may get it, it is easier to do with the engine out of the car.

PY may have to find a bigger server.

[NeighborsComplaint]

No self-respecting moonshiner ever degreed a camshaft ... line up the dots.

The harmonic damper was probably damaged when the moonshiners ran off the cliff ... the legend lives on and on and on.

[Jay S]

I bet if one of us would have read one of those last long posts we’d find out he got it all figured out and is driving it around.

[Cliff R]

I'm NOT reading any of it. I tried to help out many pages ago but sadly was unable to make a dent in the OP's armor.

I've been at this deal over 45 years, over 20 of it running a FULL TIME business dealing thousands of customers. When I closed the books on the working side of the shop almost three years ago I had completed just shy of 13,000 work orders. Most of that was carb work, but I also did quit a few engines, transmissions, distributors, set up some diff's, custom tuning, and did a few engine installs and swaps.

Over the years I had quite a few folks come in here asking me to help out with their "project" car. I learned very quickly to avoid any customer who wanted a "quick fix", "cheap fix", or ever uttered the words "just get it going for now (cheap) and I'll fix it right later". They NEVER do it right later. I don't care about that, however IF you take on their half-ars repair and charge them for it, the very first time they have any issues at all you will get a call telling you how it all worked fine BEFORE you touched it. Bottom line and getting to the point, NEVER, EVER short cut a job, bandaid fix it, or just patch it up so the car can keep going till you can do it better. ALWAYS bite the bullet, even if it's not in the budget to do it right the first time and while it's right in front of you.......FWIW.......

[Jay S]

LOL..17 pages..I don’t think anyone has put a dent in the OP’s armor, or his skills with cut and paste features…

[Cliff R]

+2

I figured that out quite a few pages ago, but still kept trying to help.

Degreeing a camshaft is simple, no need to make it complicated. Most novice/inexperienced engine "builders" get into trouble with mulitple keyway timing sets because they are either not very accurate or the directions are flawed, or a little of both. The 3 keyway variety with the cast iron sprockets are junk right to start with. I wouldn't let one within 20' of any engine I was building.......you can watch one stretch out if you stare at it long enough!

Seriously, when using stock cams, Melling in particular they are very accurate and if you are using a stock type Melling or Cloyes timing set and set it dot to dot it's unlikely you'll need to move it around at all. For builds like this one there is absolutely no need to do much more than put a 3/4" wide stock timing set on it, dot to dot, and move on. At most I'd turn the engine thru and watch the #1 intake lifter to make sure it starts moving a few degrees BTDC. That's close enough and good enough for this type of build.

I'd be 100,000 times more worried about having 7 pistons facing the WRONG direction and wondering even more about connecting rod orientation as well. Assuming all the pistons were pressed on the rods correctly you can't end up with one facing the right direction and seven the wrong way without a connecting rod or two in backwards. This potential issue would be at the TOP of my list of things to correct while the engine was out instead of knurling valve guides and Googling cam installation to the brink of extinction when all I needed to do at most was install a stock timing set, maybe a 2 degree offset key on the cam sprocket, and keep moving. I say this because every single "RAIV" cam I've installed with a stock timing set dot to dot has been within 1 degree of 112 ICL and the intake open point .050" a few degrees BTDC.

Not trying to be overly critical here, but with this type of build, (basicaly a backyard "special" with the emphasis on just getting it done on a shoestring budget), I'd want it as good as I could get it without spending money or time in areas that don't need it. Plus we've got enough compression here, too much quench, and hot climate that advancing the cam could bring more negatives into the equation that just leaving it in the stock position........FWIW........

[JSchmitz]

I think the horse has expired...