[TRADERMIKE 2012]

When we removed the Heads, we found that the Exhaust Valves, at the center of each Head, where the two Exhausts Valves are adjacent to one another, were sunk /recessed into their un- hardened factory Seats by about 1/32", possibly adding 1/16". The O/A Valve slap/noise, in an overly heated area. Duly noted, we removed the Heads, to be machined with new hardened Exhaust seats. After learning both about the Pontiac Block and 421 Head cooling mods., over this PY forum, it is just as well that I drill the Heads between the two center Exhaust cooling ports, for better cooling in that area, that is, when I get them back.

Of course, we have already drilled and plugged three holes on each Deck that the Head rests on plus, tapped and plugged them, with stainless plugs. We also drilled the 421-mod. holes between the center Exhausts ports into the Block, on both Head Decks. Thís should help in "not" allowing this overheated area from ever getting that hot.

We used a Dial indicator over the Piston and Degree wheel to find the TDC, using a stop, that we made from flat aluminum added 2 Bolt holes to lock it down to the Deck. By drilling a smaller hole in the center of the flat stock, we tapped a bolt through that hole, to measure depth along with a feeler gauge, over cylinder # 1 using the intake Valve on the compression stroke.

To find the actual ICL, we placed the Dial indicator over the edge of the Intake Valves Hydraulic Lifter and measured the duration of the Cam @ .050" on both sides of the Valve duration Ramps by passing the .050" mark on the Dial Indicator first then moving toward the .100" mark first then rotating back to exactly 050", where we took our readings off the Degree wheel # and recorded that number, adding those numbers and dividing by two equals 112 degrees for the Intake c/l and 115 degrees for the Exhaust c/l, then to obtain the lobe separation angle we added these two numbers and divided by two equals 113.5 degrees.

We advanced the Valve Timing from 113.5 to 109.5 by using the Comp Cam four-way Crank Gear, each notch is two degrees according to their directions, thus the fourth notch equals 8 degrees at the Crank and that means 4 degrees at the Cam. Because the Crank rotates twice, 720 degrees and the Cam rotates once 360 degrees. 360 degrees at the Crank equals 180 degrees on the cam, the Crank spins 2x the Cams one. Half a turn at the Cam is equal to one rotation of the Crank.

We were told by Butler Performance that Melling added 1.5 degrees to my "041" Cam and that I should install the Cam straight - up, in the Pontiac case, that is orientate the dot mark at 12 o'clock on both the Cam and Crank gears @ TDC on the compression stroke.

On my 1979 Pontiac T/A we point the Rotor within the Distributor cap toward #1 in the firing order, toward my steering wheel, where my timing order starts and rotates CCW within the Dist.

Because there is little room remaining between the 428 ci Engine and the Fire wall, under the windshield and the MSD large Distributor Cap, we orientate the Vacuum Advance canister vacuum port toward my Steering Wheel.

Currently the Rotor is pointing @ number 6 in the firing order within the Dist. Cap and we are on TDC on number one Piston cylinder, because #1 and #6 are companion cylinders plus one must consider the constant changing Valve opening and closing events.

We spent a lot of time proving that the Valve opening and closing events were happening at both 050" and .006", according to our self-made Timing card numbers that we made from information obtained over the Internet and the Melling Cam site. These numbers were exact.

The Intake and Exhaust Cam lift is .313" each measured off their respective Lifters.

The Lobe separation angle (LSA) is 113.5 degrees as well. Intake c/l is 112 and Exhaust c/l is 115 for the "041" Melling Cam and we are using 1.5 Rocker arms. Total lift is .469" on each Valve and the Cam is asymmetrical in Pontiac design as all their Cams were in the day or so I read. You take 115 - 112 = 3 divided by 2 = 1.5 degrees. I believe this is how Butler Performance had Melling build advance into my Cam by adding Intake 112 c/l to 1.5 obtained above = 113.5 LSA = new Intake c/l advanced, this is done to asymmetrical Cams.

I installed the "041" Cam straight-up initially for degreeing purposes, plus to find TDC. Then I went back into the Timing cover to advance the Cam Timing by 4 degrees, for a total of 109.5 race ready performance purposes.

The Cracked Hub is the "Vibration smoking gun", issue along with the 2 Exhaust Valves slapping away in their worn-out Exhaust seats, I am sure of that, this is my Theory and add in the fact that the Exhaust cross over plugs were not doing their jobs. is like adding the candle on top of the cake so to speak. Now through in the Valve guides only needing remanufacturing back to factory spec. no more no less, they still contributed to excessive Vibrations. Of all the emphasis put on the Pistons, I disagree to agree it matters. But it is not my problem, it is yours who experienced it firsthand. I have a lot of **** to fix and I don't want to fix anything that is not broken at this very moment. I learned much in this discussion and found out even more as I disassembled the Engine. In conclusion, I will not have to rebuild the bottom end today, I am saving for a rainy day when there is nothing else to do.

As far as the Hub is concerned, I am glad that I asked the question whether or not to buy a used or new one. Here is my related story, once on my 1981 Camaro Z-28 I changed the Harmonic Balancer only to have the Timing Gears and Chain fail one year later, causing me to sell it, as is. The fact is I loved that red luxury interior, that it possessed. Not to mention that it had T-tops, plus factory air induction, electric windows, tilt steering, rally gauges, add on AC with automatic Trans. with a center console, air induction that actually opens and closes when I smash the peddle down to the floor. So, what I am leading to is: "This is where I want to spend my money, at this time that makes a big difference, let's talk about spending Mikes money on a Hub or complete Dampener that will be strong, one that will save this poor tired Engine, so I can squeeze the existing life/miles out of the Crank and Pistons and rings that are waiting to be driven yet.

[Formulajones]

Originally Posted by TRADERMIKE 2012

To find the actual ICL, we placed the Dial indicator over the edge of the Intake Valves Hydraulic Lifter and measured the duration of the Cam @ .050" on both sides of the Valve duration Ramps by passing the .050" mark on the Dial Indicator first then moving toward the .100" mark first then rotating back to exactly 050", where we took our readings off the Degree wheel # and recorded that number, adding those numbers and dividing by two equals 112 degrees for the Intake c/l and 115 degrees for the Exhaust c/l, then to obtain the lobe separation angle we added these two numbers and divided by two equals 113.5 degrees.

We advanced the Valve Timing from 113.5 to 109.5 by using the Comp Cam four-way Crank Gear, each notch is two degrees according to their directions, thus the fourth notch equals 8 degrees at the Crank and that means 4 degrees at the Cam. Because the Crank rotates twice, 720 degrees and the Cam rotates once 360 degrees. 360 degrees at the Crank equals 180 degrees on the cam, the Crank spins 2x the Cams one. Half a turn at the Cam is equal to one rotation of the Crank.

.

OK you used the .050 method with a dial indicator. As Jay mentioned I hope you went back and checked again after you moved the crank gear.

Those crank/cam gears, as well as keyways on the cam and crank themselves are notorious for being off a few thou here and there affecting the degree readings. So just because it says 4 degrees or 8 degrees on the crank gear, doesn't mean that's what it moved. It could have be 5 or 6 or only 2 or 3. It'll have to be checked again if you want accuracy. In most cases from my experience you end up a half degree or even a full degree one way or the other and that's as close as it gets.

[TRADERMIKE 2012]

Originally Posted by Formulajones

OK you used the .050 method with a dial indicator. As Jay mentioned I hope you went back and checked again after you moved the crank gear.

Those crank/cam gears, as well as keyways on the cam and crank themselves are notorious for being off a few thou here and there affecting the degree readings. So just because it says 4 degrees or 8 degrees on the crank gear, doesn't mean that's what it moved. It could have been 5 or 6 or only 2 or 3. It'll have to be checked again if you want accuracy. In most cases, from my experience, you end up a half degree or even a full degree one way or the other and that's as close as it gets.

We too determined about 3/4-3/4 degrees Dwell/slop on either side of the original Balancer line. All the Cam specs. work out nearly perfectly to the self-made Cam card, that we manufactured from online sources.

[Jay S]

Well, it seemed to run ok before. You have that going for you.

Put a new stock harmonic balancer on it and fix the piston issues as soon as you can. That piston should fixed be right now, but if you can’t, you can’t.

[TRADERMIKE 2012]

Originally Posted by Jay S

Well, it seemed to run ok before. You have that going for you.

Put a new stock harmonic balancer on it and fix the piston issues as soon as you can. That piston should be fixed right now, but if you can’t, you can’t.

Thank you for the help, we put the Heads on tonight and all went well.

[Jay S]

Originally Posted by TRADERMIKE 2012

.

To find the actual ICL, we placed the Dial indicator over the edge of the Intake Valves Hydraulic Lifter and measured the duration of the Cam @ .050" on both sides of the Valve duration Ramps by passing the .050" mark on the Dial Indicator first then moving toward the .100" mark first then rotating back to exactly 050", where we took our readings off the Degree wheel # and recorded that number, adding those numbers and dividing by two equals 112 degrees for the Intake c/l and 115 degrees for the Exhaust c/l, then to obtain the lobe separation angle we added these two numbers and divided by two equals 113.5 degrees. .

When degreeing in a cam, ONLY the intake lobe is used. You want to find the position of the intake lobe relative to the crankshaft when the piston is at TDC. It was at 112*. Who knows were it is now that it was monkeyed with.

[Stan Weiss]

Originally Posted by Jay S

When degreeing in a cam, ONLY the intake lobe is used. You want to find the position of the intake lobe relative to the crankshaft when the piston is at TDC. It was at 112*. Who knows were it is now that it was monkeyed with.

Jay,
True. But if you don't have a cam doctor, then also checking the exhaust lets you know how close or if you really have the cam and LSA you ordered.

Stan

[Jay S]

Originally Posted by Stan Weiss

Jay,
True. But if you don't have a cam doctor, then also checking the exhaust lets you know how close or if you really have the cam and LSA you ordered.

Stan

Stan, he was finding the LSA, and calling it the ICL.

I wrote that very simply so maybe he could understand it.

[Stan Weiss]

Originally Posted by Jay S

Stan, he was finding the LSA, and calling it the ICL.

I wrote that very simply so maybe he could understand it.

Jay,
I must have missed or miss read a post as I didn't see that.

Stan

[TRADERMIKE 2012]

Originally Posted by Stan Weiss

Jay,
True. But if you don't have a cam doctor, then also checking the exhaust lets you know how close or if you really have the cam and LSA you ordered.

Stan

Ok, let me try again, since I proved that the cam is ground as the manufacturer said it is, LSA = 113.5, Intake c/l = 112, Exhaust c/l = 115 and the LSA is determined mathematically only?

Now, I use the Intake c/l @ 112 and add 1.5 degrees built into the Cam from the Melling factory, sold by Butler, together = 113.5 what? is this the new Intake c/l that just happens to be the same as the LSA?

I have 113.5 whatever?

The Cam is advanced now @ 4 Cam degrees.

8 degrees advance @ Crank.

1.5 degrees, added into the Cam at the factory. 112 Intake c/l + 1.5 advance = 113.5 what?

Given the same information that I have, can you finish the equation, in Cam degrees, please?

I believe I am at: (1.5 + 4 = 5.5 advanced), 113.5 - 5.5 = 108 degrees new Cam timing. I used the 4th notch at the Crank here.

My original target advance was: (1.5 + 3 = 4.5 advanced),
113.5 - 4.5 = 109 degrees new Cam timing. I used the 3rd notch at the Crank here.

I believe one is as good as the other because I won't be testing to see at the track.

[Jay S]

The factory advance of 1.5* is subtracted from the lobe separation angle to find the installed intake centerline.
113.5* - 1.5* = 112 *
The installed intake centerline when you line the timing marks up like the factory setting, dot to dot” is suppose to be 112*. Which can vary, and is why it is better to degree the cam in.

You simply have no business using any of the other keys (other than the zero position) on the timing set unless you degree the cam in afterward.

[TRADERMIKE 2012]

Originally Posted by Jay S

The factory advances of 1.5* is subtracted from the lobe separation angle to find the installed intake centerline.
113.5* - 1.5* = 112 *
The installed intake centerline when you line the timing marks up like the factory setting, dot to dot” is supposed to be 112*. Which can vary, and is why it is better to degree the cam in.

You simply have no business using any of the other keys (other than the zero position) on the timing set unless you degree the cam in afterward.

You said: The factory advances of 1.5* is subtracted from the lobe separation angle to find the installed intake centerline.
113.5* - 1.5* = 112 *

Mikes reply:

Thus: 112 degrees is the Installed intake center,
(112 I c/l)

Now, I added 4 degrees to the Cam timing, show me how you would proceed please next.

In addition, I agree when I am done, I will install the degree wheel again to prove that the advanced timing is actual.

I am already planning to pull the Timing cover with the water pump attached to install the degree wheel and pull back the advanced timing to the 3rd notch that is 6 degrees at the Crank or 3 degrees at the Cam.

Now that you know the plan, please do the entire math process, the way I should be doing it, so that I can see where the difference is between our thinking.

P.S. I installed the timing Chain gears at 12 0'clock each for Pontiac @ TDC of the compression stroke.

[Jay S]

Don’t change anything until you degree the cam in and find the position ICL is at now. After that you can better determine which key to use.

[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.