[Formulajones]

Originally Posted by TAQuest

Why can't you just compare two cams and figure out the difference if both are installed as the manufacturer recs?
It seems to me you are just dragging your feet. Looking for reasons to crawl off the job. Just being negative.

You can compare them that way if you want, but it's not going to give you exact results in your situation because you simply won't degree them.

On paper you can compare all you want, but unless you install them exactly how they are presented on paper, you won't have the results the papers suggest. Then you're going to blame people here for misleading you, when in fact it's not that at all.

Make sense now? No one is dragging their feet and being negative, you just simply won't listen. None of it matters at all if you don't know where you're putting the ICL on these cams.

[Steve C.]

TAQuest.... Sir, if you took my mention of that specific Crower cam as a recommendation you are correct. Not the best of choice. But my intention was to use it as an example to change the seat duration (advertised duration) and/or lobe separation on the computers and note how it effects the effective compression ratio, dynamic compression ratio, cranking compression.

Onward.


.

[TAQuest]

Originally Posted by Formulajones

You can compare them that way if you want, but it's not going to give you exact results in your situation because you simply won't degree them.

On paper you can compare all you want, but unless you install them exactly how they are presented on paper, you won't have the results the papers suggest. Then you're going to blame people here for misleading you, when in fact it's not that at all.

Make sense now? No one is dragging their feet and being negative, you just simply won't listen. None of it matters at all if you don't know where you're putting the ICL on these cams.

You claimed a different smooth idle cam would lower my compression.
Name one.

[Formulajones]

Many good examples out there. For a 400 ci, pick something with duration around 220 and LSA spread out on 112 or more. The 068 is just one that comes to mind, made specifically by GM for RA 400's and it's much larger than the Eddy cam you currently have, yet will idle nicely.

With that being said, Idle quality is going to be directly related to where you install the camshaft ICL as well as your timing and carb tuning abilities.

[TAQuest]

Originally Posted by Formulajones

Many good examples out there. For a 400 ci, pick something with duration around 220 and LSA spread out on 112 or more. The 068 is just one that comes to mind, made specifically by GM for RA 400's and it's much larger than the Eddy cam you currently have, yet will idle nicely.

With that being said, Idle quality is going to be directly related to where you install the camshaft ICL as well as your timing and carb tuning abilities.

How much would the 068 lower my compression?

[Formulajones]

Here's a quick calculator to get in the ball park. Of course we need to know specifics about your engine like exact compression ratio for example, for these to be accurate.

http://www.wallaceracing.com/dynamic-cr.php

I believe Steve posted up similar calculators that work.

Another cam that would do the same thing with a little more lift would be the 2801 from Summit. It's a RAIII type cam that should idle nice and smooth in a 400.

[Steve C.]

Stated- " For a 400 ci, pick something with duration around 220 and LSA spread out on 112 or more."

Crower 60916 cam with 221/229 at .050" and a 112 LSA. For conversation only not a recommendation, because of the static compression, and the idle quality desired here.

And speaking of that 60916 cam.....

"That cam is a great choice for the 400 engine around 9.5 to 10 to 1 compression. We're used it in slightly higher CR 400's but usually move up to the 60243 cam instead."

"I've come to like the 60243 cam better, more aggressive idle and stronger upper mid-range and top end power. We've also helped some customers out in recent years with 400 builds that wanted to run into the 11's in full street trim, and that cam has proved to be a good choice. With 230-240cfm head flow and 10 to 1 compression, a 400 engine with that cam in it will get it done. Plus they idle nice, smooth/broad/flat power (torque) curve, and strong upper mid-range and top end power."

Cliff Ruggles


https://forums.maxperformanceinc.com...82#post5538482


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[TCSGTO]

I used to use the Crane 278 HMV as the go to cam in 10-1 400 engines. 222/234@ .050. .467”/.494” lift, 114 LSA. The catalog said lopey idle but that wasn’t the case. Don’t pay attention to cam company literature.
Smooth idle in gear with a stock torque converter, drives like stock and would run up to 5500. Easy mid to low 13 second cam in stock late 60’s 400’s thru manifolds on street radials. I think one of the Summit cams is pretty close to those specs and should run virtually the same.

[Steve C.]

" Don’t pay attention to cam company literature."

X2


THANK YOU !



.

[Cliff R]

Cam companies don't even specify CID for the details. They just say they fit 326 thru 455 engines.

They don't specify the compression ratio either.

A 228/235/112 cam would produce a "turd" of a 400 topped with 6X-8 heads. Take the same engine and top it with early big valve small chamber heads and it's an "animal", plus idles nice and strong power right off idle and drives nice on the street as well.......FWIW......Cliff

[Cliff R]

"Nice run on the video link.

What cam was that?"

The cam is the "Old Faithful" HR from Dave at SD Performance. It specs at 289/308 @ .006" and 236/245 @ .050. .381" lobes and I'm running 1.65 rockers on it.

ICL is set at 109.5 degrees.

Idle vacuum is 13.5" at 750 RPM and nearly smooth, just has a very slight "attitude".......Cliff

[TAQuest]

Originally Posted by Formulajones

Here's a quick calculator to get in the ball park. Of course we need to know specifics about your engine like exact compression ratio for example, for these to be accurate.

http://www.wallaceracing.com/dynamic-cr.php

I believe Steve posted up similar calculators that work.

Another cam that would do the same thing with a little more lift would be the 2801 from Summit. It's a RAIII type cam that should idle nice and smooth in a 400.

I ran both the 2157 and the 068 on the calculator and I don't see a difference in compression.

[NeighborsComplaint]

Originally Posted by TAQuest

You really are only guessing on paper. You think you can tell everyone everything by just typing without knowing anything in the real world.
I happen to have, in the real world, not on paper or in my mind, the combo you are typing about. So sit back and listen because I know from real experience. The combo works really well. Experience trumps guesses all day long 24/7. Write down what I'm telling you because it's real. Put it in your notes and learn from real experience. Then you will have something to type about that's not your 'guessing'.

Read my sig. Engine was built 10+ years ago with my hands. Components selected carefully for optimal performance and drivability including discussions with Pontiac Guru Pete McCarthy. Cam and specific ICL selected for best compromise of driveability and performance and optimal for 6X heads' superior low lift flow characteristics. I was an IE by trade, now retired.

All guesswork of course.

Don't let your fung get in your schwei, you are the Zen tuning master.

[TAQuest]

Originally Posted by NeighborsComplaint

Read my sig. Engine was built 10+ years ago with my hands. Components selected carefully for optimal performance and drivability including discussions with Pontiac Guru Pete McCarthy. Cam and specific ICL selected for best compromise of driveability and performance and optimal for 6X heads' superior low lift flow characteristics. I was an IE by trade, now retired.

All guesswork of course.

Don't let your fung get in your schwei, you are the Zen tuning master.

I wouldn't have been as forth right without your school bus comment. Everything in context.
You were guessing about the combo I have, of course. Not the one you have. If I had the combo you have then I would be asking you about it because of your real life experience with it.
What I'm asking, besides whether or not the 'tick' is inherent with the combo of heads and cams in common with the OP, is which cam combined with my combo that would significantly lower my compression and still have a smooth idle like the 2157? An improvement. Not really urgent because the boss, my wife, says she likes it just the way it is. lol And she does the majority of the driving. Maybe next winter switch it out if I see something solid here. Not seeing it yet. My static compression is 170. The engine runs fantastic. I have to boost the octane of pump gas is the only very slight negative.

[Steve C.]

For interest only..........

Dynamic Compression Ratio
(Will my engine run on pump gas?)


http://cochise.uia.net/pkelley2/DynamicCR.html

7.5-8.5 DCR / 91 octane or better.
Another source... Desirable for a street engine, staying below 8.25 is probably best for trouble free motoring.

Use this to determine intake closing point in degrees

http://www.wallaceracing.com/cam-deg-calc.php

And remember to use seat duration, NOT .050" duration (even if the factory cam does not use .006" tappet lift. It will be good for conversation )




.

[TAQuest]

Originally Posted by Steve C.

For interest only..........

Dynamic Compression Ratio
(Will my engine run on pump gas?)


http://cochise.uia.net/pkelley2/DynamicCR.html

7.5-8.5 DCR / 91 octane or better.
Another source... Desirable for a street engine, staying below 8.25 is probably best for trouble free motoring.

Use this to determine intake closing point in degrees

http://www.wallaceracing.com/cam-deg-calc.php

And remember to use seat duration, NOT .050" duration (even if the factory cam does not use .006" tappet lift. It will be good for conversation )




.

So both cams put me in the same category, 91 or better.

I know that 93 octane still needs booster with the 2157.

Using a ratio it looks like the 068 would knock me down to 10.7 to 1 from 11.5 to 1.

Probably still need booster for the 068.

Lots of things sound good until you actually crunch the numbers.

[Steve C.]

Rough numbers....

4.120 bore
3.750 stroke
6.625 rod
10.5 static compression ratio
IVC is 65.0 ° ABDC
No boost pressure/ sea level
Your dynamic compression ratio is 8.32:1

Rhetorical question... in using the calculator, does it make a difference if it's aluminium heads or iron heads ?

.

[P@blo]

I'm going to state the obvious; Quest, start your own thread or update your old one. Your back and forth isn't helping the OP here...

[242177P]

Originally Posted by P@blo

I'm going to state the obvious; Quest, start your own thread or update your old one. Your back and forth isn't helping the OP here...

TAquest: 67 posts
GLHS116: 12 posts

[glhs#116]

So.. Crower 60919 is in and broken in. I was extremely careful with this swap but I can still see a few ways my arse could be bitten anyway. Here's what I did:

I drained the coolant not just from the radiator but I opened the side block plugs. I remember otherwise you fight coolant trying to come in from the block coolant holes. This worked well. I lubed up the cam lobes and distributor drive gear with the provided Lucas lube that Crower give you. I placed the new Howards lifters in and poured a can of STP all over the cam and lifters. Crower say to use single weight oil for cam break-in so I found a can of straight 50 weight "diesel" oil from Oman that says "virgin oil" (no SAE codes or nothing). Since I was a little nervous about the probable lack of additives and since I was also earlier advised to overfill by 1 litre or so for break-in I added a litre of 15W-40 Shell diesel oil. I then put in the pushrods and sealed up the valley. I adjusted the rockers with one turn preload one at a time in firing order turning the engine over by hand 90 degrees each time. I primed the oil pump well. I got the distributor in position to fire. I filled the carb bowl. I got it to light off almost right away and ran it a good minute at 2k before fiddling with the carb fuel inlet nut (it always leaks at first). I fixed that and then I fired it again. Changed the timing a little and fired it again. Each time I took it straight to 2k or more and each time I started it almost right away. Then I was able to run it about 12 minutes straight but the temps were climbing and climbing (it's stupidly hot here right now). After a half hour I was able to run the last 8 minutes (it was also running quite hot but below 250).

On dropping the RPM it sounded a bit clattery so I added 1.75 turns to the preload (I figured the aluminium heads expand and it needs more preload).

Well, after all of that I have "the tick". About the same as before. I recall that my first "tick" turned out to be the Lunati springs that I was using at the time. These were single springs with the spiral dampers. When I put in Crower double springs my tick (then, with the 702 and my old heads) went away. But, of course, I had other issues.. I see the Edelbrock springs are also this single coil with spiral damper design and I wonder if it's the same thing. Maybe some interaction between them and my HS rockers. For now, I'm going to choose to wait and see on it.

Post mortem on the 703 is that the exhaust lobe for #3 was starting to go away. I should add here that after I fixed my earlier "tick" (on the old 702 cam with my old heads) with the double springs I had two lobes go very bad (lifters ground down almost 1/4 inch) and it didn't make it tick. The lifter had lost its profile but wasn't yet "short". The lobe was rounded off. The rest looked pretty decent. I wasn't super surprised at the break-in problem because it took me so long to get the engine to fire the last time (first timing was 180º out, then I actually had a plugged fuel line, both took a bit of time to work out). I feel like I did the right things this time on break-in and only worry about:
• The single weight oil being too "straight" and the STP and litre of modern oil not adding enough additives
• The heat the engine was at during break-in

I drained out good looking oil and saw almost nothing in the filter, though.

The 50W oil


Nothing in the pleats really


Nothing really in the filter itself, either


Sam