Interesting cam problem

[Nick Micale]

I screwed up my previous post format, so here it is again, sorry but I cannot operate an Ipad worth a damn?


I think it was over 10 years since we installed the first Comp cast roller cam that I mentioned above, and Comp sent another cam immediately.

Shortly after that, I talked with Comp Cams in person at SEMA and they assured me this was corrected, and we have not seen it since.

There have been some close encounters over the years, and sometimes we have trimmed casting flash off the cam lobe edges to be sure of no interference.

If the cam is installed and checked with a degree wheel and the valve train installed, this should determine if there is a problem or not.

Seems like quality controls and fitment sucks lately on aftermarket parts in general, and it is not prudent to "assume" items will fit and operate like original parts.

This applies to GM parts as well, since many of them are sourced off-shore, but not by the original vendor which built the parts 30 years ago

 

[ITSAV6]

Need Boost and I built our motors at the same time side by side and my comp roller was spot on and his was close enough he checked it several times to be sure it didn't catch the other lobe.

 

[hensleyt]

#5 fitting#6 is right over the thrust bearing?
Is that correct ?
I have used up 3 trust bearings, and have 400 miles on this build. Looks like I pull the intake befor I run it again

 

[Nick Micale]

Tim, if you have lifter/cam contact the noise would tell you!

 

[hensleyt]

No noise , thanks

 

[Steve V]

Geeeez I have a NIB 212/212 ready to in one of my piles of junk soon. I will check it carefully. Thanks for the heads up.

 

[SHADOWII]

This has been very informative, I'm awaiting completion of some machining and will inspect the new cam a little closer. Thanks guys.

 

[turbofabricator]

I ran into this years ago. Didn't make contact until it was at 4,000+ rpm. Cam would walk fwd a few thou and pop an adjacent lifter open. This was a flat tappet cam. This was the only cam I have had an issue like that. I use to have flat, flat tappet cams stacked like cord wood, though. But according to Lunati I was the ONLY guy that ever flattened one of their cams. LOL.
25 years ago, Dale Robertson (who was one of the smartest guys i have EVER met, my he RIP) and I were talking about lifter bore spacing on #3 cylinder, and about the only logical reason was to move the #3 exhaust lifter away from the hot oil coming from the thrust bearing. Or it was done to make people like us sit around for hours and hours trying to figure it out, when it just a joke by a goofy GM engineer.

 

[SS/GN]

I wonder if this a result of out sourcing there blanks?

 

[cruzn57]

I wonder if this a result of out sourcing there blanks?

there are only 3 companies making the blanks, same 3 companies for last 30+yr. all cam grinders ( and OEM factories) use these 3 companies.

 

[RmvBfrFlght]

there are only 3 companies making the blanks, same 3 companies for last 30+yr. all cam grinders ( and OEM factories) use these 3 companies.

I think you hit the nail on the head with Engine Power Components (EPC) of Muskegon, MI. The very first pic that Rich posted has EP cast into the core. Shame that aftermarket parts are so far off. Way back when I was much more active in building cars & drivetrains, my nickname was "Mr. Modify."

There was hardly a part that I didn't need to modify in some way for it to work. Unfortunately it is still that way today...

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