73-454

I constantly bitched abought the poor idle bad brakes with the Comp Cam 292H. I finally had enough and decided to replace it with a Crane 272 energizer (By the way I love this cam even though it produces less of a punch it made the engine run perfect) My main question is when I look at the Comp 292H cam 3 of the lobes were worn down by at least 50% and the lifters were cupped What could have caused this ( Bad install, Strong valve springs, Incorrect cam break-in) Any suggestions. I just hope the same does not happen to the new cam. Note I bought the Vette with the 292H Cam

dman535

Possible causes :

1. Incorrect valve springs. Some Cams will require the use of special rockers or special springs for the break in period. Its possible that the installed springs are not properly matched to the cam. Springs binding at full lift.
2. Incorrect lifter preload/adjustment.
3. Not enough moly lube on the cam surfaces during installation.
4. Improper break in procedure. 30 minutes at 1500-3000 rpm, followed by an immediate oil change.
5. Improper oiling.
6. Bad metalurgey, improper hardening.
7. Lifters not being allowed to rotate in thier bores.

I am sure there are a few more, but these are the major causes.

oger

There seems to be a real problem lately with cams during breakin. I don't know I think there is only one place building cores so everyone is getting bad ones or the new breakin lubes aren't as good as the old stuff. The profiles are more aggressive that may be part of the problem. When you break in a new cam use their lube and get a can of EOS from GM. Make sure the engine starts immediately and run it a 2000RPM or so but don't let it idle.

clem zahrobsky

molykote is the best break in compound,BUT you must change your oil filter after the cam brake in because molykote will plug the oil filter when it cools off and if you do not have the oil filter bypass blocked you will never know it. also always fill the carb float bowl with gas to make sure the engine fires right away. :chevy


[Modified by clem zahrobsky, 3:15 PM 4/28/2002]


[Modified by clem zahrobsky, 3:16 PM 4/28/2002]

73Ken73

Did you or the last owner let the car idle for a long time to warm up the car before driving? The Cam doesn't get proper oil at idle an will wear out. Especially a radical cam.

Injected

BigBlock Chevys can be notorious for wiping out cam lobes because of the blocks poor lubrication design to the cam lobes, especially with a higher than stock lift cam. I'd check into all the mechanicals mentioned earlier to make sure nothing is binding and the spring pressures are in check. The other thing I've had good luck with is dry film coating the cam and lifter bottoms before install, I've had high lift cams last 3 times as long by doing this.
Good luck, I hope you don't have to go thru another PIA cam change for a long while.
Greg

jsimpson

I hve e friend who used t be a welder for an airline before they folded. Now he welds up cam cores for Crane. He does an excellent job, but it makes you wonder about the sourcing of cores for all the other cam companies!

xfactor974

I'd say that the lifters didn't spin in the bore. The only way to fix that is replace it like you did. :D

Sean82

This happened to me on my 350sb
It turned out that the valve seals had broken up and got trapped on the oil pump pick up screen. Graudualy the lifters did not get enouph oil and failed, thus wiping out the cam.

73-454

So far so good with the new Crane Cam, I logged at least 200 miles since the install so far so good. I used Crane cam break-in recommendations once the engine reached operating temp I drove the vette varying my speed between 50mph and 60mph this gave the cam a good range of rpm with max oil flow. Just as a side note an engine builder did say that BB do and can go through cams especialy in cylinder no. #6 not enough oil flow

gdh

I would suggest that you ask MountainMotor for some advice on this. He has been building race engines for 30 + years and is always willing to help. I have seen some of his engines running on SpeedVision and they are a piece technological marvel, just ask his competion.