Thread: newbee, cam questions

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Hello all,
I just rebuilt an after market 4-bolt main I picked up. I basically transfered parts from a 2 bolt except I added a forged crank, new rods and H618CP speedpro pistons. The rest was off the old motor. As soon as I cranked it, I ran it for about 10-15 minutes at 2,500 rpm to insure the motor was primed with oil. I couldnt time it properly and it was knocking from the valve train pretty bad. I originally thought I was detonating due to higher compression. To make a long story short, I tore it down and found I wiped the cam lobes on #3I and #7I and also noticed that other lifters were starting to sharpen on the edges.
When I tore the other motor down, I made sure that each pushrod and lifter went to the exact valve it ran on before. The lifters appeared to be OK and slightly rounded (not flat) where they contact the cam. Soaked them down real good with Edelbrock cam lube and everything.
I have a new cam, springs and lifters coming but I am still not sure what may have caused the cam to wipe. The cam and lifters were a matched set from Summit (1107). The springs however were only 100 psi seat pressure (I know....too low), but it ran darn good in the 2 bolt. Any suggestions?

Thanks,

I doubt that there are any 2 cylinder blocks in the world where the tappet bores are at exactly the same angle to the cam. Using the old cam and lifters in the same block at rebuild usually won't work and it most certainly ain't gonna work in a different block in my opinion.

My guess is that you had the vales adjusted too tight, thus the noise and the excessive wear.

Agree 100% with Richard....regardless of what others tell you, do not try to re-use a cam and/or lifters. I have tried it a couple times, and had the same results as you did. It just isnt worth it....especially when you can buy a brand new cam and lifters for under 100 bucks. Now, you have to tear down your new re-build, because you undoubtedly have bearing damage and metal shavings thruout your engine.

Tech's right, manufacturing tolerances aren't exact enough to permit cam and lifter swaps like that. The lifter bores can be a bit out fore and aft, too, which causes misalignment of wear patterns.
You state that it had lifter noise, that'll speed up the wear, too. Just bite the bullet and tear it down to tiny pieces and start over. It'll need a thorough cleaning.