[nUcLeArEnVoY]

Gotta love Uncle Tony. Even though he's a Mopar guy, his knowledge transcends brands, for sure.

He just posted a video confirming his suspicions regarding this camshaft and lifter crisis the hobby has been suffering for quite some time now. Check out the video: https://www.youtube.com/watch?v=WzYHae7yXiA

Basically, another youtuber confirmed by testing a batch of new camshafts from various manufacturers that the issue lies NOT within metallurgy or hardness of these new cams and lifters, but in the machining work. Cam lobes were found that did not have the proper 2-thousandths to 3-thousandths taper when looking at the lobes from the side, and some were completely flat as if the machinist forgot to change the settings when they were grinding roller cams beforehand or something. Lifters were not as subject to the issues, it was mostly the cams. As we all know, a flat tappet camshaft and its associated lifters are not actually flat, as they're so named. The lifters actually have a convex crown at the top, while the camshaft has a very mild taper from one side of the lobe to the other when looking at the tip of the lobe from the side. This taper when combined with the crown on the lifter, in an ideal setting, causes the lifter to SPIN in the bore as as the camshaft lobe lifts it, thereby eliminating the frictional component when used with the correct zinc-additive oil.

So the point is, if using flat tappet cams, nip the problem in the bud before it happens and start measuring for the proper taper at each lobe and proper crown on each lifter - at that point, failure will come down to user error (improper oil or break-in RPMs, too aggressive valve springs, etc.)

This is something I imagine all of you guys already knew or already practice, but it is nice to actually see examples of these defective brand new flat tappet cams being found out there. This issue really does need to be spoken of more. Look what the Pontiac enthusiasts did for the water pumps just for our cars - you can find cast impeller pumps everywhere now with pretty correct clearances to the divider plate, imagine what the ENTIRE classic car hobby can do if we start raising pitchforks enough for the camshafts and lifters we are offered.

[25stevem]

For the last 35 years I never took for granted that the hydro cam and lifters I put in my motor where made right .

I never put on the valley pan until I saw that by cranking the motor over I saw all the lifters spin around.

Two people viewing each bank of the motor make it so you only need to have the cam go around like 4 times.

[nUcLeArEnVoY]

Originally Posted by 25stevem

For the last 35 years I never took for granted that the hydro cam and lifters I put in my motor where made right .

I never put on the valley pan until I saw that by cranking the motor over I saw all the lifters spin around.

Two people viewing each bank of the motor make it so you only need to have the cam go around like 4 times.

There ya' go. But you have to imagine that a lot of builders just trust the manufacturers specs. "Ahh, it'll be fine," must be said a lot. Box balancing rotating assemblies comes to mind, haha.

[rohrt]

Thanks for passing on that information. Seems like cheap insurance to check the cam lobe tapper and lifter crown before install.

[SRR]

It seems now-a-days you have to check and inspect everything! Not just car parts!