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Originally Posted by Bill S
I agree with you that is most likely the assignable root cause of my cam/lifter excessive wear.
I definitely searched out and found a very reputable engine builder to go through my heads and setup the valve spring pressure for my roller cam.
I wonder how many cam / lifter failure were the results of weak / improper setup springs ? Usually the blame goes to the wrong oil and break in process.
My springs did not have many miles, but I understand the concept of fatigue and thermal cycle impact.
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I tend to think your failure was from something else. I recall 20 plus years ago I helped friends put SPC-8s in two different engines that both had completely stock original valve springs. Lots of trouble with the valve floating, and no cam trouble. A couple other non Pontiac engines I worked on were terribly abused, when I took them apart you could see abuse everywhere on the valve terrain and nicks on the pistons from the valves hitting them, but the cam’s were fine. I would think any of those could have had bad enough harmonics to get back to damage the cam, but none did. I can definitely visualize issues with harmonics creating cam trouble, but on the other hand, it is a mild HFT cam, just turns half of engine speed, and it likely is not real easy to get bad harmonics down that far with both the Hyd lifters and the rockers softening the harmonics from where it starts at the valves. But who knows, bad valve float is never good.
540RAT’s oil testing does nothing to replicate how a lifter scrubs itself over a cam lobe. My guess is you had two things happen, 2 lifters were not machined all that well, requiring more of the oil, and the oil ended up not doing it’s job. Instead of the lifter scrubbing over the lobe it slid it over the lobe. Eventually the taper was gone and the lifter quite spinning. My guess is those 2 lifters had a problem with the finish, and oil with more zddp wouldn’t have hurt, it would have helped. Quaker State 5w30 synthetic is a decent oil, outstanding for some things, but it is also known to have a fairly weak detergent package for some applications. It doesn’t seem to hold on to it’s Viscosity very well with extra use. I don’t think you can totally rule oil as not being one of the causes.
It seems like there are about seven different issues that cause failures with flat tappet cams, which is worse than ever…it is getting harder and harder to not get hit by one of them. With that in mind, and Vmax lifters now over $300, it doesn’t seem like a bad time to go roller.
I don’t think Rhoad’s or HLJ are immune to trouble right now. But either can be successful yet, I set up a Vmax lifters that had the superlube option for a friends 455 and a 60919 cam that has over 20K mile on it now. I know it has been past valve float several times. It just got refreshed and put in a different car. All the bearings were trashed, so they were replaced, but the cam looked like new and is still in it, operating again. The superlube option should extend service life, but if there is machining or lubrication problem the super lube option is not going to make much difference. All you can do is to try to stack your odds and run the best parts available.