I have a 350 chevy that has flattened its second cam . Ive never had a motor flatten a cam before . now I have one that's done it twice. the first cam was a Summit cam the second was a Lunati both properly broke in, and oil with zinc used. I haven't looked at the one that is in it now but it sounds like it may be the same lobe that is worn. could this be a defect in the block like a lifter bore slightly off? I am thinking about installing a retrofit hydraulic roller cam. what do you think? Iknow I will need a different gear on the dist. and shorter push rods. can I use the same cam button? what else should I know?
I think that you will be spending a lot of money. Make sure you upgrade the valve springs and that they can handle the new cam's lift once installed. No idea why you are wiping out cam lobes, but a hdyraulic roller cam is not a bad idea. I would still run zinc additive in the oil for other sliding parts including the distributor gear. Also consider using a plastic cam gear from Comp. I have one and it seems to be a fine piece.
I already upgraded the springs when motor was new. I know the roller costs more but so does changing cams over and over.
DAMN IT!! I hate it when that happens. There can be lots of causes for a wiped cam lobe. Shitty new oil, fuckin' cheap ass flat tappet cams, valve lash set too tight, lifter sticking in the bore, bad valve train geometry, etc., etc. In your case if it is the same lobe, I would definitely have a look at that lifter bore. If you turn the crank with just lifters installed, the lifters should rotate. If it doesn't there is a problem with the lifter bore and will wipe the cam. If it's wiped it's a little late to check it. Be sure to check that bore real good before reassembly, even with a roller lifter. Your question about the cam button makes me wonder? A flat tappet hyd cam should not need a cam button. The cam is designed to be pushed backwards into the block. I don't know, but if you had a button in there it may have been part of the problem? A hyd roller is a good choice nowadays just to avoid the problems you are having. I'll bet you have more money in the 2 rebuilds than you would have had if you had gone with the roller to start with. Not to mention the good part. MORE HP.
Happened to me twice too. Second time the motor was completely dis assembled. One lifter oil passage was almost totally plugged. Hot tanked the block and rebuilt the whole thing. No problems now for over 3 years.
I had problems with flat tappet cams going away in big blocks, with over .500 lift. They'd usually last around 20k miles, which is a problem when you put a lot more miles than that on a car. I went to hydraulic roller. Money well spent. But we don't know anything about your engine, is the cam mild, or have a lot of lift? you upgraded the springs, are they right for the cam? lots of things can go wrong, as mentioned...and sometimes a cam is just bad from the start.
the cam is a mild dual pattern 268 dur. 480 lift approx. . the springs have an open pressure of 265. I could see a bad cam maybe. but 2 in a row?
Every single passage of that block needs to be gone through, with the proper brush, by someone who knows what he or she is doing.
I agree. I ruined 2 cams for this very reason. Being 20 years old, I thought I would be smart and put spacers under my valve springs to give them a little more tension. The springs couldn't handle the lift. We found the problem by measuring the amount of spring compression and compared them to the specs. I was also bending pushrods, rocker studs were wearing to the point I had to drill them out and replace a few. This caused great discomfort in my lower abdominal tract. Took the spacers out and all my problems went away.
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