Interesting... I posted on this a couple days ago, then went out the next day to verify and work on my header leak on #8, and found a new tap coming from #3. I guess it is safe to say that I am now an EXPERT on failed lifters. I ran a bunch of tests before pulling the intake. What I found was that I had .050 space under my rocker on the intake lifter on cylinder #3. I tested the lift with a dial indicator, re-checked all my other rockers, etc. Finally I assumed I had a failed lifter and/or cam lobe. When the intake came off and the lifter came out, I found this... Sorry to keep posting the same pictures on various threads, but I think they are appropriate here. I am assuming that since the lifter wore at an angle, that it had stopped spinning and just sat on the cam getting hit on one spot until it wore down. I bought a new lifter today and will put it in the hole and check how much the cam lobe has been ground down. Regardless, I will be swapping the cam and lifters, and springs, and going to a double cam-chain, etc. Going to get much more lift out of the next cam, like .525 or so. I am also assuming that since there is a "burned" discoloration on the bottom of the lifter that it and the cam lobe probably became very hot, so it probably heat-treated the lobe making it more brittle than it was before, so it will probably fail if I run it anymore. Hopefully yours isn't this much of a hassle....
Are all those posts about bad lifters yours only? :confused: Good. Whew! I thought the bad lifter phenom was a ramped epidemic in its early stages . Good luck with whatever you decide to do .... in this thread and the others. I'll go tell you the same thing in those now.
Some notes on flat tappet cams and lifters. In the present day oils, Zinc and other compounds have been either taken out or reduced to very low levels. This was mandated by the EPA to increase the life of the cat converters. These compounds were used to prevent wear in the older motors. Now we have to search out lubes that have these compounds still in place, especially for track racing where flat tappet cams are mandated by the rules. Once the lube film fails, the cam goes first then begins to wear the lifter face. The cam has a very thin hardfacing done by an induction hardening process that is only a few thou thick. Once broken through, the cast iron is soft and wears rapidly. I have saw the info on what oils to use but would need to re-search it all out again. Bottom line is the common store oils are not so good for the old motors anymore. Last I know the DELVAC oils for truck use was a good alternitive but there are others as well as some additives. Do your homework and find the info on lubes you need for flat tappet use.
it could be that you just need to adjust the rockers.. after the breakin, they will wear a little and need to be adjusted. then using lock nuts, and you wont have to adjust for awhile again.
Just a note on Big Rig Oil,,, Most has had the zinc taken out of it now. Gm additive (mind is a blank) works good.
