How do hydraulic flat tappet lifters fail?

dartfreak75 said
Oh geez your making me really nervous with this. I have the cam a step bigger than that one the 702 cam and lifters. did you measure the guide height on the heads because mine would not clear. 475 lift! If they wasnt cut shorter that may be your problem. I'm sorry this happened to you that really sucks.

Thanks, yeah it does suck. But, hopefully I can learn from it and someone else reading this can learn as well. The machine shop did have to cut the guides down. By how much I don't remember.

'63GT said
PRH is spot on, with his comments.. Oil seems to be the biggest offender.
I had a long conversation with Tim Cole of CompCams back in the late 90's - 2K for the same reason PRH mentioned it.
His answer, then, was the centerline between lobe to lifter, MUST be offset by .050 to ensure proper lifter rotation. (this mostly applies to shivis, although it's never really been an issue with mopars )
BUT, that lifter is chipped. very unusual in my book. thinking a metallurgy issue..? bad set of china lifters perhaps ???
that lobe profile has been around since the 70's (213/.454), it's not like the Brookshire lobes, renamed voodoo by Lunati. that is considered to be a .742 lobe... it's very safe on a .904 lifter. baring a good oil has been used and correct break-in.

The offset makes sense in order to cause a spin, otherwise lobe is just pushing straight up against the center of the lifter, and maybe it'll spin, maybe it won't. The lifters are Lunati lifters that came as a kit with the cam. I've heard that the vast majority of lifters nowadays are made overseas, even big names like Comp, and in turn people have seen an uptick in failures. Is there any truth to that?

I used Lucas Hot Rod & Classic oil, 2100 ppm of zinc. However, my break-in may have been subpar. My timing wasn't set correctly at first, so it took a few tries of cranking to get the engine to start. After that, I took it up to 3000 and kept it there. I've had a couple people tell me the cranking wasn't a big deal, but it seems most here would disagree. Either way, that lifter did fail, and I'm wondering if the lifter failed because of the flattening lobe because of poor break-in, or if the lifter failed and flattened the lobe? It's been said before and I agree, that the damage is done and just move on and get it back together, but I'm still curious as to what exactly happened.