running a solid cam that i followed the manufacturers break in procedure on.(not a Comp cam)anyways after about 200 miles on the motor i decided to swap cams and all the lifters looked great except one was mushroomed...wasnt enough for it to get stuck but was pretty hard to get out...what could be some causes for this?

If its a hydraulic lifter there are still some junk ones out there as we have always used the ones from GM P/N 5232720 as they have a harder bottom on them.

no it was a solid im just trying to figure out whether or not its something i did or not,just so i dont make the same mistake again....

Cody

Same rule applies there as well as I have been using the tool steel lifters that Precision Products makes in N.C. so far I have had no problems with those lifters.

And when my cams are cut I always ask for the P-55 core as it is a performance core and is harder then most cores.

They sold me a set of hydraulic lifters last year at Autozone that came with the hard bottoms but were regular priced! They may have solids if you ask for lifters for a '67-'69 Z/28 302 or a '70 Z/28 with an LT-1.

well turns out it wiped the lobe too!!less then 200 miles...possibly coil bind but what else could cause this?

Where do you get the Precision Products parts?

Cody that sounds exactly like what happened to me. Like I said in your other post, it ended up needing a total rebuild due to all the metal that circulated thru the motor.

I sent it in to the manufacturer after talking to them and explaining what had happened. After they looked at it even they could not tell why that one lobe failed. They replaced the cam and lifters for me. Try talking to your cam manufacturer and see if and what they will do for you concerning the cam and lifters.

how likely is it that i had retainer to guide clearance problems?im just looking for a reason as to why the lobe is gone b/c i just checked the cam out real good and there is another one that was starting to go.i was told id be ok with only .455-.460 lift,(my fualt for not checking myself)but the bottom ring of the retainer is shiny,like its been hitting that valve seal/guide.had z28 springs installed at stock height.(1.5 rockers)i really hope that it was a good possibilty that it was guide/retainer clearance b/c i lost a lot of confidence breaking in cams now...

Things I was told (by many) that might be the cause of something like that are (other than the obvious like bent parts) might be springs binding, incorrect spring pressure or height, oiling problems, incorrect breakin procedure, dry starting after having the motor sitting for several months without running (like over the winter for some of us).

My cam manufacturer says if you have double springs to remove the inner and run it for the prescribed time and rpm, then add the inner and run it again the same using the breakin in lube and all that. Also they say to pre oil your motor (just like you do the first time you start a rebuilt motor) before startup after it has sat for more than 3 months or longer.

hope this helps

In most cases it is caused by the lifter not rotating in the bore. Check to make sure there are no burrs that would keep the lifter from rotating in the bore. Flat tappet cam lobes are ground with a slight taper so they can spin the lifter (like you would spin a basketball on your finger) as it travels up and down in the bore.