Never seen an exploded lifter until last night. The
(no.6 exh valve) lifter on my friends car was cracked in half with the outher top riding the push rod. What would cause this to happen? I was able to get the lifter out and the bore is fairly clean and the cam seems alright but geeze.

 

How did he know he had a bad lifter? What signs was he seeing?

 

What would cause it:

Heat treating.

As in, improper heat treating. The lifters need to be fairly hard, and if not done properly, they will be brittle. Shock loads are particularly bad for brittle materials, so it all added up to failure here.

 

You know I honestly dont have a clue why he pulled the intake but when I seen the engine the top was off. I think he thought his studs pulled out again, and they were starting to pull loose again especially no.3 intake. Anyway I replaced the lifter and ran a compression check 6 was alright but no. 3 hole was dead. Sliped in a screw driver cranked it over and the piston was at the top of the bore but never went down more then a centimeter. Its broke, probabaly the piston sheared in half.