what happens when a roller lifter fails? i'm getting an occasional bent pushrod...and was wondering if it could be due to lifter failure....i pretty sure it's not because the valve hits the piston! the motor's stock with 1.5 rockers and a mild street cam.....i am running self-aligning rockers with no guide plates.........

 

What heads? If the push rod through-holes are the slot rather than round, you're binding between that and the self-aligning rockers.

Interference between the rocker slot and stud is a good way to bend push rods.

 

i've got the GMPP #113 vette heads...the pushrods are not riding in a hole but a large slot in the head....they aren't binding.....i think maybe the rockers weren't tightened down enough...and when the lifters compress a little, the rods fall of the rocker arm and get bent by hitting something else....i'm at a loss...if i want to put guideplates on do i need to re-mill the stud bosses?

 

You need something to hold the pushrods and rockers in place, sounds like you have nothing. Those heads, you either need guideplates or self aligning rockers.

No, dont need to machine the heads for guideplates. Those are all ready to run with guideplates.

 

That's why I asked. They shouldn't be falling off when adjusted.

They probably aren't hitting something, but are binding.

It's pretty hard to get stock roller lifters to do something to push rods without doing major damage to other things (like the cam).

 

no, i DO have self-aligning rocker arms...thanks for confirming that these stock lifters are pretty bullet-proof...the cam is new.....heck, i guess i'll go with guide plates anyway....

 

i just thought of something......the heads come with springs that are good to .500 lift, but my cam has .510 lift on the exhaust side...could this be causing the pushrod bending?

 

Yes. No way to know for sure if thats accurate unless you measured the available lift and clearance though.

 

and you DONT want to be running the SA rockers and guideplates... its one or the other