Rocker arm trouble
 

Hey guys I'm drawing a blank with rocker arm troubles on my p24, put a new motor in and used a 12v block, with 12v bottom end besides cam and pistons, bought a new Hamilton 207-220, ran the truck for 20 min and broke an intake rocker. No big deal? Changed the rocker and ran for another 10 min and broke a different rocker. So I had a new set laying in the shop. Changed them and it ran for 3 pulls before it broke another intake rocker. So my question is has anyone had this trouble and found a solution?

Coil bind ?

Galling on the trunions?

I took the rockers off and all of them move freely, head is getting proper oil, the valvetrain is stock besides 110lb valve springs.

In on this. A buddy had the same issues on his p24. First it pulled the threads out of the head. We put a thread insert in and then it broke the pedestal. Put a new rocker and pedestal in, pulled the thread insert out of the head. Repaired that again with a thread insert and no trouble since.

No galling, push rods straight as an arrow, beehive springs, never over 4k rpm. Stock cam.

What size valve relief and how much clearance did you have PTV when assembled?

Hamilton calls for .080 reliefs and I cut .200 because I want to go to a bigger cam later on, truck has absolutely no knocks, ticks, nothing. And has ran 3 5krpm passes before it broke another.

See if you can get a .010 feeler gauge in the spring at max lift in 3 coils for a min of .030 clearance at Max lift .. that cam has 360 lift you likely have coil bind . That's a big cam on a 4 valve need to know your springs installed height. Next break might be a dropped valve so I would check this

Think I found the problem, cup on the pushrods seems to big and is pushing on the bottom of the rocker.