85Iroc-Z

iTrader: (4)

I just tore my motor apart looking to solve a knocking noise that the motor was making. I found that it had a bent pushrod. However, after reassembling the motor the noise is still there. Could a bad lifter be causing my noise? Or maybe a bad cam lobe?

henryd3

iTrader: (128)

How did the pushrod get bent? If it wasn't allowed to push the valve open normally because the valve hit something like a piston and stopped it, perhaps that is how it happened. If so, the valve probably has a problem now. Or the valve guide, etc.

85Iroc-Z

iTrader: (4)

I don't know how it got bent. I just found that it was bent when I took the motor apart.

ASE doc

Factory push rods are not very strong. A binding rocker arm or worn and binding valve guide may have caused the bent push rod. These push rods get softer with heat also. Verify the valve is good with a compression test, and if compression is low, a cylinder leakage test. If the valve is okay, inspect the lifter and cam lobe. Your 85 uses a flat tappet cam. The lobe may be flattened.

NAASBC355

what setup do you have is it stock? What ratio rocker arms? guide plates? what springs if not stock? what cam? what noise are you refering too? while it's true that factory pushrods are not relativly very strong you can still pick up the motor with a pair of them and not bend them. It usually takes quite a bit to bend one they don't just decide to wake up one morning and fold over something got bound up, or came to a sudden stop somewhere you just need to find it. Worn off cam lobes don't make noise it's completely silent when one goes. I'd say the problem exists in the heads.

~Couch

85Iroc-Z

iTrader: (4)

There is a knocking noise coming from inside the motor. It has a comp cams camshaft in it (specs in sig) and it has comp lifters and springs as well. The heads are stock, stock 1.5 rockers, and no guide plates. I got a new lifter for it, should I go back in again and change it?

NAASBC355

Are you sure it's a lifter and not a worn out exhaust valve guide? Listen to the motor through a rubber hose and it will take you right too the source.

~Couch