440 bent pushrod

[akiran]

What can make a pushrod bent so badly, when the rocker and tappet are ok. This is a 440 4bbl, originally situated in -68 Coronet's engine bay. Maybe over-revving?

 

[Davea Lux]

Usually they get bent because the engine has sat for a long time and the valve guides have rusted up. Usually the push rod will bend slightly to start with and as the engine runs for a while, since it it no longer straight, it will continue to bend until it pops out of the lifter or gets hung up and breaks. The same thing will happen if the rockers are not getting oil because the shafts or oil passages are clogged with sludge, so check to be sure that there is good oil flow to the top end. You would also want to check your timing chain for excessive slack, valves that are contacting pistons will also bend push rods.

Dave

 

[akiran]

Which one do you guys prefer, pushrod with oil holes or solid ball ends? The cam and the valvetrain are stock.

 

[detmatt]

No oiling happens through the pushrod in this system, they’re all solid.

 

[MEV]

If you never want to replace these again, call up smith brothers pushrods and have them make you a set.

 

[Mr C]

Running an engine on old gas can do it too. The varnish can make the valves stick.