Bent Push Rods

[parrie]

Woe is me...Finally got Daisey's fuel system cleaned out and added new fuel. After a bit of priming she fired-up and idled great, first time she's ran since at the previous POs residence. All sounded good until I revved the engine and heard the tell tale tapping of a bad rocker/lifter. Removed the valve cover to find 2 extremly bent push rods. Apparently something happened from the time I first listened to it run until until I took delivery several weeks later. Both bent rods are intake valves on cylinders 3 & 4.

This is my first time inside one of these engines. Replacement of the push rods looks pretty straight forward...any other words of wisdom for replacing the rods? Would it be a good idea to replace all the rods?

[SafeAirOne]

What is the cause of the bent push rods? If it was something fairly simple, like the engine being run with the rockers WAY loose, allowing the rods to jump from their sockets and get bent, you're all set with a change of the bent rods and their associated tappets, however, if it was due to piston contact with open valves, you might be in for a bit more work...

[jac04]

The pushrods can be replaced without removing the rocker shaft assembly. Just slacken the adjuster all the way, then use a home-made tool to rotate the rocker arm to open the valve. With the rocker rotated, the pushrod will come right out.

[SafeAirOne]

If a pushrod is bent, you should consider accessing the respective tappet(s) to closely examine it for damage or just replace it altogether, because that pushrod was most likely bent from being violently squeezed between the relatively soft tappet and the hard rocker arm. If the force was enough to bend the hard connecting rod, that it was WAY more than enough to crack/break or otherwise damage the relatively-soft tappet, especially if the connecting rod was out of its socket in the tappet when this happened.

Tappet (ERR607):



Also, have a look at this. Very interesting:

http://forums.roversnorth.com/showthread.php?11882-Bent-pushrods

also this:

http://www.williammaloney.com/Misc/EthanolProsConsDrawbacks.htm

[parrie]

Thanks for the info guys...the picture in the old thread looks very similar to my push rods. Can't say for sure what would have caused the problem but my guess is the rockers were loose and I believe the PO may have used some starting fluid which I know from experience can cause damage if used excessively. I have yet to confirm if there is a possible stuck valve nor have I checked the tappets...both next on the aggenda. Will post the results.

[parrie]

Ok guys, finally determined that the cause of the 2 bent pushrods was 2 sticky valves. My solution to unstick the valves was rather barbaric but it worked...1st, I drown the sticky valves in Berryman carb cleaning, 2nd I proceeded to take a hammer and flat punch to the top of the valve stem and continued to work them. After numerous drownings w/ carb cleaner and hammer working both valves freed completely. Installed new push rods, adjusted all the valves and she's running like a top! Barbaric yes, but effective. No smoke so hopefully there's not too much gunk in the valve seats, valve guides and piston rings. Thanks for the input.

[JimCT]

Marvel Mystery Oil

Ok guys, finally determined that the cause of the 2 bent pushrods was 2 sticky valves. My solution to unstick the valves was rather barbaric but it worked...1st, I drown the sticky valves in Berryman carb cleaning, 2nd I proceeded to take a hammer and flat punch to the top of the valve stem and continued to work them. After numerous drownings w/ carb cleaner and hammer working both valves freed completely. Installed new push rods, adjusted all the valves and she's running like a top! Barbaric yes, but effective. No smoke so hopefully there's not too much gunk in the valve seats, valve guides and piston rings. Thanks for the input.

Run MMO in your gas for a few tanks, works wonders freeing things up.