Found a bent intake push rod

Brite Idea said:
My guess is a sticking valve. Pretty easy to check, try to push down on the valve where the push rod bent. If it has a smooth motion it's fine but if you feel it hang up that's your problem. The repair is a valve job.
Click to expand...

Will check. Its seems I'm in for a valve job anyway.
 
I doubt you're going to overcome the valve spring with hand pressure. Those are probably 350# springs.
 
If it were me troubleshooting your problem I would start by
1) Pull off valve covers both sides and remove all sparks
2) With a breaker bar rotate engine by the harmonic balancer bolt see if it turns smooth
3) Check stud to see if it has pulled out or if threaded backed out.
4) Put a couple new push rods in it adjusted to your engines specs.
5) Rotate engine watching to see if valve springs are completely coiled up or binding if you feel any resistance stop rotating engine.
6) If all looks good you could try starting it again.

I would try this before pulling it apart you said the heads only have 5 hours on them maybe they were not the correct heads for your engine.
Hope you find an obvious problem like a valve stud pulled out.
This is only my opinion of where to start. Good Luck with it.
 
Bob & Sue said:
If it were me troubleshooting your problem I would start by
1) Pull off valve covers both sides and remove all sparks
2) With a breaker bar rotate engine by the harmonic balancer bolt see if it turns smooth
3) Check stud to see if it has pulled out or if threaded backed out.
4) Put a couple new push rods in it adjusted to your engines specs.
5) Rotate engine watching to see if valve springs are completely coiled up or binding if you feel any resistance stop rotating engine.
6) If all looks good you could try starting it again.

I would try this before pulling it apart you said the heads only have 5 hours on them maybe they were not the correct heads for your engine.
Hope you find an obvious problem like a valve stud pulled out.
This is only my opinion of where to start. Good Luck with it.
Click to expand...

Thanks! This is sound advice.
 
magstang1 said:
I doubt you're going to overcome the valve spring with hand pressure. Those are probably 350# springs.
Click to expand...

I have never tried so I am willing to try, but I didn't think I would be able to. I'll try everything and anything to get me closer to a solution and conclusion.
 
ATC said:
Depending on the last time someone was in there I would also be worried that the valves hung and the piston whacked them.- I'd scope the cylinder or look in the manifold for signs of water/rust on the valves. I had a similar issue at one point but my early evidence was bent pushrods (yes sloppy rockers).
Click to expand...

Great and very interesting thread, but sorry it happened to you! Not to worry about a valve being whacked by a piston. The valve spring will hold it in place, not allowing it to drop.

Bob & Sue said:
If it were me troubleshooting your problem I would start by
1) Pull off valve covers both sides and remove all sparks
2) With a breaker bar rotate engine by the harmonic balancer bolt see if it turns smooth
3) Check stud to see if it has pulled out or if threaded backed out.
4) Put a couple new push rods in it adjusted to your engines specs.
5) Rotate engine watching to see if valve springs are completely coiled up or binding if you feel any resistance stop rotating engine.
6) If all looks good you could try starting it again.

I would try this before pulling it apart you said the heads only have 5 hours on them maybe they were not the correct heads for your engine.
Hope you find an obvious problem like a valve stud pulled out.
This is only my opinion of where to start. Good Luck with it.
Click to expand...

Good advice, I'd do the same. Adjusting ALL of the valves is the prudent thing to do here. I'd be thinking your mechanic screwed up adjusting the valves and you caught it in time before any other damage occured.

Good luck,
 
Gunn, Not the valve dropping that causes the problem, it is rust buildup on the valve that will prevent it from moving freely; gets a little slow/hung up, and gets whacked.
 
ATC said:
Gunn, Not the valve dropping that causes the problem, it is rust buildup on the valve that will prevent it from moving freely; gets a little slow/hung up, and gets whacked.
Click to expand...

But he said he had just had a rebuild, or new heads installed. Rust or carbon buildup highly unlikely... :huh:
 
It seems I have good news.
Installed new rods on that bank. Checked all the valves and everything was at spec. Turned motor without plugs and sounded good. Cranked it and it is running perfect. No odd sounds and it revs clean. Will sea trial later today, but I think I dodge a bullet.

Mechanic claims the exhaust rocker nut failed due to age. He says the nuts are tranferred from the old heads on a head swap. I am not buying this fully.
 
There are plenty of old fasteners on my boat that haven't failed. Heck, some are constantly submerged on the drive or internal to the engine.

My best guess says improperly torqued fastener.
 
Great news! With regard to his explanation, six in one hand/half dozen in the other. If the nut was tired, it would have turned easily on the stud when he assembled it. His responsibility either way. (However, I'm not buying it either. I'd suggest he was interrupted while he was adjusting them and missed. As mentioned above, run through them all and double-check.)

ardeprint said:
It seems I have good news.
Installed new rods on that bank. Checked all the valves and everything was at spec. Turned motor without plugs and sounded good. Cranked it and it is running perfect. No odd sounds and it revs clean. Will sea trial later today, but I think I dodge a bullet.

Mechanic claims the exhaust rocker nut failed due to age. He says the nuts are tranferred from the old heads on a head swap. I am not buying this fully.
Click to expand...
 
After a long Sea trial she checks out. Running perfect.
 
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