View Full Version : 351 W bent push rod

04-24-2007, 07:55 AM
What would be the likely cause of only one push rod (intake valve) to bend. Cylinder number 4. Thanks.

04-24-2007, 08:42 AM
Is it possible that water got into the cylinder that belongs to the push Rod ?
Peter C

04-24-2007, 08:53 AM
Ouch. I don't think water got in. Plug was black though like a carb was flooding it. Another question: Why would the engine smoke blue with the push rod flopping around and the intake valve not opening? Thanks.

04-24-2007, 10:46 AM
Blue smoke is oil burning. Either up from the rings or down from valve seals. Closed intake could be pulling oil up past rings on intake stroke.

04-25-2007, 01:02 AM
"You should pull that valve cover and see if you can manually actuate the valve with a prybar or something similar. If the valve has seized in it's guide that would sure bend a pushrod.
If the engine was oversped and the valves floated, that would also bend a pushrod. I would think in the latter case though you would find several bent.

04-25-2007, 10:43 AM
"Bent pushrods are caused by one of two things: A frozen valve, or a super loose valve adjustment.


04-25-2007, 06:29 PM
"I think as Jeff says, a frozen valve or very loose valve adjustment are the primary reasons for bending pushrods, I have done a pushrod before in one of my engines when it got a gut full of water in one cylinder. When you stick an engine in a marine environment I think you have to sometimes think outside the square a little, water being an incompressable substance, if you get a gut full of water, things can bend.
Thats why I asked about the posibility of water in the cylinder.
But the fact that your plug came out black would discount water.
Although very unusual I have also seen Hydraulic lifters lock up in a compressed position and spit out the pushrod so you should check to see if you can colapse the lifter as well as move the valve if she is fitted with hydraulics.
What ever the cause Crabbie you have some investigating to do.
Peter c"

04-26-2007, 08:07 AM
"Actually (my 4 year old grand daughter's favorite big word) water IS compressible. It's ten times more compressible than steel, in fact.

Prof. Jeff"

04-26-2007, 09:59 AM
Thanks All. Turned out to be a collapsed lifter. Prof. Jeff? What do you get when you compress water? Smaller water?

Thanks all.

04-26-2007, 10:06 AM
""What do you get when you compress water?"

Warmer water, slightly smaller."

04-26-2007, 10:31 AM
"I recently read that were it not for the fact that water is ever so slightly compressible, the level of the world's oceans would be some 60 feet higher than they are.
What would that do for low lying coastal cities? Never mind global warming and greenhouse emissions.

04-26-2007, 05:32 PM
Hard to say exactly what it would be like at 60' higher but I'll bet there would be a lot more small lakes near the coasts.

04-26-2007, 07:46 PM
"Certainly left myself open and created a monster there didnt I.

Never mind, it was good for a chuckle. :-))

You got me,....I promise to try and be a bit clearer with my meaning next time.

I had always though that the force required to compress a liquid was greater than that produced in the compression stroke of a std petrol or diesel engine.

As I say, good for a chuckle. :-))

Just out of interest has any body got any figures on the forces required to compress water ? say a cubic meter of water, at say 20 degree C in temp and is there any difference between salt and fresh ?

Glad to hear you found your problem Crabbie.

Cheers Everyone, have a Great Weekend.

Peter C"