1991 c-1500, 4.3L, 200,000 miles, bent pushrod?

[caravanmike]

have a 1991 c-1500 4.3L almost 200,000 miles.

a lifter tick started 2 weeks ago. fast forward to yesterday when it started missing, found the Cylinder #2 intake pushrod bent and in the lifter valley.

am i looking at the lifter causing this whole problem?

i have checked and the valve spring, it is intact and the same height as the others.

no sludge what so ever found in the valve train or lifter valley.

before the pushrod got bent their were no drivability problems (full power).

i am thinking of tossing in a new lifter, push rod,and rocker arm. am i thinkin along the right lines? thanks for everybody's help! mike

 

[oggb]

Yeah, lifter might've been what did that pushrod in.

New lifter/push rod/rocker arm sounds like a good idea.

 

[HM12460]

Agreed, that truck will likely run another 200k if it isn't rusted.

 

[caravanmike]

Originally Posted By: JRed
Yeah, lifter might've been what did that pushrod in.

New lifter/push rod/rocker arm sounds like a good idea.

i just hope my cam is all right i am checking that lobes lift tomorrow.

how do i get the lifter out? pliers? screw driver?

by the way this truck has no rust! cab corners are still intact! mike

 

[troyb43]

Try vise grips on that lifter, worked on my 350 some years ago when I changed the cam and lifters

 

[RogerBacon]

To be safe, I would change all the lifters. You are all ready in there and they are not that expensive. If 1 has failed and you where lucky enought to not damage anything else, I would not take a chance on the rest. Roger

 

[artificialist]

I hope the valve wasn't damaged. If that was the case, I would rebuild the engine.

 

[Jim Spahr]

Before you rebuild the engine, why not put the push rod, lifter, rocker arm, etc. on the one cyl. Put it together and test the compression on that cyl. to see if the valve is sealing. If it is, there is no reason to rebuild the entire engine.

 

[caravanmike]

well i got the lifter out of the block and the plunger is frozen inside the lifter body.

so i took the one next to it out and i dissassembled it and it had sludge in it.

i then spun the camshaft by hand and all lobes were present and in good shape!

i think it is safe to say the frozen lifter caused the whole mess! i didn't know they could freeze up? mike

 

[oggb]

This is why I dislike hydraulic lifters...

RogerBacon has a good point though - if one has failed you should probably replace the others as well.

 

[FL_Rob]

Yup.Collapsed lifters do happen,a good assesment to replace them all.Also a floated valve could've done in the whole shibang.

Tipping the rocker arm to an improper geometry from a pulled stud,or a bent valve is another possibility LEADING to a collapsed lifter.Not necessarily the other way around.

 

[caravanmike]

got it all back together, and every thing is quiet. i checked the compression on the offending cylinder and i got 165 psi. after every thing was back together. so their was no valve damage! woot woot!

total bill for parts was $160 with myself doing the labor.
but all is well now. mike

 

[Chris142]

I don't see how a lifter could bend a pushrod. All the lifter does is move the pushrod and it pushes on the rocker arm which pushes on the valve. The most common way to bend a pushrod is to over rev it or a valve stuck in the guide.

 

[caravanmike]

the clip came out of the top of the lifter causing the top plate of the lifter to go diagonal (slightly) in its bore. causing the bent pushrod.

i have had a couple of dealership techs look at the lifter and their diagnosis was the lifter stopped oiling because of sludge and the lifter came apart soon after?

 

[mattd]

Nice work.

 

[mechtech2]

If the pushrod bent, the lifter is only one side of the sticking.
The other side is the valve, which must have hit the piston.

SOMETHING had to stop the travel. It was not luck or air.

 

[Bottom_Feeder]

The pushrod could have gotten bent as it fell out of the lifter pocket on the lobe's downstroke, then got caught at a crooked angle on the next upstroke. Who knows what it did exactly, but it certainly doesn't mean that the piston hit the valve and that there must be something else wrong.

 

[meep]

i would be very wary of heavy carbon deposits, especially at that psi. Time for several bottles of techron.