Wrist Pin Noise

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John_Aldrich
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Location: Kapowsin WA

Wrist Pin Noise

Post by John_Aldrich » Wed Jun 16, 2021 4:06 pm

What am I looking at for parts if I determine I have a noisy wrist pin?
John Aldrich
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John kuehn
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Re: Wrist Pin Noise

Post by John kuehn » Wed Jun 16, 2021 5:10 pm

Do you know if your car has cast iron original pistons or does it have aluminum pistons.
The original style cast iron pistons have piston pin bushings that can be replaced.
They are still available.
The newer aluminum pistons don’t have piston pin bushings that I know of. Others might know different. Maybe replace the piston and piston pin if it’s an aluminum piston.

If you determined which piston the noise is coming from you’ll have to pull the head and engine pan and remove the rod/piston then you will find out if it’s a loose rod, piston pin ,loose wrist pin bolt or maybe a bushing if it’s got cast iron pistons. Maybe a broken ring would cause a clicking noise? Not sure on that one.

If you find your issue a new head gasket would be needed to put it back together with. Also maybe a pan gasket/sealant.


Topic author
John_Aldrich
Posts: 57
Joined: Wed Mar 13, 2019 10:46 am
First Name: John
Last Name: Aldrich
Location: Kapowsin WA

Re: Wrist Pin Noise

Post by John_Aldrich » Wed Jun 16, 2021 6:41 pm

Thanks. Used a stethoscope today and really couldn't narrow down which cylinder.

Aluminum pistons 40 over. will pull the inspection plate tomorrow and get my hands dirty.

Sure would be nice if it was a rod cap... :shock:
John Aldrich
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Allan
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Re: Wrist Pin Noise

Post by Allan » Wed Jun 16, 2021 8:39 pm

Piston pins can be changed without removing the cylinder head. The rod/piston can be drawn down far enough that the pin can be removed just by taking off the bottom inspection plate. With cast iron pistons there is the complication of having to compress the bottom ring when pushing the piston back up the bore. With alloy pistons, no such complication.
I do wonder how the diagnosis made though.

Allan from down under.


John kuehn
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Re: Wrist Pin Noise

Post by John kuehn » Wed Jun 16, 2021 9:59 pm

You mentioned ‘if’ in your post. You mentioned your engine has aluminum pistons which could mean it’s been rebuilt? Does your engine have adjustable lifters? Maybe something in the camshaft bearings or lifters? The noise you can hear in these engines can fool you. Good luck in your checking it out.


Bill Coyle
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Re: Wrist Pin Noise

Post by Bill Coyle » Wed Jun 16, 2021 11:26 pm

If you take the rod out, it might be a good idea to check it's alignment to be sure it doesnt have a little twist or bend in it. I've heard they can be bent when tightening/loosening the wrist pin bolt.


speedytinc
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Re: Wrist Pin Noise

Post by speedytinc » Thu Jun 17, 2021 8:11 am

Any time you are working with an old motor or Installing NEW rods they should be checked. The last guy may have twisted them installing pistons. New rods are frequently a bit twisted. The last re- rebuild had new rods with a little twist. Verify, verify.


Allan
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Re: Wrist Pin Noise

Post by Allan » Thu Jun 17, 2021 9:27 am

The rods can be checked for bend and twist once you have them out. Still no need to pull the head, but probably easier if you don't have access to a hoist.

Allan from down under.

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