Sticky Wrist Pin

[Tinactin]

Hello!

After pulling the head and cylinder block for extensive gasketry, I noticed that the #1 piston is somewhat stuck at the wrist. It appears that the pin is seized to the rod, and the piston is rotating about the pin, as opposed to the pin rotating within the rod (which is what is happening in the other three pistons). I'm seeking advice about how extensive of a problem this is and how to fix it. On a related note, how might one go about removing the wrist pin without the use of a wrist pin puller?

Thanks for reading and apologies if this has been posted two hundred times before.

[7981GS]

Hello!
On a related note, how might one go about removing the wrist pin without the use of a wrist pin puller?

Find a 3/8" drive socket that just barely fits into the pin bore and with a long extension on the socket, drive it out with a hammer.
After removing the cir clip, of course.

Daniel

[Tinactin]

Hi Daniel,

Considering that the piston is still attached to the connecting rod, I don't think that hitting it with a hammer is a good idea. I think that would damage the crankshaft.

I did, however, solve the problem. I nabbed a 1/2 deep socket, an old 9/16 plug socket, and a large C-clamp. Worked out fine. I'm still looking for advice on what to do for the repair...polish down the pin a bit? New pin? New rod? New motor? Walk?

[razor02097]

Is the rod pin bearing surface damaged? how does the pin look?

[Tinactin]

Is the rod pin bearing surface damaged? how does the pin look?

The pin has a couple dark hoops around it, but so do all the others. The part that mates with the bearing surface of the rod looks very shiny and polished. The bearing surface looks pretty good too. I was thinking maybe dipping the pin in some chem-dip and, if it doesn't work after that, gently polishing it with some 00 steel wool. Is this a terrible idea?

[SqDancerLynn1]

Lightly hone the small end of the rod

[gearhead13]

Get new pins, and clean up the small end bore of the rod.

[Tinactin]

I nabbed a brake cylinder hone and cleaned up the connecting rod a bit. It fits better, but still won't rotate in the hole. I suppose I'll just hone a little more at a time until it fits and rotates like the other pins. Perhaps I'll update about how it goes.

Thanks for the replies!

Update: It took quite a bit more honing than I expected, but the piston finally moves much more freely. I used a Lisle 10500 brake cylinder hone that I picked up from a local chain for ten bucks. I spread a little motor oil on the stones before honing, and made sure to thoroughly clean the rod of any dust before fitting the pin.