Tight Wrist Pins

1990C4S · 09-24-2016, 07:56 AM

I am tearing down an old Wisconsin engine. I have removed the wrist pin clips from both sides, but I can't get the wrist pins out.

Could they be pressed into the pistons? Is that normal?

DanielDudley · 09-24-2016, 09:22 AM

I have seen pressed in pins, but never with c clips. You need to find a forum for your engine.

nota · 09-24-2016, 09:52 AM

built up varnish ?

1990C4S · 09-24-2016, 11:10 AM

The con rods are difficult to get off, I was hoping to salvage the pistons without digging deeper.

Oh well, I'm into it now....con rods are coming out too.

VINMAN · 09-24-2016, 11:10 AM

Wrist pins would be pressed into the rod, not the piston itself. Normally if there are clips, they are full floating pins. May have to heat the rod bushing, or as Nota said, just might be stuck with varnish build up.

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RANDY P · RANDY P's Garage

heat 'em.

rjp

wdfifteen · wdfifteen's Garage

I've seen pins pressed into the rods, but never into the Pistons. Piston temp is so high it seems they would loosen unless they were REALLY pressed tight.

1990C4S · 09-24-2016, 12:29 PM

I will break out the torch tomorrow. Thanks for the suggestions.

crustychief · crustychief's Garage

I would try the oven if Mrs 1990c4s isn't around. Then press them out. I did that with an old Nissan I rebuilt 500 degrees for an hour then quick to the press.

Por_sha911 · Por_sha911's Garage

Could be worse, you could have limp wrist pins.

LakeCleElum · 09-24-2016, 05:51 PM

Can press them out with a nut, bolt, washers and a deep socket for a spacer.....

Nickshu · Nickshu's Garage

Heat is required. I would take them to your local machine shop and have them removed. Not uncommon for them to be a PITA.

When the time comes have a machine shop install them. It's tricky business heating them up then pressing them in and properly aligned.

Pay attention to the pins original positions, some engines have them purposely offset to prevent piston slap or for crank clearances.

yetibone · 09-25-2016, 05:16 AM

Go to the smokstak and ask. I believe there's a forum specific to Wisconsin Robin engines.

john70t · 09-25-2016, 08:45 AM

Quote:

Originally Posted by Nickshu

When the time comes have a machine shop install them. It's tricky business heating them up then pressing them in and properly aligned.

I would do this.
Using the side of the piston as leverage might end badly.

1990C4S · 09-25-2016, 01:18 PM

Quote:

Originally Posted by LakeCleElum

Can press them out with a nut, bolt, washers and a deep socket for a spacer.....

Winner. All done now. Good idea.

LakeCleElum · 09-25-2016, 04:34 PM

Quote:

Originally Posted by 1990C4S

Winner. All done now. Good idea.

Thax....Done it many times over the years on snowmobiles and motorcycles. To heat for disassembly, it's hard to just heat the piston/rod and not the wrist pin.

For re-assembly, heating the piston in the oven usually works....You can freeze the wrist pin, but not dropping it all that much from room temp; I usually don't bother with the freezer.