
I recently acquired a set of Forged pistons for my 1965 coupe from the son of the original owner. They have a casting number of 3866954. When I got them home I was inspecting them a little closer and noticed that the pins do not slide in and out of the pistons.
Acording to the 1963 corvette overhaul manual the pins should have from .0005-.001 clearance and when covered with light engine oil should not fall trough the bore.
I tried to knock one out with a hammer and socket and it did not move. ( I did not apply a lot of pressure because I did not want to distort the piston.)
I am thinking that maybe there is a small amount of corrosion holding the pins in place. Or maybe they galled the pin bores when removing the rods the last time.
Than I read a post on another forum where a gentleman had used these pistons and had trouble with the pins fitting and had to hone the pin bores to make them fit.
This made me wonder if maybe these pistons are different than most press fit piston pins. Could it be that the pin is press fit into the piston and floats in the rod?
If that is not the case does anyone have any ideas about how to free up the pins? I have applied WD 40 and let it soak overnight but this did not make any difference the pins still wont move.
Any comments or suggestions would be greatly appreciated.
Thanks in advance,
Bill

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