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Re: Tight gudgeon pins

John, I would say that if they become easily movable when heated as you describe, I would leave them as they are, making sure that there is a thin film of oil on the pin and the bore in the piston.
Attempting to ream the pistons might cause irepairable damage unless done by a good machine shop.
Awaiting return fire!

Location: Bonnie Galloway

Re: Tight gudgeon pins

Hi Dave,
Put your tin hat on and take cover!!!
Is not the whole point of a reamer to achieve an engineered finish of the correct diameter? Back in the dark ages when I was an apprentice we were taught that, where applicable, all holes were drilled under size and then hand reamed to fit, especially on air frames where even holes for bolts had to be reamed first!
John has told us that he has had to heat the piston, and con-rod in boiling water, but no mention of heating the gudgeon pin as well.
"When hot the gudgeon pins went in no trouble and everything was free" well yes it would do, but if the pin is heated to the same temperature, would he not be back in the same situation. Tight gudgeon pins are not a good idea. In my "Little box of horrors" I have gudgeon pins with bright blue ends!
Imagine you had just re-bored the block and two of the pistons went in easily but the other two needed, in John's words "Much more effort" No I don't think I'd be happy either.
Just a thought on a cold Sunday afternoon.
J

Location: As far east in Kent as you can get