Gudgeon Pin Fit

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
jack clegg
Posts: 62
Joined: Wed Feb 01, 2017 1:48 pm
Location: BUCKS UK

Re: Gudgeon Pin Fit

Post by jack clegg »

A modern forged piston should not require heating to fit the pin. Cast pistons, such as the Indian type fitted to Royal Enfields do require heating to fit the pin. Low expansion alloy saves a lot of burnt fingers.
John Marshall
56G80S
Member
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Joined: Wed Oct 12, 2005 10:45 pm
Location: N YORKS UK

Re: Gudgeon Pin Fit

Post by 56G80S »

At the risk of being derided, if the piston is slack on the gudgeon pin is it possible that the gudgeon pin then operates on the piston and the pin remains semi stationary in the little end?

With adverse consequences?

Johnny B
jack clegg
Posts: 62
Joined: Wed Feb 01, 2017 1:48 pm
Location: BUCKS UK

Re: Gudgeon Pin Fit

Post by jack clegg »

Yes. However all pins move in the piston. It's just that the older/cheaper types have to warm up first. Note the oiling holes in the piston bosses above or below the pin. I had a little end which was tight & the only movement was that in the piston bosses. Not good but it still functioned.
John Marshall
bodgert
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Posts: 27
Joined: Mon Jan 01, 1990 12:00 am
Location: CHESHIRE UK

Re: Gudgeon Pin Fit

Post by bodgert »

A lot of modern car engines have the pin captive in the conrod and all movement is in the piston
Andy51
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Joined: Thu Mar 31, 2005 1:00 am
Location: BERKS UK

Re: Gudgeon Pin Fit

Post by Andy51 »

Not just modern cars. My old '61 Austin A55 had the gudgeon pin clamped in the small end by a pinch bolt. Andy
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