1953 / 4 G3LS build

[EddieDay]

2023-12-19 13.37.14.jpg

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I managed to upload photos of the pitted crankpin sleeve and conrod liner. I am hoping I can use these because the club spares shop do not stock them. Thoughts welcome.

[ajscomboman]

Nasty, I'd not use it if it's as bad as it looks.

[ChrisTheChippy]

I think I would reuse the con rod but the crank pin sleeve looks a bit iffy and I would be thinking of getting that sorted before reuse . Just my opinion , others may be able to offer better advice .

[g80csp11]

is it not AMC6 assembly with 017020 crankpin according to spare parts list , our spare part no 900595
Is that right Rob Swift ?

But you do need to know what you are doing to hone cage once fitted to the conrod . thats always been teh procedure otherwise it will be too tight to turn ( tolerance closes up when fitted to the rod )

In stock at Kettering

should fit the following : As fitted to:
350cc G3L/G3LS/G3LC/16MS/16MC (1940-1951)
350cc G3LS/G3LC/G3LCS/16MS/16MC/16MCS (1952-1954)
350cc G3LS/G3LC/16MS/16MC/16MCT (1955-1963)
500cc G80/G80C/G80CS (1938-1952)
500cc 18/18S/18CS (1946-1953)
500cc 18/18S/18CS/G80/G80S/G80C/G80CS (1952-1963)

[EddieDay]

Yikes! £354 for the 2 piece crank pin. I will have to think about that.

[jackstringer]

Is that coated in white metal? Can you not just get it recoated?

[EddieDay]

Jack, no it's the hard surface the rollers run on. I believe that the surface could be stellited but I don't know if I can find anyone here who can do it.

[ajscomboman]

is it not AMC6 assembly with 017020 crankpin according to spare parts list , our spare part no 900595
Is that right Rob Swift ?

But you do need to know what you are doing to hone cage once fitted to the conrod . thats always been teh procedure otherwise it will be too tight to turn ( tolerance closes up when fitted to the rod )

In stock at Kettering

should fit the following : As fitted to:
350cc G3L/G3LS/G3LC/16MS/16MC (1940-1951)
350cc G3LS/G3LC/G3LCS/16MS/16MC/16MCS (1952-1954)
350cc G3LS/G3LC/16MS/16MC/16MCT (1955-1963)
500cc G80/G80C/G80CS (1938-1952)
500cc 18/18S/18CS (1946-1953)
500cc 18/18S/18CS/G80/G80S/G80C/G80CS (1952-1963)

According to the Alpha site it's AMC 6 but for CS models it depends Peter, they list AMC 12 for short stroke and the AMC 6 for long stroke CS

[ChrisTheChippy]

Could you have 5 thou turned off the crankpin then a new con rod liner fitted and bored to suit?
Would that be a solution or am i missing something obvious?

[EddieDay]

Chris, I am not sure the cage and rollers will fit if the crankpin and conrod liner are reduced in diameter by 5 thou. Over sized rollers are available, +0.001", and I might try to get the pin skimmed by that amount and see if that removes most of the pitting. I have also found another crank pin sleeve which might take a 1 thou grind.