Ruddertwin Connecting Rods

[chris-p]

I was asked today what the difference was in the connecting rods used on a Rudertwin, as the Port and Starboard Rods have different Part Numbers. I am not sure without opening one up to have a look. Anyone know off the top of their head?

[pm-t2]

Model year would help.

Checking my early parts (pre-1923) I can’t find any difference between port and starboard side rods. No part numbers on the beam.

PM T2

[garry-in-michigan]

My thought is the later rods had a longer wrist pin bearing and it was offset. The difference between right and left depended on which side of the rod they drilled the oil holes. The holes are always on the "up" side. . . 🙂

[chris-p]

That is exactly what I thought as well Garry. He told me he had oil holes on both sides though, so I think someone in the past use two ports or two starboards and drilled new oil holes. Not sure.

[pm-t2]

The set of rods I have out are from a Model F, they are both drilled on both sides for oiling, so I believe this makes them interchangeable. Measuring features on them indicates no difference between the two. I would have to think later Light Twins adhered to this as well. Just my thoughts.

Best,
PM T2

[chris-p]

Thank you Chris. Perhaps I should check for myself, but I was told that they have different PN#s, yet looked identical?

[wbeaton]

I know who you were talking with. I mentioned this to him last year. The 1924-25 Model C/D manual clearly states a right and left connecting rod with different numbers. I don’t know what the difference is. In 1926 the manual states the same part number implying that the rods are interchangeable. I believe the later rods have a different part number than the earlier ones, but I’m going from memory which is often unreliable.

Wayne
Upper Canada Chapter

uccaomci.com

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