Oil ring question

BERT · Dec 18, 2023

There is an interesting short youtube video where Jim Comstock quantifies oil ring friction difference by shortening the expander. Sorry, I don't know how to attach the video. Google search "Jim Comstock oil ring" and see.

marinatlas · Dec 18, 2023

marshg246 · Dec 18, 2023

marinatlas said:

Three problems:

1) That has nothing to do with the discussion here - that's a 3-piece ring, not a 2-piece ring.
2) Hepolite only ever used 1-piece and 2-piece AFAIK. Hepolite were supplied with Hastings for some time which were 3-peice
3) He did not say if he considered it as a good or bad thing to have less rings pressure

olympus · Dec 18, 2023

marshg246 said:
seattle##gs: Hastings still makes Triumph and BSA rings.

I would suspect that the number of BSA bikes number less than Norton ....so is there any idea why Norton ring production was ceased.... i stand to be corrected

worntorn · Dec 18, 2023

I recall reading that in the early 60s one out of every four motorcycles in the world was a BSA.
Then about ten years later they were bankrupt.

Glen

marshg246 · Dec 18, 2023

olympus said:
I would suspect that the number of BSA bikes number less than Norton ....so is there any idea why Norton ring production was ceased.... i stand to be corrected

Corrected, you are

Triumph biggest, BSA second, and Norton barely a blip in the count.

For one thing, the Triumph 650s were made from the early 60s to early 70s and the Triumph Twin 750s from early 70s to the 80s. And the Triumph twin 500s from the early 60s to the late 70s. Some Triumph and BSAs had the same rings. I can't find the numbers, but I bet there were more BSA/Triumph singles than Nortons.

If I remember right, a BSA A65 +40 ring set is the same as a Triumph T140 standard rings set. And a B25/TR25 ring set is the same as a T150.

So, there's a LOT more Triumph/BSA business than Norton business.

BERT · Dec 18, 2023

marshg246 said:
Three problems:

1) That has nothing to do with the discussion here - that's a 3-piece ring, not a 2-piece ring.
2) Hepolite only ever used 1-piece and 2-piece AFAIK. Hepolite were supplied with Hastings for some time which were 3-peice
3) He did not say if he considered it as a good or bad thing to have less rings pressure

I would think that eliminating friction where possible would make a more efficient, cooler running engine

Triton Thrasher · Dec 18, 2023

marshg246 said:
For one thing, the Triumph 650s were made from the early 60s to early 70s and the Triumph Twin 750s from early 70s to the 80s. And the Triumph twin 500s from the early 60s to the late 70s.

There weren’t any late 70s 500s. C Range Unit 500s were introduced in 1959.

B Range 650s, that can have piston rings in common, were introduced in 1949.

marshg246 · Dec 18, 2023

BERT said:
I would think that eliminating friction where possible would make a more efficient, cooler running engine

I have no idea, but:

1) Continuing that thinking, why not remove the rings or at least the oil control ring? (Tongue in cheek)
2) They are called oil control rings for a reason. Does making them tighter or looser control the cylinder wall oil film better?
3) Rings and cylinder walls are not perfect. Does making them tighter or looser make them touch the walls all the way around and all times?

marshg246 · Dec 18, 2023

Triton Thrasher said:
There weren’t any late 70s 500s. C Range Unit 500s were introduced in 1959.

B Range 650s, that can have piston rings in common, were introduced in 1949.

Yes to 49 and 59, didn't want to cloud things with the pre-unit years but even more reason why Triumph rings are more in demand.

Correct on the 500s - ended officially in 73. I was thinking of a bunch built but not sold as T100D later but should not have considered them.

Stephen Hill · Dec 18, 2023

Question: "Does making them (oil rings) tighter or looser make them touch the walls all the way around and all times?"
Answer: "No".

marshg246 · Dec 18, 2023

Stephen Hill said:
Question: "Does making them (oil rings) tighter or looser make them touch the walls all the way around and all times?"
Answer: "No".

Out of context and it's not a Yes/No question!

According to the Hepolite ring manufacturer and the one AN uses, the 2-piece rings are tighter for that purpose and to ensure that the oil is scraped evenly around the cylinder wall.