Rings and Things

[olev]

I was talking to an old digger the other day when the subject of rings came up.
He said he fits some sort of Mitsubishi rings to his Vincents and reckons they are far superior to the originals. A few years ago I helped replace the rings in a Hyundai Excel and was suprised at the detail the designers went to. The top compression ring was chamfered, the second was tapered and the oil ring was in three pieces and they all had a correct side up. The NOS rings that came with my pistons are the same ones we fiddled with forty years ago. While I intend to use these rings, I'd be interested to hear if anyone has information or experience with the use of modern rings in our motors. The excel motor was hardly state of the art so there must be some benefits.
cheers

[beezalex]

The bottom line, newer steel ring technology has provided for better sealing.  This reduces blowby and oil consumption, both necessary for today's cleaner engines as it reduces HC emissions and potential contamination of catalytic converters.  Less blowby also increases compression and, hence performance.  Steel rings to require a finer surface finish in the bore, though most shops are capable of doing this today.  You can get these new rings such as gapless rings even for your old machines.  Unless you're racing, though, the added compression and resultant performance advantage over stock cast iron rings will likely not be noticeable.

[Triton Thrasher]

I think there's a danger that the fantastic rings are for fantastic engines, not heat-distorting air cooled cast iron barrels with big piston clearances.

Know what I mean?

[stratcat]

I think there's a danger that the fantastic rings are for fantastic engines, not heat-distorting air cooled cast iron barrels with big piston clearances.

Know what I mean?

Aint that the truth!

The problem is a kind of weakest link situation, where you upgrade one part only for another to become the weak link in the chain, before you know it you've replaced so much you might as well have grafted a honda engine in there!!

[olev]

Thanks Beezalex,
Interesting site that, and it got me looking at a few others.
I've since found the gent with the vincent only uses the 3 piece oil rings from a mitsubishi 300C. He has to machine the piston a little. He does 2 engines out of a set for about 25 bucks and he doesn't keep his bikes in the lounge room. I wasn't really expecting a performance increase but rather suspected the modern technology would provide efficiency and economy as well as providing better lubrication control. I had hoped to hear from someone who had actually used them but conjecture is good too.
Cheers

[beezalex]

Well, I used gapless steel rings in my race bikes and have had good results there.

I did install a set of replacement pistons that came with a 3-piece oil ring in my A50 that never did run in.  I think the hone on the cylinder walls was to coarse for them...I've never had problems with cast oil rings.

[Triton Thrasher]

I had hoped to hear from someone who had actually used them but conjecture is good too.
Cheers

You're right to look for 1st hand experience- even then you may have to sift out some people's wishful thinking or bullshit. It's an occupational hazard on the go-faster (or go-better) engine scene.

[BSA_54A10]

Well a little non BSA but I use total seal gapless rings in my rollers without exception.
A friend who punishes his B50 without mercy ended up installing a set in his much modified (675cc) B50 and has never stopped thanking me for steering him in that direction.

On the down side they are a right royal PIA to fit & not cheap.
Better sealing rings will put more pressure on the valve stem / guide fit which if not good will cause a lot of smoking due to oil being sucked down the inlet valve. ( smoking on acceleration).
They are also not going to do any good if your bore is oval or tapered.

On the up side they make life much easier on the antiquated cast iron one piece oil ring ( even better to fit the 3 piece steel oil ring).
 bike Beesa
Trevor