Merc ring?

[mercrazy]

What are the advantages/disadvantages of 1.5mm vs. 2mm rings?

[David - WI]

The thinner the ring, the higher the rpm you can run before they "flutter"... thicker rings have more bearing surface so they're supposed to last longer.

[mercrazy]

I may have to change my name. Since the simple 2.5 stuff is gone, I’ve kinda lost the feeling.

[tlwjkw]

jus made me think of something i can't remember.. back in tha early 80's we used a brand of forged piston thats usually only associated with car motors.. tryin' ta remember tha name?.. ran O-ring heads anda ton of comp.. rings were paper thin, ductile.. only good for 'bout 8 ta 10 (pushin' it) hard pulls.. sometimes less.

anyone remember those?

[KIRCHNER]

TRW lw/lr?? JANS?

[tlwjkw]

TRW's...... was tha ones.. never forget how tiny tha rings were!.. my fingernail was twice as thick.

[KIRCHNER]

i ran them on my s/p 400 s/b nova, 630 bhp all motor, holly 830 4bbl. 1/8 mi @ 6.4 sec, 106 mph. oh yhose were the days, wheelstands,girls,beer, 110 octane & 5500 stall converters!

[David - WI]

TRW pistons are part of the SpeedPro line now, but I haven't seen any 2-strokes listed.

[tlwjkw]

40+ years ago!...... '83/'84 maybe?.

didn't know at tha time they made 'em.. knew something was up when tha dealer told us ta be sure and order a bunch a rings............

[mercrazy]

After tearing down several engines, there are always broken 2mm rings. I’ve never seen a broken 1.5mm ring and I can’t break one even when I try. This worries me about using 2mm rings. On the other hand, since the 1.5mm are not as hard will they have a shorter life? Thoughts?

[WaterZebra]

After tearing down several engines, there are always broken 2mm rings. I’ve never seen a broken 1.5mm ring and I can’t break one even when I try. This worries me about using 2mm rings. On the other hand, since the 1.5mm are not as hard will they have a shorter life? Thoughts?

The 2mm rings may be breaking from thermal expansion of the ring itself plus contraction of the piston ring groove?

[tlwjkw]

After tearing down several engines, there are always broken 2mm rings. I’ve never seen a broken 1.5mm ring and I can’t break one even when I try. This worries me about using 2mm rings. On the other hand, since the 1.5mm are not as hard will they have a shorter life? Thoughts?

we've never seen a broken ring (any size) on any of our junk... ya gotta think of jus how many 2 mm rings are out there on tha merc production stuff.. best i remember tha '91 200 was tha first ta use 'em (tha 1.5's) .. then they went inta 225 PM for a while... i never understood their reasoning for tha difference in tha production type motors.. jus doesn't compute ta me.... jmo.

[mercrazy]

Maybe they’re low tension like they use in car engines now? I think I feel better using rings that won’t break even if they don’t last as long.

[tlwjkw]

Maybe they’re low tension like they use in car engines now? I think I feel better using rings that won’t break even if they don’t last as long.

[skialot2]

The only time I have seen broken rings is when the piston is completely detonated. Sometimes piston are completely detonated and the rings still are not broken. Check out the piston still in the cylinder. The cylinder itself is broken. The piston is so detonated you can see the unbroken ring almost all the way around.