flexi
flexi New Reader
7/26/15 4:53 p.m.

First rebuild, so lots of stupid questions.

Have Supertech 83.5mm pistons 8.6:1 and Wiseco rings. Wiseco says 0.010 min, Supertech says 0.015 min.

Just use 0.015" gaps for the oil rings?

Both Wiseco and Supertech agree for the 1st and 2nd ring gaps.

Knurled
Knurled UltimaDork
7/30/15 7:43 p.m.

Oil rings don't hold compression, they just loosely scrape/wipe the oil off of the sides. Some oil HAS to get by to keep the compression rings lubricated, after all...

The gap should be wide enough to not butt if they get hot, and more than that doesn't really hurt all that much. .015", .030", whatever.

David S. Wallens
David S. Wallens Editorial Director
8/1/15 12:02 p.m.

Since this is more of a tech question than a build thread, I moved it to the general forum. You should get more discussion there. (Not that Knurled wasn't helpful at all--thanks for helping a newcomer.)

Knurled
Knurled UltimaDork
8/1/15 12:43 p.m.

How was that not helpful? I explained the purpose and the rationale for there not really being a "spec" for oil ring gaps - they don't hold compression so the gap is not super critical. Extra wide gaps don't hurt a thing.

spitfirebill
spitfirebill PowerDork
8/1/15 12:59 p.m.

Mayhaps he meant to type not instead of note.

oldeskewltoy
oldeskewltoy UltraDork
8/1/15 1:10 p.m.

factitious maybe.....

Dr. Hess
Dr. Hess MegaDork
8/1/15 1:15 p.m.

He must have forgotten to smiley encaption it for the humor impaired.

Kenny_McCormic
Kenny_McCormic UltimaDork
8/1/15 3:59 p.m.

As Knurled noted, those are recommended minimums, depending on your plans for the engine, wider might be warranted, maybe even much wider.

Knurled
Knurled UltimaDork
8/1/15 5:27 p.m.
spitfirebill wrote: Mayhaps he meant to type not instead of note.

That makes more sense.

I'm a bit on edge/agitated... I am critically short of funds right now, won't be able to get much time off work so I'll need to pull an all-nighter after work Thursday night to get to Nationals, and I should be in Columbus doing emergency Miata repairs but I'm stuck up here with some sort of bronchitis thing or another. So I apologize for being a bit short...

iceracer
iceracer PowerDork
8/1/15 6:39 p.m.

The difference between the two is so small that it is insignificant it the over all scheme of things.

David S. Wallens
David S. Wallens Editorial Director
8/2/15 1:54 p.m.
Knurled wrote: How was that not helpful? I explained the purpose and the rationale for there not really being a "spec" for oil ring gaps - they don't hold compression so the gap is not super critical. Extra wide gaps don't hurt a thing.

Sorry, should have said "Not that..." I fix.

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