Your thoughts please, on my ring gaps?
Turbo Mini Forums

Right as some of you know I've been having a pig of a year, I think it might be my fault for not rebuilding the block this year :(

Any way I'm not looking at a worse case set up and that's to do a hogster and rebuild and replace the engine in the season, not ideal for me as work and energy are at a premium.

Anyway I've just measured my top ring gaps, and do you agree with me that 8 tho is a little tight for the top one, I normally set them at 12 - 15 tho, what are your thoughts.

Not measures the bottom one yet but I normal set that a little less.

Cheers chaps.
MW

Edited by Miniwilliams on 17th Jun, 2007.

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

I'm not too experienced with turbo motors but I'd say 8 thou is too tight,

I'm not totally sure off hand but I think i normally set my 73.5 omega ones to 9-10 thou on a NA motor, for forced induction i'd guess another 2-3 thou on top of that,

so for a 1293 bore i'd say ballpark to be 11 thou although i'm sure others will disagree

No that makes good sense, and is along the lines of what i was thinking.

Just wanted it confirmed lol, any other thoughts.

The reason why i'm confused, is a certain company told me to run 18 tho!! that seems huge, when i took the rings off one year they were only 15 tho, so that's whaty i've keep to ever since, but may be that's still a little big lol.

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

18 thou does seem massive to me too,

I'd also say on an engine with oil jets for the pistons i'd try leaving the gaps at or 1 thou over what i'd run for a NA motor. not that that'll interest you LOL.

different rings, run different gaps..

Isnt it something like 0.005" per inch of bore size on some rings ?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

aye it does depend on the manufacturer of the rings! i run my na rings a bit loose at 12thou, but its designed to rev its nuts off. I plan on setting the turbo a bit tight at 8-10thou, but im probably not looking at the kind of boost as you are.

For what type of piston/ring was 18thou suggested?

I've seen the future and tbh its Pie

http://www.jepistons.com/dept/tech/dl/piston_instrc4032.pdf

hope that link works matt
it should help .
regards robert

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

8 is definitately too tight with the boost you're running. I'd gor forapprox 10-12 on the second ring, and 12-14 on the top one.

18-thou?

WTF? maybe on a 120mm piston!

I go 13-14 (absolute max) on the top, and 11/12 on the second.

Great link Robert.
And cheers for all your thoughts and comments.
Andeh, the 18 tho was when i rung up MED and they said to run that gap with a set of Omega pistons i was going to get from them.

So it Looks like what i've been doing isn't to far off the mark, but it's great to have it confimed

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

On my Ross Pistons, my top ring is circa 22thou, 3.9" bore.


one way to look at it.

if its too big a gap, you might lose a little compression.....a very little.

What might happen if its too tight ?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

very true steve scuffed bores and cracked rings.

about 14 -15 thou sounds about right

always looking for them bigger bunches of bannanas

Yes that is a good way of looking at it Steve. I can't afford to lose any compression though, it might drop me 2 bhp lol

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

Asking lots of people & getting different opinions. Pulled my engine apart, measured the gaps on my Omega rings. Top & second rings are .020"
Obviously these are used & worn. What do I set new ones at?
This is engine is for race use only. Not sure if it makes any difference.
Advice needed. May just go for an average figure.

Edited by Jason G on 10th Nov, 2007.

well when fitting my new pistons on the first 1310 the top ring were about 18 thou.

i measure the frshly bored cylinders and there were spot on, so the rings i stuck in.

the second set which went in the other day are still the same, so seems like for the turbo application they like bigger gaps.

i will see how this fresh engine runs and when run in will carry out compression and leak down test and see how much blow buy i get, but at the moment there is very little , as there is very little coming out of the breathers .

i will keep you all posted

always looking for them bigger bunches of bannanas

On new, correct size rings and a fresh bore, as long as the gap is not too small it wont matter what size the gap is as long as its not HUGE, it wont be an issue. Just make a note of the actual gap for when you tear down the engine again, that way keeping track on wear.

Larger gaps than normal in an all new instalation wont matter much.

On a used engine measuring the gap means nothing if you dont have the measurement of the gap when the rings were installed new, this is mainly the reason a max ring gap is specified by the OEM, that way the wear indicator is standardised, so anyone tearing down an engine can measure the ring gap, look at the book and determine the amount of wear.

Dont forget that the ring pack generates a labarynth seal so a slightly larger gap wont produce much more blow by. Loss of ring tenssion due to wear will produce 95% of the blow by, rather than blow by trying to get past three 18 thou gaps in the rings.

As long as the gap isnt too small which could cause the rings to bind, i wouldnt wory about it, seriously.

Sorry for the resurrection of an old thread chaps, but I was just checking my forged +20 Omegas yesterday and noticed that both first and second rings are at 8thou. MED recommended that gaps should be between 10 and 12thou. So I am a bit on the tight side which I reckon might be a bit worrying, more and more considering it is for a turbocharged engine.

I've been watching on Youtube that whenever this happens you can just file square the gap. This is even recommended by Mahle. Have you ever done this with Omegas ? I've never done this before so I'm trying to be extra careful. Thanks

Yes just file them bigger. You can get a special hand powered grinding tool to do it then clean up with a file.

Just use a good sharp file, it'll remove material quite easily.

Just hold the ring down securely on a block of wood or something.

Make sure it's as square as you can, and remove any burrs after...and even a little loose will do no harm whatsoever.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Thanks guys ! I bought a small ring grinding machine off ebay. Should do the job I think.