Just asking them what I should do for rings gaps on a B18c1 Im building. They guy asks me about what HP level its for...I say somewhere between 500-550 max. I tell him the bore (.5mm over) and he says go with .019"-.021" on the top ring and .020"-.023" on the bottom. This surprises me because I was expecting to hear around 17-18 top and 19-20 on the bottom, so I ask him if they ever have oil consumption or compression problems with these specs and he says no...some stock gaps are as big as .045" and the only place that really matters is the actual ring to wall seal as far as blow by is concerned.

What does everyone think of this? After reading something Earl said about not trying to outsmart CP, I gaped them to these #s so hopefully its fine.

And a side note...holy **** that top ring is some hard metal, took way longer than the JE ones i just did for my motor.

 

Remember ring gaps are the call of the engine builder and not the piston company. Everyone does it differently. You could have been talking to a V-8 guy there also.

 

How would his view on ring gaps be different than mine? Just used to bigger bores?

 

Bore size x 0.006 = top ring gap

Add 0.004 to top ring gap to get lower compression ring gap.

Minimum of 0.0012 for the oil rail spacer ring gap.

I have built 30 + customers engine this way, all with excellent results, all using CP piston sets.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted hybrid &raquo;</TD></TR><TR><TD CLASS="quote">Bore size x 0.006 = top ring gap

Add 0.004 to top ring gap to get lower compression ring gap.

Minimum of 0.0012 for the oil rail spacer ring gap.

I have built 30 + customers engine this way, all with excellent results, all using CP piston sets.</TD></TR></TABLE>

Good to know. thanks. The gaps I did line up with your bottom ring formula but my top is .002 larger. oil scrapers are at .015". Think it will be fine as a DD street car motor?

 

Top ring gap is fine. You might leakdown slightly worse by a few % with the larger gap, but nothing significant.

0.0012" is the minimum gap, you can have more with no issues.

 

Can you just leave the oil rail spacer ring gap untouch? meaning don't file them and just leave it alone? thanks.

 

never touch the oil ring gaps

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bailhatch &raquo;</TD></TR><TR><TD CLASS="quote">How would his view on ring gaps be different than mine? Just used to bigger bores? </TD></TR></TABLE>Most V-8 guys are used to running NA or maybe nitrous. They are still pretty new to high revving DOHC turbocharged scene.

 

My botom ring gap is .024 top is .017 or .018 cant remember, CP and Earl said that is fine, and it sure was, I have no problems at all with 2500miles on the engine.

 

huh, Ya i wish i did the top a little tighter like 18 or 19 but based on the input here I guess it should be fine. At least this way he can really heat the thing up on the highway and not risk the top ring binding. Thanks for the input guys

 

so according to earl's post:

81.0mm/81.5mm/82.0mm/82.5mm
Top = 0.019
bottom = 0.023

83.0mm/83.5mm/84.0mm/84.5mm/85.0mm/85.5mm/86.0mm
top = 0.020
bottom = 0.024

however. My previous build had the gaps at 0.013-0.014 and it didn't burn a drop of oil. However, my friends build at 0.019-0.020 is burning about a quart of oil every 250 miles. These are both fresh motors on CP's.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by itralex &raquo;</TD></TR><TR><TD CLASS="quote">however. My previous build had the gaps at 0.013-0.014 and it didn't burn a drop of oil. However, my friends build at 0.019-0.020 is burning about a quart of oil every 250 miles. These are both fresh motors on CP's.</TD></TR></TABLE>Not really a fair comparison of to make of two different engines based on ring gap only.