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[walter]

Hi guys, im rebuilding and SR20DE engine, got new rings but first are bigger, gap is 0.55mm, the oem spec is about 0.23mm, so it's +0.32mm, not sure if i could have problems with compression or something like that, second is 0.58mm, oem spec is 0.50, so it's ok for me but im worried about the first one.

Any help will be appreciate a lot.

Thanks.

[92CXyD]

are you measuring the ring gaps while part way down the bore?
 
0.55mm => ~0.022" gap and suspect that to good for >300bhp setups

I'd look at what is the ring gap from OEM or the manufacture of the rings.

Also are you doing this in a freshly machined block?

or a well used block that probably needs a bore and hone? 

[walter]

yes of course, im measure as it should be go, into cylinder, first ring eng gap oem spec is  0.20-0.30mm, as i said in the first post , this new first rings is +0.32mm bigger.

cylinders are honed already and measured . (check OG section  )

my concern is if 0.55mm should works good runing NA, limit is 1mm but i dont wanna go bigger!!!

[92CXyD]

yes of course, im measure as it should be go, into cylinder, first ring eng gap oem spec is  0.20-0.30mm, as i said in the first post , this new first rings is +0.32mm bigger.

cylinders are honed already and measured . (check OG section  )

my concern is if 0.55mm should works good runing NA, limit is 1mm but i dont wanna go bigger!!!

Are the new pistons 0.5mm o/s from the original bore and the cylinders match, but the rings are for a standard piston?

[walter]

using everything stock. bought pistons rings, full kit bearings std size and gasket kit.

[92CXyD]

using everything stock. bought pistons rings, full kit bearings std size and gasket kit.

Rereading your build thread post you mentioned, do you still have the old pistons?

I think your block was already bored and honed, 0.5mm over 

If you look at the old pistons, I bet they do not say std on top but 0.5 o/s or something similar. 

[walter]

huh? it's not my civic project, im building a SR20DE, not a D16 SOHC!.

im using stock(old) pistons,etc..

P.S. this is another shit 

[92CXyD]

huh? it's not my civic project, im building a SR20DE, not a D16 SOHC!.

im using stock(old) pistons,etc..

P.S. this is another shit 

Something does not make sense then, your top rings are .5mm too small 

Or use them and you will have a little excessive blow by and will not pass emissions (if you have to worry about that)

But if you are pushing the engine to some high power numbers, then that top ring gap will work for ya. 

[walter]

 my english is a shit..

oem specs are 0.20-0.30mm.

used piston ring size is 0.23mm (ok but it's used).

new brand piston ring i got is 0.55mm, it's too big, not smaller.

[NoPistons!]

Not good.   Did you try asking this on nico or zilvia?  I'm not sr saavy, in fact i fucking hate them with a passion. Who'd you get your rings from?  Nippon/rock?  Would contact them and see what the deal is.

[walter]

Rings are NTP.

[HiProfile]

http://www.laskeyracing.com/shop/ringgap.htm

That is for an 81mm bore, so increase those numbers proportionately. Meaning 86mm/81mm x 0.019" = 0.0202" = 0.51mm, so 0.55mm isn't that bad. If this was a bone-stock project in california (emissions inspections), then I'd get different rings. Same if it was a bone-stock car driven daily, you'll get a bit better gasoline milage and longer oil life.


To be more accurate, you'll want to calculate it this way:

Upper (farthest from oil control rings)
0.006 x 86mm = 0.516mm

Lower
0.0065 x 86mm = 0.559mm