projectTeG

ok, got a 82mm lsvtec with ITR piston(us) and stock b16 head. my compression was 245 across the board, but now its around 220. i know there is a reason for the loss, but i added oil to the cylinders and the compression shot up to 320, which it has never been there before.

the engine smokes sometimes in high rpms, but mainly in between shifts or after high vacuum situations(i assume its valve guides since the heads got 270k+ on it and suffered a few bent valves) but now im wondering if it could be rings, but the engine was just rebuilt no to long ago using new parts are everything came to spec, now im wondering if the oil just filled the cylinders more and cause the jump in pressure because of the decrease in cylinder volume.

GEN2 LS

iTrader: (3)

bump i'd like some answers to this as well, just did a compression test on my b16 block with 81mm ctr pistons, got 210 across the board, I expected higher numbers.

dbsharp

Did you bore the block and use new pistons or did you just replace the rings?

projectTeG

bored, plateau honed and used the supplied rings from npr for my 82mm itr pistons.

Natural Aspirations

Probably oil control rings

projectTeG

im hoping its just the ring, i dont feel like blowing alot of money in the head. rings would be easier and faster

because if it was valves the compression wouldnt have changed?

Natural Aspirations

Im not ruling out the valve stem seals completely, but I commonly see the oil control rings with issues. Especially with cheaper rings. How is your PCV system?

projectTeG

elimanated into a breather

4g hatch

how much oil are you buring? i was thinking crankcase pressure since you got ls rods with b16 bearings so your really not getting any oil on tha cylinder walls,even if you had bad oil control rings. but you said you got a catchcan so im puzzled.are you using the block fittings or just the valvecover fitting? in my experience valve seals/guides will cause smoke but not that much oil consumption,where oil control rings will cause lots of oil consumption.

projectTeG

yea i think the rings were shitty to begin with because the problems was with the engine from the starts, im putting some hastings in this week and hopefully fixes the issue. i mean because when the pcv system is in the oem places i blow alot of oil into the intake.

im just using a breather on the valve cover.

projectTeG

found the problem

3 blown pistons. cars been having these problems, since right after building it. i ran a 100mph trap with this engine in this condition....

.Manny.

iTrader: (1)

wow!!! what are you putting in there next?

projectTeG

another set of ITR pistons. dont want anything special with this engine anymore. just want the damn car to run and not break.

i just need to find a set of 82mm itr

4g hatch

dam,i would get the rs itr pistons. never seen or heard anything bad bout them

projectTeG

yea, those are suppose to be npr pistons which are the oem pistons, but i dont think so. the ringland break is identical on all three of the damaged pistons. no cylinder wall wear or maring, just a few broke rings from the blown lands.

im hoping good things from the rs pistons, im just paranoid.

im hoping the pro's will have good things to say about them

4g hatch

i dont blame you for being paranoid. really thats your only option with that bore unless you go with forged. ive never seen or heard anything bad on any site about rs pistons. i doubt there the same as npr.last i heard they came with hasting rings,and the npr's dont.at least you caught it before your cylinders got scared up.

projectTeG

they got marks on them, but the crosshatch is still there.

****ed up part is i just ordered cp 82mm rings for 104, and i can upgrade to the same rings with the rs kit with pins and the pistons, rings, pins and shipping would be 215.

4g hatch

yeah thats messed up. could you cancel the order? i know mar77c on here has the rs 81.50 pistons and rings in his gsr block for several years now and he's makeing 226whp. his compression and leakdown #'s are still very good.

projectTeG

yea im going to try and cancel my order tomorrow after i order the rs pistons. i think i got ripped off on these pistons i think the were nippon racing instead of npr.

i just want to run the hastings rings with the pistons and call it a day. people told me that it was detonation that caused the damage, but i see no damage on the piston indicating it was detonation. no damage on the plugs or anything. to me the engine was burning fine.

4g hatch

idk...im not a tuner or anything. maybe someone will chime in with that experience. you wasnt running aftermarket cams was you? also was it tuned?

projectTeG

it was afc tuned later in the engines life, but the car was origionallly broke in and driven on a map from a similar engine. same bore itr pistons ls/vtec on stock cams.

when it was first built i heard pinging and i guess i was too late on getting into the map to pull timing, and thats where the issue came from.

4g hatch

well,at least we know they wont take much!!! this time i would invest in a street tune,on at least crome or something. i dont think tuners charge much just for a street tune

projectTeG

yea, i neglected that for to long. ive got a tune set up once i get done rebuilding it. i just have to figure out if blown ringland would cause oil/air/fuel mixture to circulate into the intake manifold and cause wet valves

4g hatch

im sure it would,i think blowby will cause excesive crankcase pressure