Bseriescivic5

Hey guys, car has been running very strong for a little over 2 years now, mostly weekend driving as im not around that much these days. Just want to get a few opinions before I swap out shortblocks. Here is a basic run-down of the setup.

Bone stock b16a2 from oil pan to valve cover
-ARP head studs
-Catch can setup, 2 ports on valve cover, one from block
-GSR cams
-s300 tuned by Jeff Evans 11lbs made 315/205, 8200 limiter with safety features installed by Jeff (boost and fuel cut? not sure what he did) (im mean to my cars)
-Full race manifold
-Holset HE351cw
-Custom 3 inch DP with full 3 inch exhaust
-Tial 44 gate....
-ID1000's

Ok so basically we did a compression test cold and hot previously and came up with 200,205,195,165 cold; then again when warmed up and 200,205,190,185 So we are pretty sure the one cylinder is a bit weak.... But these numbers are again arbitrary, and when warmed up that is definately less than 10% difference. Now heres the pathology;

Cold start car smokes from exhaust (not all the time, but sometimes) and has a bit of a rough idle.... But as soon as its warmed up she purrs and the smoke goes away.

No smoke out of catch can breather, no smoke under load or driving... So my guess is that the piston expands a bit once warmed up and this stops the smoking and brings compression back up to basically normal.

So, is this the start of a bad ringland, already cracked ringland, and should I proceed with the teardown or could I have something else going on?

Thanks.

sp00led

If you have the time it's not a bad idea to pull the head and pan and check out that one cylinder. If you don't and it does drive good while warm you can keep on but you're probably on borrowed time.

At the end of the day it's a stock b-series cast piston so even with a good Evans tune it's not going to take abuse (having fun) forever.

I had a boosted stock GSR crack a ringland and just put a new piston on a used rod while the block was still in the car. Compression came back and the engine is still running back as NA for over 50k miles now.

Bseriescivic5

Agreed.... I think im going to wait till the winter gets here and go through the engine then. I have a known good spare stock shortblock ready to go in with 220 across the board, but as many of us know, its a royal pain in the *** to take all the turbo components off and put back on in a weekend..... I ALWAYS fight with this manifold getting back on.

Thanks for the insight, just making sure my diagnosis is right and there isnt something else going on here.

turbohatch96y7

iTrader: (15)

Is that he351 with the variable turbine housing?
Are you using the vaines? Or just an external gate?
Pics??

Bseriescivic5

No, its not the "VE" version, this one is a standard t3 footprint with the 9cm housing... no vaines. Here is a link to my dyno session... dont think you can see too well though.

wantboost

iTrader: (2)

The cw is a standard geometry turbo. The ve is the variable vane unit. I have one im planning on using eventually but due to the turbine inlet flange and the overall size of the turbo you'dhave to have a custom manifold made.

It could be ringlands. Although our motors tend to sound like subarus when a ringland breaks. Low compression could be something as simple as or a headgasket on its way out. Have you checked the turbine housing and downpipe for any oil residue?

LightningTeg

Is it oil smoke? What fuel are you running?

Bseriescivic5

93 octane pump, turbo is clean on both compressor and turbine side, no obvious signs of blown seals and the like. Also, if the turbo was the source of the oil leak (and hence smoking) I would think it would smoke all the time and not just at cold starts and dissapearing once warmed up.

Had the head off about 2 months ago to replace headgaskett, as we originally thought I might have popped a head gaskett... compression inmproved marginally and probably just variation from the compression tester (went up like 8-10psi on the one cylinder we suspect is hurt). While the head was off we did our best to inspect that cylinder but couldnt find anything wrong on either piston or the cylinder walls, although this certiantly does not negate a cracked or damaged ring land...

Oil looks good, no coolant mix, and otherwise the car runs very strong once warmed up.... the entirety of the issues are cold start for first 7-10 min and then runs perfect as far as my limited knowledge can tell.

And yes it is oil smoke im pretty sure.... classic whiteish-blueish smoke

Bseriescivic5

I realize at this point there is nothing much left to do other than pull the piston out and examine... I would like to comment though that maybe we should make a sticky of "symptoms of ringland issues" because as many of us know, the pathology is quite variable from situation to situation.... some people know right away (the classic smoke comeing out of valve cover, running like **** all the time) to less noticable problems like mine where car runs pretty damn good for most of the time....

Sorry MODS if there isnt a plethora of tech in this thread but I do think a lot of people running stock blocks would be interested.

Thanks.

racebum

check manifold vacuum. see if the needle is stable or if you have flutter. if you have cracked ringlands you should have flutter in the vacuum and quite a good deal of smoke under boost

SiRCiviC94

Run her till
She blows man. What's a short
Block 150-200 tops? :p

Bseriescivic5

Thats the thing..... there is absolutely no smoke at all under boost.... just on start up for a few minitues, once warmed up it completely goes away... ive had someone follow me while under boost and no smoke at all. I think its the start of a broken ring land..... makes sense sorta cuz the compression gets better once normal operating temperature achieved....... I think as the car keeps getting driven the symptoms will get worse so we will see.... IF it is a headgaskett... your basically limiting it to the oil passages getting into the cylinders becuase I still have no milky oil what so ever...

Bseriescivic5

manifold vacuum based off of my boost gauge is dead stable... no fluctuations what so ever unless of course I apply throttle. again, I think this is just the very early stages of a broken ring land and the symptoms will just continue to get worse.

Bseriescivic5

New compression #s 200,205,190,150 cold; 190,200,195,170 warm; still dont like the fluctuation with the reader, but its pretty obvious I have an issue on the one cylinder.... going to pull motor in a few weeks and swap out short-blocks.

Thanks.