BQuicksilver

As some of you know, I've been chasing an issue with the car tossing some oil smoke out the exhaust at the track, mainly right after high vacuum situations like at the end of a straight and on through the following corner. The car is running fine, but it's consuming oil (about 1qt/day) and makes track workers nervous that my engine is ready to let go or something. I'd like to fix things, and maybe someone here has dealt with the same.

2002 coupe with AFR 205's (63cc) and 224/228/114 cam. 20k on the heads now. 430whp...seems to run fine other than the smoke.

I have already plugged off the free air line and PCV to the intake/TB and went to an 04 z06 PCV setup with both plumbed into a canton catch can with breather on top. Therefore there is no path for oil to get up into the intake, and it looked dry up there after this change (previously had oil up top), but the darn thing still smoked and the can filled pretty fast. I did a compression test the day before the last smoky event and all was well. I recently changed the springs but was dumb enough to no do the seals, though it doesn't smoke on startup. I'm running out of ideas here. Could the valve guides be bad...I haven't heard of many failures there. I didn't use teflon seal on the rocker bolts when I put them back on?? Would restricted pushrods or different rockers fix anything?

Any other ideas?

AU N EGL

Rings? and oil blow by?

BQuicksilver

Possibly. I did break a ringland on #7 and replaced it recently. I have the old style of rings on my 2002. Compression was checked twice recently to make sure the new ring was fine and everything was about 180-192. Would that cause the smoke at only high vacuum spots?

My gut feeling after some reading is that lots of oil gets up top from cornering, and that oil gets sucked down under high vacuum. I vaguely recall someone posting that valve guides could cause this (smoke under vacuum), and that if the valve seals were shot I'd see smoke on startup, so I've ruled them out. That being said, I haven't seen many valve guide issues here.

sperkins

There's lots of good information from a guy with similar problems as yours in this thread. Below are some highlights. His problem turned out to be valve seals. My immediate guess on your car is intake leak.

http://forums.corvetteforum.com/show...ak+burning+oil


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Cobra4B

If you've got the PCV plummed that way then it can't be that anymore. That really only leaves valve seals. I'd think if the rings were bad it'd show on a compression test and you'd be down on power.

I'd say you need to seal the rocker arm bolts and install new valve seals.

BQuicksilver

Thanks sperkins, I had read that thread but picked up some more info this time around.

My Current Plan of Attack (let me know what you think)

- new valve seals (do GM seals work with AFR heads?)
- seal rocker bolts (exactly what is the preferred sealant?)
- change from 10w-30 to 10w-40 (help cooling and less thin to sneak by seals/guides)
- smith brothers .040 restricted pushrods (less oil up top to reduce severity of the issue)

The only remaining unknown is the question of guides needing fixed. It sounds like you need to pull the heads for this, so I'd prefer to wait, but if it sounds like these are the issue I want to do things right.

Cobra4B

Not sure if I'd want less oil up top when racing, but some people swear by them. Who'd you get the heads from? Call them and ask which seals to use. Reason is that with the oem heads you have two different seals, one for the intake and one for the exhaust. However when I went with my cam the LGM kit comes with all the same height seals. I called LG and they said because of the increased lift you want to go with the shorter eals on all valves as the valve is being pushed open farther.

BQuicksilver

Thanks Brian. I'll PM Tony Mamo...I got the heads from him. I've thought about the PR's causing too little oil up there, but I know there certainly is too much up there right now. I may do a little more research.

Cobra4B

My point is that restriced pushrods my treat the sympton but not cure the disease. If it's something like bad valve seals then putting in the restricted pushrods would be a bad idea as it wouldn't fix the issue and you'd have less oil gettnig to the top of the motor. See what Tony says, he's an expert on his product.

RogueVette

Exact same thing is now happening to me Brody.

Cobra4B

^ What heads do you have? Could it be an oil drainback issue? I know EG (england green) posted up about a mod to drill your lifter cups to let oil drain back faster.

BQuicksilver

Sorry to hear that Jeremy.

I think Dale had a good idea with the PCV and free air reroute into one of those breather catch cans. At least I know the intake is dry now.

Lots of reading tonight strongly points to valve seals, so I'm doing that next. I'll report back.

Brian, I think i'm going to wait on the pushrods until I see if the valve seals fix this. I'll report back.

I PM'ed Tony, so hopefully he'll get back to us here.

AU N EGL

Brody

You running a dry sump or accu-sump? and what wt oil are you using?

Put my accu-sump in March of 04 and have been running 15-w50 ( except In Jan 0-w40) and have not had oil blow by or oil in the TB.

I dont have a catch can ( I should) but the TB is clean.

Timz06

Quoted above, this is a very important point

If the heads are ported to the extent that the rocker bolts extend into intake runners (common) then you need to use Teflon sealant on the bolts not Locktite. An amazing amount is sucked down those bolts into runners.

I have hand ported heads, and all of my rocer studs thread into the intake passages. I was burning a ton of oil, and this was the reason. Take your studs off and put thread sealant on them, while you are doing your valve seals.

Ojustracing

Jeremy yeah I saw that at Beave run, I did think it was that bad from my Spot, but you werent there very Long

John

0Tony Mamo @ AFR

I'm actually away on vacation so excuse me if my response is a bit brief.

In short, I would change the obvious first....no thread sealant on the intake bolts is an oversight that needs to be corrected. Remove all the bolts and clean them with brake clean before applying a teflon paste sealant on the bolt threads.....then I would encourage you to replace the valve seals as well. You should use an AFR valve seal so your not worried about compatibility issues. There cheap (I think less than a dollar each) so order them from AFR directly when you get a chance.

Do both of those items first before you rack your brain another minute.

If that doesnt cure it my guess is your guides are worn and/or your ring seal on decel may be not up to snuff. The oil rings on the earlier LS engines were prone to allowing oil to pass them by (not enough tension on the expander rail) so you may be dealing with a lower end issue. Do the easy cheap stuff first....it may help or completely eliminate your problem. If not then its time to dig a little deeper.

Good luck....keep me posted

Tony

RogueVette

I noticed it at VIR in Feb, just a bit coming onto the front straight and in turn 1, then again and a little worse at BeaveRun mainly in 4 and 10, but this weekend at Putnam it was noticably worse, plus it's such a Right hand heavy track.

Brody let me know what works for ya' or vice versa if I get mine fixed first.

BQuicksilver

I don't have a dry sump or accu-sump yet. They're #2 on my list right now after a decent race seat.

I'm running 10w-30 M1. I've considered 15-50, but I'm not sure if it's a good idea for a dual duty street track car. Heck, I'm not sure if pretending a true dual duty car works either.

BQuicksilver

Jeremy, did you have issues with the Putnam Park staff during all this? After chasing this issue at three tracks now I noticed they were definitely the most nervous crew when it comes to smoke from the car.

Ojustracing

Jeremy I wasnt close to you at those points, I do remember seeing some from the turn 7-9 area(WOT), but I dont think heavy enough for you to see it from the inside your car. I was going to mention it to you,
and got sidetracked.

Sorry for getting off topic.
John