[jmart]

Last weekend I pulled the y8 head off of my block and put the a6 head back on because I am leaving the country and want my car to be cali smoggable while I'm gone.

I cleaned the carbon buildup off the valves, lapped them and reinstalled them. Cleaned up the gasket surfaces and the ports a little too. Torqued it all down, put it back on with a metal y8 head gasket. I'm running a z6 intake on it as well. Degreed the cam, fired it up, and its been running great all week.

But today I looked in my side mirror as I took off on a left hand turn and noticed what looked like a little bit of smoke where I'd taken off. So when I stopped for some food I reved it while watching the tailpipe and sure enough the smoke was coming from me. Looks like greyish and heavy to me. Smells like either oil or fuel, I think.

This motor was running like a top 2 months ago in stock form before I started the mini-me swap. Never burned oil once. Always passed emissions tests easily. What gives? I don't see how I could have damaged the rings. Maybe I should have replaced the valve seals? This motor and head have about 130k miles on them total. Thoughts?

 

[tubafreak]

Is it just hand-oil residue burning off from the build process? Drive it again and see if it happens again. Could be a bad headgasket seal (although if you torqued everything down right it shouldn't be). Could be the valve seals, you never know.

 

[jmart]

Ya, so, um, I know its bad, but I was in a pinch and I reused head bolts.... Perhaps that is my problem.

 

[Tiersin]

I don't knowe about the validity of this, but the guy I get all my machining done from was telling me about metal head gasket sealing. He says that usually, to seal well, the head and block need a very smooth finish. This is due to the fact that the metal wont conform into the small little grooves left over from even a normal milling. It could definitely be bad valve seals though. I know that my car smoked and after I replaced the seals, it stopped for the most part.

 

[tubafreak]

The head bolts could do it. They'd need more torque second time around (although they're really a one-time thing). ARP studs are like $45, it might be worth it to spring for some of those.

 

[mattminerDOTcom]

ARP studs are more like 85, but theya re great.

[email protected]

 

[tubafreak]

I thought I'd seen them at Summit for $45. Might have been something else and my mind was just messing with me. Still a good investment.

 

[jmart]

Do they make stude in correct length for the a6 head? All I see int he catalog is for the z6 nd y8. Also, who is a good supplier of this? I'd need ot get them soon.

 

[jmart]

upon inspection last night here is what comes out of the tailpipe:

Light colored smoke constantly. But it doesn't smell as harsh and heavy as when I've seen cars burn oil due to leaky valve stem seals in the past.
Also, ablack watery mix is coming out and spraking the garage floor. Its not really oily, but more like water mixed with carbon soot. And it would shoot out quite bit of it.

I need help here.

 

[tubafreak]

A cloged cat maybe? There could be some sootiness in your cat and the water that's part of the combustion process could be washing that out the tailpipe. The light smoke could be any number of things, I'd still say check the cat.

 

['9445]

upon inspection last night here is what comes out of the tailpipe:

Light colored smoke constantly. But it doesn't smell as harsh and heavy as when I've seen cars burn oil due to leaky valve stem seals in the past.
Also, ablack watery mix is coming out and spraking the garage floor. Its not really oily, but more like water mixed with carbon soot. And it would shoot out quite bit of it.

I need help here.

Well, since we're on the headgasket sealing here, have you checked your coolant level? White smoke could be just steam, i.e. coolant leaking into a cylinder. However if that's happening, you should also be getting some leakage the other way, i.e. pressure into the cooling system. Try starting the engine with the radiator cap off (from cold of course) and see if you get any strange bubbling and burping (this could be a messy experiment)

Reminds me of my first headgasket job ... a friend's '78 civic 1200 was running ok but wouldn't keep coolant in the radiator because the pressure from the leaky headgasket would just blow it out of the overflow. We did it in an afternoon in his apartment parking lot. No oil in the coolant though ...

 

[jmart]

Latest update:

1) Oil level is low (first time this has ever happened in the past 30k miles that I've owned it).

2) Coolant is low (also a first).

3) Compression test yield ~155psi in all four chambers (tested hot and cold).

4) Lots of wet sooty mes blowing out of the tail pipe at all rpm, and light smoke constantly.

5) Reused head bolts.

6) Metal head gasket.

7) Head surface probably scratched a little by me try to remove that darn steel core paper head gasket.

THis seems to indicate that my valve seals are fine as are my rings. The only way, it seems to me, for me to be burning oil and coolant at the same time is that my head gasket isn't sealing as a result of imperfect head surface everywhere and inadequate clamping force from the re-used head bolts.

Unless anyone has any other ideas I'm going to order another steel core laminate head gasket (probably felpro because its cheap and quick) and some arp head studs from Summitracing.

 

[downest]

Though I hate to recommend it, the papery stock headgasket might be better in this case. I think it would conform better to imperfections, since it's more pliable and thicker than the MLS one. You'll be leaving the car with someone at home right? I don't think your mum is going to wail on the A6 while you're gone... and when you come back from England it's getting the Y8 head again, right?

 

[jmart]

Well Tom, I'm unsure about the y8. Not because I don't want to do it nd have a crazy na d-series. But see I'm in California and I have to pass rigoous emissions testing unlike you rufeans out there in NH. So we'll see. If I cn import a ukdm crx back with me, this car will stay d for life. if not it may see a b in the future...

 

[jmart]

So, after much discombobulation over this smoking, running rich and severe oil burning condition of my car I am convinced that my ring, or at least my oil control rings are bad. Here is my reasoning (without giving thought to possible causes):

1) Smoke gets worse the higher the rpm, and there is a lot of it.

2) There doesn't appear to be any large ball of smoke on startup that would be symptomatic of even minorly bad vavle stem seals, let alone ones abd enough to be billowing out smoke at high rpm.

3) There is no coolant loss, or mixing of oil and coolant, which seems to eliminate the head gasket. Plus its been replaced just to be sure. I'm now a pro at high speed d-series head swaps, with minimal mess!

4) When I loosen the oil filler cap while its running I feel a ton of positive pressure that seems to me to be more crankcase pressure than there should be. The valve cover vent is clear and feeding into the intake, and the PCV valve is good.

5) MY compression test yielded 150-155psi in each cylinder which I initially thought was good until I actually looked up the d16a6 spec of 185psi. :/

Does this seem like a logical conclusion to anyone else?

Now, on to the possible causes. I had none of these problems before the y8 head swap. Is it possible that detonation from an ill-timed mini-me running 10.3:1 compression could have toasted my rings, or worse, my ring lands?

Bah. Anyone else have anything intelligent to inpout here? THis has been and will continue to be the beign of my existance until i know for sure what it is.

 

[andystart]

Could it be just the oil rings being coked up?
I have similar symptoms to yours. I replaced the valve seals without success. I have 160 psi in each cylinder which, supposedly, is within tolerance.