Help please...smoke under valve cover.

[Steve95GST]

Alright, here's my problem... ( see bottom of post for reader's digest version**)

Just got a built 6-bolt swapped into my 95 GST. Shortly after, I blew the headgasket (only thing that wasn't aftermarket on the entire engine, go figure ) so it was replaced with a 4-layer metal HG from Mitsu.

After changing the head gasket out, I started the car up, and besides the idle surge I was experiencing prior to the HG blow, it ran good, and sounded good. Shortly thereafter (before I even drove out of the garage ), I heard a cracking noise, at which I turned the engine off. Inspected everything over and under and noticed a small hole in the lower timing cover just below the oil pump sprocket. Upon further inspection noticed that a broken piece of bolt had fallen into the timing cover during re-installation and had caught on the timing belt and shot out of the cover. Checked timing, its was still perfect, so the timing belt didn't slip off, but it put a gouge in the belt. So I went about changing the timing belt. Now I start it back up and noticed the idle surge, and high idle, again, but still sounded good. Turned it off and checked the timing again, and it was still perfect. So I mess with the idle settings on the MAF-T and then take it for a test drive to see how its running.

Now here comes the problem...when I come back I noticed a little oil around the oil fill cap so I take it off and find some white smoke pour out. After letting it out, I started the car again and check the oil fill cap again, and more white smoke coming out. It almost smells like exhaust. Now I'm aware of blow-by and what not, but it seems a bit excessive for a newly rebuilt engine. The only negative thing that happened was after the timing belt change I let it overheat slightly on accident due to the temp sensor being unplugged (totally different story), and the only other thing that is out of normality is that when I topped off the oil before I took it for a drive, I over filled it slightly.

**To sum it all up...

Freshly built 6-bolt swap into 95 GST, high idle, and idle surge experienced (beleived to ISC, problem is being diagnosed). Blown stock headgasket, replaced with mitsu 4-layer HG. Broken bolt put hole in timing belt after HG replacement, and Timing belt changed. Overheated car once, and oil is slightly over filled. Now experiencing white smokish vapors from oil fill hole in valve cover, but seems a little excessive for blow-by on fresh engine.

Any input, help, or suggestions would be greatly appreciated. Thanks for your time...

 

[chrisfullwood]

sounds odd, but you might check the compression on it.
maybe the cracking noise was a valve cracking, and thats why your seeing exhaust gas.
as far as i can imagine, that would be the only way for you to be seeing exhaust gas from the valve cover. unless the head cracked.

good luck.

oh, by the way, often on a hot engine you will see some smoke come from the valve cover, thats normal. but it depends on how much you will see, you shouldnt see much.

 

[romeen]

Your PCV may be plugged up. Unscrew it from valve cover but leave it hooked up to the IM. Use your finger to check for vacuum at the snorkel end while the car is idling. Also make sure that the hose from the valve cover to the intake pipe is hooked up.

If these check out ok then you may want to check compression.

 

[oldman]

oh, by the way, often on a hot engine you will see some smoke come from the valve cover, thats normal. but it depends on how much you will see, you shouldnt see much.

No, that is not normal, that usually means your crankcase ventilation system (pcv/breather) has been compromised.

 

[Steve95GST]

So when I got off work, I took the car out to warm it up for about 5 mins. Got back to my shop, opened the hood, and sure enought I opened the oil fill cap and more smoke. So I did a compression test and here are the results:

(From cam gears to thermostat housing)
193 psi
190 psi
191 psi
192 psi

If I'm correct thats pretty high compression(Per vFAQ, the standard compression is 164, with a service limit of 121). I'm completely lost, and not sure where to go from here... Thanks for your time.

 

[Steve95GST]

Also, the PCV valve is brand new, I replaced it first, and it did nothing to help the problem.

-Steve

 

[oldman]

Also, the PCV valve is brand new, I replaced it first, and it did nothing to help the problem.

-Steve

Is the PCV routed to your intake manifold? Is the breather routed back to the intake pipe?

 

[Steve95GST]

Is the PCV routed to your intake manifold? Is the breather routed back to the intake pipe?

I'll have to check on that to make sure of the exact routing of the PCV, but the breather is not routed back to the intake pipe, it just has a small filter on it.

-Steve

 

[Steve95GST]

Ok, forgot to check the PCV route when I was working on it the other day.

Does anyone think that these problems could be from using a MLS headgakset without maching the block and head?

-Steve

 

[Talesin]

Well, you're supposed to machine the block and head before going to a metal HG, otherwise it can end up not sealing correctly. From your comp test it looks like it shouldn't be a problem though. And if you're going with forged pistons, the compression can be a bit higher. After having mine built, about 10K miles later it was still reading 184-186 after it has a chance to heat up and seal.

Make sure the vac line to your PCV isn't blocked, and replace the PCV (they're cheap and take two minutes to swap). Then make sure that your breather filter isn't blocked.. take it off and blow into it, make sure air can flow through easily. I'd also try checking the breather nipple on the VC, but can't think of an easy way to really do that, aside from maybe poking a rod in if you have one of the type with a straight nipple.

 

[Steve95GST]

Well, you're supposed to machine the block and head before going to a metal HG, otherwise it can end up not sealing correctly. From your comp test it looks like it shouldn't be a problem though. And if you're going with forged pistons, the compression can be a bit higher. After having mine built, about 10K miles later it was still reading 184-186 after it has a chance to heat up and seal.

Make sure the vac line to your PCV isn't blocked, and replace the PCV (they're cheap and take two minutes to swap). Then make sure that your breather filter isn't blocked.. take it off and blow into it, make sure air can flow through easily. I'd also try checking the breather nipple on the VC, but can't think of an easy way to really do that, aside from maybe poking a rod in if you have one of the type with a straight nipple.

Ok, thats somewhat good to hear about forged pistons, I was actually a little worried about the compression being so high.

I checked the oil on it the other day when I was working on it, and it was about 1 1/2 quarts low, when I know I had overfilled it before all these problems. So its burning oil, somehow, in some way...

I'll give these a check, and report back.

Thanks again!

-Steve

 

[Clutch GSX]

I'm having the same problem. Did you ever figure out what was causing this?

Thanks,
Ryan

 

[BLINKY619]

So when I got off work, I took the car out to warm it up for about 5 mins. Got back to my shop, opened the hood, and sure enought I opened the oil fill cap and more smoke. So I did a compression test and here are the results:

(From cam gears to thermostat housing)
193 psi
190 psi
191 psi
192 psi

If I'm correct thats pretty high compression(Per vFAQ, the standard compression is 164, with a service limit of 121). I'm completely lost, and not sure where to go from here... Thanks for your time.

damn man when i had my 6 bolt swap... it had 210 across but one cylinder had 205 witch had nice compression... now it only has 190