Blue Smoke

[B Fa SHO]

I went to look at a 94 ATX SHO for my friend and everything looked good. The engine revved smoothly but the only thing that stuck out was the smoke from the exhaust. I'm not sure if it's from the car sitting in the lot for days/weeks??? or if it's a big problem.
I did a search and it seems that everyone suggests the valve seals are shot as an indication to why blueish/white smoke would be exiting the exhaust pipes. How hard of a job is it to fix and what kind of money would be involved?
Thanx in advance,
~BW~

 

[MotoArts]

Yes, smoke on startup (puffs, then quits) is usually valve seals. Continuous smoke on acceleration or deleceration is usually piston rings or faulty PCV system. Also consider potentially fouled converters and/or O2 sensors. The car sitting on a lot will not cause oil smoke. Don't believe the salesman if he tells you that. That's why he's a salesman and not a mechanic. wink

Valve seal change shouldn't be a bad job, just time consuming. Piston rings, on the other hand... eek! headbang

 

[SHODWN]

Really? Thats a new one. My 92 dont smoke a bit if its run alot. but if it sits for over a month it smokes like a bastard. and a round trip to Tulsa costs me only 3/4 of a qt.

 

[B Fa SHO]

What would a valve seal change require? Is tearing down the engine necessary?

 

[Rockledge]

How long did the motor sit for?

How long did it smoke for after it was first started?

Did it smoke during hard throttle or when downshifting when the motor was warm?

These are important things to know, I would think.

And how about starting it up and driving it the next day? Can you do that? If it smokes again at startup the day after being run well, then you might have issues like MotoArts says.

My SHO sat for about 3 months before I came along. I know this because I drove past it every day and saw it buried in the middle of a used car lot. When I eventually asked the dealer if I could take if for a spin, he couldn't even find the keys at first, all the tires needed some air, the battery was dead, etc.

Anyway, the first time I started my SHO it blew some blue smoke which cleared up after a short while. I took note of that and went for a good ride, looking and listening for all the other things you do when you're test driving a used car.

As you can probably figure, I became interested in the SHO and decided to follow up on it. The next day when I started it, no blue smoke. And the next time I started it after that, a few days later, still no smoke. And I haven't seen it since.

 

[B Fa SHO]

I have no idea about the history of the motor or how long it's been sitting there. It's at the dealership, so I'd assume a couple of weeks because the guy said he recently got it. Haven't taken her for a spin yet, I planned to do that next time we checked it out. It smokes at idel (not violently, but the exhaust that comes out of the pipes is white/blue smoke. Then when I popped the hood and had my guy goose the throttle, there was a noticeable amount of smoke out of the exhaust. That's why I'm hoping it's not a major problem because if it is it wouldn't be worth going back up there to show more interest in purchasing it for him. Guess we'll have to run her for 5-10 minutes and take her for a spin and see if it goes away.
Thanx all for your help
~BW~

 

[SHOguy 92]

Hey, how did you pop the hood have the guy hit the gas and watch the exhaust? Anyways, I burn a quart ever 400 or 500 miles. It seems to be under accel and not at idle. At idle the smoke is white. But if I downshift a puff comes of blue comes out thats if I am going from 5th to 3rd you know. I'm thinking piston rings, how much would that cost me for a shop to do it if I pulled the heads off for them. I mean how much are rings and how long would it take them to stick on the rings if the heads are off for them? Also do they hve gaples rings I could buy for the SHO?

 

[DHMag]

to replace the valve seals, you have to remove the heads. to remove the heads, you need to....*deep breath* drop the y-pipe (removal not necessary), remove intake, remove fuel rail, front manifold comes off, rear manifold comes off with the head then seperated outside the car, cam covers off, remove heads from car, remove the cams, valve buckets, then using a suitable compressor or equivalant, remove the valve springs and keepers. remove the valves, then you can remove the valve seals. the entire job took me about 20 hrs. 5 hours complete disassembly, 10 hrs on seals, valve gapping, and carbon cleanup on valves and chambers, 5 hours reassembly.

 

[SHODWN]

DHMag:
to replace the valve seals, you have to remove the heads. to remove the heads, you need to....*deep breath* drop the y-pipe (removal not necessary), remove intake, remove fuel rail, front manifold comes off, rear manifold comes off with the head then seperated outside the car, cam covers off, remove heads from car, remove the cams, valve buckets, then using a suitable compressor or equivalant, remove the valve springs and keepers. remove the valves, then you can remove the valve seals. the entire job took me about 20 hrs. 5 hours complete disassembly, 10 hrs on seals, valve gapping, and carbon cleanup on valves and chambers, 5 hours reassembly.

why would you go through that to replace valve seals?
The Y pipe and the heads do not have to come off.

 

[B Fa SHO]

SHOguy11:
Hey, how did you pop the hood have the guy hit the gas and watch the exhaust?

There's a lever on the intake that you can move to rev the engine, and I was at the back of the car while my guy was doing that.

 

[SHOguy 92]

Oh, thats how you did it. Ok, don't get why that way, but I just had to ask.

 

[B Fa SHO]

We popped the hood to take a look at the engine, it was already running, so why go back in the cabin to rev it. wink

 

[DHMag]

SHODWN:

DHMag:
to replace the valve seals, you have to remove the heads. to remove the heads, you need to....*deep breath* drop the y-pipe (removal not necessary), remove intake, remove fuel rail, front manifold comes off, rear manifold comes off with the head then seperated outside the car, cam covers off, remove heads from car, remove the cams, valve buckets, then using a suitable compressor or equivalant, remove the valve springs and keepers. remove the valves, then you can remove the valve seals. the entire job took me about 20 hrs. 5 hours complete disassembly, 10 hrs on seals, valve gapping, and carbon cleanup on valves and chambers, 5 hours reassembly.

why would you go through that to replace valve seals?
The Y pipe and the heads do not have to come off.

Kirk,
i was chasing a mysterious smoking condition. replaced head gaskets too (well, all gaskets on top end). and unless there is a valve stem seal removal tool, i found it easier taking the valves out to remove/replace the seals.

 

[SHODWN]

Yep there is a tool just for that, it comes in the esentials took kit for the v6. Its pretty easy to do to, just need the adaptor to charge the cylinder with air (not in the kit) then just pop the keepers and have at it..

I sold my kit years ago, otherwise I would get you the part number, incedentaly I did try to buy another last night but was out bid at the last second by a few A$$holes.. (rant) I hate snippers and people that dont have a life or the software and sit there untill the last second. I beleive if you want something bid what you want to pay for it when you see it..

ANyway back on topic Crane has a great write up about stem seals and what they do.. They are actually made to leak a bit to keep the lower half of the Valve train lubed up. cars that sit a while will leak into the combustion chambers.

So judgeing a car that has sat a while bed because it smokes is not tottaly correct.

 

[DHMag]

not everyone owns the "essential tool kit" for the SHO.

<small>[ November 28, 2003, 02:23 PM: Message edited by: DHMag ]</small>

 

[SHODWN]

Uh thats why its called Essential thumb