Smoke SHO

[Racer X]

And not in a good way, either.

I took the SHO up to New England and back this weekend, and tooling around back in NYC, I noticed smoke out the tailpipe.

Lots of smoke.

It's definitely oil (from color and smell), so I'm curious of how to determine whether I'm dealing with bad oil rings or valve stem seals.

Valve stem seals I'm not so worried about, as I have a spare set of heads that I can get cleaned, and then replace all the valve stem seals and guides. Anything else would make for a ****** spring involving pulling the engine.

Thoughts? :corn:

Thanks all.

 

[Ishodu]

Check to make sure the make up air hose on the front of the valve cover to the TB is free and clear as well as the hose under the TB to the top of the gallery. Did it start smoking lots all at once or over a while and work its way up to a peak?

 

[BaySHO Performance]

A leak down test would help determine what the problem is.

First, do a KOER cylinder balance test to see if there's a weak cylinder. Get a leak down tester, plug it into the weak cylinder's spark plug hole, apply compressed air and listen for where the hiss is loudest:

Oil Pan = rings
Exhaust Manifold = Exhaust valves
Intake = intake valves.

It can't test for worn valve stem seals. The leak down tester will also give an indication of what the compression is like in the cylinder being tested.

From your description, does sound like worn rings, I'm afraid. Valve stem seals wouldn't be putting out that much smoke.

 

[Racer X]

Worn rings would explain the slowly increasing oil consumption I've been seeing, and excessive oil in the intake tract.

The crop dusting when dropping a gear and going WOT was probably a good sign as well.

Although, on startup the morning after the excessive smoking at idle event, there was a large puff of smoke, followed by slowly diminishing smoke to the point where it's almost indistinguishable.

I'll perform the leakdown test and report my findings.

 

[SHOZ123]

Get some Auto RX and drive your problems away.

 

[Racer X]

Haha, Paul I did an AutoRx some months ago. I'm going to go ahead and say that we're past the point of a fix in a bottle.

In all honesty, I'm not 100% surprised that something like this would happen. I remember thinking to myself when I first opened up this engine a couple of years ago how clean the 220k mile 3.0L I was replacing was compared to the incoming 3.2L. The heads were barely golden on the 3.0L, where the 3.2L looked like it had lived it's life on molasses.

 

[chevrolet]

Its common for the oil control rings to carbon up and get stuck. If you pull the crossover off the intake you will see all the blowby that distilled itself in pools in the intake plenum. This is a sad reality for these old SHO motors. When you gas it hard the oil puddled in the front plenum dumps in and when you brake hard the rear plenum dumps in. The result is smoke & oil stink. There are no crankcase cleaners that will break up the very hard carbon deposits behind the oil control rings. The catylitic converters do a amazing job of hiding the smoke. The pistons need to be scraped out by hand, reringed and the good news is a quick hone is usually sufficiant. I was using a QT in 150 mi.

 

[Racer X]

Its common for the oil control rings to carbon up and get stuck. If you pull the crossover off the intake you will see all the blowby that distilled itself in pools in the intake plenum. This is a sad reality for these old SHO motors. When you gas it hard the oil puddled in the front plenum dumps in and when you brake hard the rear plenum dumps in. The result is smoke & oil stink. There are no crankcase cleaners that will break up the very hard carbon deposits behind the oil control rings. The catylitic converters do a amazing job of hiding the smoke. The pistons need to be scraped out by hand, reringed and the good news is a quick hone is usually sufficiant. I was using a QT in 150 mi.

Wow.

As many times as anyone has discussed oil consumption, and oil finding itself in the runners and surge tanks, this has to be the best answer I've seen yet.

Kudos, sir. What's your oil consumption look like now?

 

[chevrolet]

I put the motor back together and did an oil change after ten minutes of Idle/fast Idle and drove 145 miles to Brainerd International Raceway and pounded it. Did another oil change after the 6 fast laps(1 mile long staightaway W.O.T. 10 turns 2 3/4mi) and all was good. It went from 150mi to a qt. to 1500mi to a qt. on that engine that was very fast. I think all of them are fast. In stock trim. Only mods were port matched. K&N, & 70MAF, no cats. Oldsmobile muffers. I did rebuild the heads but no valve job. I just lapped the valves.

 

[Vnuk1]

I put the motor back together and did an oil change after ten minutes of Idle/fast Idle and drove 145 miles to Brainerd International Raceway and pounded it. Did another oil change after the 6 fast laps(1 mile long staightaway W.O.T. 10 turns 2 3/4mi) and all was good. It went from 150mi to a qt. to 1500mi to a qt. on that engine that was very fast. I think all of them are fast. In stock trim. Only mods were port matched. K&N, & 70MAF, no cats. Oldsmobile muffers. I did rebuild the heads but no valve job. I just lapped the valves.

So your from MN huh?

 

[chevrolet]

Yes sir, Born in Mpls. Worked for the city of Mpls for 17 yrs.

 

[Vnuk1]

So are you coming to the meet next sunday?

 

[chevrolet]

I sold all my SHO's and live in N.C. now. I drive a caddy(slowed down)and have trained on the course across from the prison at St. Cloud. The dopamine was gonna get me. Nice track there but hazardous and tight, ******* brakes. I made over a half century now and not pushing the envolope anymore. I am 1300 miles away. Not gonna make it. I would suggest you get envoled with the ACNA (audi club of north america) and you will be able to push your car to the limit on world class road race tracks. Its relativley cheap and you will have professional guidance by actual race car drivers. No shit. You will need an approved(snell rated) helmut. Thats about it. A little class room and you are doing 135 in a crown vic approching a downhill 90 degree 45mph turn. Good luck.

 

[Vnuk1]

Thanks too bad you don't live in MN anymore well enjoy the Caddy!

 

[chevrolet]

I know they put some beef in those crown vic's startrng in 04-05. Mpls started cycling them in and all of them had trick looking stuff by 06, 400 machines. Big brakes, alloy moving parts DOHC's 300hp sweet! We had to struggle with putting the gas tank plates on before.... Not unlike a Pinto.The drivers(cops) were worse. No mercy.

 

[SHOZ123]

I think you did not give the Auto RX enough chance. For one you do not want to follow the directions but extend the time it is in your engine by quite a bit. If you were to do ARX treatments for about 10k total on two bottle I think you would have gotten different results. And yes ARX will clean the carbon out from behind the rings.

 

[chevrolet]

BxxxSxxx, Too good to be true. Thats a fact unless you are selling the stuff. I thought so.

 

[SHOZ123]

No I don't sell it.

But had a '93 SHO that went through a quart every 500 miles. Get on the accelerator and plenty of blue smoke.

After using two bottles over a 6 month period the oil burning virtually had stopped and I was at a quart every 3k miles.

First bottle I went the 1500 mile and did an oil change like they recommend. Then went to a rinse oil for 1500 miles, second bottle I left in 5k miles.

I highly recommend it before ever tearing apart a motor for oil burning. You will get better perfromance and fuel mileage too when you are done. Also removes the thick sludge that covers everything internally.

 

[Racer X]

Just to follow up on this... AutoRx would not have helped the 22 out of 24 leaking valve stem seals in my heads.

Or the years of neglect in the block.

And as looney tunes as Chevrolet was (remember him?), he was right, there was a ton of carbon built up behind the oil rings.