Smoking ABY Avant

[volcano rs]

my intercooler is clean but i'm having same problem as you .i've been told it might be the rings that need bedding in .

[quattronutter]

had similar troubles on an old lancia,turned out the intercooler was half full with old oil,best thing to do is give it a good clean out with some petrol...

[T2Andy]

Would changing the oil viscocity help matters ,ive found it help my S2s to a certain degree.

[~Delta]

I've tried 15w - 40 and even real nasty thick stuff, 20w - 50, no joy. I'm dropping the intercooler tomorrow, give it a good swill out with petrol, hope thats all it is, oil residue.

[Corey]

oil residue.

It's not actually oil residue, although it does contain some, it is mostly fuel condensate.

[~Delta]

At last! For the first time, the Avant now idles and drives clean, hot or cold. No more smoke!

I have had to modify the breather, and now have more negative crankcase pressure (vacuum) at idle. It's more to do with certain specs of bigger turbos, not rings needing to bed in. Volcano if you need a detailed description, get in touch, you may well be experiencing the same problem.

[AndyP]

Delta,
Can you post up what you did to this car? I have a similar problem with my 3B coupe and I'd be interested to know what you meant when you said you 'modified' the breather.

Andy

[s2avant95M]

[~Delta]

I created more negative pressure (vac) in the crankcase as follows, this an ABY, but procedure should be similar for ADU / AAN / 3B:

1) Disconnect the breather to turbo intake boot and plug the boot.
2) Fit a one way valve from the rocker, making sure vacuum will CLOSE the valve TOWARDS the rocker cover.
3) Locate the metal "cup" on the engine block (right hand side when facing engine).
4) Pry cup off and drill a hole, large enough for a one way valve to be fitted. Make sure the valve is fitted to ALLOW vacuum to be drawn through. Replace the cup
5) Connect the other end of the valve into the intake manifold, using a T-piece into existing vacuum lines AFTER the throttle body.

That's it. On idle, there will be more negative pressure on idle, all oil mist will be drawn back into the crankcase. Under boost, the one way valve connected to the block closes, preventing the crankcase from being pressurised. It's a trick used on rally cars, but they fit the vacuum line to the dipstick tube as opposed to the block as described above, but not practical on a road car - you'll need to remove the connection each time you check the oil level.

The one way valve I used at the front of the rocker cover I purchased from a local firm, Engine Advantages, they also have a decent 4WD RR. The valve I used on the crankcase is a one way valve from a vacuum brake servo.

[Jamo]

I've got a customers '93 Avant, he thought the turbo was whistling badly, so he decided to bring it down for a replacement.

Initial diagnosis, when the engine was revved, on the overrun (in neutral) there was a 'whistle', akin to an intake leak. The car has done 130,000 miles. I removed the turbo, and I've never seen anything like it. The turbine wheels were seized solid. So, while I doubnt the whistle on overrun wasn't related to the turbocharger, it was certainly dead. The induction pipe and the boot which connects it to the throttle body were absolutely dripping oil. My customer said it did smoke a little on occasion (a little?)

I took it to my local turbo recon. company, whom I have used for many years, and have always found very helpful. They too tried to turn the comp. wheel by using a socket on the retaining nut, and shock, horror, the nut actually detatched from the shaft! I'm not sure how tight it was, but if it was easier to loosen it rather than turn the shaft, it must have been pretty hard for the exhaust gasses to move it.

2 days later (yesterday morning), I collected a recon. unit, a spec I have used in the past with no problems. It's a K26 - 6411, with a slightly larger comp. wheel than the stock K24, and definitely a larger hot side. Fitted the unit, and fired the car up.

1 minute on idle produced plumes of blue smoke, which I presumed was the residue in the induction system and probably the intercooler. I took it for a test run. It pulls very strongly, not as low down as the stock K24, but not as high up the rev range as an RS2 either. It pulled strongly and revved cleanly to 7,000 RPM without any flat spots.

On returning, the smoke had dissappeared, running really clean. Left it stood for 10 minutes, restarted and lo and behold, that offending blue cloud was back again. It takes about half a mile of driving to clear, and it appears to be ok, even after mixed driving, which lasted fo 2 hours. When cold, the 'whistle' on overrun is evident, last about 5 minutes into the warm up phase, when blipping the throttle doesn't produce the noise.

I have now fitted the same turbo to another ABY, and guess what? No smoke! While it was off the Avant, I checked the oil return pipe for any obstruction, and made sure the oil was at the right level. I have since carried out an oil change, but refitting the turbo still produces oily smoke. I'm not sure if it requires a long, hard run, possibly oil still in the cats? (they'll be knackered then) or in the intercooler?

The owner says he keeps losing water, he can see drips where it's been parked, possible headgasket? I'd appreciate some feedback on this, before I literally put my fist through the screen.

Was this a dark blue Avant owned by Frank?

[Greg_S]

Most of saturday was spent correcting these modifications so that the car was stock again. the intake pipe connection to the breather had been chopped off and was sucking air in after the MAF. the oil breather was venting to air and oil fumes were getting onto the exhaust.

I know this is done on oil catch tanks, but it doesnt vent oil fumes onto the exhaust then.

The PCV valve was replaced for one that hadnt been drilled.

After these corrections the car ran alot better.

I created more negative pressure (vac) in the crankcase as follows, this an ABY, but procedure should be similar for ADU / AAN / 3B:

1) Disconnect the breather to turbo intake boot and plug the boot.
2) Fit a one way valve from the rocker, making sure vacuum will CLOSE the valve TOWARDS the rocker cover.
3) Locate the metal "cup" on the engine block (right hand side when facing engine).
4) Pry cup off and drill a hole, large enough for a one way valve to be fitted. Make sure the valve is fitted to ALLOW vacuum to be drawn through. Replace the cup
5) Connect the other end of the valve into the intake manifold, using a T-piece into existing vacuum lines AFTER the throttle body.

That's it. On idle, there will be more negative pressure on idle, all oil mist will be drawn back into the crankcase. Under boost, the one way valve connected to the block closes, preventing the crankcase from being pressurised. It's a trick used on rally cars, but they fit the vacuum line to the dipstick tube as opposed to the block as described above, but not practical on a road car - you'll need to remove the connection each time you check the oil level.

The one way valve I used at the front of the rocker cover I purchased from a local firm, Engine Advantages, they also have a decent 4WD RR. The valve I used on the crankcase is a one way valve from a vacuum brake servo.

[S2central.net]

Urr yes - I spent the most of Saturday afternoon undoing this so called modification (with Eric's help too).

Lets just say it is not one that mod I would like to see again. Crankcase fumes and oil vapour were blowing out to atmosphere just ahead of the exhaust manifold - no wonder it smoked... Never mind the oily mess in that side of the engine bay.

It had been implemented such that joints weren't airtight - causing boost leaks in some places and unmetered air intake in others.

Using the parts we had available to us (thank goodness had a spare PCV valve) we were able to get the car back to normal configuration and it ran just fine.

There was some smoke still apparent - which we put down to the amount of it around the engine bay, but we also suspected a leaking oil connection on the turbo - perhaps not sealed properly. A leakdown & compression test would be needed to determine if the head gasket, rings and valve guides are all OK, but time did not permit.

The other weird thing about this car was that someone had 'modified' the airbox by cutting huge holes out of the bottom of it - presumably in an attempt to breath better but the location of the airbox above the exhaust is such that it would suck in mostly hot air unless a coldair feed was ducted into this area.


Paul

[Jamo]

Bry has an RS2 airbox for sale.

Yeh we looked at the turbo as well and it looked standard not a K26

[S2 Ant]

Sounds like great handy work here then

Garage meet saves the day again!

[S2central.net]

The one way valve I used at the front of the rocker cover I purchased from a local firm, Engine Advantages, they also have a decent 4WD RR. The valve I used on the crankcase is a one way valve from a vacuum brake servo.

The so called valve at the rocker cover was nothing more than two pipe adapters screwed together - it was a straight thru connection.

Paul