Rebuilt B6 burning oil
 

Hello MT.net,

I'm posting here because I'm stuck with a problem that I can't find the real culprit. Before making any more moves ($$$) I need opinions from experts.

So last year the engine was smoking oil on decel and oil cosumption was kind of a big deal. So I decided to rebuild my 1.6 following advices from good friends and the interwebs.

So I ended up with new ACL bearings, de-glazed cylinder, OEM rings and Supertech valve seals. Valvetrain rebuild was done at reputable shop near my place. As for the bottom end, I was done by myself. Everything was in specs... A regular engine rebuild with brand new gaskets.

So here's the problem :

- Engine is burning oil on idle 3-4minutes after startup.
- Engine is burning oil when idling.
- Engine is burning when starting from a full stop.

Here's some facts :

- Break-in was done using FM insctructions. Dino oil + high vaccum + RPM variation + etc.
- I get 210psi compression on each cylinders.
- I tested 10W-30 and 20W-50. Looks like it got a bit worst with the 20-50. All dino oil for now.
- It's not the turbo. I removed the CHRA and installed a plug with same result (see image : https://i.imgur.com/kkCW5Mk.jpg)
- No more PCV valve. Everything is connected to a catch can. Catch can is pretty much empty.
- I reinstalled PCV valve. Same result.
- Car is not burning oil in decel and while boosting.
- If I bring the car up to 6000rpm, let it coast and hit the gaz pedal again... nothing.
- Looks like it's smoking a bit more after staying a long time at a red light.

Some people blame the rings, other the valve seals. I'm lost right now.

Here's a video of the car running. Note the car burning oil on redlight and stops sign. No smoke while boosting or in decel.


Thanks for your help MT.net!

CAT TAX (My cat Rocky)

Attachment 233229

Scope the bores for cylinder wall scoring or polishing. Last time I saw a car smoke at idle, one of the cylinders was worn completely smooth.

Your rings haven't seated. Scoring or polished cylinder walls as stated.

Also, you mention "deglazed" cylinder. Did you do that yourself? How?

Angle of cross hatches can either contribute to accelerated wear (too shallow) or oil pumping (too steep). That's the kind of thing I would entrust to a good machine shop.

Thanks for your input guys.

I forgot to say that I drove 1200 miles since rebuild. As stated on FM site, the first run is the one that seats the ring properly... I guess if that failed, I can't expect to get the problem fixed by itself in the next thousand miles.

As stated ealier, I'll try to get a view at the bore and see if anything shows up.

So far I'll keep the whole thing running as it does right now... I'll pull the engine out next winter and see what I'll do about it. Right now, it's racing season. ;)

Nope, I sent the bottom end to a machinist to take care of it because I didn't want to screw this part up. Which in the end, I did.

I checked closely, patern was good. Instructions to the machinist were clear : it's a simple ring job so just de-glaze the bores, that's it.

One thing that might have happened is he removed too much material off the bores. Once the engine came back, I didn't have the gauge to check cylinder measurements.

At least, I'm learning ;)

Ive got the same problem, check the turbo if there is oil in the piping to the intercooler.

My turbospecialist was thinking it was probably the crankscase pressure wich was to high. When boosting the pressure in the piping is higher than the crankcase and also in the turbo. So it wont leak. When deaccelerating or idle the crankcase pressure is higher then the pressure in the piping and then it will leak trough the oil seals of the turbo.

I hope this weekend i can solve it with larger ports for the crankcase ventilation.



Also rebuild forged engine and a brand new core for my TD04L


I didnt read everything and you already checked. But this was my problem

My guess is he used the wrong grit hone. Likely, he honed it rough, with say a 220 grit hone, and then you installed new chrome rings and the rough pattern damages the rings, causing what you just described.

speaking from experience..........

Ask your machinist what grit hone he used.

Will do! Thanks

I've recently build my engine (first time doing that!!) and it burned a lot of oil after idling or high vacuum. It didn't smoke while wot.

After a lot of searching, I found that 4 intake valve seals were not installed correctly and popped out (floating)
I'm pretty sure that I installed every one, but it was like midnight, maybe I was simply sleepy...