What's causing the smoke???

[rodpaslow]

I have my '92 1.6 td apart again after a recent rebuild and all internally looks fantastic.  I used prothe pistons and after about 20000 km they look fine, rings were loose after I pulled the pistons out no broken ones, and no bad scratches in the cylinders.  All looks fine. (rebuild was done .5mm over)

The problem that let me to do this was after a 20 min run, sitting in traffic at a stop, smoke would start billowing out of the tail pipe pretty bady and the smoke smelled like burnt oil. 

I want to confirm my what I'm thinking - I have a new VNT 17 and the drain came off at a 90, then I had a loop downwards with -10 an hose into a drain in the center of the pan.  Would 90 fitting cause the turbo drain not to drain fast enough and blow or have oil go past the turbo seals?  Is that what was smoking?  turbo maybe has 1000-2000 km on it.

[R.O.R-2.0]

I have my '92 1.6 td apart again after a recent rebuild and all internally looks fantastic.  I used prothe pistons and after about 20000 km they look fine, rings were loose after I pulled the pistons out no broken ones, and no bad scratches in the cylinders.  All looks fine. (rebuild was done .5mm over)

The problem that let me to do this was after a 20 min run, sitting in traffic at a stop, smoke would start billowing out of the tail pipe pretty bady and the smoke smelled like burnt oil. 

I want to confirm my what I'm thinking - I have a new VNT 17 and the drain came off at a 90, then I had a loop downwards with -10 an hose into a drain in the center of the pan.  Would 90 fitting cause the turbo drain not to drain fast enough and blow or have oil go past the turbo seals?  Is that what was smoking?  turbo maybe has 1000-2000 km on it.

my drain has a 90* bend in it, and my VNT doesnt smoke..

[libbydiesel]

Is the supply at 12:00 and the drain at 6:00?

[theman53]

I think your 90 could possibly make that happen. Another thing I have heard from my truck diesel buddies is run at least one size bigger hose on the drain side as you do the feed. Their thinking is it will never be a problem unless it is blocked...It shouldn't even be under pressure, but I see their logic.

[R.O.R-2.0]

I think your 90 could possibly make that happen. Another thing I have heard from my truck diesel buddies is run at least one size bigger hose on the drain side as you do the feed. Their thinking is it will never be a problem unless it is blocked...It shouldn't even be under pressure, but I see their logic.

my feed line is 1/4" id.. my return is 3/4" id.. thats alot more than one size bigger..

[theman53]

I similarly have a 1/4" ID feed and IIRC 7/8"ID one wire suction line for the return. I tend to practice overkill as I have found there is no such thing as underkill. I was thinking since mine entered the pan instead of the block if there was any back flow the extra volume would be a good thing. I don't know what I would recommend for a regular build, but I definately would go bigger than the feed.

[rodpaslow]

I don't think the drain is undersize -10 an line is 5/8.  Regaurdless, I'm changing to a aluminum line 1/2" id and getting rid of the 90 and going to a 45 out of the drain of the turbo.  It's a vnt 17, so roughly the feedline is 1/4" id and this drain is double the size with feed and drain being roughly 12:00 and 6:00 positions.  This is a new turbo purchased from Kerma, and I didn't re-clock the turbo main body at all, I just moved the position of the cold side.

I don't know what else would cause that type of smoke, because internally engine looks fine.

[libbydiesel]

Any possibility that the mesh in the valve cover is plugging?

[rodpaslow]

I though about breather system too.  I have a 1" line coming off the valve cover (g60 cover) going to a Provent 200 unit.  It has a check valve in the drain line as instructions show, and goes into the front of the oil pan near the oil pump.  There is also a 1" line going to the intake. this line is about twice as long as the oem one.  I have this unit just behind the rad, so when it's winter it would hopefully get some heat from what's coming off the rad to keep from freezing.

If I take the top off the provent 200 at idle there is a bit of stuff coming from it, but not much.  What's nice about it, is if blowby is too much it has it's own release valve, but it has never opened as the outside of the unit is clean.

The other this is the smoke smells real bad like its burnt, not like if your engine burns oil, it's a different smell than that.  I've removed all the pistons and all the rings, even the oil rings were intact, no issues (they were grant rings, not what came with the pistons).