White Smoke on Idle & Decel 4A-GE Turbo. Need opinion on oil drain.

[ballpencil]

Searched, but no satisfying answer.

Engine:
4A-GE Turbo with TD04H-15G Journal Bearing Turbo
RWD config (Daihatsu Charmant, similar chassis to AE86)
Low Comp 8.9:1 Pistons, if it matters.
Engine runs and pulls fine, making 125 RWHP at 0.55 Bar.

Problem:
No smoke coming out of the exhaust after cold starts.
Once engine has warmed up,heavy white smoke after about 5 sec of idling and puff of smokes just after deceleration (going down hill in gear).

Stuff done so far, with no success:
1. Change oil from 20W-50 to 10W-40
2. Put some restriction on the oil supply line to the turbo by making my own nipple bolt.

Original one is on the left, two holes of approx 5mm diameter on the side. Current one i'm running is on the right. Just one hole of 2.5mm on the side. Should be restrictive enough, especially since this is still journal bearing?

That leaves either restrictive oil drain line, turbo seals going bad or bad piston rings/valve stem seals? Really hoping it's not the latter as the engine had just been rebuilt a few months ago. What's the signs of each possible problem?

A note on the drain line. The engine is slightly tilted to the side (not exactly vertical) and causing the sump walls to slightly tilt down as well. This causes a minor kink on the drain line, i.e not exactly going straight down.


Here's a bad rendering of the condition


What do you think about my drain line? Is it too restrictive causing oil piling up in the CHRA? It's a 10AN line.

[fixeruperer]

you need a minimum of a 1/2" ID fitting, mounted at the highest part of the sump possible. the angle of the engine wouldnt help, but your return is far too small and probably the cause. what size restrictor did you use in the inlet ?

[ballpencil]

The highest part of the sump - already did this, as high as possible without interfering the sump bolts.
I looked inside the turbo oil inlet and noticed it already has some kind of restriction but right now the smallest restriction would be from the banjo bolt for the supply line. As i stated above, the banjo bolt/nipple is made from a normal bolt and drilled with 2.5mm drill bit. so i'd say that's the restrictor size?

I got the drain line from a taiwanese Ebay oil line kit.. 10AN is already 5/8 inch > 1/2 inch.. but yes, i'm already planning on working on the drain line next. If that fails, turbo rebuild comes next. If i have to take off the sump, what do you think about reusing the rubber seal? Or will a high-temp silicone sealant work as a replacement? I don't think i can get the sump seal easily here.

[trdee]

you can use high temp gasket maker for the sump, all good.

turbo drain pointing down like that is deffo not good. if you have blown seals you should be able to see oil residue in the inlet or exhaust housings of the turbo. have a looksee...

also you are not supposed to restrict oil flow to a journal bearing turbo.

[Keek]

Pcv :-) :-)

[ballpencil]

ummm.. i'm not running one if that's what you mean? from the valve cover vent, it goes to a custom catch tank and that's it. it doesn't get plumbed back to the intake manifold. that's ok right? no turbo pressure coming to the crankcase.. oh and i should say that blow-by is minimum so that ruled out the rings?

[fixeruperer]

yep as said, hitemp solvent resistant silicon will be fine. i just use that toyota black silicon.

and your breather line from cam cover to catch can is fine, but the catch can must have a breather on it also.

[ballpencil]

just took off the drain line flange attached to the sump.. some oil dripped out so no doubt it's piling oil and not draining properly. good thing no oil came out from the sump hole which means i'm above the oil level (engine is still cold which means all the oil should still be in the sump).

what bothers me is that with 2.5mm restrictor, i'm still burning oil. assuming valve stem and rings are ok, that means the supply line still feeds more oil than the return line can drain properly?

going to a welder now to make another drain pipe. i will update you with the result.

edit: catch can has breather. i'm using an old AC dryer bottle as the catch can.

[fixeruperer]

i doubt that return line can return enough through them little banjo holes, you need a min of a 1/2 hole !!!!.


i dont think you can use a receiver dryer as a catch can, as the dryer absorbs moister. once you get steam/ moister in that dryer it can block up.

[jonathan yee]

The banjo bolt is for the oil feed not drain as I understand, he has -10 for drain.

As somone already said, your not supposed to restrict oil feed to a journal bearing turbo, only ball bearing.

You more likely have valve stem seal issues.

[fixeruperer]

oh my bad. sorry.

valve stems if leaking, should smoke dead cold as its burnt oil. a turbo could leak when cold (but not hot enough to smoke) untill it warms up and start to smoke from exhaust heat.

[thechuckster]

are you getting oil accumulate in the intercooler or compressor outlet?

And, do you have a functioning PCV for the motor.

[Keek]

Moje ST185 měla stejný problém důsledkem odpojené PCV. Musí být zapojeno do sání. Zkuste to a uvidíte. Omlouvám se za jazyk. Použijte translator :-)

[BlackSupra]

+1 for turbo seal. Does it smoke when your on boost?

[ballpencil]

are you getting oil accumulate in the intercooler or compressor outlet?

And, do you have a functioning PCV for the motor.

i haven't checked for oils on the charge pipe. i'll go and check it when i've confirmed my new drain line doesn't work.
is PCV necessary? i mean, do i need to connect the catch tank to a vacuum source as well such as the compressor inlet?

just yesterday, i welded a new drain pipe for the sump, shown on the left. my old one was on the right. you can see the old one goes straight first before going upwards. the straight part caused oil puddling on the knee part.


ugly i know, but here's the drain pipe in action.

you can see now it no longer points down. goes straight up.
so far i'm not getting any smoke but i've just driven the car for maybe 15 minutes. not long enough to warm the engine completely. today i'll be driving for a few hundreds kms so that should show whether it works. i'll update you with the result.