nofrills

Hey guys, just a few questions. I've got oil backing up through my turbo and pouring into the exhaust. Rebuilt the turbo and replaced all the seals etc, still the same problem.

I hooked a hose up to the feed line on the turbo and blew through it, I can hear air hissing out of the return fitting, but there seems to be a fair bit of restriction. I realise that I'm blowing through the journal bearings (HT18 core), so should I be worried about it being restrictive? Should I be able to blow freely? Because this is very much just a "hssssss". The turbo was stripped, cleaned and inspected by a proper shop, so presumably they dug out any carbon in the galleries.

The only other possibility I can think of is that I've put in a much lighter weight oil than the previous owner has been using (this is my first oil change after buying the car), I put in 15w-40, temperature ranges here are very mild. Would going up to 50w make any appreciable difference? Just wondering if the thinner oil is running through the turbo faster than it can be returned...

The turbo is on a slight angle to facilitate thermal siphoning, but it wasn't smoking prior to the oil change, so I'm not sure if that's a problem.

nofrills

UPDATE:

I just disconnected the oil return pipe and ran it up, there's a small but even flow of oil coming out of it, probably 100ml over a minute of running. At the same time, the smoke cleared up. I reconnected the line, and took the car for a drive up to the top of the driveway, and the smoke had cleared up altogether. I wonder how much of it was residual oil burning off.

Anyway, I turned the car around and gave it a decent rev up, and smoke poured out of the exhaust again. I wonder if I should fit a restrictor to the oil inlet?

ArmyOfOne

iTrader: (12)

Are the vent tubes at the oil filler tube capped off? If so pull the dipstick up while it is smoking and see if you hear pressure. Those lines need to be vented to a free venting catch can. Saw the same thing a few weeks back.

mono4lamar

iTrader: (32)

Going to a thicker oil will only elevate your problem. It sounds like there's too much oil pressure, too much oil volume, or the turbo is damaged. It would be wise to look into the crankcase venting as described above also...

nofrills

Sorry for the late reply guys, I've been away. The oil filler neck ports are currently open to atmosphere, I ran the car with the oil cap off altogether, and had the same problem.

I dont think the turbo is damaged, it's just been rebuilt... I reassembled it myself (uh oh) but everything seemed to go back together fine... yes the oil seals are in there, haha. I may pull it to bits again, if it comes to it.

I'll also have a look at where the oil feed is tapped off the engine, in case my new oil filter is causing a blockage and elevated pressures?

ArmyOfOne

iTrader: (12)

Where do you have your oil return running to?