1993hiluxsr5

Hey guys i hope theres somebody out there that knows turbo's

Basicly i just fitted a brand new ct20 to my hilux 2.8, i just finished it tonight, i started it for the 1st time and was very excited, it sounded great and seemed to work.
Then i noticed a small amount of oil in the outlet (pressure) side of the turbo as if its blowing out engine oil, WHY ?
This turbo is brand new ! im very worried as i cannot afford to buy a new one or fix it if its broken.

Is this normal? is this just part of the wear in ?

i also saw somewhere on the web that becuase i dont have any ducting hooked up ( turbo is just spinning, not boosting into engine) that the exhaust pressure may be blowing small amounts of oil through the turbine, but when the ducts are attached the pressure acting against it stops this ? is this true?

Thanks
IMG_0123-1.jpg?t=1292662573
IMG_0121-1.jpg?t=1292662928
IMG_0122-1.jpg?t=1292662964

blake.nemitz

i think you need a small amount of boost, just above atmospheric pressure, to seal the thrust bearing inside the carteidge as it is just behind the compressor wheel.

1993hiluxsr5

Yeah I was hoping that was the case, but I noticed that when others added this turbo to there trucks they did not use the oil feel that I did, they just used the alt feed, I think I may have to much oil pressure going into my turbo, so I'm going to make a reducer for the feed and see if it helps

Thanks !

James Woods

iTrader: (1)

It could be flowing to much oil, I know on the Subaru STI's and WRX's the oil feed line is pretty small and it also has banjo bolts with a screen to restrict it also. Some oil residue is normal though.

tried4x2signN

Mine does it on my RET... I think it's pretty common, but don't ask me to prove it.

Get another Turbo, move on from the CT20. LT or not.

jimep

X2 on everything he said... both my ret's had a sticky coat of oil in the intake line all the time, Hows ur pcv valve and intake (suction) side to the turbo?

Tweasl

First post so here goes:

Oil in compressor discharge is caused by a few different things. First you must remember that the compressor side of the turbo builds a bit of boost even at idle. This boost pressure not only makes the turbo work for your engine, but provides a positive pressure seal from behind the compressor wheel into the bearing housing thru which the shaft and wheel of the turbo runs. This effectively will not let oil flow out from the bearing housing into the comp cover and to where you see it in the comp cover volute.
The shaft the compressor wheel is bolted to will usually have some type of mechanical seal as well. Also, an oil flinger might be incorporated here which will also effectively keep oil from migrating out of the bearing housing. Make sure all these parts are there and are functioning correctly. Next, take a look at your oil drain from the turbo back to your crankcase. If this is kinked or restrictive in any way it will oil to back up in the drain line and cause the problems you have experienced. Lastly, excessive crankcase pressure might contribute to this so be sure that your system is functioning correctly.

Excessive oil pressure and or flow usually will not cause this, however be sure you have the correct flow and pressure that the turbo manufacturer recommends. This is critical for bearing life and is not so much a leakage issue. Journal bearing turbos and ball bearing turbos have different oil pressure and flow requirements. I would know cause I blow them up all the time testing these where I work. Hope this helps.

Tweasl

1993hiluxsr5

i dont currently have any intake/outtake piping for the turbo yet so its not actually boosting.

1993hiluxsr5

i really hope your right, and yes this does help Alot! as i do not have any of the air ducting hooked up yet so the turbo is not boosting, it is just blowing/sucking around in the engine bay, could this cause my troubles ?
Thank so much guys !!!
ps it blew quite alot of oil today on a 500m run, i was running it fairly hard tho..... pic's if wanted

Tweasl

Having no boost pressure certainly does not help matters since there is no positive seal pressure form the the comp side to the bearing side.

Larry

1993hiluxsr5

Ah i see, so me being an idiot probly isnt helping my turbo out very much ?

oil from 500m drive....
IMG_0126.jpg?t=1292810389

shaeff

There is no boost built at idle. At idle the engine is in vacuum, just like it is while cruising under constant throttle. The turbo does NOT have to be creating boost to have a good seal. And oil leaking out the compressor side is NOT normal.

Agreed on the oil drain- but that usually doesn't cause oil buildup in the intake tract (compressor side), but instead it'll cause the turbo to blow smoke by forcing oil into the turbine housing (and thus, burning out the exhaust)

I agree with checking the PCV system. If it's not operating properly that will cause oil buildup in the intake system, and often times push oil past the rings and blow oil smoke.

Usually a -3 to -4AN hose/line is used for turbo feeds. I highly doubt this turbo needs any sort of restrictor as it's not a ball bearing unit, but rather a journal bearing.

To the O.P.- did you prime the turbo before you started the truck? (pour oil into the oil inlet and spin it by hand, or at a minimum pull the EFI fuse and crank the truck until you had oil pressure?) This is an absolute MUST when installing a turbo. If it's not primed and you start the truck, you've got the journal bearing spinning at several thousand RPM in a bone dry, oil-free environment which will kill it with a quickness.

Edit: and boost pressure has nothing to do with the turbo oil seals...

1993hiluxsr5

well when i installed the turbo i poured in some brand new engine oil into the turbo then connected all the lines up, then when i started it there was maybe 1-3 seconds with no oil pressure, the turbo spins pretty slow at idle (550 rpm)
could my oil seal be screwed already ? after less than 5minute use ?

shaeff

Since you poured oil in it, that's usually enough to prime it. Did the turbo sit on the truck for long before you started it?

Without priming the turbo, you can pretty much consider it dead the moment you start it up with no oil in it. Turbos don't take well to oil starvation and tend to die quickly without oil.

1993hiluxsr5

yes the truck sat for about 1 day before startup (exhaust troubles) so would 3 seconds really be enough to kill a brand new turbo and make all its seals fail, even after priming ??
That sucks if so

James Woods

iTrader: (1)

Well not sure if it is different or not but when I worked for Subaru, I put on probably 3 dozen new turbo's out of the box and never primed them and they were fine. Why are you running it without the piping any ways?

1993hiluxsr5

becuase i havnt got round to buying he pipes yet, been worrying about the turbo failing, im going today to get some hopefully but i dont really want my engine ingesting this much oil.
that much after 500m, imaging after a 5 hour drive !! there would be none left

James Woods

iTrader: (1)

Well that does seem like a lot of oil coming from the turbo, it would appear that the seal is bad, usually when a customer would complain of turbo problems and the intercooler was full of oil, that was my clue to sell them a turbo. I am in now way an expert on turbo chargers so possibly someone with more experience can chime in with their feelings on it. So as long as your drain hose is clear and empties back into the pan above the oil level, and your PCV system is working good, I would say try to return it.

Tweasl

"There is no boost built at idle. At idle the engine is in vacuum, just like it is while cruising under constant throttle. The turbo does NOT have to be creating boost to have a good seal. And oil leaking out the compressor side is NOT normal."

There IS boost pressure at idle...we measure this in "/H20 and even at idle the turbo is putting out some boost. This may or may not be enough to overcome the crankcase pressure of a particular engine at idle. Also it depends on the state of the engine, Is it worn out or not. If the rings are worn you might have high crankcase pressures at idle.

"Edit: and boost pressure has nothing to do with the turbo oil seals..."

Boost pressure at idle and seals go hand in hand. Seals are designed to work with certain bearing housing to turbine housing and compressor housing Delta Pressures. If these are exceeded the turbo will shows signs of leakage.

Lastly, different turbo trim packages will create different seal conditions. Compressor wheels are actually shimmed higher and lower relative to the bearing housing face in order to limit leakage across the seals. On the Turbine wheel side, the heat shield can be modified to produce the desired effect.

There is much more to all this.....

Larry

shaeff

I think we're not on the same page here. Anything below 0 on a vacuum gauge is not boost. While there may be some pressure, it's not boost. There is less vaccum, perhaps, but nothing that reaches the boost threshold, obviously.


OP- check your shaft play. There should be minimal side to side, and almost nothing for in/out play. Have you been running that turbo with no piping on the compressor side? If so, that'll kill it too, by overspinning it. Air filter on there? I sure hope so, any debris that turbo sucks in will kill it with a quickness!

Perhaps it is your terminology that's throwing me off here. Boost pressure is nonexistent at idle. Idle = vacuum. Often times you can't even get into positive manifold pressure while free-revving the motor. If there is no load on the motor, the turbo will not usually spool enough to create positive pressure (unless it's a very small turbo)

Turbos need load to spool, hence why they do not create positive pressure during cruising conditions, but only under acceleration.

I think it's just a communication gap between us, Tweasl, we're using different terminology. You're calling pressure "boost". The turbo does need pressure inside the compressor and turbine to help seal in oil, but that is not to be mistaken as boost, which would be positive manifold pressure used for acceleration. I agree with you to an extent, and perhaps your right and the way you're wording your replies isn't making sense to me. Good discussion, no less.

I'm willing to bet that if the OP puts intake piping on that turbo, it'll stop leaking to some extent. Give it a try and get back to us.