Custom 2.7 Turbo Problems
 

I believe I am having an issue with the drain on my turbo. I am getting alot of oil out of my exaust making enough smoke to make the car very embarassing to drive. I have the drain to the lower cam cover as low as I can get it and it is at a slight angle. I'm not sure the eisiest way to tell if the turbo rebuild is bad or if it's my drain or maybe something else. Any advice would be great.
http://forums.pelicanparts.com/uploa...1097526557.jpg
http://forums.pelicanparts.com/uploa...1097526621.jpg

You could go here to view picture of how oil is drained from turbo charger. http://www.clearimageautomotive.com/Porsche%20Products.htm

I think oil is not getting drained fast enough and pushing oil pass the turbo seal. Just my guess.

youngkang,

Looking at that setup, it appears to be using a catch tank and sump.

Built4sound is using a gravity drain system.

Both setups appear to be very nice.

yes I am using a gravity drain and I do agree that oil not draining fast enough could be my problem. Reconsruction is a large project and I am just looking for comfirmation.http://forums.pelicanparts.com/uploa...1097530237.jpg

Here is the rear view of the drain.

could also just be a bad seal; was the turbo new or recently rebuilt by a reputable outfit? Where do you get your oil supply?

The oil comes from a tee fitting on the pressure sender in the rear of the engine. The turbo has 20 miles on it. I had it rebuilt buy Performance Techniques.

Is that a Rayjay turbo, I have had an issue with oil pass since my rebuild.

Very nice setup!

Looks like the drain back line isn't big enough to me. I would have gone for something like a -8AN or -10AN drain line. It could also be a bit higher too. Use another flange inbetween the turbo and collector to raise it up a bit ;)

Otherwise I'd say you have a seal issue in the turbo :confused:

Sounds like it's probably the drain; some engines have pretty large diameter drains, even when the drain is almost vertical; the oil will tend to get whipped up in there. But it's hard to tell for sure.

Yup, I would have to concur. Increase the drain diameter and angle of the flow. It should be at at an angle of at least 30degrees upwards (from the chain cover perspective).

Keep us posted. Looks like a nice fabrication job :cool:

If you are tapping off of the oil sender, you may be getting too much pressure to the turbo. You usually need a restrictor in the turbo feed line to control the pressure. 40, 60, 80-psi will push oil past the seals and or damage them. Corky Bell refers to restrictors in his book Maximum Boost. I can look up his recommendations if you need it.

I would guess your problem is too much oil pressure going in and not enough draining out fast enough. However lowering the oil pressure in may help more than the draining.

Looks good. Good luck.

Ed

Thanks for the compliments and replies. I did use the rajay turbo and upper pipes, Chappy was nice enough to forward me some directions. Moving the turbo up a little is possible but i could never get 30deg.

i like the restriction idea. at least to try. don't the factory turbo's use some sort of ball to resrict the flow of oil to the turbo?

I doubt it's your feed. I am tapping off the oil sender too and I run a -6AN into the K27HF turbo (I could get away with a -4 or -3AN but I was paranoid of under-oiling the KKK). I have no issues with too much oil pressure. I am gravity draining into the lower valve cover since my turbo is mounted on the side of the engine.

Try the bigger drain line first and moving the turbo up a little. The oil won't back up into the turbo if the slope is sufficient.

From Maximum Boost.

Edhttp://forums.pelicanparts.com/uploa...1097542119.jpg http://forums.pelicanparts.com/uploa...1097542187.jpg

You may be right, BUT it is certainly possible that Rajay (or whatever he has) and KKK use different types of shaft seals. Maybe everyone uses the same type now, but I remember there are different designs for this seal.

I've been having problems with my Rayjay passing oil after the rebuild ( Turbo City).
At first I thought it was the Tilton electric scavenge pump I have to use ( installed in a 914 ) thinking it wasn't keeping up with the flow, but after fabricating a 10oz sump and restricting the oil feed down with a .18 nitrous nozzle jet which is as small as a pin point I still see occasional oil passing.
I am replacing both the Rayjay and the electric pump. I am going to use a cam driven 930 turbo oil scavenge pump and go with a Garrett or K27 turbo.
There are others out there running the same setup you have with a Rayjay and the gravity drain without problems. I tend to believe the problem could be with our old turbos maybe they dont rebuild them like they use to.

Correction on the restrictor I am using .018.
And the other installs I was mentioning are using the Rayjay unrestricted and supply oil from the pressure sender.
If someone knows of a small adaptable oil pressure regulator available I certainly would be interested in regulating down the pressure to 25 and see if things clear up.

IMO, modify your setup to use gravity drain instead of all the added cost and head-aches of using electric, or cam driven scavenge pumps etc...

That gravity drain looks fine. It doesn't need to slope down to work.

The oil supply line should be -4AN and a restrictor to 1/8 or smaller.

That would be quite difficult in a 914.
Richard Clewett has been using the cam driven oil scavenge in a 914 with good results. I do believe my problems are in the turbo itself. A new Garrett or K27 would be a nice upgrade to the 25 year old Rayjay.

http://www.clewett.com/

Agree, Garrett T04B's can be had pretty cheap these days and come in hundreds of different configurations ;)

just a though, If i were to disconect the drain from the cam cover and run into a bucket and run the car it would still blow oil if the pressure was to high or the turbo was no good, correct?

Thanks for piping in Tsuter, after all you did inspire this project.

Yup, if the seals were shot, it'll still blow oil.

When you remove the turbo, can you see oil in the turbine housing? If so, then definately seals are shot.

Also, try running it up at idle without the wastegate in place. If smoke still comes out of the post Turbo plumbing, then the turbo is the culprit. If the smoke comes out of the wastegate pipe, then you could have engine problems (valve guides, rings etc).

1. Line going trough turbochargers oil inlet and drain shouldn't tilt more than 15 deg. from vertical.

2. KKK turbochargers have high oil-flow. Most other turbochargers need less, you might need restrictor.

3. Your seals might be shot, either from excessive oil-pressure or from bad rebuild.


You need to troubleshoot this step by step. First of all, make sure oil isn't pooling up in your drain-pipe. Do it either by installing translucent pipe or by using small electrical scavenge pump (Tilton?) that dump oil back into oil-tank.

If it stops smoking then it's the drain. If it doesn't then it's time to install oil-pressure restrictor. If that doesn't help either it's time to change turbocharger. RayJay's aren't top of the line nowadays anyway...

It's common to find some oil in compressor housing even if seals aren't shot, it geats there trough oil-breather hose.

Exactly... do that next. The oil coming out the drain will be a lot if you have a large supply and not much restriction. So get ready to catch a lot.

Then start restricting your supply.

Troubleshooting 101: Did it have this problem before the rebuild?

Just from the picture it looks like the turbo is sitting lower than mine is. I have a 2.7 Turbo w/Rajay turbo and have no problems. I will look at my car but it seems that mine sits higher. What type of HP are you getting?...Also, when does your turbo come on, and what size is the cross over pipe going to the turbo? Mine come's on late and I am looking at fabricating a new pipe that will have a smaller diameter to increase velocity.

thanks

Oscar
76' 2.7 Turbo

You need to keep the turbo oil drain and feed as close to the vertical plane as possible. from the picture it looks like you are nearly 30 degrees from vertical. That will add to the problem.

On my rajay turbo I modified the drain flange by welding in a 1/2" piece of stainless steel tubing that has a fairly gradual bend, to a 5/8" piece of hose going to the chain cover. That was probably overkill but it works.

Before you get too carried away I would suggest you try and re-index the turbo so the drain is as close to bottom dead center as possible and see if that helps.
I do not run an oil restrictor on the feed and have no problems with smoking.

on the troubleshooting aspect, i didn't do a full rebuild. just cosmetics, oil fed tensioners, valve adjustment, msd ignition, intake/exaust gaskets, clutch, tune-up and the turbo. i did have a puff of smoke on some starts before but i think that is typical of this engine.

Oscar as far as the power HP is hard to guess but definitly way faster than without it. the turbo comes in rather smooth and has no lag. i haven't driven it enough yet to say much more.

I have a good size pipe welded to mine as well. But the turbo is at an angle for sure. I left it that way to put a pitch on the drain hose. I suppose at a poor angle it could pool in there before the drain?

Was the this turbo being used before it's rebuild? If so did it have this smoking problem before it's rebuild?

Not sure I bought it used and had it rebuilt. So I know no history behind it.

Rayay's don't have oil seals per se, they have what look like piston rings. they act more like an oil deflector than a seal. If the oil does not drain fast enough these rings get overwelmed and will let oil past them.

When I first installed my system I ran the oil drain to the lower valve cover. Big mistake. The longer line meant more oil, and when I jumped on it the g-forces cause it to back up into the trurbo and kill moskitos.
I shortened the line up and ran it to the chain housing and leveled the turbo so the drain was on bottom, no more smokey.
Rayjays are sensitive to proper oil drain, and the lower location of the turbo on our cars just makes it worse.

I'd also use a shorter drain pipe under that turbo and use a silicone -10AN high-temp, flexible hose to interface to the chain cover. It'll allow you to place it in a way that allows a smooth, unrestricted flow down to the chain cover.

Hypothesis confirmed! :D thanks, sammy!

thats pretty much any turbo, there called hook seals and yes too much pressure will kill them ive found garrets are verry pcky with high oil pressure, i use restricers, saves allot of turbos.

An updated Garrett turbo typically has an inbuilt oil restrictor in the centre section anyway, so Garrett's are generally happy with -3AN oil feeds.

This Oil Restrictor might help :cool:

yes when you use a -3 oil line you generally dont need the restrictor but with the low return angles used in porsche applications the restricter helps control flow

Perhaps a dumb question: Would it be feasible to plumb a guage to monitor pressure? Maybe an adjustable valve/restrictor as well?

Edit: for spelling as usual. Who wants to Plump a guage anyway?