For anyone who may be wondering - the reason for getting the oil drain up high is because the oil comes out of the turbo all whipped up with air mixed in it. This makes it less dense than the oil in the sump so if you run your return into the sump below the oil level the oil returning from the turbo won't mix properly and can build up in your return line until it starts blowing out the turbo seals.

The other thing is that you want as good a downward flow out of the turbo as possible so you don't get a build up of oil from going to horizontal with it.


So what you really want is a return that comes back in above the oil level but not necessarily has high as possible.

the turbo has nissan casted in to the compressor housing and from what iv discovered its a T28 off a skyline possibly a twin turbo 1 it got a 3 bolt on flange outlet and no flange on the inlet when i pick the turbo up from the shop ill ask the guys about oil lines and restrictors ect thank for all the help
cheers Harley

I would recommend to sit your tubo in position and then take a look at the best location for the oil drain (up high) as mentioned.
With the oil pick-up i used a Brass T piece off the oil sensor with my oil pressure guage on one end and the other for the turbo.

Once you have the thread size off the T piece and the T28, go to Pirtek and they will make it the length you want with the fittings you need ready to go.

Finally with the water lines.

Its hard to explain but i'll give it a go.

I cut the front water pipe where the bottom radiator hose connects to, leaving only enough pipe for a good clamp to hold. then the piece left over is like the letter Y. With one side smaller pipe than the other, normally the heater hose connects to it. I then cut the bottom radiator hose and fit this Y piece inline.( Like A Tee) This will leave you with a connection for the water out from the turbo and back into the radiator.

The water in for the turbo is the heater hose you havnt connected up yet.

I hope this makes sence, ive seen it 100 times before but i dont know the correct names for all the engine parts. anyway i hope this helps.
P.S the 120 in your Avatar looks Tuff as, is that the shell your putting the turbo motor in?

i'd like to hijack this if i could.

My troubles are that i have quite a bit of smoke from the exhaust every time the revs pick up.

My first thought was the seals in the turbo. So i rang the guy i bought it off and he was suprised, because it ran fine when on his engine (a CA), and he was happy to give me my money back if i was unhappy with the turbo (something you don't do if you are shonky).

Anyway i found a pic of the T25 on a CA head and realised i had the oil going through the turbo the wrong way. so i changed the lines and got that sorted, started and still lots of smoke (yes i let it run and burn all oil out of exhaust, but still smoked).

So then i read this thread last nite and thought i mite try a restrictor (2.5mm) in the oil suply line (8mm). This helped reduce smoke but still lots too much as revs rise.

My theory is now (apart from the seals being stuffed) that because of the manifold i am using holds the turbo on its side, the oil goes through the turbo horizontally, not vertically. Could this add enough restriction to the flow of oil that would make it seep past the seals and leave me with a smokey exhaust? i understand that the seals in a turbo aren't designed to hold pressure, but are they that weak? or are mine just buggered?

i would like to hear what people think and what other ppl have done who have used the same sort of manifold setup as me (holds turbo on its side) have found/done.

ps. my oil return line is 5/8" and goes from turbo to top of sump

Definitely having the core on its side will cause oil drain issues. You should be able to loosen the front and rear housings and twist the core so that the oil flows vertically.

Another problem you could be facing is too much crankcase pressure, this is quite common and many people put extra rocker cover breathers on to let out the air. I had to do this on my 4age as I couldnt get it to stop smoking.

in some weird way that is quite pleasing to know... i don't wanna pay the 550 for a turbo service if it doesn't need it. or pay 440 for a second hand one off a wrecker that can't give me a warranty.

i don't think with the T25 you can rotate both housings???

Yeah you absolutely have to have the core vertical with the oil feed at the top.

You also can rotate both housings on the turbo. The compressor housing can be rotated just by sticking a breaker bar down the outlet of the compressor and holding the exhaust housing on a vice and then it should move just leaning on it.

The exhaust housing is more obviously movable but they usually seize up so it might take a bit of a soaking in wd40 around the seam of the housing to get it to loosen up to move once you've backed off the bolts.

Yeah the oil has to go with gravity, so it has to flow vertically as everyone has stated.

The first turbo i used, smoked on idle but as i was driving relitivley no smoke.

sorry i should have mentioned that with my manifolds you have to rotate the inlet housing on t25s (should be 6 or 8 bolts on the inlet and a circlip on the exhaust or vice versa), and as everyone has said they can be a bitch to loosen the bolts i would say a can of bolt off will do the trick and if you can get your hands on some freeze spray aswell that helps.

While we are on the topic, can anyone help with where is the best place for the catch can would be on the A series turbo's?.