RB30DET TEETHING PROBLEM-Guru needed

[QQQQ]

Conversion complete, run in complete and all is well ....... except

- On SUSTAINED high rpm runs, when you backoff its sucking oil into the intake and smoking BADLY!. Everyday driving with a bit of right foot action is fine. Even 2 dyno sessions(inc initial run in) did not show issue

-Background, the rb30 block I used only has one oil return so both my head and turbo oil drain pipes are tee'ed together and use this.

I have a used a high volume N1 oil pump during the build up.

NO oil is coming through the breather from the rocker cover but oil is in the inlet side so I can only assume its coming from the turbo(which is a brand new garret gt35).

I have two theories,

1 Its not breathing enough, thus ressurising the the sump, the head and turbo cany drain properly and the vacuum on throttle closure is sucking oil through the seal on the turbo.

2 Not enough oil is being drained away via just the one oil return in the block, the head and turbo can't drain properly and on throttle closure its sucking oil through the seal on the turbo.

Does anyone else have any idea's? I am but a poorly IT guy and this sort of stuff is not my specialty....Cheers Lads!

[wrxkilla]

does your catch can vent back into the inlet?

have you done a comp test just to be sure its not blowby?

mick

[Beer Baron]

from my limited knowledge of the RB30DET conversions you will need to add another oil return so that you have a dedicated oil return from the head.

[QQQQ]

hEY mICK,

BLOWBY ON A NEW ENGINE...GEE i HOPE NOT! NO CATCH CAN AT PRESENT,RUNNING MIN BOOST (14PSI DUE TO EXT WASTEGATE) BREATHER PIPE VENTS DIRECTLY INTO THE INLET PIPING IN FRONT OF TURBO, IT IS DRY AS A BONE! hAVE NOT CHECKED COMP SINCE JUST BEFORE FIRST STARTING THE NEW ENGINE, ITS NOW 1500KLM'S OLD AND RUNNING ON ITS 2ND CHANGE OF OIL (MINERAL FOR RUN IN)........

[pnblight]

what type of turbo are you running?

what sort of oil pressure levels are you reaching?

can you determine where the oil is coming from (is it possible compressor seal blow by)

if so there are some relatively easy fix

pete

pnblight@hotmail.com

[slow_r31]

does your oil line have a restrictor? from my understanding a BB turbo requires a restrictor in the oil inlet line.

[Skyrine-Dave]

i think mine did that to me today....

unleashed 1st gear, wasted 2nd gear, into 3rd and cruised.... tyre smoke and oil smoke then filled the cabin, had a look and i had oil coming out of the breather fittings (not correctly plumbed as yet)... i drove about 15secs with smoke billowing from the car

I know i have a bit too much oil in my engine at the moment anyway

[MonstaS4]

A restrictor is not needed with GT turbos as they have the restrictor built in.

Mine also has the head drain and turbo drain tee'd togther. I do get blowby at high RPM as the cooler piping has an oil film in it. Sounds like yours is sucking oil through the PCV pipe on vacuum.

[Cubes]

What oil pumps are every one using?

I'm using a rb25det one and haven't noticed it yet.

I ran ~1500km's on running in oil & the rest of the 10,000km's with mineral oil.

Then switched to synthetic and had it tuned, currently I don't have the slightest smear of oil in the inlet tract.

I did have a slight smear that I cleaned every few hundred kays up until 1,500km's.

I have missed the head and turbo train T. Mine hasn't got it.

Simply bolted the head on. I will have to check pics to see what Andrew did with the oil drain.

[Cubes]

My RB30 block definitely has 2 head drains.

Between cyl 1 & 2 and cyl 4 & 5.

With regards to oil pressure. I've only got the stock guage.

Cold starts oil pressure is over the 8.

Idle is just over the first line or 2.

Cruise is over 4

WOT 4000rpm+ see's approx 7.

I don't understand, I need to see pics?

I did quiz my engine builder about the problem GTR's tend to have with dumping oil in their head, he assured me mine wouldn't have the issue.

I'm unsure if he fiddled with the oil drain.

[StockyMcStock]

the oil drain for the turbo return on an RB30 block is simply a big hole drilled through the block above the level of the oil in the pan. i don't know what you guys are on about :confused: it's exactly the same as if it went into the sump, above the oil level of course.

[sky30]

is your PCV valve in the inlet manifold connected to the breather hoses still???

[Cubes]

I'm not exactly sure.

The head has 2 oil return galleys, I think. lol

It also has 2 oil restrictors, the rb30's oil restrictors are 1.8mm vs the rb20det's 2.8mm's.

RB26's generally have one of these blocked off.

But we have to remember the rb26 head requires less oil so to speak, solid followers vs hydraulic and no vct.

[pnblight]

A restrictor is not needed with GT turbos as they have the restrictor built in.  

Mine also has the head drain and turbo drain tee'd togther. I do get blowby at high RPM as the cooler piping has an oil film in it. Sounds like yours is sucking oil through the PCV pipe on vacuum.

yes they do BUT garret australia recently told me that the bb turbo is only surpose to see 60psi oil pressure and on cold starts and n1 pumps etc that mark is well and truely over shoot ,the answer is the resistor can be replaced with a smaller unit (std garret part) to protected the seals from to much supply pressure, and unwanted blow by.

pete

ps this is why i wanted to know what type of turbo you are running as bb turbos dont require nearly as much oil flow as a plan bearing unit.

[R31Nismoid]

I'll say im 99% sure to be the PCV sucking it all up and making you blow smoke.

Get a catch-can and it'll all go away. I suspect thats happening with my car, and others here in Vic have done it also. Common issue with more boost/lots of rpm

Even a stock pump on coldstart would overshoot 60psi wouldnt it?

no-one ive heard of runs an extra restrictor. The cartridge one is fine

[Skyrine-Dave]

Ive got an autometer oil pressure guage and on cold start it see about 100psi, once the oil thins a bit it will make 60-80psi depending on conditions, then down to 20psi sometimes on idle

[the_tonkau]

Monstas4, BINGO! Ran the pcv through a catch can and no more smoke! actually, no oil was coming through the turbo, there is a pipe from the back of the plenum(firewall end) that feeds back into the inlet just in front of the bov.that was the inlet source of oil coming out of the bov,not the turbo! next problem is that my oil pressure has a low pressure moment after sustained high revs then jump on the brakes. I'm thinking n1 pump combined with the rb30 flowing heaps of oil flow rb25 head (some people have been putting in restrictors as these heads need less oil flow than the rb30 apprently)and poor oil drainage back to the sump via the 2in1 system is causing some oil surge...bugger. Time for a bigger baffled sump maybe? Wish me luck lads with my next "tuning" issue!

thanks everyone!

[pnblight]

I'll say im 99% sure to be the PCV sucking it all up and making you blow smoke.

Get a catch-can and it'll all go away. I suspect thats happening with my car, and others here in Vic have done it also. Common issue with more boost/lots of rpm

Even a stock pump on coldstart would overshoot 60psi wouldnt it?

no-one ive heard of runs an extra restrictor. The cartridge one is fine

yes on cold start you can run over 60psi

Yes the cartridge one is fine BUT we went to a smaller cartridge resistor (garret part) and it was all tested on a test bench to unsure there was adique oil flow. And was the result of talking direct to Garret themselves and they supplied the parts.

So this wasn't a charge i took lightly but it should give the turbos a longer life spand and stop any seal blow by.

pete

[QQQQ]

Options are....Looks like I might have to put another oil return directly into the sump to stop starvation. Might as well put in a bigger baffled sump while I'm at it. Mmmmmm, does the engine have to come out for sump change?

[R31Nismoid]

have you got a catch-can yet?

thats the problem