Oil drain not low enough
Turbo Mini Forums

Well, my Mini is run in now, but I have 2 problems - oil leak from turbo oil drain somewhere even parked up, and the exhaust oil smoke which was getting better is now worse than ever!

I've been talking to Doug Sport in Wordsley - very helpful guy who gas said the following about my setup:

- engine breathers too small. Thinks crack car pressure may be building and trying to exit through turbo return, stopping oil returning properly.

- return point is too high for the turbo. Our home made manifold seems to sit the turbo slightly too low to return to the fuel pump blank without it going slightly uphill.

His suggestion was to turn the fuel pump blank into a breather, and drill/tap the block lower down for a turbo return. Had anyone ever done this before on here? Or is there somewhere lower I can return to than the fuel pump hole?

1994 Mini Mayfair, 1330, Mspd Ph2 cam, Benross turbo head, 9:1, GT1752, TT Intercooler, MegaJolt, BMW M3 leather seats.

On mine I had breather issues that caused smoke. It turned out that my little filter on the catch can had become saturated with oil and would hold just enough pressure to make it smoke. A baffled catch can and rerouted breather setup has solved it.

As for the return it must be downhill. Maybe best to return it into the gearbox?

Yes i moved to the darkside

Instagram @jdm_brett

I don't think there's anywhere else you can fit it without disassembling the engine now, I would have a good look at seeing if you can improve the oil return, failing that, it would be modify the turbo manifolds, less hassle than removing, dissassembling, modifying, reassembling and reinstalling the engine and gearbox.
Failing that, you could fit a scavenging pump and return to a breather hole elsewhere.

Edited by Carlzilla on 27th Nov, 2016.

As much as I would rather not remove the engine, I'm not scared to.

By returning it to the gearbox, is it possible to do that above the oil level? I assume there are no current places you can tap into without drilling and tapping?

Will have a look at the breathers, see of they're clogged!

1994 Mini Mayfair, 1330, Mspd Ph2 cam, Benross turbo head, 9:1, GT1752, TT Intercooler, MegaJolt, BMW M3 leather seats.

Simple question..does the turbo have a good, free flowing gravity drain ?

Doesnt matter whether it is high or low as long as you can answer Yes to the above question.

If you were really really really stuck and didnt want to pull the engine or other stuff, you could use a scavenge pump to evacuate oil from the turbo and then return it to the engine. Not really the cheapest or neatest solution on all cases though. Usually only essential for low mount turbos where gravity drain is impossible.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Well, it should be able to drain by gravity OK, it is downhill and it's a good size - 19mm. But, it does kink up slightly which would at least hold oil overnight.

I'll check the breathers first, might help.

Had anyone made a breather out of the dizzy blank plug?

1994 Mini Mayfair, 1330, Mspd Ph2 cam, Benross turbo head, 9:1, GT1752, TT Intercooler, MegaJolt, BMW M3 leather seats.

I returned my oil to the Speedo Drive hole when I ran a side mount and it never gave me any issues.

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


Fibreglass Parts? - http://www.tdkracing.co.uk/
Split Rims? - http://www.force-racing.co.uk/

Speedo drive could possibly be done with engine left in too.

In the 13's at last!.. Just

1994 Mini Mayfair, 1330, Mspd Ph2 cam, Benross turbo head, 9:1, GT1752, TT Intercooler, MegaJolt, BMW M3 leather seats.

1994 Mini Mayfair, 1330, Mspd Ph2 cam, Benross turbo head, 9:1, GT1752, TT Intercooler, MegaJolt, BMW M3 leather seats.

U can see it in my thread on first page if ya look close... but its as simple as catch can bolted to drivers brace bar, return to dizzy hole, and other to rocker cover and one to just below of intake filter

Quick update:

Breather canisters are now venting straight to air temporarily, and the smoke has reduced massively. Not gone completely, but the inside of the exhaust is coated with oil, which isn't burning off quickly! So, it might just be that I'm seeing now - we'll see.


But, the breathers were definitely a restriction. Basically, we had used the normal breather pipes Tee'd into the 6/8mm pipe that normally connects to the Carb, but connected this straight to the Air filter feed (so it doesn't get pressurised by the Carb/inlet). But, I hadn't considered that there is now nothing putting the breathers under vacuum like there was before, so teh 6/8mm pipe is just a massive restriction.

It's due an oil change this weekend so I'll get that sorted, and use Millers CTV. Then, see how it goes after that.

1994 Mini Mayfair, 1330, Mspd Ph2 cam, Benross turbo head, 9:1, GT1752, TT Intercooler, MegaJolt, BMW M3 leather seats.

Double and triple check the oil pressure

Oil pressure is 20psi at idle hot; 40psi at 2000rpm+ hot.

Not to jinx it, but haven't seen any smoke the last few times I've been out. Before, it was constant!

1994 Mini Mayfair, 1330, Mspd Ph2 cam, Benross turbo head, 9:1, GT1752, TT Intercooler, MegaJolt, BMW M3 leather seats.