Oil in throttle body?

[m_jermyn]

Been doing a bit of snooping around my engine trying to solve a stuttering issue and I have found that I have oil in my throttle body. I know its normal to have a little bit.

As far as I can tell oil vapor comes from the breather in the cam cover up the rubber hose and into the side of the throttle body where the engine will ingest it and effectively recycle it through the normal combustion process.

But I seem to be getting a excessive amount of this vapor.



The result is this oil then runs down the rubber boot throught the AFM and into the air filter.

Thoughts as to why?

Its a new engine with about 800 miles on it.

Mike

[Jim320i]

My touring is doing exactly the same, although its not a new engine...

I made a thread the other day.


http://www.e30zone.net/modules.php?name ... c&t=186162


Although I still dont know the answer, someone suggested fitting an oil catch tank. But I still need to find the route of the problem. You's looks remarkable clean compaired to my sorry throttle body.

[StuBeeDoo]

Don't like to worry you Mike, but that was why I binned my last 2.7. It was "blowing-by". The oil is forced through the breather(s) by excess crankcase pressure due to piston rings not sealing against the bore wall(s) correctly.
AFAIK (and I'm sure someone will put me right if this is incorrect) there shouldn't be any oil in the inlet tract.

[m_jermyn]

Believe me im worried

[eltel]

the m20's by design will try to reburn/recycle some of the oil, most m20's i have seen have traces of oil/muck in the throttle bodies and pipes.

did you replace all the breather pipes etc with the new engine?

keep your eye on it but it could just need a few more miles to settle in and run correctly

[e30topless]

M20's are designed to eat their own "shit" ! and this is exactly how the TPS gets full of oil...

I wouldn't worry about it so long as it's not using a lot of Oil

[Alex]

M20's are designed to eat their own "shit" !

Only Tech 1 sports

[e301988325i]

Its a new engine with about 800 miles on it.

Mike

Engines not bedded in yet IMO, anothing to worry about unless you've got excessive oil consumption and blue smoke in the exhaust.

New style M54 b30's are renound for using oil circa 1L per 1000miles or so. The engines low down torque means that people don't need to rev them, which in turn means they aren't being revved high enough to bed the rings in.

[StuBeeDoo]

M20's are designed to eat their own "shit" ! and this is exactly how the TPS gets full of oil...

I wouldn't worry about it so long as it's not using a lot of Oil

That's interesting Steve. The only time I've ever had a problem with oil in the inlet tract (or the TPS, come to that) on any of my 3 M20s was when I had the shagged bore in the first 2.7.
2.0 was bone-dry even at 170k
Current 2.7 is dry, but then again it's only done 9k since the rebuild.

[mrLEE30]

New style M54 b30's are renound for using oil circa 1L per 1000miles or so. The engines low down torque means that people don't need to rev them, which in turn means they aren't being revved high enough to bed the rings in.

M54 burn oil due to the bore coating, all modern engines do it to reduce friction and increase economy and performance, this is not the same as mikes m20. As above I would clean the pipes and monitor the oil level.

[Black_Potato]

When you say new engine what do you mean ?

Assuming its pretty new as in honed bores, pistons, piston rings etc.. what oil are you running it in on and how are you driving it ?

You should really be on a mineral and using the whole rev range but not thrashing it.

[e30topless]

M20's are designed to eat their own "shit" ! and this is exactly how the TPS gets full of oil...

I wouldn't worry about it so long as it's not using a lot of Oil

That's interesting Steve. The only time I've ever had a problem with oil in the inlet tract (or the TPS, come to that) on any of my 3 M20s was when I had the shagged bore in the first 2.7.
2.0 was bone-dry even at 170k
Current 2.7 is dry, but then again it's only done 9k since the rebuild.

are you putting oil in your car Stu ?

I have owned many M20 powered turds and have got used to the fact that 99% have residue in the TB , even my 320i when it had 32k on the clock has some in there !

[StuBeeDoo]

Perhaps there was never enough for me to notice Steve.

IIRC the 2.0 never used more than 500ml between changes.

[Grrrmachine]

My M20B20 does this same thing too, but the oil level hasn't dropped noticeably in the past year (it's due a fluid change.) The TPS was filled with gunk when I got it, but I've since drilled a hole to let the oil drain out, as per Brian's instructions.

Seems oil in the TB is a common situation, and doesn't signify imminent engine death or anything of that ilk.

[Brianmoooore]

Check that the space above the plate fixed to the underside of the rocker cover isn't full of sludge. If this area can't drain properly, it'll encourage oil to flow along the vent into the TB.

[aeberbach]

Looks just like mine (thought maybe yours has more?)

The space under that plate in the rocker cover is very hard to get to. Has anyone drilled out the rivets to clean it? How did you re-fasten it? Or do you need solvent (what kind?) and maybe some pressure?

[Jim320i]

If you have access to a decarboniser, that should do the trick... If not... Maybe leave it in some petrol over night to clean it up a little... Or maybe a dishwasher if the missus doesnt catch you, but try and get some of it off first... But make sure you let it dry out regardless of what you do.

[m_jermyn]

Everything is brand spanking new....

The plate beneath the breather on the rocker cover is all cleaned out as I socked it in a chemical for a couple of days to clean the sludge out then tested it with running water... All ok there.

I have just switched over to full synthetic as everything I have read tells me the engine should be ran in by now, might swap back to mineral and see if this changes anything...

[DaveD]

I always thought it was quite natural to get some oil in the t/b and inlet manifold...that's why BMW put that oil drain tube from the manifold to the sump

[Brianmoooore]

Drain tube runs from the head to the sump. The tube fits into the inlet manifold casting at the top, but not into the manifold itself. It was just convenient to cast the outlet elbow as part of the manifold.

[eltel]

do the drain tubes cause a severe leak if the little o-ring fails at the bottom??..my friends is dropping oil on his drive and the only logical place is the base of the tube..but i didn't think there would be enough pressure there to unload so much oil?

[m_jermyn]

oil pressure switch can leak to

[eltel]

yeah, but this oil leak is definately common from the passenger side, above the sump level but not as high as the top of the block.. the oil seems to sit in and around the base of the tube.
i initially thought it was running down and collecting there but on closer inspection it cant be..oh well ill change the o rings and go from there..sorry to switch topic.

[e30topless]

getting the tube off with the inlet attached is difficult !

remove the inlet and replace that gasket too ,

[Brianmoooore]

Failed O rings on the drain tube can cause quite a severe leak. The seals are subjected to pulses of pressure caused by the pistons going up and down, which acts as an effective pump.

[eltel]

wow..never have thought it oh well thanks for that brian, have changed them in the past when doing heads etc but never done it for an oil leak..thanks guys.

[f22raptor1]

just to bring this old thread back up would faild o rings on the cranklcase breather cause the car to run rough at idle???