Gentlemen...and ladies, should you feel forgotten.
The issue with this is the fact the engine would have gone 'runaway' with oil of this quantity
being ingested into the combustion chambers....this is NOT what happens
when a oil breather is blocked on a turbo engine.
You have to understand how turbo's work.....
someone said they have 40 psi oil pressure...not so.
There is a restrictor in the supply to the turbo bearings because the bearings are ZERO pressure bearings !
They are flooded with oil, true, but not pressure.
The oil leaves the turbo due to gravity for the most part.
this being so, any restriction will back the oil up into the turbo oil housing and pressurize the shaft bearings....
and oil will be pumped into the exducer or exhaust turbine side and be expelled out of the muffler as wet oil and clouds of smoke.
Most turbo's will past some oil into the intake side and a little oil will enter the motor this way.
On a gas engine, the plugs foul out. On a diesel, the idle is lazy coming down and there is
sometimes detonation from the ingested oil firing off before normal injection angle.
Some oil will be pushed out of the breather, but you will hear detonation when it gets past a dribble.
During crankcase pressurizing, there will be no oil going down the valve guides, this only happens
when there is a pressure differential between the crankcase and intake air where the intake air is lower that the crankcase pressure.
Most crankcase pressure is a result of turbo pressurized intake air getting back out by way of the intake stem seals.
When the rings come under load they seal much better and blow by is reduced past them.
So to recap.....the oil was BLOWN out directly into the exhaust through the turbo shaft seals due to high crankcase pressure.
This happens because the exducer end of the shaft is very hot and thins the oil increasing the drain.
The inlet side is a lot cooler and passes much less oil.
Make sense to you ?
BTW...bin doin' this mechiniking stuff fer 45 years....
Last edited by dkveuro; 02-02-2005 at 10:19 PM.
Reason: just though o' summat !
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