Date: Sun, 8 Aug 2010 14:28:29 -0700
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: Diesel - too much oil saga
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there is always oil in the intake tract of a turbo diesel VW engine .
not because it's comrpession igntion, but because the intake manifold is
presurized by the turbo ..
so crankcase blowby can not be introduced right into the intake manifold
like it can on an NA diesel engine or a gasoline engine with throttle plate
..
In othe words, on a TD engine it doesn't suck there, it blows,( in the
intake manifold )
so crankcase fumes have to be introduced upstream of the turbo air inlet..
( between air filter and turbo, so oil fumes dont' go through the air filter
element and get it all oily ) ..
so there's always going to be some oil in the intake tract of a turbo
engine.
And very true................ it should be designed so there are no low
spots for oil to collect.
and factory turbo installations with an intercooler often have a drain plug
on the bottom of the intercooler ...to drain oil out of it if any collects
there.
naturally, the more worn the engine, the more blowby fumes there are.
It has to be pretty bad before runnaway happens.
and I would expect runnaway to happen more from oil getting past the rings
into the combustion chamber than from crankcase oil in the intake tract ..
but once it happens, it doesn't matter too much how it happened..
it's a seriously bad thing to have happen.
and one very crude 'patch' on an engine with excessive blow by is to just
dump crnakcase fumes overboard , rather than try to run it through the
engine and burn it.
I had a 1.9 TD that would 'stay on the power' by itself in right hand turns
if the oil level was a bit high ...
I think oil was sloshing up onto the cylinder walls ( engine is tilted to
left, so right hand turns tend to push oil in the pan to the left ) and it
was more than the rings could control mementarily.
only did it a few times, but the first time it happened..
and it was always at fairly high boost and speed, in sweeping right hand
turns, like at 60 mph ..
first time it happened it was a bit 'exciting' in a not fun way.
Scott
www.turbovans.com
----- Original Message -----
From: "Dennis Haynes" <d23haynes57@HOTMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Sunday, August 08, 2010 6:21 AM
Subject: Re: Diesel - too much oil saga
> Oil carry over on even the original Vanagon Diesels is a problem. I
> remember
> the crankcase breather at one point being recalled to address this
> problem.
> Overfilling will definitely make things worse. A number of things could
> have
> happened here.
>
> Since you knew the dipstick may not have been accurate, did you pass that
> information to the shop? Does your conversion have an inter-cooler on it?
> That will have to be cleaned. It is even possible the failure was the
> turbo
> itself and it was coincidental.
>
> Since the Diesel is a compression ignition engine, once engine oil gets a
> path into the air/turbo inlet the engine can run away. The only way to
> stop
> it is place it in gear and stall it out. Many Diesels get destroyed from
> this. It is probably why the truck and industrial engines usually run open
> crankcase breathers. The 2007 and later machines that don't use an oil
> vapor/liquid separator. Crankcase vapors also mess up the insides of
> intercoolers. On modified vehicle one has to be careful to design the
> intake
> track so oil cannot collect and puddle and then get sucked into the
> engine.
>
>
> Dennis
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Peter K
> Sent: Friday, August 06, 2010 10:57 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Diesel - too much oil saga
>
> I've read the threads about too much oil with great interest as I took my
> westy in for its first oil change here in Toronto. She has a 1.9 turbo
> diesel from a 94 jetta, and the dipstick isn't "normal" in that a proper
> level of oil is below the low mark. The shop put over 6 liters of oil in
> her, topping it up to the full mark, and when I drove her it wasn't long
> before she blew oil out, then promptly sucked it back in thru the turbo
> and
> ran wild for a full minute (even with the ignition shut off). Max revs,
> first a blue cloud and then a black one, and then she finally stopped.
>
> Now she's very hard to start, appears to be pumping oil into the cylinders
> and when she does fire up it's with a big blue cloud. Once the engine is
> warm, it runs fine and will start fine. However she is on a steady diet of
> oil (at least 1 liter every few hundred miles). She's in the shop now,
> thought I'd ask here what people suspect might have blown... Mike said he
> will start with a compression test.
>
> I suspect the glow plugs are fouled, and some piston ring damage.
>
> As a side question, anyone know where i can get a longer dipstick? Or
> confirm what the correct one is so I can avoid this in the future?
>
> sigh
>
> --
> Regards, Peter Kraiker
> studiofstop.com
> '82 Westfalia 1.9TD
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