Need help - rebuilt turbo whines like a siren - Page 2 - PeachParts Mercedes-Benz Forum

Doktor Bert · #16 01-11-2011, 09:19 PM

Quote:

Originally Posted by Diesel911

Dish Soap and water sprayed on a Cold Intake Manifold bubbling might tell you where an Intake Manifold leak is when you rev the Engine.

90% of the "oil leaks" on a 617 can be traced to the intake gasket 'bleeding' oil down the side of the block.

#17 01-11-2011, 09:23 PM

Quote:

Originally Posted by Doktor Bert

90% of the "oil leaks" on a 617 can be traced to the intake gasket 'bleeding' oil down the side of the block.

The other 90% are either from the turbo return tube or the oil separator return tube. An additional 40% are from the lower pan bolts loosening up, and about 32% are from the valve cover gasket.

Hmm, it looks like 617s leak about 252% of their oil.

leathermang · #18 01-11-2011, 09:35 PM

What about people reusing the copper crush washer under the oil drain.... ?

ForcedInduction · #19 01-11-2011, 10:43 PM

Quote:

Originally Posted by mcneil

There's a cut taken off the compressor wheel that could be for balance. It's visible in the picture slightly hidden behind the nut.

That is for the compressor, not the assembly.

vstech · #20 01-11-2011, 11:17 PM

Quote:

Originally Posted by Craig

The other 90% are either from the turbo return tube or the oil separator return tube. An additional 40% are from the lower pan bolts loosening up, and about 32% are from the valve cover gasket.

Hmm, it looks like 617s leak about 252% of their oil.

oil cooler hose rupture from worn motor mounts! or just old cooler hoses leaking... that's gotta be an additional 30% or so...
perhaps we can find over 300% OIL leaks?

ForcedInduction · #21 01-11-2011, 11:37 PM

Lets not forget the rear main with 20% of leaks, the front main is another 33% and the CCV oil separator nipple at the filter housing accounts for 75% of common leaks.

At 410% of leaks, can we add oil fast enough to keep up?

leathermang · #22 01-11-2011, 11:40 PM

Clearly these cars are going to need an oil tank inside the car with a manual pump just to make it home.

mcneil · #23 01-12-2011, 12:33 AM

Quote:

Originally Posted by leathermang

Clearly these cars are going to need an oil tank inside the car with a manual pump just to make it home.

It helps keep the speed holes in the oil pan from getting oil starved.

Doktor Bert · #24 01-12-2011, 01:44 AM

Quote:

Originally Posted by leathermang

Clearly these cars are going to need an oil tank inside the car with a manual pump just to make it home.

Here is what I have discovered about 617 'oil consumption.' Yes, when these engines wear out, they do develop a lot of blow-by. However, after installing an oil separator (off one of our dry sump race cars) on my 617.950, I discovered that my engine wasn't burning oil at all; it was blowing it out the PCV.

It is inevitable, except when using gapless rings (as I used on Dad's 617.952) that some combustion leakage past the rings just happens by virtue of the pressure escaping through the ring gaps.

I can take the oil cap off my 617.950 with it running and get no visible vapor out of the crankcase, but you can feel some pressure escaping. Some of this is due to the up and down movement of the pistons displacing space in the crankcase, but some of it is leakage past the ring gaps.

However, once the oil separator was installed, I was recovering 1 pint of engine oil from the separator tank every 3,000 miles, which was exactly the amount the engine was apparently 'burning' according to the dipstick.

Gas will escape past a ring gap REGARDLESS of the ring's seal against the cylinder wall. This is a fact that does not change, except with gapless rings. Even with a gapless 1st and 2nd ring, you can still lose some combustion gas AROUND the rings, but this is greatly reduced.

My theory is that what ever gas is escaping past the rings rises up through the crankcase, through the head and timing chain area, where it passes through an oil mist created by the spinning camshaft and timing chain assembly.

This mist is pushed out of the PCV, as there is no baffling whatsoever in the 617.950 and only very limited baffling in the 617.952 camshaft covers.

This mist is pressurized by the turbocharger and in the case of my 617.950, some of the mist collects in the wastegate hose and bubbles up between the two halves of the intake/exhaust gasket, which leaves a trail of oil film down the side of the engine block.

Interestingly, once the oil separator tank was installed, the ‘oil consumption’ totally disappeared. The ‘missing pint’ is simply drained from the separator tank every 3,000 miles and can be re-introduced into the crankcase or simply disposed of properly.

I am notorious for running my 617.950 up to 10,000 miles between oil changes out of laziness and not wanting to change oil in foul weather. I try to stick to a 5,000 mile oil change regiment, but I often fall short of that mark.

I have used Delvac, Delo and Rotella 15w40 with excellent results. I have also used Valvoline 20w50 racing oil, since I buy it by the case for my other cars and the 617.950 seems to like that oil just as well.

ForcedInduction · #25 01-12-2011, 02:06 AM

Just like ol' Bert to convert a joke into an oil thread...

Doktor Bert · #26 01-12-2011, 03:11 AM

Sorry, mate...

Just sharing what oils I use....

I'm like a drunk I guess...I will use any good oil that I can find on sale. Lately, the Delvac has been pretty cheap; about $9.00/gallon at O'Reilley's. I usually have lots of 20w50 Valvoline on hand, because I use it in my Firebird, so I use it sometimes too. I'm sure the extra zinc doesn't hurt....

Doktor Bert · #27 01-12-2011, 03:17 AM

P.S.

For those of you who have asked.....No one makes gapless rings for the 617. Total Seal Inc. will convert any new set of rings to gapless, which is what we did on Dad's 617.952. We used a conventional top ring with a gapless second. The next 617 I build will use gapless top and second rings, like we do on all our gas engines....

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