I have about 70,000 on my 617.950 rebuild running 14.7 psi of boost. I burn no measureable oil between changes, but I do get oil residue in the wastegate line and in the intake elbow.

Here is my theory:

The early 617's, like mine, had a very crappy tube-style vent in the cam cover and no oil separator. The oil residue isn't blow-by, per-se, but rather the oil mist being thrown about by the camshaft and being carried out the vent under normal crankcase pressure.

I can start and run my 617.950 without an oil cap and get nothing out of the opening until the rpm's come up, and then it is simply slinging oil out off of the cam.

I solved the problem by installing an oil trap, used in body shops on the air lines, in the vent tube.

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Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership