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spuggy spuggy is offline
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Join Date: Jul 2003
Location: Glorious Pac NW
Posts: 2,835
Alan, blue smoke on the overrun is normally the indicator of worn guides on an N/A car, as you say. Blue smoke under power normally means rings. Or excessive crankcase pressure (forcing oil past good rings). Do 930's even have PCV's?

As I understand it, compression rings are one of the first things to go with detonation - and someone here had photos of his amazing 157-piece top rings. I think this often doesn't affect leakdown or compression readings that much...

There is an oil seal internal to the turbo, I guess it's possible this could be leaking and allowing oil into the intake - in which case, this would be visible in the intake, no?

Causes of this on other cars are apparently poor turbo scavenge (e.g. clogged with coked/burnt oil deposits) or excessive oil feed (didn't some folks post here regarding turbo oil feed restrictors, which some folks didn't have?), either or both of which may result in oil getting forced into the intake and burnt in the combustion chamber.

Gotta be easier to check for that than to strip the top-end...

Here's a URL for Volvo turbo refurbish
'77 S with '78 930 power and a few other things.
Old 08-15-2008, 05:16 PM
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