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Registered
Join Date: Oct 2002
Location: Phoenix, AZ
Posts: 484
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Max oil pressure aluminum crank plugs
Does anybody know what the maximum oil pressure is, that can be run with the factory crankshafts? I have a GT3 crankshaft I am going to install in a high boost/high rpm 930 engine and the crank has the factory aluminum plugs installed. On stock GT3's the max oil pressure is limited to about 5 bar, whereas on 935 and 962 race cars the max oil pressure was around 8 bar. Will the aluminum plugs hold at the race car pressure or will they blow out?
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02-11-2019, 07:18 AM
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It's a 914 ...
Join Date: Jan 2008
Location: Ossining, NY
Posts: 4,703
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I initially read your post and thought 8 bar was too high, but just referred to a copy of a 935 factory manual someone gave me years ago. Sure enough, it specifies 7.4-7.6 bar at 80 degrees Celsius oil temp. I wonder if anyone runs race motors at such high oil pressures these days.
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02-12-2019, 08:06 AM
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Join Date: Oct 2002
Location: Phoenix, AZ
Posts: 484
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If you go to YouTube and search for Spezial Motorer 935 dyno, you can see the oil pressure on the dyno screen is a steady 7.5 bar (reasonably recent, I guess). I also have a dyno sheet from an Andial/Schuppan 962 that shows 7.8-8.0 bar oil pressure. Question is, did those crankshafts have aluminum plugs or did the RSR/935/962 cranks have threaded or welded plugs?
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02-12-2019, 09:53 AM
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Registered
Join Date: Jul 2001
Location: Portland Oregon
Posts: 7,007
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Quote:
Saved a lot of time and effort!!
__________________
Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com |
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02-15-2019, 11:26 AM
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Registered
Join Date: Jul 2003
Location: Back in B'ham, AL
Posts: 3,459
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What would it be considered too high oil pressure for a standard 3.3?
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05-16-2019, 11:42 AM
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Registered
Join Date: Feb 2005
Location: California
Posts: 724
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Quote:
What size? I am guessing you use an NPT plug but would like to be educated. andy |
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05-16-2019, 07:17 PM
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Registered
Join Date: May 2004
Location: Boulder, Colorado
Posts: 7,275
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A friend with decent skills (paid for college by working as a machinist) once tapped his crank for this purpose. He said it was very difficult due to the toughness of the steel, and I think he broke a number of taps in the process (which is a problem all of its own).
I don't know if there are cobalt or other tougher taps the way there are drill bits. |
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05-19-2019, 03:37 PM
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