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914World.com _ 914World Garage _ Another trick for you guy building high RPM sixes

Posted by: TimT Mar 13 2004, 08:49 PM

OK...8000 RPM plus...the engine needs some "oiling" help.

have the crank cross drilled... Its mentioned in BAs book...

To compliment the cross drilled crank, you have to modify the center main bearing..

Made a fixture to hold a bearing (this can be reversed one end holds a 3.3 the other a different main) A finished bearing is in the fixture in this pic

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Posted by: TimT Mar 13 2004, 08:50 PM

fixture and bearing chucked in my lathe

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Posted by: TimT Mar 13 2004, 08:50 PM

Finished product

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Posted by: TimT Mar 13 2004, 08:52 PM

This helps with extended high RPM running....

Posted by: Brad Roberts Mar 14 2004, 01:14 AM

You may need to explain a little more.. I'm sure the person at home who has never seen a 911 main bearing is completely clueless right now.

B

Posted by: ChrisReale Mar 14 2004, 01:18 AM

Kinda like what you do to rubber suspension bushings?

Posted by: TimT Mar 14 2004, 01:22 PM

OKIE... the way the 911 crank gets oil can lead to the 2&5 rod bearing getting starved for oil during extended high RPM running. This isnt a good thing.

To get a better supply of oil to the center of the crank and the 2&5 rods you cross drill the crank, and cut a groove in the center main bearing..