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crankcase line boring (2.7 7R mag case)

Posted: Mon Jan 03, 2022 10:47 am
by Diesel76
Following a dry build of the bottom end (1976 911 2.7 7R) it appears the crank is nipping up. The crank has been ground back .25mm and DTI spot on for each journal. Plastigage also shows ideal clearances.

I can only presume the case is warped, I believe best course of action is to skim the mating surfaces and line bore it (I can reuse my new std outer / .25mm inner bearings)

Anyone recommend somewhere in S. England and approx costs?

Cheers, Jack

crankcase line boring (2.7 7R mag case)

Posted: Mon Jan 03, 2022 1:46 pm
by Gary71
I had my case line honed (so a less dramatic version of what you describe) by Rob Walker engineering in Oxford.

They are now https://fiennesperformance.co.uk/our-story/

Worth a call as they certainly had the competence for this task.

Re: crankcase line boring (2.7 7R mag case)

Posted: Mon Jan 03, 2022 4:07 pm
by Diesel76
Thanks Gary I will give them a call in the morning.