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Bearing clearance... whats optimal?
Porsche gives a huge range for main bearing clearance... .0004 to .0028.
Rods is even greater, ok to .0035.
Rule of thumb mentioned in various threads is .001 per inch, then add .0005 for racing, or about .0025
Then there is threads that .0025 is too much, and almost completely out of spec...
Then there is threads that 200k SC's are specing out at .0015...
The there are posts from engine builders that "in spec is in spec."
Is there a clearance folks are shooting for (not like we have 5 different bearings shells to play with like the chevy guys do)?
Hypothetically if you can achieve either a rod spec of .0022 or .0032 (both in spec), which is better. The latter will give lower oil pressure...
Same with the crank. If one can get .002 or less, or .0028, is one "better," or as Porsche specified, they are both "in spec."
Porsche's normal crank spec is as tight as .0004... which is hard to believe!!!
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