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Author Topic:   Main and rod bearing clearances
34Racing
Dirt Forum Racer

Total posts: 97
posted January 17, 2003 08:41 PM
What should the main and rod bearing clearances be for my 350 race motor with out running into any trouble?

outlawstock17
Dirt Forum Champ
Total posts: 620
posted January 18, 2003 08:55 AM
i like .0015 to .002 rods and .002 to .003 mains, on my race 351w fords. you're kind of at the mercy of the crank grinder on this one, unless you buy special bearings. if you scotchbrite the bearings you might gain a little clearance.

34Racing
Dirt Forum Racer

Total posts: 97
posted January 18, 2003 02:31 PM
Hey Outlaw I checked my clearances and I was getting around .003 to .0035 on rods and about .0035 to .0045 on mains do you think that will cause a problem?

outlawstock17
Dirt Forum Champ
Total posts: 620
posted January 18, 2003 05:23 PM
that's pretty loose. does the crank have a fresh grind? or are you just freshing up the engine? oil pressure will probably be low with that much clearance. if it's a standard crank, you can get special bearings that are .001 undersize, which will help. it might be time for a regrind on the crank. i don't like to run them that loose.

rico 08
Dirt Freak

Total posts: 372
posted January 19, 2003 08:45 AM
that's typical for a used standard crank the factory doesn't grind the cranks really close so when fitting bearings they use a std or a .001 to tighten it up you can see this when you tear down a factory original if you'res has been ground though,it's on the loose side.

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