crank machining? please help
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Joined: Mar 2005
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crank machining? please help
i have a 85 351w ho, i beleive the crank was machined down cause theres like more than 7 thou clearance with regular sized bearings, hows the best way to find outif it was machined?, and how much do machine shops usually take off? , and how do i figure out what size bearings i need?the journals look in real good shape so im hopin to just get the right sized bearings and run it like that, any suggestions would be awsome, thnx
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Joined: Jul 2004
Posts: 139
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From: Front Range of Colorado
If a machine shop did the work there are probably some numbers punched on it indicating the job number and shop and possibly the under sizes. You can also take it to a crank grinder and have them mic it for you just to make sure of the sizes.
Pam
Pam
Senior User
Joined: Oct 2001
Posts: 300
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From: Crosby TX
Originally Posted by killbabies
i have a 85 351w ho, i beleive the crank was machined down cause theres like more than 7 thou clearance with regular sized bearings, hows the best way to find outif it was machined?, and how much do machine shops usually take off? , and how do i figure out what size bearings i need?the journals look in real good shape so im hopin to just get the right sized bearings and run it like that, any suggestions would be awsome, thnx
Save the old ones
Joined: Dec 2002
Posts: 666
Likes: 4
From: Boyne Mich
Often, on the back side of the bearings, there is a number stamped in. Example. std for Standard, .010" for Ten Thou undersized. Also, it may not have any numbers stamped, in that case look for a ford part number, again thinking it is Standard. I used to here that you could get .001" or .002" under bearings for cranks that were a little worn, But at .007" the prev post states that it is time to turn it.
More Turbo
Joined: Mar 2002
Posts: 508
Likes: 2
From: Easthampton, Ma.
These motors are known for bad bearings. I have extended the life on a bunch of these Ford motors (6 cyl, 302's, 351's) by simply replacing the worn out rod and main bearings with standard (std) sized bearings with 100% success rate.
As the other posters stated:
The crank, if turned down will have .010 or .020 stamped unto a counterweight
The backs of the bearing halves (if oversize) will have .010 or .020 on them.
If the crank doesn't look too buggered up, I would just slip in new bearings and rear seal and call it a day (providing this is a good running, non oil burning motor)
If the integrity of the motor is questionable, at this point I would rebuild.
Good luck!
Steve G.
As the other posters stated:
The crank, if turned down will have .010 or .020 stamped unto a counterweight
The backs of the bearing halves (if oversize) will have .010 or .020 on them.
If the crank doesn't look too buggered up, I would just slip in new bearings and rear seal and call it a day (providing this is a good running, non oil burning motor)
If the integrity of the motor is questionable, at this point I would rebuild.
Good luck!
Steve G.
