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Old 08-12-2017, 01:46 PM   #8
Brian
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Join Date: May 2010
Location: Masterton, New Zealand
Posts: 3,816
Default Re: Scat 221 stroker cranks

No, in all other respects the crank is right; all journals are ground to correct diameter, but the front and centre mains are of the same length as the later large journal [post 1939] cranks. This Scat crank has the double slingers on rear main to suit the 221 configuration. The other difference [no big deal- just use 81A 6211 bearings], is the width of the rod journals which mimic those of the post 39 cranks, which again are narrower than the earlier versions which ran flanged floaters. Rod journals are double drilled, probably to permit running Scat rods and Buick bearings, but I'll run 21A rods and 81A floaters.
I'm off to work today to machine in the required clearances. This machining would have been required had I adapted a 'real' Merc 4" crank, along with considerable grinding down of all journals, dealing with rear main seal [again no biggie- use 19B 6336 and 91A 6335 positive seal holders in the block/cap], along with purchase price and cost of shipping, total cost difference wouldn't be much.
But better material that doesn't rust the same!! Oh well, live and learn, it's off to work I go! Brian
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