4" Merc crank & rods

F

flatheadfool

Junior Member
I'm trying to figure out what a 4" stroke crank 2" rod journel
crank and matching set of rods are worth . Rods are standard and mains
are -.020. Both are in good shape for reconditioning .
 
As stated if it does have a 4 inch stroke with a 2 inch rod journal it is most likely stroked.
As I recall all stock cranks with 2 inch rod journals were 3-3/4" stroke (including Mercury)
 
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Maybe there are 2 different cranks? One a 4" stroke and a different one with 2" journals??
 
In the past we would turn down a Merc crank to 1.998 to save it and use 91 or 21A rods. However the saay should be re-balanced. Some where in my stash I have a bad Merc crank and if it passes Magnafluxing , that's what I'd do. But I din't need it yet???
 
Hi all, The rods have B38 marked on 1 side and 91 over H4 on the other
side of beam. The #2313 is on a counterweight. It does not appear
to be offset ground . I would measure the stroke but it's not easy
without a block. I guess I'll put it on the lathe . The mains are only .010 under.
Maybe it is a 3 3/4 crank ? Thanks for reply's''''''''''''''''''' RJ
 
flatheadfool said:
Hi all, The rods have B38 marked on 1 side and 91 over H4 on the other
side of beam. The #2313 is on a counterweight. It does not appear
to be offset ground . I would measure the stroke but it's not easy
without a block. I guess I'll put it on the lathe . The mains are only .010 under.
Maybe it is a 3 3/4 crank ? Thanks for reply's''''''''''''''''''' RJ
Click to expand...

Measure the width of one of the big counterweights and what size are the rod journal oil clean-out holes?

Here is a link to some information that should help:

http://myflatheadford.com/identify-4-mercury-crankshaft/
 
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