[AJD] 40 vs. 'M' Engine Block

[Bus Driver]

The aftermarket offers a cylinder head for replacement, the same number for
both the M and 40. The original 40 head had more compression than did the M.
The rare all-fuel option had a very low compression head. So the aftermarket
item is not correct compression for all the applications for which it is
listed- and perhaps not correct for any of them.

Now I have a question. I have a largely parted-out  40T, bought it in that
condition. The engine is said to have been rebuilt shortly before the
tractor was junked. The back flange of the block is broken for the lowest
bolt on the right side. Looks to me as if they might not have had the clutch
aligned, tried to pull the tractor back together with a bolt and snapped off
that bolt flange- just my guess. For a wheel tractor, that part (lower
flange) of the block is the most stressed when serving as the "frame" of the
tractor and for that reason, I hesitate to use the engine as-is in another
wheel tractor. But looking at M and 40 crawlers, the engine appears to be
cantilevered from the rear block flange, no front engine support at all. Is
that correct? If so, this block would be fine for a crawler since the
cantilever stress would be on the top part of the flange. Comments on this?
My thought is that someone needing an engine for crawler might consider this
one to have some value. Or I could find another block, etc.
----- Original Message ----- 
From: "David Smith" <gulfwashing at yahoo.com>
To: "Antique John Deere mailing list"
<antique-johndeere at lists.antique-tractor.com>
Sent: Monday, June 06, 2005 9:29 AM
Subject: Re: [AJD] 40 vs. 'M' Engine Block


> thanks for the info. Bus Driver.  I just borrowed my buddies '40' manual
and in comparing it to my 'M' manual, you hit it right on.  There a few
internal parts that are the same, but other than that crank, rods, and even
the head have different numbers.
>
> David
>
> Bus Driver <mpmbd at yadtel.net> wrote:
> All the M64 T blocks are identical. Parts catalogs show a successor number
> which I assume is also interchangeable. But many internal parts are
> different from the M and 40. A parts catalog for each tractor will be
> invaluable in determining the parts that are different. In the absence of
> that, just assume that the bare blocks are where identical ends.
> ----- Original Message ----- 
> From: "David Smith"
> To: "Antique John Deere mailing list"
>
> Sent: Thursday, June 02, 2005 8:34 PM
> Subject: [AJD] 40 vs. 'M' Engine Block
>
>
> >
> > I am looking at buying a 40 Standard. The engine block has a crack in
it.
> Does anyone know the cast number of the block for a 40? My 'M' has 64T
cast
> on it. I know that both tractors have a 4" bore. Has anyone compared the
> two engines? I have found a spare block for an 'M' locally.
> >
> > Thanks for any help.
> >
> > David
> >
> > NC
> >
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