320 Engine Identification

Brent Hill · Jan 28, 2013

Following up on a 1957 320-U, I have attached a couple of photos. As I understand, the block casting should be M64T - this one just has M64-. And the engine code number should be 3 or 4 digits followed by a letter - this one is 5 digits, 91139. The original engines were not sleeved? - this one is sleeved. Question is, does this appear to be a replacement engine?

jdcornborex2 · Jan 28, 2013

Replacement blocks didn't have numbers stamped and They are blank.The blocks are stamped at the factory and a replacement block can be bought and installed by anybody.I'm sure somebody wouldn't bother with re stamping the numbers. Lot of people don't even know where their at on the block.

Mark-Ia · Jan 28, 2013

That's a original block.

OhioTractorGuy · Jan 28, 2013

The paint on the block (yellow with green over it) matches the paint on the front axle bolster -- my vote is also that your block is an original. I know the 40 engine blocks had only numbers stamped into them. . . the later models had higher numbers. I cannot remember how many digits are on the late 40 blocks at home but Id say five digits by the time the 320 tractors came around is reasonable. Even later numbers had letters intermixed with the numerals.
It is odd that the block is sleeved. . . normally an engine rebuild would bore out the pistons to a larger size. At that same time the block would be dipped and any paint would be removed in the process. . .
Id be interested in a picture of the top of the block with the pistons in it.

jdfun · Jan 28, 2013

I checked my 1958 320U and the block no is 2903 , only 4 digits. I have a pair of 1955 40w's and they both have M64T blocks with 6 digit block numbers. I noticed my 40W have the M64T cast on the block towards the back of block while 320U the cast no is toward the front of the block. So when you git this figured out please let me know. Thanks , Tom

MikeinKy · Jan 28, 2013

About the sleeves, I had a 40 a few years back, and when I rebuilt it it was already bored all that it could be, so I had it sleeved back to stock. That could be the answer.

Brent Hill · Jan 28, 2013

Perhaps this is not a 320 but a 40 - added a couple photos if anyone can tell. According to jd40.com, the engine number would fit into the 2/8/1954 category.

Also, I might be mistaken on the sleeves. When I looked inside the block it seemed like it but with the pistons out I buffed an area on the top of the block and it looks to be stock. The cylinder casting must run long inward a bit on these.

I'm guessing either there is not much time on the engine or these were pretty long lasting. I find no ridge, the cylinder looks to be right at 4.00 bore, the main a hair under 2.400 and the rod journal a hair under 2.5. Too bad it was so rusted up inside the engine - the rest of the tractor seems great.

Zeke67 · Jan 29, 2013

I think your tractor ia a 40U. The 1 pc grille screen was used on early 40U's. Later 40U's, as well as 320's, had 2 pc grilles. Have the cylinders and pistons checked by a machine shop. You may only need to hone and re-ring if they aren't worn too bad.

Rodney Middleton · Jan 29, 2013

See if there is a stamped number on the transmisson case top right side of where shifter is bolted to the case. That number will match the engine if it original. Rodney

OhioTractorGuy · Jan 29, 2013

Your Tractor is a 40U.
As far as I know the 320 tractors had a different steering box/worm/pedistal setup than your tractor is showing (as well as the differences in the grille mentioned below). Still a nice tractor; that block should be fine to use if it checks out ok.
Some of the early 40 tractors just had M64 cast into the block, which is why your "T" may be missing.

buickanddeere · Jan 29, 2013

You have one mighty nice keeper and family heirloom. You will never regret keeping that tractor intact and accurate.
I can't recall what the largest factory tire size was used on a Utility but they look better when not short in the backside.

Brent Hill · Jan 30, 2013

I guess it"s not that important to my wife and she still says "sell it" (with more emphasis). It needs some engine internals replaced, a few externals cleaned or replaced, tires and paint but she really does not see the point of keeping it.

buickanddeere · Jan 30, 2013

No offence intended here but who wears the pants in your house?
What has your wife decided that she wants to spend the $$$ on?
Once it's gone , it's gone? Any grandchildren or other decendants in the family?

Brent Hill · Jan 30, 2013

None taken. One must combine "wearing the pants" with tactical marital operations - 'If Momma ain't happy, ain't nobody happy.'

It's really her little tractor but there's options. I'll probably just look for a package of all the parts I need and get back to it as I have time.

jdcornborex2 · Jan 30, 2013

Brent A few of past projects.

320 Engine Identification

Brent Hill

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jdcornborex2

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Mark-Ia

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OhioTractorGuy

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jdfun

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MikeinKy

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Brent Hill

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Zeke67

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Rodney Middleton

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OhioTractorGuy

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buickanddeere

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Brent Hill

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buickanddeere

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Brent Hill

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jdcornborex2

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