251 in the American M37

[AMGeneral]

Dang,I had a 53 M37 that someone had swapped the engine /trans in,it was 12 V and I remember it having Spitfire cast in the cylinder head. I'm pretty sure it was out of a 1 1/2 ton Dodge,it did have the winch pto bolted to it and it functioned properly.It also had 4 combat rims on it vs the later split rings.I need to see if the fellow I sold it to still has it.

 

[maxim]

If you are around any farm equipment junk yards they used 251's in some Massey combines and on pumps. If you are lucky the combine still has the hood over the engine as they exhausted out of the top. If nothing else the manifolds are busted. Down facing exhuast are tough to find.

 

[SasquatchSanta]

I've done quite a bit of business with Bob Stahl of Veterans Vehicles out in Wrentham Mass. Bob is old guard --- no computer & no website but he is one of the most knowledgable people I've ever met in the M37 and civilian Power Wagon area. I'm almost certain that he has some 265s. I'm certain he has 251s. Bob is the guy that had the 489 gears made for the M37. His phone number is 508-384-7698.

The only thing I have to add concerning repowering an M37 with a long-block (251 or 265) flathead is that it is an easy mod. The radiator can be moved forward by simply installing the radiator on the other side of the mounting flange. The stock 230 flywheel, clutch, bellhousing, starter etc can be re-used. Be careful to use the m37 flywheel with the M37 starter as some of the 251 flywheels have different teeth counts. Outside of moving the motor mount and radiator forward and installing new exhaust it's a lot easier than installing a 318.

I personally gave up on trying to locate a 265 engine a couple of years ago. At one time I thought I had two engines located but both turned out to be 251s. I currently have two real nice 251 Spitfires in storage. Not long ago I was seriously considering selling all my trucks but recently I've changed my mind therefore I'll be balancing and building one of the 251s in the future.

In retrospect, I'm now of the opinion that the 251 is probably a better engine for my purposes than the 265. I'm running 36" rubber and 489 gears. According to my calculations, to run 65 MPH the engine has to produce 3,000 RPM! That's a lot or revs for an the 4-3/4 stroke 265. The 251 has a 4-1/2" stroke --- a characteristic that I feel is much more conducive to higher revs. If anyone disagrees with this in that they feel that the 4-3/4 stroke 265 ("balanced") engine wouldn't have any problems producing 3,000 RPMs please speak up.

Everyone I've talked to that's in the know say that the lower end on the 251 & 265 engines are a LOT stronger than the 230 engine. The only difference in the 265 over the 251 (except for some blocks that have full flow oiling systems) is the 265s 1/4" longer stroke. The crank and rods are different in the 265. Here are some comparatives:

230 Engine: 3.2500 Bore X 4.625 Stroke

251 Engine: 4.4375 Bore X 4.500 Stroke

265 Engine: 4.4375 Bore X 4.750 Stroke

As you can see, the 251 has a shorter stroke than both the 230 and the 265. People I've talked to say the 251 delivers appreciably more power over the stock 230. The 265 is a "real" powerhouse but like I said before, I don't know about running it above 2,500 RPM --- even when balanced. The 265s are also extremely scarce.

Because so many of these old engines have been rebuilt about the only way to tell for certain if an engine is a 265 is to measure the piston stroke or drop and pan and look at the crankshaft. The only part number used for the 265 crank is 1400188.

IF ANYONE KNOWS THE PART NUMBER FOR THE 265 RODS PLEASE PM ME.

The exhaust manifolds for the long block flatheads (251 & 265) engines are scarce as hens teeth.

The following block numbers were used for the 265:

1400929, 1402429, 1551229, 870744, 1402529, 1115829.

The following block numbers were used for both the 251 and the 265:

1400229, 1138129, 1115829

The following block umbers were used for the 251 only:

870729, 1400229

The following trucks offered the 265: (The 265 was built from 1955 thru 1961)

W500: 1957, 58, 59 & 60
D600: 1957, 58 & 59
D500: 1957, 58, 59 & 60

1955 - 1956: J6, JS6, JMC, K6, KA6, K5
1957: K6, W500, K6, D600, K6
1958: LS-D000, School Bus, LS-5600, LSW-500
1959: M6, D600, M6-5600, M6, W500
1960: P6, W500
1961: ?

I hope someone finds this information helpful.

 

[saddamsnightmare]

December 28th, 2009.

Curiousity killed the cat, so it is said. I would not have suspected that a 237 to 251 CID conversion would change the top end speed on an M37 very much, as the speed is set by balancing speed of the engine, transmission and axle ratios is it not? And to some lesser degree by tire sizes. I have driven the Canadian radio truck conversion of the ambulance body (M43-I think) and it was probably one of the slowest trucks ever seen in the West Virginia hills, and I don't think the M37 was any better. For my money, I would rather have an M715 with the original six cylinder engine, ours could do 55 with four skids of brick on it and the only limitation was that the NDT's weren't balanced worth a hoot......
I see a lot of M37's getting converted and modified, but I'll bet you twenty years from now some poor devil's going to be looking for all the parts we took off them to restore the trucks..... Ditto for the wildmen that must chop and drop a historic vehicle.... 20 years from now their names are gonna be anthema....

Just my two cent's worth, now let's rage on... Back to you, Howard....

Cheers,

Kyle F. McGrogan

 

[pwrwagonfire]

Sasquatch Santa, I really enjoyed your breakdown of the different engines in your latest post, thank you!

I have heard AND observed the same thing (I think)....at work we have 2 WM300s, one with a 230, and one with a 251. I have been told by my boss (someone whos been running these since 1976) that the truck with the 230 always was a TINY bit faster, but didnt have as much juice. Our 251 has always been a bit slower, but pulls hills/weight better. After I began to drive these things I noticed the differences he was talking about....big time. The 230 also is MUCH MUCH different to shift than the 251, as engine speeds go....I got in it to drive it for the first time after driving the 251 for two years, and had trouble on that first roadtrip untill I realized the differences.....

Just my 2 cents!

 

[citizensoldier]

Ernie has listed some very good info folks..Thank you it has been saved and printed. I am not sure you can compare these unless you were comparing two brand new engines on a dino or in the same truck and trans combo.. To many variables that could effect the outcome like valve lash, engine wear,drive train wear, trans type, tire size,recent tune up and so forth. Very good post going fellas.. and thanks again Sas!

 

[SasquatchSanta]

December 28th, 2009.

Curiousity killed the cat, so it is said. I would not have suspected that a 237 to 251 CID conversion would change the top end speed on an M37 very much, as the speed is set by balancing speed of the engine, transmission and axle ratios is it not? And to some lesser degree by tire sizes. I have driven the Canadian radio truck conversion of the ambulance body (M43-I think) and it was probably one of the slowest trucks ever seen in the West Virginia hills, and I don't think the M37 was any better. For my money, Kyle F. McGrogan

You are right --- one engine to the other shouldn't normally make any difference in top end speed. My original post was a little ambiguous and also contained an important typo. I've since edited it --- sorry about that --- Here is what I was trying to say:

There is an appreciable power difference between the 230 and the 251 and even more of a power & torque difference when compared to the larger 265. More importantly, the 251s and 265s have a much stronger lower end (crank and rods). I've been told that the 230s are bad about shucking rods when ran it conatant highway speeds for long periods of time. The 251s, because of their better low end design do not share this problem. Unlike the 230 and 265 engines (and perhaps the industrial 251s that are in the Canadian M37s) that are unballanced, or "poorly" balanced industrial engines the 251 Spitfire with it's shorter stroke was designed (balanced) for higher RPMs. I'm told a 251 Spitfires will tolerate 3,000 RPM where the industrial engines want to jump out from between the frame rails at anything over 2,600.

Given that I use my M37 as a daily driver and I want to be able to run 65 when need be my plan is to zero balance a 251 Spitfire and cam it for a power curve that will accomodate the 3rd to 4th gear split with 489 gears and 36" rubber with an RPM ceiling of 3,000 RPM.

December 28th, 2009.

..............I see a lot of M37's getting converted and modified, but I'll bet you twenty years from now some poor devil's going to be looking for all the parts we took off them to restore the trucks..... Ditto for the wildmen that must chop and drop a historic vehicle.... 20 years from now their names are gonna be anthema.... ........

Forgive me father for I have sinned

 

[saddamsnightmare]

December 28th, 2009.

Dear Sasquatch Santa:

You're absolved! I guess what you're gonna do is reversible, but I have seen some very cruel conversions done to what otherwise are rare autos..... Wonder why nobody ever chopped and dropped a White Scout car, for instance? It is a wonder why a different engine wasn't used in the M37 originally, as Chrysler had some more sophisticated 6's then what they used in these trucks. Are you gonna be doing 65 in Thailand with this critter? If so you better paint it for the Thai Army MP's, otherwise the local's will never get outta yiour way fast enough. Behave for New Years Eve, otherwise I'm gonna send Robin Williams to keep an eye on you wild Minnesotans.....

Cheers,

Kyle F. McGrogan

 

[SasquatchSanta]

With the economy the way it is I came to the conclusion that this is not the time to make a move that required selling anything --- like trucks, boats, house and land --- all of which would be required for the Thailand venue. I guess I'll just grow where I'm planted --- for a while anyway.

 

[offroaddiesel]

Where did you find the 251? I am in the process of procuring an M37 and I will definitely want more power than stock for hiway speeds over 55! Thanks guys! Awesome site, glad I stumbled on it!
Art

i have a couple , could get rid of one , they are both in a wc

 

[SasquatchSanta]

Ernie has listed some very good info folks..Thank you it has been saved and printed. I am not sure you can compare these unless you were comparing two brand new engines on a dino or in the same truck and trans better do so before I get hit by a big Honda

 

[citizensoldier]

Or a white Toyota!!

 

[SasquatchSanta]

Or a white Toyota!!

Tell me more!

Did someone mistakenly install the left windshield glass on the right side or is the steering wheel on the wrong side?

I want one.

 

[citizensoldier]

The only info I can find on that truck is it was built by Toyota and is in Pakistan. I know Toyota built versions of the M37 from the 50's to 60's with both diesels and gas engines but that is all I know about them.. Pretty cool huh! Maybe someone will see it and knows the story and has more info but I cant read Japanese so I am stalled out.. This is the caption with the picture they also made a deuce but maybe I will start a Toyota military truck thread so we dont get off topic here..Oh and here is the kicker its from the Islamabad jeep club!!

This Toyota military truck is shrouded in mystery. It was designed, much like the original
Landcruiser, to be used by the Japanese Defense Force and the U.S. military stationed in Asia. It
almost looks identical to a Dodge M-37, but it's indeed a completely different truck, designed by
Toyota. It uses the Landcruiser inline 6 cylinder petrol motors or the diesel. It was built sometime
between the 1950s and 1960s. A few were sold surpluss and used in Japan and even Australia as farm
or utility trucks. Nothing else is known about these models. If you have any information, any at all,
please email me. I'm completely in the dark about these extreme rare Toyota 4X4s.

 

[citizensoldier]

I started a new thread on Toyota military trucks Sas.. We can maybe find out more about them on there..

 

[Superdave]

To try and answer a few of the questions here goes. I took my M37 and upgraded it to the 265ci from the 251 with a crank and rods from a 265 as the block/bore is the same for the 218,251,265 with just a crank/rod change to make the different ci. I used the original (Canadian) block as it has the bolt on oil fill tube which is a push in style type on civilian blocks. I did a total rebuild on it including balancing the rotating assembly. I installed a pair of 4.89 gear sets from the older dodge one ton trucks as they are identical carriers with the 4,89 gears and all I had to do was to change the pinion yoke. I installed 11:00x16 tires on a set of the older combat rims for ease of repairs if I am stuck down the road with a flat. As for the performance I am quite happy with the results, I can drive it all day long at 60mph and still have some acceleration on some of the smaller hills and average around 12mpg on the hwy.

As for the connecting rod part number I have only one number for it as: 1400244.

Another way to tell what rod you have is with a simple tape measure and measure the center to center as the 218,251,265 are 1/8" apart.

218 is 8" from center to center

251 is 7 7/8 from center to center

265 is 7 3/4 from center to center

All in all I think the 265 balanced will be good for miles down the road as I have put about 6000 miles on mine with no problems whats so ever.

 

[SasquatchSanta]

Hey Superdave --- Thanks for sharing that. I've been looking for the specs on the rods forever.

I'm told your fuel mileage would probably go up a little if you go rid of the heavy combat wheels but If I had a set I'd run them too.

My personal opinion is that the long block engine (be it a 265 or a 251 and the 489s "makes" the M37 into a practical road machine and the balancing "makes" the engines.

Thanks again.

 

[Superdave]

Glad I was able to help.

 

[Matt Wilson]

Hi Guys,

New to the forum here, and I know this thread is WAY old, but I'm hoping Superdave will chime in to answer a question I have for him.

Superdave, does your 265 engine have a harmonic balancer/crankshaft damper on the front end, or does it have just a plain pulley? In the last several years that have gone by since you posted this, how has your engine held up? How many miles would you say you've put on it? What kind of driving do you do mostly - i.e., highway driving, like the 60 mph cruising you talked about above, or low-speed off-road crawling, or towing heavy loads, etc.?

Reason I ask is because I'm planning to put a 265 into my 1949 Dodge Power Wagon, which originally had a 230 in it, and while I suspect it's not necessary to have a harmonic balancer/crankshaft damper on it, I'd like to know for sure. Engines that need a damper, but are run without it, will self-destruct eventually, usually sooner rather than later, and I obviously want to avoid that. The 265 came with so many different dampers, depending on application, I wouldn't know which one to put on my truck, and some of those wouldn't fit anyway.

Thanks in advance for any info you might offer.


Matt

 

[Superdave]

I would call it more of an hub than a balancer that the pulley bolts to, I used the factory piece. Engine has been great with no issues what soever. I usually drive highway around the 60 mph as I live out of town around 30 miles from the city. I would say that if you are building one that BALANCING the rotating assembly is a must for the longevity of the 265 as it has a 4 3/4" stroke which is a long throw in any engine.