13 mpg m37

[SasquatchSanta]

Some may find this hard to believe but I'm getting between 12-1/2 and 13 MPG on my M37 (The Pumpkin)!

I did two checks --- the first on Monday and the second yesterday. Both days I made 135 mile trips, driving between 50 and 55 MPH. Monday I got 13.14 MPG and yesterday I got 12.54. Yesterday I had a head wind during part of the trip and I pushed it a little harder than the day before.

I'm running 489 gears, lockout front hubs, Denman Mohawk radial tires. a civilian carter carburetor and no water pump fan. Outside of being bored .030 over and .040 milled off of the head I'm running a stock (fresh) 230.

I always figured it was impossible to get over 10MPG on an M37. Not so.

 

[gimpyrobb]

Well, when you drive 13mph, what did you expect!?

 

[SasquatchSanta]

Well, when you drive 13mph, what did you expect!?

Oops

I fixed it

 

[stampy]

LOL I thought the same thing 13mph is no problem for me either!HA

 

[Militoy]

Some may find this hard to believe but I'm getting between 12-1/2 and 13 MPG on my M37 (The Pumpkin)!

I did two checks --- the first on Monday and the second yesterday. Both days I made 135 mile trips, driving between 50 and 55 MPH. Monday I got 13.14 MPG and yesterday I got 12.54. Yesterday I had a head wind during part of the trip and I pushed it a little harder than the day before.

I'm running 489 gears, lockout front hubs, Denman Mohawk radial tires. a civilian carter carburetor and no water pump fan. Outside of being bored .030 over and .040 milled off of the head I'm running a stock (fresh) 230.

I always figured it was impossible to get over 10MPG on an M37. Not so.

That's pretty outstanding milage for a 230 with such low (stock) gearing. Which model Carter carb are you running? My brother-in-law also has an M37 that gets great MPG - but he's running a Nissan diesel in his.

 

[SasquatchSanta]

The carb is an old Carter Ball & Ball that came off a civilian power wagon.

I think I'm going to order a webber progressive linkage two barrel carb and manifold adapter tomorrow. I doubt that it will improve the fuel mileage but it might get me more power.

 

[gimpyrobb]

32/36dgav? I had one on a toyota, good carb.

 

[Militoy]

32/36dgav? I had one on a toyota, good carb.

I also used a progressive Weber on a Toyota - but mine was a 32/36 DGEV. My 63 FJ45 shortbed pickup was the only Landcruiser I know of with a stock engine that got over 17 MPG. That carb was great under vibration and severe angles, and I would recommend it for any engine within its 'breathing range'.

 

[rosco]

What fuel pump are you running? The stock military one? Sometimes they put out excessive pressure, and when they are regulated down, it improves milage. That is incredible milage though, considering the weight of the vehicle, and a little engine with a 4 & 5/8 inch stroke. Nothing about the vehicle was designed with fuel efficiency in mind.

Lee in Alaska

 

[bpj911]

Weber carburetor? What size do you need for a 230? I have solex off a Unimog that I was considering although I think it will be too small.

 

[SasquatchSanta]

Lee in Alaska wrote:

What fuel pump are you running? The stock military one? Sometimes they put out excessive pressure, and when they are regulated down, it improves milage. That is incredible milage though, considering the weight of the vehicle, and a little engine with a 4 & 5/8 inch stroke. Nothing about the vehicle was designed with fuel efficiency in mind.

I'm running a carter diaphram pump like you would find on a divilian Power Wagon or Dodge or Plymouth car. I've toyed with installing a Holly 12-804 3-1/2 PSI fuel presure regulator. After running the engine (when it's hot) and I shut it off and let it sit for a few minutes it sometimes acts slightly flooded. I "think" that is being caused by too much fuel pressure. I thought about trying to find a rubber tipped needle valve but if the fuel pressure is too high it probably needs to be addressed??

I was really surprised about the 12-1/2 to 13 MPH numbers. The 489 hears and oversized tires work the little 230 really hard but it keeps coming back for more. I'm still thinking about purchasing a Carter/Webber 32/36 2-barrell progressive linkage carb from Tom Langdon's Stovebolt website. I don't know that doing so will get me any more mileage but it might get me more power. With the 489 gears I need all the power I can get.

Whether I make the move at this time will have a lot to do with whether the carb for the 230 cab be used later on a 251 or 265. I still intend on building one of the Spitfire engines I bought last summer AND --- I'm still looking for a 265 crank and rods.

I'm suppose to talk to Tom Langdon tonight. I figure the complete carb mod kit with air filter, linkage, adapter etc (less fuel regulator will cost $180.00 with UPS charges.

I'll know more tonight.

 

[SasquatchSanta]

I called Tom Langdon at his Langdon's Stovebolt Online Catalog
Stovebolt website. This is mainly a six cylinder Chevy site but he also sells Moppar stuff.

Tom Langdon has an excellent reputation as a knowledgable guru but I have to say he had his wires crossed in a couple of places. He insisted that the 230 (short) flathead engine like the one used in the M37 is a Plymouth and not a Chrysler of Dodge. He seemed to think the only thing the 230s were available in were Plymouths. He also took isue when I stated that the top safe RPM of the M37 engine was 2,500 RPM insisting it should continually spin at 3,500 RPM without a problem. To move on the the carburetor questions I finally agreed that he was right about the RPM and Plymouth factor.

He said at 3,500 RPM that he recommends the Holly/Carter 32/36 progressive 2 barrel. He sells these rebuilt for $75.00. He said the engine needs 3,500 CFM at 3,500 RPM. When I asked him if his opinion would change if I only ran the engine at 2,500 max RPM he said no --- that he would stay with the Holly/Carter 32/36.

He said properly jetted, it might get me a little more HP --- possibly 5HP. The nice thing about these carbs is that different sized jets are available.

He said that at 2,500 RPM the current single barrel Carter Ball & Ball was adequate. He had a problem with my saying the max safe RPM was 2,500 RPM versus 3,500 therefore I don't know if I got his best opinion or not. I've got the weekend to make a decision.