Modifying My Deuce

[jason41987]

I have an M35A2 I purchased about a year ago, I've since decided that I would like to a rather large number of modifications to it.

First, I am looking to redo the entire braking system, I have read many forums on here in regards to doing this, so I already know what that will take to do it.

Second, I will want to do an engine/tranny swap. After reading this forum, here is the general idea I seem to be getting from other forum members relating to alternative engines. Keep in mind these are just assumptions based on general opinions from others, so I could be COMPLETELY wrong. I've read that many people find the stock multifuel engine to be on the short-lived side, and not as reliable as other engines. It seems the cat 3116 used in the A3 has its issues with reliability as well. I've read that while the DT466 is a great engine, it might be a bit too hard getting it to fit. The DT360 and DT408 seem to be good options. I've also read that the 5.9L cummins and the powerstroke diesels could also be viable choices and both of these are very long-lived engines.

Are there any other options for engines i should consider? The DT360 and 5.9L cummims seem a bit small for a 13,000lb truck although they are capable of the horsepower that far surpasses the multifuel. What would my best choice be for an engine larger than these, something thats a true medium duty truck engine? And can any of these bring the deuce over 65mph with the stock differentials?

As for transmissions, I havent really looked into these and I guess a lot of this would be determined by which engine I choose, but I think i would like to stay with a manual for greater fuel economy

Other modifications I would like to add are power steering, possibly insulate the cab for colder climates, warmer heat, a real air conditioner, 46 inch single tires (haven't decided on a make or model of tire yet.) I would like to make it quieter on the inside, hopefully a new engine and cab insulation will provide that. I would also like to add at least a basic sound system, I wouldnt need more than a couple speakers, I'm not going to go fancy here. And lastly, I would like to do something to the suspension to make it more comfortable for longer rides.

Basically what I am trying to do is improve its on-road characteristics and adding a little comfort hopefully without sacrificing its offroad capabilities. So when adding more power, I would like to add more speed so i can cruise at lower RPMs but still have the torque for offroad. And for the suspension I know this will be very difficult to make more comfortable onroad without sacrificing offroad, so I was wondering if there was some kind of adjustable suspension I could use for going between the pavement and the dirt?

I also want to keep it a tandem, so no bobs for me.

Any suggestions, advice, questions, or comments?

 

[swbradley1]

Just buy an over the road tractor. Less expensive, less work and you'll probably be happier in the end.

That being said it's your truck do what you want.

 

[jason41987]

Umm, no. I do not want anything nearly that large or that heavy, I like the size of the deuce and want to modify that, how boring would it be to just buy something? Anyone and their grandmother can go out and just buy something already done, no fun in doing it yourself, no chance to be creative and make choices, forget that.

 

[Warthog]

With enough $$$ you can accomplish everything you want to do. But I ask why.

The Deuces where not designed to be an on road truck. You can put lipstick on a pig but it is still a pig.

Now with that said, it is your truck and you can make it anything you want it to be. Just be prepared to spend the $$$.

 

[61sleepercab]

You will not gain much speed with a motor/tranny swap unless you get something with a deep overdrive or you are going to be in high RPM range of newer engine. You can switch to taller tires for some help . The best modification overall would be to change the axle ratios to gain speed without over revving the engine. Cab comfort would be helped by insulation sound deadening material which I would cover with soft material or Naugahyde with holes in it. Acoustical material really helps---Our courthouse had sound deadening ceiling title which was painted and then the hallway sounded like an echo chamber. Have fun with your mods and post results. Mark

 

[jason41987]

Would spray-in bed liner work to cancel sound and insulate or would I need to maybe fabricate some interior body panels and sandwich some kind of insulation in between? Also, I was considering changing out the gear ratios as well, the max speed I would want would be about 80mph so 60 or so would require lower RPMs to do so. How many RPMs would be necessary to achieve those speeds with stock differentials and are there any good diesel engines that can achieve it?

I didn't hear anyone correct the statement in which I said the general forum consensus was that the cat 3116 and multifuel engines tend to be short lived, but I havent been able to really find an explanation as to why? Perhaps with some aftermarket parts or modifications one of these engines could be made to be quite reliable? If I am not mistaken I have read that head gaskets tend to be what goes, would a newer, better headgasket solve this issue or are there more problems?

 

[Woodsplinter]

The multi-fuel in my A2 deuce has been running strong for 30 years- I wouldn't consider that "short-lived".

Personally, I think you bought the wrong vehicle. The deuce is a great off-road vehicle because of its stock configuration. The only thing you didn't mention changing was the gas cap.

I'm all for making it more comfortable (I did) but that other stuff is just a waste of money in my opinion.

 

[jason41987]

What did you do to make it more comfortable?

 

[gimpyrobb]

Charter bus seats on a springer seat base!

 

[Lieutenant Dan]

80 mph in a deuce your nuts unless you upgrade the brakes and steering..... my truck has 49" tires and it's little scary at 65 to 70 and that's my limit. I did it once and said Yup it will go 70 and back down to 55 I went. If I'm in a hurry I'll take my jeep.

Don't get me wrong my truck is far from stock. The number 1 reason I bought the deuce was for the multifuel. I run WMO and hardly put any money into fuel. The multifuel isn't bad IF you take care of it and run it sensibly. I have my fuel turned up and have a boost gauge and pyro. The truck is plenty fast for me.

 

[welldigger]

Charter bus seats on a springer seat base!

A pair of a3 driver's seats.

 

[Woodsplinter]

What did you do to make it more comfortable?

I added A/C, insulated the cab from noise and heat using products from DB Engineering, www.800nonoise.com, and installed a muffler.

There are many threads here about insulation and mufflers- lots of different products available.

I also added air-o-matic air-assisted steering.

Oops, also added Humvee seats on springer bases- much better than stock seats.

 

[jason41987]

I've seen some large, comfortable big-truck bucket seats, I was considering putting a couple of those in the front. My first priority as I have stated is a disc-brake conversion, likely using F550 calipers. After this, I will probably work on the suspension. I would love to be able to have air-adjustable shocks, something I can flip a switch and adjust from within the cab between going on-road and off. I seen custom 4x4s using these type of shock absorbers but I'm not sure if anyone makes shocks large enough for a 13,000lb truck. This would greatly improve the comfort on-road without sacrificing offroad performance as i can switch between two settings

For increasing speed without losing offroad performance I will probably put an engine in there producing 250-300hp and way more torque than the stock tranny can handle. This will allow me to have enough torque to perform just as well if not better offroad while still being able to run either a higher gear in the differential, or an engine that can safely and comfortably run at higher RPMs (my highway goal is only 80mph

So I think everything I want is doable, it just depends on what kind of shocks I can find, the disc brake conversion, and the engine/tranny swap. These are the largest projects for this truck, the rest, adding real A/C, better heater, cab insulation, audio can come second so for now, lets focus on those first three.

 

[rustystud]

To get the deuce to go 80mph safely will take a complete restructuring of the front end. The system used now is the same as the 1950's and they never meant it to go anywhere near that speed. Have you even driven a Modern medium duty truck that fast ? I have and the pucker factor is HIGH ! That's in a modern truck, not something over 60 years old ! Our busses have state of the art front suspensions and at 70 mph they are down right scary !!! Any little rut or pot hole makes the rig want to change lanes, and don't forget the wind ! Big trucks push a lot of wind and the wind will push right back ! I was driving over to Spokane in the 3ton with a trailer and the wind hit me. Next thing I knew I was in the other lane ! I didn't even move the steering wheel ! Talk about a Jesus moment ! I slowed down after that . You also say you want 46" tires. Ask anyone here who has them how fast they go on the highway. They are not even rated by the manufactures to go that fast . So what I'm trying to say in this rambling post is the deuce is the wrong truck for what you want to do. Buy a 1ton Chevy or Ford or Dodge, you will be much happier in the end and we will not be reading your obituary in the paper.

 

[jason41987]

Wheres the fun and challenge in making something meant to go comfortably at higher speeds do what it was designed to do? The fun part is being creative and solving the problem with what you have and have something unique.

 

[porkysplace]

Wheres the fun and challenge in making something meant to go comfortably at higher speeds do what it was designed to do? The fun part is being creative and solving the problem with what you have and have something unique.

Do you have a engineering background ?

 

[Sephirothq]

BE Nice Porky

 

[jason41987]

Do you have a engineering background ?

Yeah, I actually do, why? I COULD replace the entire drivetrain, axles included with something designed more for on-road, like the drivetrain out of a bus, but I don't know, I'd like to keep the rockwells. What would you even swap them with?

 

[doghead]

My stock pickup truck is electronically governed at about 116 mph.

Now, if I were to want to double(within 5 mph) it's top speed, that would be 232 mph.

It's also 4x4, so I would not want to loose any of it's off-road capabilities. With the modifications needed for the increased speed, it would help off-road too, right?


This is what you just said you want to accomplish with an M35a2.

Sounds nuts, don't it?

 

[jason41987]

My stock pickup truck is electronically governed at about 116 mph.

Now, if I were to want to double(within 5 mph) it's top speed, that would be 232 mph.

It's also 4x4, so I would not want to loose any of it's off-road capabilities. With the modifications needed for the increased speed, it would help off-road too, right?


This is what you just said you want to accomplish with an M35a2.

Sounds nuts, don't it?

I don't think its very difficult to increase top end while still having more pulling power at lower speeds too when your engine is only 130hp and what? 300ft/lbs of torque?. A 5.9 cummins is capable of 300hp and 550ft/lbs of torque. It would just be a matter of the right gear ratio to have more top end while still having more pulling power over the original multifuel engine. A shorter gear in the differentials would increase top speed to 80mph+ but requires more torque to be able to pull like the stock multifuel with the stock differentials and i think a 5.9l cummins or DT360 engine could deliver that. So yeah, I think it is possible to get a little bit more top speed while maintaining its ability to pull or chug up a hill. An extra 150-200hp could go a long ways.