Which multi-fuel engine is the best choice?

[Lonesome715]

I have a 5.9 waiting for a swap. But I want to stay with a multifuel for this project.

 

[vtach]

From what I understand, the internals are the weak point. Adding much more boost and it will probably through a rod. These are not like the 5.9s.

 

[Lonesome715]

What is thier displacement? Has any one tried to locate stronger internals? Has any one tried any internal or external performance mods?

 

[11Echo]

What is thier displacement? Has any one tried to locate stronger internals? Has any one tried any internal or external performance mods?

478 C. I.(7.8 L), 305 lbs torque, and most lisings I see rate it at 134 hp but mine clearly states 140hp at 2600 rpm on the ID plate on my motor and it's NSN Report. Engine weighs about 1650lbs.

 

[Lonesome715]

Thanks for information. I know they are not power monsters, but I was hoping to at least make it a little more efficiant at least.

 

[beck]

Power thoughts of mine

I'm new to this site, and the deuce. I have not turned a wrench on a deuce yet. That is about to change.

This isn't going to be any new info for you guys that are already turning up your diesels. Please correct any of my misinformation.

If you install a bigger turbo you are adding more air. Air alone doesn't make more power. The fuel has to be turned up before the power goes up. Turning up the IP after the turbo upgrade doesn't necessarily mean more smoke, unless the fuel is increased above the previous AF ratio. With the extra fuel you are making more power and pushing the turbo even harder. Now you need to worry about the bottom end and head gasket of the motor. I have no experience with the LDT's so I don't know their strengths or weaknesses. From my reading here it sounds like their IP timing is pretty advanced. That puts a bigger strain on the motor. The extra advance on the pump may be a necessity caused by the mulit fuel. Any thoughts on that would be appreciated. If running diesel can this advance be turned back down or does the combustion chamber require it?

I just put a larger turbo on the truck in my avitar. I see I have more boost. I have not turned up the IP yet so I haven't noticed much increase in power. The diesel will tolerate running lean, unlike the gassers.

I would like to hear from anyone turning up the LDT with either success or failures. It is hard for me to believe that the military put this powertrain in the deuce without an generous amount of overengineering.

 

[Lonesome715]

You are correct. When I metiond installing a bigger turbo I was not talking about somehting that would put the engine at risk. However, I do want to look into injector upgrades and some head work.

 

[gimpyrobb]

Best bet if you want to stay with a multi, is to send it to one of our turbo gurus Ken or Jwaller. They can rebuild it and make it flow more air. Then put in a pyro and boost gauge. Turn the fuel up till you get in the 1000* range. If you need more power, have the heads ported and polished. If you want max power, have your rotating assembly balanced.

 

[Lonesome715]

You hit the nail on the head. I was planning on some mild internal mods like you just mentions. How hard is it to get internals for them?

 

[gimpyrobb]

I wouldn't think its too hard. Find someone parting out a truck and ask if the'll sell the internals for just over scrap. I think that would be a good deal for both partys.

 

[Lonesome715]

What about new internals? Oh and not to mention gaskets, seals and so on.

 

[gimpyrobb]

I don't know why you would spend that kind of cash. New internals will require LONG dollars. Get some good used stuff(internals or whole motor) and buy bearings accordingly(if it needs bored out or a crank needs polishing), then get a rebuild gasket kit. Thats how I would go about it anyway.

 

[Lonesome715]

I completely agree. I am just curious about thier availability. I am also wondering where I would go to get store bought parts for these engines.

 

[beck]

Stronger than stock parts

gimpyrobb,
I think what Lonesome715 is looking for is high performance parts. I doubt these are available as on the shelf items like with the 5.9 Cummins. Anything can be built with enough money, but those custom parts are expensive. The 5.9 Cummins is like the small block Chevy of diesels. The LDT will ever compare to the Cummins. The LDT/Cummins comparison is like the small block Chevy/Rambler V8 gasser. The potential just isn't there, but there is room for improvement. I'd like to stretch the envelope on the LDT, but not far enough to break it. I want more power but not unreliablity.

 

[gimpyrobb]

I figured it was a given, the LD series of motors is too old for anyone other than MV parts dealers to worry about. They were designed a WAY long time ago and it is just an outdated motor. Just like the 230 I had in my M725. If you want to stay with the stock motor, it can work just fine with a little work. Will it be a powerhouse? No. Will it get the job done? Yes.

 

[Lonesome715]

A more efficiant engine is what I am going after. I know they are detuned a bit for longevity. But I just want to tweak it a bit. The internal mods mentioned before are a good start.

 

[elkhunter]

The 465LDT D quiet turbo (from what i have read from various articles) is the cleanest (Meeting EPA Regs for emissions) Mine is a 1972 AM General with a Hercules and the data plate indicates it (engine) is a 1987). The turbo is not a whistler!! Hope the info helps

 

[Lonesome715]

That does help, thanks.

 

[elkhunter]

Glad it helps!! That is my two cents worth.I did read the article in a military vehicle magazine and on the web.

 

[Lonesome715]

Now, the question stand, if that is the best choice how do I locate one?