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[G744]

Wise words!

 

[cattlerepairman]

@G744 Thank you!

The LDS could turn 2800 rpm but I deliberately left the governor set to how a motor pool SGT that apparently thinks similar to how I do, had it set . 2450 rpm. 2800 rpm is the max. rated rpm for the LDS, but with the OD and tall tires, the resulting top speed is well beyond what I want my truck to be capable of.
The LDS will run all day and night long at 2000-2200 rpm, sounding relaxed, without an issue.

 

[ToddJK]

@G744 Thank you!

The LDS could turn 2800 rpm but I deliberately left the governor set to how a motor pool SGT that apparently thinks similar to how I do, had it set . 2450 rpm. 2800 rpm is the max. rated rpm for the LDS, but with the OD and tall tires, the resulting top speed is well beyond what I want my truck to be capable of.
The LDS will run all day and night long at 2000-2200 rpm, sounding relaxed, without an issue.

It appears that the lds edges out the ldt in terms of power, performance, and wider range of rpm. Makes me wonder why the lds never became the standard for the deuce and why the ldt was the standard. If there's a thread about this somewhere, perhaps someone could point me to it, that to me, would be an interesting read.

 

[rustystud]

It appears that the lds edges out the ldt in terms of power, performance, and wider range of rpm. Makes me wonder why the lds never became the standard for the deuce and why the ldt was the standard. If there's a thread about this somewhere, perhaps someone could point me to it, that to me, would be an interesting read.

There is only a few differencess between the LDS and the LDT engine that we know of. One being the rocker arms, and the other major difference is the way the Injection pump is configured. The pump allows quicker acceleration and a little better engine surge protection. I cannot prove it as I don't have access to an LDS engine, but I believe the LDS engine was put together better. What I mean is, I believe it was balanced and possibly had the heads slightly ported. All the components on this engine are the same as the LDT.
Now I have one Shop manual that mentions a different camshaft. The numbers don't match up to anything today, and no one has any information on this mysterious cam. If someone had an LDS engine, they could use a dial indicator and measure the cams lobes for height and more importantly the degrees of opening and closing. This would tell a lot about this engine's capabilities.
I know for a fact, as I talked with a tractor pull guy that had used the multifuel engine and had made over 500 HP on a stock block, that the camshaft he used made over 200HP in itself. He had it made special from a company back east. He went on to make his own block and was making over 5,000 HP when I talked with him last. That was over 4 years ago now. One of the two major roadblocks to making higher power was the lifters. You need roller lifters for the amount of air this engine needs to breathe properly. You cannot use roller lifters in the stock multifuel engine. Surprisingly he used the stock crankshaft up to 3,000 HP . He said it never failed him, he just wanted to know the crankshaft could handle the power he was making so he had a special one made up.
Secondly, the stock injection pump does not put out enough fuel to support over 300 HP. I believe it could if you had a new larger plunger made and increased the orifices sizes. American Bosch made hundreds of different pumps. Some were for 12-cylinder diesels. That is putting out a lot of fuel. I have several pump manuals for many different applications of the American Bosch pumps. The pumps design was so basic and incredibly strong that they used it for decades. I know it could be made to handle 500HP easily.

 

[ToddJK]

There is only a few differencess between the LDS and the LDT engine that we know of. One being the rocker arms, and the other major difference is the way the Injection pump is configured. The pump allows quicker acceleration and a little better engine surge protection. I cannot prove it as I don't have access to an LDS engine, but I believe the LDS engine was put together better. What I mean is, I believe it was balanced and possibly had the heads slightly ported. All the components on this engine are the same as the LDT.
Now I have one Shop manual that mentions a different camshaft. The numbers don't match up to anything today, and no one has any information on this mysterious cam. If someone had an LDS engine, they could use a dial indicator and measure the cams lobes for height and more importantly the degrees of opening and closing. This would tell a lot about this engine's capabilities.
I know for a fact, as I talked with a tractor pull guy that had used the multifuel engine and had made over 500 HP on a stock block, that the camshaft he used made over 200HP in itself. He had it made special from a company back east. He went on to make his own block and was making over 5,000 HP when I talked with him last. That was over 4 years ago now. One of the two major roadblocks to making higher power was the lifters. You need roller lifters for the amount of air this engine needs to breathe properly. You cannot use roller lifters in the stock multifuel engine. Surprisingly he used the stock crankshaft up to 3,000 HP . He said it never failed him, he just wanted to know the crankshaft could handle the power he was making so he had a special one made up.
Secondly, the stock injection pump does not put out enough fuel to support over 300 HP. I believe it could if you had a new larger plunger made and increased the orifices sizes. American Bosch made hundreds of different pumps. Somewhere for 12-cylinder diesels. That is putting out a lot of fuel. I have several pump manuals for many different applications of the American Bosch pumps. The pumps design was so basic and incredibly strong that they used it for decades. I know it could be made to handle 500HP easily.

Thanks for the info! I still wonder why though, why the ltd was the standard and not the lds?

 

[HDN]

Thanks for the info! I still wonder why though, why the ltd was the standard and not the lds?

Maybe it had to do with the contract proposals and the DoD was none the wiser

The M35A3 is the same way - it doesn't have the same Cat 3116 as the FMTV which can do well over 200 HP compared to the A3's 170. It's my understanding that it's all the same block like the two multifuel motors, but there are different pistons, maybe heads and other stuff. I know it's not just about turning up the fuel.

There are marine 3116s that can do up to 700 HP I believe.

 

[ToddJK]

Maybe it had to do with the contract proposals and the DoD was none the wiser

The M35A3 is the same way - it doesn't have the same Cat 3116 as the FMTV which can do well over 200 HP compared to the A3's 170. It's my understanding that it's all the same block like the two multifuel motors, but there are different pistons, maybe heads and other stuff. I know it's not just about turning up the fuel.

There are marine 3116s that can do up to 700 HP I believe.

That makes sense, I would believe it was contract and they weren't the wiser or didn't care. It shouldn't surprise me, I mean once the "government" did their thing with the M16, we all know how that went down.

 

[Mullaney]

That makes sense, I would believe it was contract and they weren't the wiser or didn't care. It shouldn't surprise me, I mean once the "government" did their thing with the M16, we all know how that went down.

.
54 year old toy...

 

[rustystud]

Thanks for the info! I still wonder why though, why the ltd was the standard and not the lds?

My best guess is cost. If you have to add extras to the engine to make slightly more power, that is just extra cost wasted in the military's view. Remember the life expectancy of a Deuce in combat was measured in hours, not years. Just as a side note, the life expectancy of a main battle tank was 10 minutes.

 

[HDN]

Remember the life expectancy of a Deuce in combat was measured in hours, not years. Just as a side note, the life expectancy of a main battle tank was 10 minutes.

WW2 jeeps were only expected to last 60 days in combat, therefore they used less steel in their engine blocks and heads I believe. Makes me wonder if there's a chart somewhere

EDITED to add more context to the jeep's life expectancy.

 

[SCSG-G4]

My best guess is cost. If you have to add extras to the engine to make slightly more power, that is just extra cost wasted in the military's view. Remember the life expectancy of a Deuce in combat was measured in hours, not years. Just as a side note, the life expectancy of a main battle tank was 10 minutes.

Creighton Abrams had at least five Shermans (maybe six) shot out from under him during WWII. He, and his crew survived all of those incidents.

 

[rustystud]

Creighton Abrams had at least five Shermans (maybe six) shot out from under him during WWII. He, and his crew survived all of those incidents.

I know ! Isn't that crazy !!!
They told us stories like that in Tank school, but reminded us that with the newer weapons our enemies have chances were slim to none surviving a sneaky little "bastard" shooting us in the rear.