LDS VS LDT and the real differences

[ShearerLegal]

Any info on part number for ARP head bolts?

 

[Floridianson]

I think head studs are better.

 

[rustystud]

Any info on part number for ARP head bolts?

I guess you could call them and ask them for the number. I know Tracey (the guy running the 5000hp tractor) had talked with them about head studs and that they stock them.

 

[59apache]

Let's make a list...
new sleeves / piston 6+~150 = $900
ARP head bolts for a cummins ~$450 (i guess for a multi they are not cheaper)
full gasket set ~$450
camshaft reground ~$500
lifters
ARP rod bolts
main bearings (2sets for full groove)
cam bearings
balancing
checking the heads for cracks
valves springs checked
a proper calibrated IP
injectors

Thats for my opinion absolutely the minimum. It doesn't make any sense to me to go the half way and assemble the motor with worn out or questionable parts.

maybe:
heads: new valve liners, valves grind in,
crankshaft reground



I guess we are talking about $4500 - $5000. Just parts. Much money for just making a multi reliable and getting about 250HP.

 

[59apache]

double

 

[Jeepsinker]

Don't nitpick too much Jurgen, remember that was originally a GERMAN design... Hehe.

 

[59apache]

I worked enough on motors over the years. It doesn't pay off to make a work only half or taking shortcuts. Do it once, do it right.

Actually i've to made a decision:
Rebuild & improve my multi
replace it with an other multi
replace it with an other motor
throw the whole c...p in the garbage....

 

[rustystud]

Have you priced out a rebuilt Cummins lately ? After all the balancing and better bolts, studs and cam, I'm sure we can bump up the injection pump to get 300HP and still be reliable. So $5000.00 for a quality rebuild (since we will be doing the rebuild we all will be doing our best ! ) that's not bad ! Our engines at work cost around $8000.00 to $10,000.00 for complete rebuilds. Also after all that work and cost, this engine will last my lifetime and probably half my sons life. Not a bad investment in my book. Plus we keep the multifuel ability which the Cummins or any other engine does not have.

 

[59apache]

I don't want to rain on somebodys parade or stop enthusiasm. What i want to say is, it's not just throw a cam and a few bolts for 1K in and you have a reliable motor.
If you or any other start this project, go from a-z i'm the first one that salute.
What stops me are a few facts? :
To make (really) more power, you will need more boost. With the high compression ratio, not possible.
To keep the EGT low, you'll need an intercoooler, ok, not a problem.
Cam grind is a very special field. Over the years i've learned that a cam is not a cam. With a Chevy SB, no problem. I know the manufacturers and have my own experience.
But with a multi???? Has anyone real, reasonable results with different cam designs so i could choose the right one for my application?

IF it was THAT easy to make the multi reliable, i'm shure the military would go this way. Engine failure on the road ist bad, but much worse in the field, i guess...
The multi is known for failures without any further notice...
I've drive my M35 on some longer trips ( 400 mls is long in europe) and i never thought about a damage. Oil pressure good, temperature good, EGT normal, boost normal, stock pump, good fuel (diesel).
With this data a motor should run 500k. Especially with a motor that get only 130Hp out of 7,8 ltr / 478ci. Not a high reving, beaten to death, whoknowswhat engine.

So the question is for me:
Is it worth to invest 5K into that motor? A good swap to a 6BTA would't be cheaper. I don't know.

 

[welldigger]

The fact that old good running international trucks are laying around CHEAP I see no benefit to spending a fortune on an increasingly obsolete engine.

A dt 466 has more power and torque from the start. It's also easy to build up to monstrous power. All while having parts easily obtainable at any heavy truck parts dealer.

That's just my opinion though.

 

[Djstorm100]

Hey everyone, not sound like a complete newbe but can did the m35's come with LDS and LDT (change during years maybe?) If can you tell which one is which by looking at it? From my research they look the same, no?

 

[gimpyrobb]

Hey everyone, not sound like a complete newbe but can did the m35's come with LDS and LDT (change during years maybe?) If can you tell which one is which by looking at it? From my research they look the same, no?

Yes they came with both. It just depends on what the motor pool put in the truck.
The only way to tell is to look at the data plate(unless you've been around them to know).
IMHO, an LDT with an LDS IP is just as good.

 

[gimpyrobb]

I also agree with welldigger, but for me, the motors are plentiful and I like their economy. When tuned right, they are no hot-rod, but have good power.

 

[red]

So the question is for me:
Is it worth to invest 5K into that motor? A good swap to a 6BTA would't be cheaper. I don't know.

5k into a complete engine build is very little, even more so for a medium duty engine that when maintained properly and not abused should be a long lifespan motor. As a cost perspective the Detroit 60 series engines that we use (one of our smaller engines, 10-14 liter) costs 65k for a rebuild. The CAT's are even higher.

Each engine option does have it's benefits. The mutifuel is a sleeved engine with cheap parts, easy to work on, and not picky about it's fuel quality. Limit the rpm's to 2300 or less and bump up the fuel some for slightly more power and it will serve you well. So long as you didn't pull a hole in the block it can be rebuilt over and over again.

Cummins 5.9L is a great engine, no doubt or argument there. Cost to rebuild is higher than a multifuel with the same upgrades. Cheap to increase the power a significant amount, good fuel economy with a 'not too picky' taste with fuel.

Current plans with my multifuel is to stay with it. The ability to burn less than quality fuel for long distance travels is a big plus for me. Travel to remote areas where the fuel sitting in the tanks at the station might be 6 months old, tends to cause problems for other engines (besides fuel filters). I'll pick up a rebuild kit with a set of head studs for reliability and maybe let an old school engine builder in my area make a cam for it (he loves the oddball engines like that). Provides the parts to rebuild it down the road.

 

[welldigger]

I also agree with welldigger, but for me, the motors are plentiful and I like their economy. When tuned right, they are no hot-rod, but have good power.

I don't think the multifuel is a bad engine. I have no plans on swapping mine out. It's just when people start throwing out numbers like 5k to gain 50 to 100 hp with no guarantees I just don't see the point or value. You can find a good running truck with a 6bt cummins or dt 466 for around 5k. You gain horsepower and reliability for the same money. Then those 2 engines start where the multifuel ends.

 

[gimpyrobb]

I know, and agree. I will run mine "stockish" till I am out of parts to throw at it.

I have an LDS motor with new Dturbo, new IP, new injectors, and gaskets. Once I get over the whole "doesn't rotate" hurdle, it will be getting a 5ton air filter and housing I have blasted and primed sitting on the shelf. I won't spend big money on it, but will use as many "upgrade" parts as I can find dirt cheap. I have one of those new blow-off valve turbos to try out sometime too.

 

[Djstorm100]

Yes they came with both. It just depends on what the motor pool put in the truck.
The only way to tell is to look at the data plate(unless you've been around them to know).
IMHO, an LDT with an LDS IP is just as good.

LDT with LSD IP is just as good as LDS is what your saying? Didn't one put out more horsepower from 130 to 210?

 

[welldigger]

The lds has more power than the ldt. There are more differences between the 2 engines than just the pump. You can tune an ldt to near lds power levels. It's not hard to do.
Basically, if you have a deuce with a good running ldt there would be no point in spending the money on an lds. Just turn the fuel up on the ldt and a few other little tweaks and your at lds power.

If you had a truck with a bad engine and you found an lds for a good price by all means get it.

 

[Jeepsinker]

Not 210, more like 170-maybe 190. That assumes you are talking about the most common one, which is the LDS465-1a.

 

[rustystud]

I don't want to rain on somebodys parade or stop enthusiasm. What i want to say is, it's not just throw a cam and a few bolts for 1K in and you have a reliable motor.
If you or any other start this project, go from a-z i'm the first one that salute.
What stops me are a few facts? :
To make (really) more power, you will need more boost. With the high compression ratio, not possible.
To keep the EGT low, you'll need an intercoooler, ok, not a problem.
Cam grind is a very special field. Over the years i've learned that a cam is not a cam. With a Chevy SB, no problem. I know the manufacturers and have my own experience.
But with a multi???? Has anyone real, reasonable results with different cam designs so i could choose the right one for my application?

IF it was THAT easy to make the multi reliable, i'm shure the military would go this way. Engine failure on the road ist bad, but much worse in the field, i guess...
The multi is known for failures without any further notice...
I've drive my M35 on some longer trips ( 400 mls is long in europe) and i never thought about a damage. Oil pressure good, temperature good, EGT normal, boost normal, stock pump, good fuel (diesel).
With this data a motor should run 500k. Especially with a motor that get only 130Hp out of 7,8 ltr / 478ci. Not a high reving, beaten to death, whoknowswhat engine.

So the question is for me:
Is it worth to invest 5K into that motor? A good swap to a 6BTA would't be cheaper. I don't know.

I agree with you about the cams, that's why I would use the "Vogel Manufacturing" company which has already designed many cams for Tracy who runs his 5000HP motor now. He didn't just get there, it took him years of research which Vogel has now on the multifuel.
As far as the military doing upgrades, WHY ? The truck worked for them.
I know a lot of guys don't think the multifuel is a good engine. I know a lot of guys who think Fords suck ! and a lot of guys who think Chevy sucks, and Chryslers suck. So the engine sucks, lets make it better !
I am no fan of the modern diesels with all the computer junk on them. Half the repairs on our engines is replacing failed sensors ! Sensors are not needed on our multifuel.
The multifuel engine has some great things going for it too. Like the crankshaft which is made from 4140 forged steel ! The block which is made with high nickel alloy ! The cam is also forged steel. This engine with some modern rebuilding techniques can be a real winner ! According to Tracy, ( who has done the leg work on research) you don't need more boost, just a better cam and more fueling from the injection pump, which a lot of guys are already doing. The cam is the key here. Do some research and check out the differences of the Chevy small block from it's origins in the early 50's to the last generation in the 90's.
The biggest difference is the cam, then the heads and manifolds. We don't need to play with the heads to make 300hp, just the cam. Yes it will run higher rpm's , but that's why it is getting balanced and the full groove main bearings, rod bolts and head studs.
Once I get a spare engine, I'm planning on doing the mods Tracy gave me. It might take awhile (money) but it will be fun doing it !