LDS VS LDT and the real differences

[midcounty]

i'm just questioning where the air is coming from. i know that diesels (and this MF does operate off of the diesel principle) make power by increasing fuel and stay alive by increasing air.

but the turbos have already been stated to be found interchangable from the LDT to LDS - and not that they are swappable, but are suitable substitutes. is this not correct?

anyway, so if the turbos are not producing larger amounts of air to manage the increase in fuel (LDT vs LDS, that is), then where is the increase coming from?

the only other difference stated that would relate to this is the intake rocker arm ratio. so the intake rocker arms and injection pump (with respective injectors) are really the only differences with regard to power increase?

The weather, and my lack of free time, are hindering my ability to check in to the rocker ratio issue. I have a LDS and a LDT. I would like to pull a valve cover on each, set up a dial indicator, and measure the valve movement on each. This would tell if the rocker ratios are different. If someone else has the ability to check this before I have a chance, please let us know the results.

 

[doghead]

Please check duration also.

 

[midcounty]

Please check duration also.

I thought I read somewhere, maybe in this thread, that the cams were the same. The rocker ration would slightly change the duration at the valve. I know years ago I used higher ratio rockers on a couple engines to give a little boost in performance, and although not a huge gain it does add a little.

 

[bigugh20]

if the block is thought to be weak, how about using hydraulic concrete, or hard block or something similar in the lower coolant jacket area to strengthen the block?

 

[ltrdiesel]

Hey im sure you guys have alternative charger apps and numbers, but I thought I would throw you a good avenue. High Tech Turbo . Find them on the web. The guys name is Josh. They are super nice and can build whatever you need. I have worked witht hese guys for a few years and have never been steered the wrong way

 

[Kohburn]

You guys are hung up on the piston cooling... there is one reason: air

You add more fuel via the larger injection pump and increase the timing advance; making said fuel burn closer to TDC - this makes the power go up - also makes the heat go up...

To combat the heat you add more air so the mixture burns completely - you can fake the extra fuel with the LDT pump but the turbocharge cannot keep up so you go into thermal overload.

seems another factor in that is the oil cooling and cooling of the pistons

hopefully this link works, seems to show an updated oil cooling passage int he replacement pistons

http://www.steelsoldiers.com/attach...5-1c-vs-lds-465-multifuels-lds-ld-pistons.jpg

 

[m16ty]

if the block is thought to be weak, how about using hydraulic concrete, or hard block or something similar in the lower coolant jacket area to strengthen the block?

While that may work for pullers or drag racers, it won't work for a driving truck. It will overheat.

The block isn't really a problem anyway. I know some of the pullers are having problems with the blocks but they are more than likely heavily modded engines. The main problem with getting more hp or rpms with our trucks is EGT and thrown rods. Unless you can find a solution to these two problems, you're not going to get too much more power out of them.

 

[jesusgatos]

Having custom rods made is no big deal, and we've talked about having ARP make some studs for the stock rods to see if that might be a step in the right direction.

 

[doghead]

Guys remember, this thread is about the differences of an LDT vs LDS engine, not about modifying a multi-fuel engine(for tractor pulling perfomance). We don't need custom rods to make 40 more HP.

 

[gimpyrobb]

YEAH, check yourself before you wreck yourself, fool!

 

[gimpyrobb]

Bump for JJ

 

[Mikey90744]

I thought I read somewhere, maybe in this thread, that the cams were the same. The rocker ration would slightly change the duration at the valve. I know years ago I used higher ratio rockers on a couple engines to give a little boost in performance, and although not a huge gain it does add a little.

FYI the rocker ratio doesnt alter the duration it alters the lift

 

[JJensen]

FYI the rocker ratio doesnt alter the duration it alters the lift

Although it doesn't greatly effect duration, it does some.

Taken from Comp Cams website:

[FONT=Verdana, Arial, Helvetica, sans-serif][SIZE=-1]Many people incorrectly assume that a change in rocker arm ratio has no effect on the duration the valves are open. In actuality there is some change to the duration at the valve depending on the lobe profile of the camshaft. Comp Cams explains that by lifting the valve an additional 7-8%, but beginning and ending the lift at the same point, the opening and closing rates become steeper. This increases duration, measured at the valve at 0.050" lift, by 1-2 degrees. You can measure the actual duration change by using a degree wheel and dial indicator set on the valve retainer. Coincidentally the principle of a steeper rate of opening and closing is what Comp Cams has engineered into their Extreme energy camshafts to enable more valve duration for a given lobe duration.[/SIZE][/FONT]

 

[Mikey90744]

your right, I forgot duration is measured at .05 lift not just the beginning of movement

 

[tco3129]

OK I've read till my eyes are crossed. Maybe I missed it because my eyes crossed. I have an LDT with a bad IP. I bought a M39 5 ton with a LDS in it for parts. Short and sweet If possible, can I put the LDS IP on my LDT without problems? The LDS's condition will not allow for a total engine swap. I'm going to strip any parts that will fit my M35 and sell or scrap the rest.

 

[gimpyrobb]

Yes, the LDS IP will fit on the LDT and work just fine. Is the condition because of the starter? That is only because of the different bellhousing. Once you swap from one to the other, you will be fine.

 

[randini]

I have really enjoyed this thread. I learn from the differences. I am always amazed at the low HP and Lb/FT. And wished thay made more power.
Having said that, It is a Multi-fuel engine. Its not a tractor-puller, or a drag racer. Given a choice between a 500 HP motor, or a motor that will last me the rest of my, or my trucks life. I would want a life long motor.
I often see treads about more power. But not so many about making it last. I dont beleive there is much that can, or needs to be done to extend the life of a multi-fuel, beyond what we are already doing.

OK, Maybe one thing, I could MEMORIZE the TM's...

 

[tco3129]

The LDS just needs some work to bring it up to speed. It does not run and hasn't in I believe a good while. The LDT was running till the IP went south. I don't have the time or facilities (work outside) to fool with an engine swap at this time. Maybe next summer. BTW can replacement IP heads still be purchased (for future repair of old IP) ?

 

[flyxpl]

I have a lds I was selling .If it does not sell I will put it in my A2 this winter . Do I only need to change the bellhousing ? Is the flywheel different ? What is the horsepower of the lds? I thought I had read 210hp , but in my research I came up with 185hp .

 

[gimpyrobb]

LDT is 136hp and LDS is 187 from what I recall. The bell, flywheel, clutch, and pp are different. Also the starter is the same you just need to re-clock the nose cone.

Tco, there are heads in the classifieds.