LDS VS LDT and the real differences

[Wildchild467]

Thanks for checking up on my G.

I just saw this thread now. Yes these 2 ring pistons are not any good as I see it so far. Knowing they are only 2 compression rings instead of 3, that had me concerned from the start.

To better clarify what 74M35A2 said, the truck ran good for about a week, up there with about how the LDS runs in my M109A3. Then I started getting lots of blow by where you could see it in the headlights when I stopped at a light. I need to inspect the piston rings to make sure they were installed correctly from the factory. I never checked them because they were already installed by the factory... i would think they put them on correctly. So anybody going to put these piston kits in their truck, check that first. we'll see how mine are when I pull them out this weekend. Hindsight, since my pistons were in fine shape that i pulled out, I should have just put rings on them and just honed the cylinders. Im sure I would have been ahead of the game. I cant see why burning WMO would hurt the engine. These pistons should be designed for the multifuel capability and withstand everything that the data plate on the dash says. Lots of people out there have been using WMO for fuel for years and have not had any problems. When I first put it together and drove it, I had about 40% diesel in the tank, 5% gasoline and 50% WMO. No settings on he truck deviate from stock settings other than the fuel turned up. I cant see how any of that matters because I did it for years and never had a problem, ever. Now i rebuild it and have the same problem within a week? That's terrible. I cant wait to see what these pistons and rings look like this weekend. I do not think they are the latest and greatest pistons as of right now.

I'm not bitter at all, am I?

 

[Wildchild467]

I did not measure the ldt piston that I had removed. I looked at both ldt and the lds piston and I did see a difference. The only thing that was different was the duel tip piston cooler that came with the lds kit. The other difference was the oil port on the lds rocker arm that pools more oil on the top of the combustion chamber.
With the lds piston installed the truck is harder to start in the cold unlike the ldt pistons. I installed the Pistons and liners with my ldt injectors, ldt rocker arm and ldt injection pump and ran the engine for 100 mile before I did the rest of the mods to my engine.

i have had brand new engine melt a piston from a piston cooler coming apart and that piston melted in like 30 mins under the full load test that I was running on MTU 2000 V12. My point here, is maybe the only difference is better piston cooling

How does your truck run now? Is it still running good? No Blowby? What fuel do you use?

 

[ShawnIfert]

I have been running pump diesel for over 200 miles without any issues with piston kits part number 57k1318/ 2815-00-134-077 after my LDS conversion. I did have to turn down my injection pump 4 flats and my EGT's are at 1100. I had installed the Pistons before I did the LDS conversion and had over 1000 miles on the engine with pump diesel.

 

[ShawnIfert]

Pump diesel. Eveything looks normal. I did turn down my injection pump 4 flats and my EGT's are 1100. Piston kit number 57k1318.

 

[ShawnIfert]

The 57k1318 piston kits have two compression rings that have a different part number instead of three rings of the same part number. I have also deleted my fuel compensator. The piston kit were made in 1998 and I think running multiple fuels was not in mind with the changes in the piston. That is just my thought on that. When I got my truck from GL the compensator was deleted. My engine was made in 1989 and the truck was rebuilt in 1994.

 

[ShawnIfert]

So how is it going this time around?? Back up and runningyet??

 

[daytonatrbo]

Well, I'm glad I read all 67 pages.


I'm curious as to how the fuel delivery actually changes with the LDS pump. I wonder if they are injecting more fuel, but also in a slower manner.

I know it would be difficult with the pop-type injectors, but if you look at the new common rail diesels they continue to inject fuel after the combustion event has started to allow the computer to control the burn. I wonder how much of that sort of thing you could emulate with a "dumb" IP.

 

[rustystud]

Well, I'm glad I read all 67 pages.


I'm curious as to how the fuel delivery actually changes with the LDS pump. I wonder if they are injecting more fuel, but also in a slower manner.

I know it would be difficult with the pop-type injectors, but if you look at the new common rail diesels they continue to inject fuel after the combustion event has started to allow the computer to control the burn. I wonder how much of that sort of thing you could emulate with a "dumb" IP.

The answer is none. You need electronic injection control to adjust the flow amount like that. The speed of injection is also the same between the LDT and LDS pumps. It's just that the LDS puts out a higher volume due to a larger chamber. The question has always been "can you make a LDT pump put out the same as a LDS pump by enlarging the pump chamber" and how would you go about doing it.

 

[Jeepsinker]

That's easy, install a 90101 hydraulic head, LDS pump governor, and advance springs. Also, the boost pump.

 

[Jeepsinker]

Or just get an LDS pump, because that's the only way you're going to get those parts anyway.

 

[rustystud]

Or just get an LDS pump, because that's the only way you're going to get those parts anyway.

Ahh come on, that's the easy way out ! LOL !!! We need someone who can machine out there LDT injection pump. Now that would be hard core !

 

[gimpyrobb]

I'm pretty sure I sent LDS gov springs to Rayzer and he said it made an improvement. Not sure if the IP had an LDS hyd head or not.

 

[jbayer]

Has anyone just put the 90101 LDS Hyd. head on an LDT pump?

 

[rustystud]

Has anyone just put the 90101 LDS Hyd. head on an LDT pump?

Yes, but there is a number of differences like the governor springs "Gimpyrobb" mentioned and the total cam height which pushes the plunger in the hydraulic head.
If I would just get off my butt and teardown the LDS and LDT pumps I have I could come up with some specification differences.

 

[jbayer]

Has anyone just put the 90101 LDS Hyd. head on an LDT pump?

Yes, but there is a number of differences like the governor springs "Gimpyrobb" mentioned and the total cam height which pushes the plunger in the hydraulic head.
If I would just get off my butt and teardown the LDS and LDT pumps I have I could come up with some specification differences.

I guess I should have been more specific, as in "Has anyone JUST put the 90101 LDS Hyd. head on an LDT pump, and if yes, what was the result.
Did it run better, worse, no different at all, or would not run.

 

[Jeepsinker]

Is the cam height different? I was under the impression the the 90101 head produced more volume at the same lift, and just has a larger bore. I don't remember seeing two different cam part numbers in the pump rebuild tm.

 

[rustystud]

Is the cam height different? I was under the impression the the 90101 head produced more volume at the same lift, and just has a larger bore. I don't remember seeing two different cam part numbers in the pump rebuild tm.

Your right, there is only one cam "Federal Stock Number 2910-871-5432" . I thought I had read about two different cams, but I was mistaken. There are many different sizes of governor springs though which control the rate of fuel delivery.

 

[ShawnIfert]

All of that info is in TM9-2910-226-34. There is a chart with all the differences and part numbers.

 

[ShawnIfert]

It will take a few hour to make a parts list for each pump the way the manual is configured but all the info is there.

 

[rustystud]

All of that info is in TM9-2910-226-34. There is a chart with all the differences and part numbers.

Actually there are about 4 manuals like TM 9-2910-226-35 . If you go to all of them you will see different "NSN" and "Federal Stock Numbers" on certain parts, as they where changed throughout the years.