LDS VS LDT and the real differences

[Heath_h49008]

In know you guys hate dumb questions, but I'm looking at my first deuce in 3 weeks or so... is it worth holding out for the LDS engine, or possibly paying more to get one? Is the extra 40hp/longevity a deal maker or breaker? (My price range is $3000-$4000, and I know that won't get me a winch.)

FWIW I am an ASE cert parts tech, licensed mechanic, and ME major who used to sling parts at a Freightliner dealership. I'm going to use her for some work, some projects, and a whole lot of fun... but I don't think I'll be driving more than an hour in any direction with her.

Thanks for all the information you all share, I never would have thought this a possibility without you guys. I'm especially interested in the HEMTT wheel conversions and the overdrive gear upgrade, and have been watching those threads with interest.

Heath

 

[Flyingvan911]

I have an LDS and love it. The 40 extra HP do make a difference. Especially on hills. If you will be running up alot of hills I'd wait a little to find an LDS.

 

[Heath_h49008]

I have an LDS and love it. The 40 extra HP do make a difference. Especially on hills. If you will be running up alot of hills I'd wait a little to find an LDS.

Point taken. LDS it is.... as long as it doesn't add $1000, anyway.

I'll try to find a PTO and winch later... or maybe just a hydraulic pump to put on the PTO to pipe for ports up front and in back to run whatever I want. (winch, hoist, dump-ram, pump, generator, log splitter... oh, the ideas I spend money I don't have on!)


Thanks for the advice, man!

Heath

 

[gimpyrobb]

I don't think an LDT should be a deal breaker. They can be tuned to make similar power to an LDS. Just make sure you have a pyrometer on it.

 

[Heath_h49008]

I don't think an LDT should be a deal breaker. They can be tuned to make similar power to an LDS. Just make sure you have a pyrometer on it.

Or, if my reading is correct, I would need to install LDS pistons, intake rockers, and adjust the fuel pressure to match... The turbos, fuel pumps, timing, heads, exhaust, cams, and injectors were all identical, or interchangeable, between LDT and LDS engines... and I can safely turn an LDT into a poor-mans LDS. So, find a junk 5ton multifuel and start yanking parts. There is no difference in the oil pumps to feed that extra oil passage in the pistons? In fact, the "oiled" LDS pistons may be optional, as the oil only reduces ring temps by 100deg, and add 1 more ring...

 

[Heath_h49008]

Wait a minute...

TM-9-2815-210-34-2-1 Say the differences are:
Piston... oiled vs unoiled
Intake Rocker arms of increased lift ratio on the LDS
LDT&LDS -1 timed at 20deg BTDC, LDS-2 @ 22deg

The injectors themselves are interchangeable, as are the IPs, blocks, heads, lions, tigers, and bears... oh my. At least for the LDS-1... the LDS-2 seems to have a large number of small updates that make it unique.


Am I missing anything? Does anyone have a better grasp on any changes to the oiling system between LDT465-1C and LDS465-1?

 

[gimpyrobb]

You missed the rpm settings of the IPs, probably more, maybe less.

 

[JasonS]

Wait a minute...

TM-9-2815-210-34-2-1 Say the differences are:
Piston... oiled vs unoiled
Intake Rocker arms of increased lift ratio on the LDS
LDT&LDS -1 timed at 20deg BTDC, LDS-2 @ 22deg

The injectors themselves are interchangeable, as are the IPs, blocks, heads, lions, tigers, and bears... oh my. At least for the LDS-1... the LDS-2 seems to have a large number of small updates that make it unique.


Am I missing anything? Does anyone have a better grasp on any changes to the oiling system between LDT465-1C and LDS465-1?

Can you point me to the portion of the TM which indicates a different rocker arm ratio? My understaning was the the LDS465-2 rocker arm difference was the additiion of a squirter for the pushrod ball/socket.

 

[Heath_h49008]

Can you point me to the portion of the TM which indicates a different rocker arm ratio? My understaning was the the LDS465-2 rocker arm difference was the additiion of a squirter for the pushrod ball/socket.

You seem to have nailed it.......!

Again from the books: ALL model engines use the same part#10899107 rocker arm for the exhaust valves. Code C,D, E and G engines (LDTs, LDs and LDS 427 resp.) also have these for the intake valves, BUT.....
Code A, B and F engines (the 5ton Multifuel's) show a different part# 11641736 for their intake rocker arms.
It sure would make sense if they were of a higher ratio, in fact!!
Anyone having some laying around? I want 6 now......

G.

I'm looking for the part diagrams as we speak.

 

[gringeltaube]

Different part number is FACT.
Different ratio is only a THEORY! ... until someone could measure both and confirm...

(I may have to check on mine, tomorrow...)

G.

 

[Heath_h49008]

Diagram found, but other than the quote from earlier in the thread, I cannot verify that.

TM 9-2815-210-34 has a picture.. Fig 18... but the exact ratio isn't listed. It is, however, the only difference that makes sense, considering the exhaust is the same old LDT part, and the LDS is getting extra air with the same cam, pump, injectors and timing.

It makes sense, but I want to verify it.

I also want to find out if the later rebuilds done on the LDT engines included the LDS pistons, considering how many received LDS fuel pumps and other items, it would stand to reason the .gov only kept one type on the shelf for both engines. Secondly, will LDT pistons adequately handle the heat from the LDS combustion? I would think so, but 40hp and 125ft/lb of torque is a bit of a jump... I would feel better being sure. Or, if LDS pistons can be retrofitted with the LDT oiling system in as an option.

I'm an ASE parts tech, but these are new beasts to me. I'm going cross-eyed in these manuals looking for good part descriptions.

 

[Heath_h49008]

JATONKA M35s NEW NOS LDS PISTON AND LINER KITS


LDS pistons and sleeves can be interchanged according to Jatonka...

I think we are down to the rockers may be a different ratio, the pump gets cranked up to use all that new air, and the oiled pistons are there to keep it alive. The air filter and associated gear gets switched to feed the larger air needs. Starters are swapped for clearance of chassis parts in the 5 ton... and the increase fuel usage spec comes from the pump being cranked?

Heck, looks like we can beat this yet. Gringletaube, you are looking like the one to to solve it!

 

[gringeltaube]

This continues to be a mystery....

Checked X-many rocker arms in my pile of (takeout)engine spare parts and also pulled valve covers of three different engines this morning: a LDS427-2; a 5ton LDS465-1A and a LDT465-1C. All are Continentals, in perfect working order, depot-rebuilt between '89 and '90 by TEAD....

....just to find out that ALL rocker arms look exactly the same, measure the same and are exactly the same part number, clearly stamped 10899106 on the side of the arm !!!

The numbers stated in my post #92 were taken from the 1974 TM 9-2815-210-34P, page 35 and corresponding figure 18. This manual is kind of confusing - the whole rocker arm assy #37 is numbered #10899106 and the arm itself goes as #10899107 - but it clearly shows that the A,B and F- coded motors do not have these for the intake valves...!?

Who knows what the difference really was. Fact from today is that even back in 1989 they managed to use 2.5ton rocker arms to (re)build at least this one, a genuine 5ton Multifuel engine, designed LDS465-1A, assembled and equipped with all accessories to run in a 5ton and surely enough set to its std output rating, about 175HP.

After this I think I'm one step closer to my original plan for a "homegrown" Multifuel with 5ton power...: retrofit that sound "TD" LDT465-1C with a set of 5ton LDS pistons/sleeves (thanks Kenny!!!), turn up the fuel, eventually re-adjust timing and of course ensure plenty of air supply via extra size air filters.....
Also means I no longer want those super special, stinky 5ton intake rocker arms....

G.

 

[randini]

Has anyone ever dyno'ed either of these engines? You can quote whatever you want for output. In auto engines, I have seen output off by a big percentage, both too low and too high. I would bet there is not as much difference and we are led to beleive. Or not...
I just cant get my head around such difference in output, for such little differance in engine. ?????

 

[Heath_h49008]

I really wondering how many LDS parts made it onto LDT engines after the late 80s. The airflow requirements for the LDT465-1 and -1a are listed as 405cfm, where the LDS465-1 & 1A are listed as 450cfm... Again, LDS465-2 is the monster at 550cfm (Numbers as per TM 2815-210-34-2-1) These engines are nearly identical, and considering putting the higher output parts on the low output engines would cause no negative side effects, it would make sense from a logistics standpoint to simply use the part number that covered both.

I believe we have people who have found oil channel pistons in otherwise factory LDTs as well?

I'm wondering what a dyno might have to say about these "updated/rebuilt" LDTs packed with LDS parts. Randini might have the best idea.

 

[JasonS]

I really wondering how many LDS parts made it onto LDT engines after the late 80s. The airflow requirements for the LDT465-1 and -1a are listed as 405cfm, where the LDS465-1 & 1A are listed as 450cfm... Again, LDS465-2 is the monster at 550cfm (Numbers as per TM 2815-210-34-2-1) These engines are nearly identical, and considering putting the higher output parts on the low output engines would cause no negative side effects, it would make sense from a logistics standpoint to simply use the part number that covered both.

I believe we have people who have found oil channel pistons in otherwise factory LDTs as well?

I'm wondering what a dyno might have to say about these "updated/rebuilt" LDTs packed with LDS parts. Randini might have the best idea.

Based on Continental's own literature, the oil channel in the piston doesn't do very much (100F reduction in upper ring land temperature).

My BELIEF is that you can realize most if not all of the LDS horsepower by simply turning up the LDT's fuel.

 

[Heath_h49008]

You may be right. But if there is no interference issue the idea of higher ratio intake rockers might be one to consider, even if the LDS turns out to be the same as the LDT. Those wouldn't be bad to knock out in the machine shop. Small chunks of good steel, a fairly simple shape...

I have three goals... longevity, mileage, and power when it is needed. The LDS pistons are nice from a longevity standpoint, being cooled better than the LDT. The power would be a benefit on slopes and while pulling... but as long as I can keep the engine in it's happy zone and drive 65 on 395s, I'll be giddy. In my neck of the woods all of the truck traffic drives at 63mph. As long as I can do that at a liveable RPM, I won't bother a soul.

Propane can give quick bursts of power, but at what cost in engine life? I don't know. Methanol? Again, I don't know.

But factory parts, with development history and the bugs already worked out? Sign me up!

If anyone can point me to another manual or re-builders shop guide, I would happily go blind reading to find the answer.

 

[gimpyrobb]

With my LDS and 395s, 2500rpm puts met at 62.5mph according to the GPS. I wouldn't say I have power for days, but I truck pretty good up hills and pulling stuff.

 

[mikew]

Heath_h49008.

I have the re-build manuals here:

Technical Manuals

Look under the "Drive Train" section for the two "Maintenance Manual - Engine, Multifuel LDS-465 & LDT-465" manuals.

 

[Heath_h49008]

I'll do my best. Thanks! Parts list as well? Awesome...