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upgrading the ldt

SasquatchSanta

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Every LDT and LD that I've seen has the regulator on the side of the block for the oil cooling. The only difference that I am aware of is that the LDS has an extra cooling channel in the piston which results in 100F reduction in top ring land temperature. Not significant IMHO.
All I know is I've always been told the reason the LDS can be pushed harder is because of the pistons.
 

Oldfart

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Check out TM 9-2815-210-34-2-1 online. There are more differences than just the piston. Oil pumps are different and total oil flow is different. Most of the differences seem to be directed toward better lubrication and internal engine cooling. There are camshaft differences as well with the -2 series at least which relate to the higher RPM and the automatic transmission. There are injector differences and fuel flow differences as well.

TM 9-2815-210-34-2-1
 

mudguppy

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Is an LDS worth having if it has 2 1/2 ton pistons in it? Jim
read this thread: LDS vs LDT the real differences. essentially, the only differences are the pistons, injection pump, injectors, and intake rocker arms. everything else (including camshaft) can be found in both LDTs and LDSs. don't know about the oil pump, though - don't remember it being discussed.


... which relate to the ... automatic transmission. ...
what automatic transmission?
 

Oldfart

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what automatic transmission?
The LDS-2 was used with an allison 6 speed auto transmission. The engine and transmission were designed for the M657, XM756 and XM791 series of 5 ton trucks. I believe the -2 camshaft difference also allow a higher RPM. There are more differences to the -2 engine over the regular LDS, but those are related to acessories for the trucks rather than any increase in HP or RPM.
 

SasquatchSanta

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How far can i turn up the fuel on my 73 a2 running wvo
Somewhere buried in the TMs (and in one of my old posts) is a procedure for measuring droop screw (low end/RPM) and main setting (high endRPM) fuel settings by measuring boost pressure under load.

It involves running the truck in low gear at certain RPMs and applying maximum brakes and maximum throttle and measiring the boost pressure.

There is a low RPM test for droop screw setting and a higher RPM test for the main setting. I performed the tests and recorded the results in a post but I'll never do it again as performing the tests is a very violent procedure --- maximum brakes and maximum throttle.

The engine feels like it's going to come out of the frame rails. I don't recommend it.

I've turned my pump down several times and still haven's experienced a power drop.
 

stumps

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I seem to recall reading somewhere that the -1C engine was 130HP, and -1D was 134HP.... and yes, I know that the dash number doesn't necessarily indicate which turbo you got. I suspect that it did when the engine was new, but after it got into the hands of the government, all bets were off.

-Chuck
 

gringeltaube

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.................... everything else (including camshaft) can be found in both LDTs and LDSs. don't know about the oil pump, though - don't remember it being discussed................
Oil pump part# is the same for all Multifuel engine models except for the LDS465-2 (TM 9-2815-210-34P, Fig. 20)

Somewhere buried in the TMs (and in one of my old posts) is a procedure for measuring droop screw (low end/RPM) and main setting (high endRPM) fuel settings by measuring boost pressure under load. .............
LDS465-1 Trouble Shooting Manual, pages 33 to 45...
Procedure would be the same for all, only different (prob. lower) manifold pressure for the LDTs.


G.
 

gringeltaube

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LDS has differnt plumbing for the oil pump from LDT & LD. It is my assumption that is to provide for more oil (better cooling).
Pickup tubes are different, yes, depending on application, how the oil pan is oriented.
Only the LDS465-2 has its oil pump outlet specified as 29 gpm at 2800 rpm; ALL others are 22 gpm @ 2600 rpm (TM 9-2815-210-34-2-1, page 1-14)

G.
 

SasquatchSanta

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Pickup tubes are different, yes, depending on application, how the oil pan is oriented. ...................
Yes --- That's correct.

When I did the LDT to LDS conversion I wasn't sure exactly that I needed plumbing wise so figuring Memphis Equipment would know what I needed I purchased a set of what they called "Reo Plumbing." I could have used the plumbing out of the LDT take-out engine but it is in good shape and I didn't want to break it open.

The oil pan is reversed on the LDS. The dip-stick tubs also has to be relocated.

Here are some pics/
 

Attachments

Oldfart

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Don't have my -2's running yet so all I know is what the TM says. A couple of guys on SS have these engines running and they might know.
 

stumps

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I thought anything over 2500 RPM and the multifuel's like to go kaboom? Jim
As diesels go, the MF engines are all race engines. They don't put out a lot of horse power, but they do put great stress on rods and pistons when they are spun over 2500 RPM. Their true redline is around 2950 RPM unloaded, but ....

Given that the engine is 40 years old, and has been worked on by numerous mechanics with skills levels that are unknown to you, using parts that are either used, or made by the lowest bidder; do you feel lucky?

-Chuck
 

OPCOM

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I attribute 17000 highway miles with almost no engine wear on my deuce to having never over revved it. That meant doing 50-55 with 11.00x20's. Not doing the full 59MPH with 11.00x20's which is the 2650RPM redline. stay off the redline. That's 56MPH with stock 9.00x20 tires.:deadhorse:
 
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