LDS VS LDT and the real differences

[JasonS]

also the oil cooling in the head of a LDS piston is probably not marginal or they would not have done it. the LDT does not have it, just washed with oil.

It is really hard to say if it is still important. The continental literature claimed it was done to "eliminate the requirement for high additive oil to prevent excesssive ring groove carbon formation." Has anyone had ring sticking with modern oils? The piston bowl is cooled on all engines.

 

[m-35tom]

My point was, the difference is all in the pumps and the hydraulic heads if the question is "Where does the extra power come from." Also, if all things are equal, buying the HD90101A as opposed to the HD90100A would seem to make sense if increased output was the goal.

EDIT: In case my point was missed by my roudabout way of saying it... just crank the fuel and get a pyro.

i agree, the 'extra' power comes from more fuel and timing advanced to help keep it cooler. so set your LDT to LDS-2 timing and give it as much fuel as it can handle. must have pyrometer or very real risk of melting pistons. this is just a very old engine design that was never meant to have the power to c.i. ratio of todays modern designs.

 

[Squirt-Truck]

?????? Sure that was not to advance timing? Advanced timing reduces EGT, increases MPG, increases smoke, increases chamber pressure, and adds turbo lag. Retarded timing, decreases smoke, reduces chamber pressure, reduces MPG, reduces lag and increases EGT. To much advance can result in hard hot starting and increased advance makes for rough idle. Increased timing helps at high RPM and retarded timing helps on the lower end. Thoughts??

 

[JasonS]

so set your LDT to LDS timing and give it as much fuel as it can handle.

The LDT465-1C, LDS-465-1, and LDS465-1A have the same timing: 20°BTDC so no change has to be made if you already have an LDT. The naturally aspirated LD series are 25° BTDC and the highest horsepower version, the LDS465-2 is 22° BTDC.

 

[Ford Mechanic]

How much advanced timing are we talking about will help?

 

[Heath_h49008]

How much advanced timing are we talking about will help?

None. Don't screw with it. The LDS was set at the same 20deg as the LDT. Only the LDS-2 had a paltry +2deg.

As for messing with the advance/gov springs... I would only do that if you have it done by a shop with a test bench. This is NOT a simple task.

Just get a pyro and turn it up a little at a time.

On a side note, I was working on my truck yesterday and found the safety-wire was gone and the governor spring end cap was almost falling off. Both bolts had backed out, one so much so I can't believe it was still there.

There was much rejoicing. (And she free-revs to 2700+ like a champ as opposed to her issue of dropping out at 2400 last week.)

 

[jasonn]

Ok I started this thread so we could clear up the differences to answer the why more hp. I said before its more fuel and the bigger turbo. put an LDS big whistler on your truck and turn up your fuel screw and you will get the same hp. We have played with these trucks swapping parts around and this is the difference that makes the hp. My brothers truck has the LDS-2 pump and the two hole injectors in it and the small whistler and it doesn't make any more hp than the LDT with a whistler. I took apart the LDS that we had here and took apart an LDT. More air more fuel more hp. The turbo is twice the size the air inlet is bigger the exhaust is bigger. the fuel screw can be turned up on all the trucks. We had a truck we were scraping. We turned the fuel screw up 12 flats and you could clearly tell a difference in hp. Don't do this with a truck you plan to keep very long. But it's like Heath said +2 * is not much the injector talk 2 hole vs 1 hole. I have saw those both in the LDT with no hp difference. Many of the deuces out there have the LDS ip on them no hp difference.

 

[welldigger]

Bump since this is the topic of discussion on another thread.

 

[m16ty]

35 pages and still we don't have a definitive answer on the differences in the two engines.

I'm of the opinion that if you need a engine and a LDS comes along for a good price, go for it. Would a pull a perfectly good LDT and buy a high priced LDS to replace it with, no.

If your LDT is mechanically sound, buy a pyro, turn up the fuel, and be done with it.

 

[Jeepsinker]

Yeah I just got a couple (yes two) in one day for almost nothing. I saved them from the scrap heap.(LDS motors, that is)

 

[rustystud]

Has any one looked at the cams ? According to TM 9-2815-210-35 there where 3 cams used in these engines. I know Gringeltaube has said there is only one available now, but has anyone actually took out a cam from the LDS engine and compared it to the LDT engine ?

 

[Heath_h49008]

Did you read the thread?

 

[Jeepsinker]

I read the thread. So far it looks like we have a different spring in the injector pump timing mechanism, modifying the timing curve, a different hydraulic head(possibly to deliver higher delivery pressure), in some cases we have different injectors, different pistons, Possibly a different cam, but nobody can verify by removing and comparing cams. So we may have the same block and rotating assembly, but we certainly do not have the same engine.

 

[acesneights1]

I skipped around this thread as Im on a tablet but has anyone ever tried using a wastegated hx40 holset and maybe add an intercooler to drop the iats or run water mist ? Not sure how water mist would work on hypercycle engine.
Added boost and lower IATs usually bring the egts into check.

 

[Jeepsinker]

This thread isn't about modding the two engines, it is about the differences between the two. But yes, the water mist works well as long as you have a large enough tank. It goes through water fast.

 

[rustystud]

View attachment Scan0027.pdfView attachment Scan0028.pdfView attachment Scan0029.pdfView attachment Scan0030.pdfHere some data sheets for the LD-465-1 and the LDS-465-1 engines. The data for the LD-465 is the same for the LDT-465 except the turbo. There is a different cam used for the LDS engine, though it doesn't look much different. If you put all the small differences together, ie: the timing, the cam, the injection timing and different springs I believe this is how you get the extra 60HP, and higher torque.

 

[JasonS]

View attachment 499699View attachment 499700View attachment 499701View attachment 499702Here some data sheets for the LD-465-1 and the LDS-465-1 engines. The data for the LD-465 is the same for the LDT-465 except the turbo. There is a different cam used for the LDS engine, though it doesn't look much different. If you put all the small differences together, ie: the timing, the cam, the injection timing and different springs I believe this is how you get the extra 60HP, and higher torque.

Are you talking about the LDS465-2? The LDS465-1/A did NOT have 60 more horsepower or different injection timing. The -2 was spun faster so I can see it having a different camshaft. I can also see it having poorer reliability....

 

[HETvet]

Question, could the water heated intake manifold be modified to get rid of the coolant jackets, thus increasing flow and decreasing boost pressures? Also making the use of an after cooler more useful/friendly? I can't wrap my head around how cooling the intake charge to no lower than engine operating temperature could be useful for power generation, much less keeping EGTs under control.

 

[Jeepsinker]

You could modify it to do away with the cooling jacket. It has been done. The reason for it in the first place was for cold weather starting, not so much for cooling intake air temps. If you figure out how to stuff an intercooler in there the way things are please let me know.

 

[Jeepsinker]

Are you talking about the LDS465-2? The LDS465-1/A did NOT have 60 more horsepower or different injection timing. The -2 was spun faster so I can see it having a different camshaft. I can also see it having poorer reliability....

You are right, it had more like 40-50 more horses. And it does have the same static injection timing, but I has a different timing curve. I believe that the different timing curve is what helps it keep the pistons from melting with the added power.