Help LDT IP on a LDS motor

[rickdavis81]

I've been struggling with my m51 having a lack of power. When I bought it the previous owner said he installed a different ip because the old one leaked. I've had to turn it up quite a bit to get it to start and run decent but still doesn't like to pull 4th or 5th gear. I noticed tonight it has a LDT IP on it instead of a LDS. I've been trying to find some threads on this subject but 99 percent are putting lds on a ldt. Besides turning up the fuel screw and watching my pyrometer do I need to turn up the droop screw too? Just keep turning up the fuel screw till my temp gets to an appropriate level? Or just order an lds ip?

 

[Floridianson]

If the FDC is bypassed the droop screw no longer works as it should because the FDC piston no longer moves. If the FDC is still there then get the main fuel turned up first then the droop could be turned down to see if you can get some of the low rpm smoke to calm down. Are you running Diesel? You are adjusting the main fuel at the double nuts right? You should bypass the FDC if not already and that will bring you main fuel up. From there you might be able to add more on the main fuel or you might need to reduce the main fuel adjustment. Also you don't have to tighten the outer jam nut on the stud till you find the correct amount you want so this might save you sometime when adjusting the main fuel. After you find the correct amount of increased / decreased fuel then lock the outer nut down while holding the inner nut.

 

[gimpyrobb]

It might be 180* out of time.

Set the timing mark on the harmonic balancer and check to see if you can see the red scored tooth on the hydraulic head.

If not, its not timed right.

 

[rickdavis81]

I’m 99.9% sure it’s timed right. When the mark lines up with the balancer and valves are in the right position I can see the red tooth. The fdc is bypassed. I didn’t realize that took the droop screw out of the equation, guess that explains why moving it made no change. I’ll turn the fuel up at the double nuts some more and try driving it today. Oh and yes 100% diesel with fresh filters

 

[gimpyrobb]

Sounds like you just need to keep turning the fuel up. Honestly there is little difference in the motors, I have a tuned LDT in my M62 wrecker and it moves the truck just fine. For the money you would spend on swapping out the LDT IP for an LDS IP, you wouldn't be very far ahead. Also, have you pop tested the injectors? Many have reported big gains in power and economy with good injectors.

Start with post #31 and then read the rest of this thread, good info here:
https://www.steelsoldiers.com/showt...-testing-and-TM-and-compression-testing/page4

 

[rickdavis81]

I turned it up a little more and gave it a short run this morning. Seemed to be a little better. I’ll add some more this afternoon. I popped tested the injectors, ended up sonic cleaning them and resetting them not long ago. Thanks

 

[Floridianson]

With the FDC bypassed the droop screw will lower or add more fuel just like the main fuel adjusting nuts. If you go to far clockwise it will be hard to start. When the FDC is bypassed just leave the droop alone and deal with a little extra smoke at lower rpm. When you get a good puff of smoke when you blip the throttle and it clears when high idle is reached you looking good. Then when driving same thing smoke on take off but clears when running high rpm or watch you pyro and adjust to you altitude / amount of hills. Here in FL. being flat and sea level I can run more fuel.

 

[74M35A2]

When we changed the engine in WildChild467's M35a2 with the engine he got from gimpyrobb, we had the IP timed 180 out, and it would not even start. Just white smoke out the exhaust when cranking. Just FYI, so that is probably not it.