New style injectors in 5 ton multifuel

[Heavy Hooker]

I have a M543A2 5 ton with a multifuel. The fuel pump is turned up a bit so the power is good for a 39,000 lbs truck with a small motor. My question is this motor is running some worn single hole nozzles in it for injectors and I have several sets of the latest LDT4651D injectors, will these flow the same as the single hole tips? I've built several hundred multifuel nozzles but have never flow tested them. The 1D engine also has a bit different piston c-chamber sphere and I don't know how they would burn in an older piston. Anyone have experience with these new nozzles in older engines?

 

[gimpyrobb]

Are you asking about the 2 hole injectors? I have taken apart a motor that had some of each in it. Don't know if that answered your question or not.

 

[Heavy Hooker]

The LDT4651D late M35A2 engine uses the AMBAC made in Italy 2 hole injectors with a high 3600-3750 opening PSI, I just don't know if these will flow the same rate is the lower PSI 3050-3150 single(large) hole injectors. The plunger in the head of the 5 ton pump is bigger thus pushes alot more fuel. You can only push so much fuel before is causes extreme pressure on the plunger and pump drive system. The two small holes and higher PSI make for alot better burn due to better atomization of fuel. If you find a mixture of nozzles in a 5 ton engine it is because the single hole nozzle NSN was superseded by the 2 hole nozzle around the time the old 5 ton was phased out of the military. The two types should not be mixed in an engine.

 

[gimpyrobb]

Good info there! Man, I really need to setup that injector tester we got.

 

[cranetruck]

Is it possible to tell by the part number which came first, if so, in what order were these nozzles introduced?

Just curious....

 

[Heavy Hooker]

The three NSN's you have there are for the different "useable on codes" the "A", "B", "CDE" you will have to look in the front section of the book to see what engine they go in. Example-LDS 427, LD 465, LDS 465 or LDT 465. The latest injector used was NSN 2910-01-214-2684, this is the two hole tip 3750 psi pop off. At the end of the multifuel's military carreer the LDS 465 1A (5 ton) and the LDT 465 1D shared the same fuel system and rates, the same engine internals with only the oil pump, pan, flywheel end and a few other external pieces being different. There was a piston used in the last bunch of engines produced that had a larger piston sphere and a smaller injector tip relief cut, if you used the older longer tipped injectors there was very minimal clearance between piston and tip. I had a catastrophic failure on the dyno at max RPM no load that took out the pistons, liners and one head, what a mess!