Komatsu d65e-6 cranking problem

[kshansen]

Well I do know the NT380 engines we had in the old M-30 Mack had a "Float Tank" on the side of the frame. Those trucks had the fuel tank mounted across the frame behind the cab. The float tank is very similar to the tank on the back of a toilet. Fuel flows under gravity to inlet to the tank and a valve with a float connected to it operates just like the toilet, when fuel gets to a set point the float lifts up and shuts off the flow of fuel. There is a breather, at least on ours, like you might see on a rear axle to allow air in or out of the tank.

Maybe someone else can say why this set up was used unless it is just a "safety feature" to protect the engine in the event the fuel shut off solenoid did fail or if someone stalled the engine and failed to turn off the key.

The other possibility is if the engine was equipped with mechanical shut off valve, yes they do exist, there is one sitting on the shelf were I worked. Someone could kill the engine using it and then push the shut down cable back in and effectively leave the valve open for days.

 

[kshansen]

Oh! forgot to mention we have had a Komatsu WA600 where I worked since 1996 with a KT 19 Cummins so yes they do use Cummins engines in some Komatsu machines.

Okay had to do a little digging on Google and found this that at least gives some explanation of the need for "Float Tanks":

 

[jughead]

my D75S has a cummins in made in japan under license from cummins. been a while since i looked at it but know it has a float tank. like to drove me crazy till i found it my manual didnt show it. i think it is listed as 12000 cc engine. will try to look tomorrow to be sure.

 

[Neily]

Hi all, sober this time :/. Yeah have seen cummins in Komatsu loaders etc, what I should of said is that I have never seen one of these ie wasn't sure what engine it was exactly. Ok float tank setup I have never seen, makes sense to stop fuel coming back through the return line or if it has a manual shutdown. Seen plenty of river pumps and line drive bore pumps with massive overhead fuel tanks but never a float tank fitted. All these engines had electric shut down solinoids and most likely a check valve in the return line, they never give any trouble that I've seen or heard of. Nh220 is an engine I have seen a few times but very little experience with, it's a pt setup anyway so same difference. I'll still say that if its pumping plenty of fuel to the injectors and won't run something is wrong with the set. I'd suggest pulling the covers and eyeball the top for bent or loose pushrods bar the engine over and have a good look at what's going on as a starting point. Most people don't have a very good understanding of how a pt system realy works which causes lots of problems, ever tried doing a set when the acc drive isn't timed?, makes it interesting lol. Another example a injector can be set at 60"lbs or 6"lbs depends what method you are using. I know of a "mechanic" that tried to adjust the injectors on a vt190 to 60 ft lbs, he kept breaking his flat screwdriver bits trying to get to 60

 

[Scrub Puller]

Yair . . .

Thanks for that kshansen.

Would my understanding be correct in assuming the unit injectors in the Cummins system can stop on the cam in such a position that fuel can leak into the cylinder . . . is that essentially the difference between Cummins and "normal" injection engines?

Cheers.

 

[lantraxco]

Cummins and Komatsu had a joint venture going, maybe still I don't know, Komatsu built engines to Cummins design under license, and vice versa I heard with some of the BIG Komatsu diesels made here by Cummins, but I can't swear to that.

 

[Neily]

Hey scrub puller yes that is correct. I wrote a long explanation and my iPad froze and I lost it and couldn't be bothered to re write it. I will if your interested?
Ps, not trying to sound smart but a pt injector isn't a unit injector. Something like a 71,92 Gm has is what a unit injector is.

 

[jughead]

my hat is of to you guys-gals that know how to tune these diesel engines properly. always thought i was a decent auto tech for 40 years or so but i take a back seat to what i read on this website

 

[Scrub Puller]

Yair . . . .

Gotcha Neily. thanks for the heads up. Showing my ignorance. Never did have much to do with Cummins and never understood their fuel system and assumed the injectors were operated by a cam similar to Detroit two strokes.

Any information you can post would be of interest to me.

Cheers.

 

[kshansen]

Yair . . . .

Gotcha Neily. thanks for the heads up. Showing my ignorance. Never did have much to do with Cummins and never understood their fuel system and assumed the injectors were operated by a cam similar to Detroit two strokes.

Any information you can post would be of interest to me.

Cheers.

Well if you have about ten minutes there is a pretty good YouTube video on the PT system here:

https://www.youtube.com/watch?v=KzuwdxEJfQA

 

[Scrub Puller]

Yair . . .

Gotcha kshansen. thanks for the link.


Cheers.

 

[Shimmy1]

I once rebuilt a V12 28 litre Cummins on a standby generator and serviced it for about 3 years.

One like this, TC?
https://greenville.craigslist.org/hvo/5665047375.html

 

[tctractors]

Shimmy, that looks about the same engine, they fitted this Cummins into the Komatsu 475 dozer, also into the big heavy haul road trucks 1710=VTA 28.
tctractors

p.s. I have rebuilt a 50 litre Cummins that had a plate attached to the engine stating 3 peoples names that built it, I so wanted to put my own plate on it "Re-Built by a Donkey"

 

[Burl]

Hi! It's been a while since we have done anything with this Dozer. It's a 1979 Komatsu d65e-6. I really appreciate everyone who originally posted on this thread trying to help. With the help of a mechanic we did manage to get the Dozer cranked. Had to install new injectors and new push rods (which a previous mechanic damaged by tightening them up too much). So, it cranks but now it has no power. It will crank and run but it will not turn and if you drop the blade there is NO power... at all. Any suggestions?

 

[tctractors]

The injectors on the Cummins fitted to the Komatsu are set to a lower torque setting than the standard engine found in general, it also has the 4 valve head but with single springs,they often fail when the tractor has been stood some time, if the torque set on the injectors is to high it will be hard to start and weak power, to low and all you get is Gun Smoke, the fuel inlet and outlet lines can be fitted incorrectly. tctractors.

 

[Burl]

tctractors, thank you for you reply!