L10 vs SA6D125

[michel]

Why on some komatsu excavator we have the cummins L10 engine and on others we have the SA6D125 komatsu engine, usually we find these engines on the PC400. Do they have the same horsepower?

 

[John C.]

The L10 Cummins engines were seriously underpowered compared to the SA6D125. The Cummins engines will slow down because they don't have near enough torque to pull the pump loads. You have to set up the pump flows completely differently.

I've have worked on a few of the Cummins units that developed the typical slobbering piston ring problems with around 4,000 hours on the clock. I haven't met an operator who ever wanted to trade his Komatsu engine for the Cummins.

The issue came about because Komatsu would not certify their own engines to US EPA certifications back in the late nineties. Since Komatsu and Cummins were already in bed together and Cummins had already certified their lot, it was easier to fit the Cummins in the US bound machines. Most of the Komatsu line as far as I know now have gone back to the Komatsu engines.

 

[zxa]

and they still in the same bed.... the komatsu engine are in fact a disguised cummins engine....

 

[John C.]

That particular Komatsu engine design would be like comparing a sailing ship to a passenger jet.

The L10 used soft liners a single head with PT fuel system that barely injected at 2,100 PSI. The SA6D125 had hardened liners, high alloy rings, a Bosch style fuel system with the injectors hitting at 3,200 PSI. The Komatsu engines never wore out with decent maintenance. They ran so long they broke. The Cummins you had to do a major at least every 6,000 hours and many times less.

 

[michel]

John you said you have to set the pump flow on L10 diffrently than on S6D125 I think you are completely right, because with machine equipped with L10 they sett the TVC at almost the max and with S6D125 they put it at the half between the min and the max. I think the reason is that the L10 have their torque curve different than S6D125 maybe they have the max torque at lower speed

 

[John C.]

michel,
You are correct.

 

[Dr Komatsu]

zxa

You are incorrect that Komatsu engines are disguised Cummins Engines the 6D95
6D125 ,6D140 and 6D170 are Komatsu engines. The 6D102,6D114 were in fact Cummins built depending on country factory was located or licence built Cummins by Komatsu themselves . The latter versions of some Komatsu engines have joint Komatsu/Cummins parts fitted. The newer Tier III onwards fitted to PC's have either Komatsu or Komatsu licence built or Cummins built units.
Also some Cummins engines not fitted to any Komatsu's have Komatsu parts contained in them as part of there sharing of design and components to reduce development costs and duplication of engine lines.

 

[MrKomatsu]

the pc 400lc-6 came out with the m11 cummins....but due to the avance hyd. system on the komatsu's the engine was overpowerd by the pumps resulting in major valve
train damage...that is why the a82000 nd up units came out with the s6d125e...a more suitable engine for the application/......more hp as well

 

[MRRPM]

Hate to resurrect an old thread, but I've got an old PC300LC-3, S6D125 engine, engine is worn out. Around here, I can buy old road tractors for way less than a rebuild kit for the 6D125 costs, thinking of switching it over to the Cummins. I own a complete fab/machine shop, so mounting it is no problem at all. This way if the L10 blows, all I've got to do is slap in another motor & go. I think some of the L10's came out at 300hp, seems like this would pull the 300 really well. I think the 6D125 is around 250hp??


Thoughts??

 

[Toyboy3b]

Just to clear up all the ******** and ignorance about the whole Komatsu/Cummins engine thing.

http://www.ipalliance.co.jp/eng/

http://www.ipalliance.co.jp/eng/knc/

http://www.ipalliance.co.jp/eng/company_info/outline.html

http://www.ipalliance.co.jp/eng/company_info/history.html

 

[MRRPM]

Decided to rebuild my Komatsu motor. Line bored it, new liners, bearings, turned crank, pistons, etc, should be running first of next week.

 

[MRRPM]

Got the 300 back to running, runs perfectly! 60 PSI oil pressure at 180 degrees, no smoke, no blowby, cranks instantly, around 10 hours on it so far.

I done all the work in my shop, me & my guys, had over $5000 in just parts, no labor, and did the line bore myself.

 

[John C.]

Glad to hear your back up and running.

Thanks for letting us know how it worked out