Cummins L10 owners, good and bad about the motor?

[Adarian]

Lots of information about DD engines. I see a few of us have Cummins L10 engines.
What are the good points and bad points about the motor?
Best practices for maintaining it?
Best practices for driving it for fuel economy?

I have only had my bus for 6 months and all seems fine. But I have no idea of what is normal.
I have a leaking fuel pump, coolant leak from a hose that connects the water pump to the thermostat housing and a oil leak that appears to be coming from the top of the oil filter.
The above appear to be easy fixes with the fuel pump being the more costly repair.

Spec on motor
It has the conventional aftercooling system.
270 hp, and I don't recall the torque.
Mechanical

[Melbo]

Adarian

Before you tackle that fuel pump get some information from Mike L He had his rebuilt and bumped up his HP if I remember correctly. 

From my experience they are easy to start easy to run easy to cool and not bad on fuel.

The only real headache I had was trying to install a king cruise on the engine.

The air throttle also supplies air to the fuel pump so it is not completely mechanical and the king cruise needs to be attached to the air throttle at the front of the bus.

Now all is well and I have about 25 thousand plus miles on mine.

Melbo

[luvrbus]

L 10's are like any other engine depends on the way maintenance was done, to me they are a dog for power but did get fair fuel mileage and they have their share of problems .  


good luck

[Melbo]

Clifford

I agree that they don't have as much power as some might like but it is WAY better than my 8V71 and spicer were. ( I have a hp590 ZF four speed ) As of yet I haven't taken it drag racing but I have driven it over some 12000 foot mountains and a couple of times over Raton Pass. Does just fine once it finds it's speed.

Looking forward to meeting you at Qzite.

Melbo

[luvrbus]

Melbo, did Gray Benett in Vegas do that setup for you ?



good luck

[Melbo]

Gary and Dan in Las Vegas

About three years ago I think

Melbo

[JohnEd]

Clifford,

So what is the BEST engine in the 350HP realm in terms of power and then economy?  Fresh out of the box.....mechanical and then electronic?

Thank you,

John

[Tom Y]

Adarian, There are a few on this board ( L10 owners ). Does yours have a turbo? If not and you want more power a M11 will bolt up if your tranny will handle the torque. My L10 is new, less than 5k on it and electronic. 330HP and 1250 ftlbs of torque. I was hoping to do better than 10mpg and have not made it yet. Some don't like Cummins, some do. I know when I start mine in the morning I am not ashamed to walk outside while it warms up.  What model bus do you have?   Tom Y

[TomC]

While the L10 is a mechanical engine with 330hp being at about the top of its' horsepower output, the M11 and ISM are virtually the same engine from the outside, but have the capability to go to 500hp and 1550lb/ft torque for motorhome use.  Used with an Allison 4000 series, would make for a nice hotrod.  Good Luck, TomC

[mikelutestanski]

Hello:   I support melbo with all his comments. My L10 is 1994 Cpl which is a transit @270HP 860 ft lbs torque@1300 (factory specs) ; with an allison B400R computer tranny. I did have the pump rebuilt by pittsburg injector for 580 dollars (I removed the pump) . They added 20% to the pressure curve and it produces around 300 hp.THe engine is slightly overfueled by that I mean it is more smoky at light loads and when starting out. but the mileage is the same at both hps   I average 7.4 so far.  ANd there are times when the power is nice.  
  It is interesting to note that at last years rally Mr Russell from Russell diesel service NC predicted that the fuel pump would leak because of the new fuel and low and behold 6 monthes later it did. I happenend to be in the pittburg area so had the repairs done .
THey also added some Rs to the engine it tops out with 210 psi @ 2200 rpms.   MY turbo probe is in the exhaust manifold and the only caution is to not get to 1200   so far I have only seen 1100 and When I do I back it down.   It generally runs 950 to 1050 aprox.

    The B400r is a 6 speed double overdrive  with a 4.6 rear . It likes to run at 1700 in my opinion so in 6th it is @ 70 mph. In 4th it maxes out @56 @2100.
     The newer computer engine has more hp and the engines are slightly taller. approx 2 inch . I think the THe setup that TomY is about the best you can do with the L10.   My setup is older technology with slightly lesser efficiency.
   As far as cooling the MCI 7 radiators are handling everything just fine even with the transmission retarder.
 
          FWIW  and this info is from my limited bus experience.....  
   Cheers and happy bussin  .
    Mike
   

[Adarian]

Motor has a turbo.
The fuel pump started leaking a month after I purchased it.
The previous owner was running fuel that was at least 2 years old in it. He maybe drove it 200 miles in 2 years.
The fuel pump leaks right at the throttle shaft lever. a slow drip.
Cpl is 774
I have an 88 Flx Metro with an engine build date of 12 july 1989 and warranty start date of oct 1989.
LTA10-BUS (270)
Voith 3 speed transmission

The bus does not tow anything and does 65 to 70 on the hwy and did 45 up the grapevine.
There is not much in the bus except for 2 treadmills and seating for 9 people. It does not carry much of a load.
But if I can get more power with a fuel pump rebuild, I will take it, if fuel use does not go up.

[Tom Y]

Adarian, What is the Voith top ratio? 1 to 1 ? What is the rear end ratio? My L10 is set at 2000rpm, and I have a 1 to 1 top end Allison with 3.38 rears. I would not worry about the old fuel.  Tom Y

[Adarian]

I don't know about the rear end ratio.
3rd gear is 1:1
I wasn't worry about the old fuel. I think that the new fuel started the fuel pump leak.
I think the data plate said 2100 rpm

[gus]

I helped a buddy drive his 18 wheeler with this engine a few years ago and this engine never gave us a bit of trouble in many hundreds of thousands of miles. It already had 500K+ miles when he got it.

It was developed by Cummins as a fuel miser and didn't have a bunch of HP but plenty of torque and we only had a 9sp trans for it hauling 80K lb loads.

I would think it would be an ideal engine for a bus with the proper transmission/rear end combination.

It isn't as smooth as a DD 2 stroke though but has nice lugging torque.

[Tom Y]

A local trucking firm here ran them also. They gave me a junk engine ( the crank broke at # 3 throw ) but they drove it back to the shop. They then went to the M11 ( as they bought trucks ) then to the Mercedes and now are back to Cummins. The broken crank was one of the few problems they had, and the only bad crank.  Tom Y