Cummins vs MaxxForce

[LoneStarBQ]

We are looking to purchase a diesel pusher and I would like to know if there are any opinions about the MaxxForce 10 engine vs. the Cummins ISB.

Thanks!

[wolfe10]

Kind of difficult to compare-- almost apples and oranges. It would surprise me that the same size coach would offer both engines. Most are familiar with the Cummins B engine in its current 6.7 liter parent bore rendition. It may be more appropriate to compare the Cummins C or L with the MaxxForce 10 in terms of size and performance.

The International MaxxForce is new to RV applications and is larger, of different design (wet sleeve), different emissions control systems, etc than the Cummins B engine.

MaxxForce 10 specs:

Engine Type: Diesel, 4-Cycle

Configuration: Inline 6-Cylinder

Engine design: Wet sleeve

Displacement: 9.3 L (570 cu. in.)

Bore & Stroke: 4.59 in. & 5.75 in. (11.7 cm & 14.6 cm)

Compression Ratio: 17.2:1

Aspiration: Two-Stage Turbochargers, Intercooler & Aftercooler

Combustion System: Direct Injection

Engine Lubrication: 30 Quarts (28 L)

Total Engine Weight (Dry): 1,425 lbs. (646 kg)

Dimensions: L 45 in. x W 42 in. x H 47 in. (L 114 cm x W 107 cm x H 119 cm)

Valves: 4 Valves per Cylinder

B50 Design Life: 550,000 mi (885,139 km)

[LoneStarBQ]

The ISB is on several of the MH I am looking at. However, you're right in that it comes on the lesser end models (all are within a foot of 40'). The Fleetwood has the ISC engine and is more comparable to the Monaco with the MaxxForce 10.

Is one easier to get serviced than the other? Are both equally sturdy?

Jack

[wolfe10]

Jack,

The ISB would be at the low end of the power/weight curve pushing a "just under 40' motorhome". Still get you there, but just slower on grades.

The ISC or MaxxForce10 would give you a better power/weight ratio, particularly if looking at a 30,000 GCW coach/toad.

The ISC is well known as a very long-lived engine. And with the new MaxxForce B50 of 550,000 miles I suspect it will be very long-lived as well. The Cummins B is also a good engine, but not necessarily in the same league with these OTR truck engines. But, with decent care, most motorhomes will have fallen apart before even the B engine wears out.

Most engine work is not done at RV dealers. And since the MaxxForce (or any of the Navistar engines for that matter) are brand new to the RV market, few RV dealers would be familiar with it anyway.

But, since engine work is normally done by engine/chassis dealers, the Cummins has been used in RV's for decades, so Cummins dealers are familiar with the engines AND the engines in an RV application. The Navistar engine will be familiar to Navistar truck dealers, but they probably have never worked on an RV.

Brett

[LoneStarBQ]

Great Feedback!

Thanks,

Jack

[Spike45]

We are looking to purchase a diesel pusher and I would like to know if there are any opinions about the MaxxForce 10 engine vs. the Cummins ISB.

Thanks!

I would agree with Brett that it is odd that an ISB6.7 is on the same list as the Maxxforce 10. Those two engines are not in the same league.

The ISB6.7L for 2010 and later will require the use of diesel exhaust fluid (DEF) which is a urea water solution that is required to meet the emissions requirements set by the EPA for MY 2010 and later engines. The Maxxforce engine does not use DEF systems but has a more complex system in that it uses twin turbochargers, a low pressure stage feeding a high pressure stage. Any issues with turbos could mean the replacement of two turbos not one as in the case of the Cummins engine. International chose not to use SCR (selective catalyst reduction) as a means to clean the exhaust. The SCR process uses a fine mist of DEF sprayed into the exhaust ahead of the catalyst to reduce the oxides of nitrogen. Maxxforce is trying to accomplish the same by forcing more air into the engine to reduce emissions. The forerunner to the Maxxforce engines that used the same technology was the Caterpillar ACERT engines with twin turbos. They had plenty of problems with those when they were issues. Even when there were no issues, the twin turbos and associated air plumbing make for more engine complexity and higher repair bills.

While I am biased for the Cummins (I do work for a Cummins company, Fleetguard) it is still true that the Maxxforce engine has more complexity than the Cummins models which all run a single turbo with a DEF injection system.