aussiesmg
aussiesmg MegaDork
4/11/21 11:50 a.m.

What does the hive have to say for or against the Cummins 7.2 L6 ISB engine?

STM317
STM317 UberDork
4/11/21 2:43 p.m.

I'm not aware of any 7.2Liter Cummins engines. What vehicle/chassis is it in?

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) MegaDork
4/11/21 4:48 p.m.

No ISB 7.2L.  3.3, 3.9, 5.9, 6.7.

Next largest that I know of is ISC and ISL which start at 8.9L

gearheadE30
gearheadE30 Dork
4/11/21 5:05 p.m.

The Cat C7 is a 7.2 liter I believe...as others have said, no Cummins that size. The ISB is 6.7 and the old ISC was an 8.3, but is now the ISL9, 8.9 liter.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) MegaDork
4/11/21 6:08 p.m.

If it's the Cat C7, it's basically the electronic version of the old 3126/3116.  That was the first generation of ACERT and it was not exactly without problems.  The regen cycle was messed up and caused numerous low power/mpg issues.  It would start a regen cycle regardless of duty cycle, so suddenly you find yourself climing a hill with reduced power and 235 degree coolant puking out of the radiator.

The B-rating on the C7 was pretty poor.  Less than half of something like a Detroit 60.

In comparison to something like a small block chevy, great.  In comparison to a D60, DT466, or Cummins N17, they don't really shine in the truck world.

This is assuming you plan on using it in a truck application.  If you want to put it in a Miata, it will last forever laugh

A 401 CJ
A 401 CJ SuperDork
4/11/21 6:10 p.m.

Is somebody getting a pusher?

Wally (Forum Supporter)
Wally (Forum Supporter) MegaDork
4/11/21 6:25 p.m.

If it's the C7 I'd avoid it and look for a 3116.  They should be easy to find, GM put them in a ton of medium duty trucks, I had them with six speeds and autos and never had trouble with them. 

aussiesmg
aussiesmg MegaDork
4/12/21 7:44 a.m.

Hmm the seller listed the details, I will question him further. The vehicle is a F650 bus

aussiesmg
aussiesmg MegaDork
4/12/21 8:27 a.m.

He ran the VIN and it is a 6.7 Cummins

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) MegaDork
4/12/21 8:59 a.m.

Then drive and enjoy.  EGR cooler will give you relatively expensive fits, but otherwise a great oil burner

Wally (Forum Supporter)
Wally (Forum Supporter) MegaDork
4/12/21 1:48 p.m.

Still trying to corner the market on medium duty Fords? 

wawazat
wawazat Dork
4/12/21 4:26 p.m.

My 5.9 ISB was solid except for the fuel control actuator, a N/C solenoid valve in the fuel line.  During my 190k miles of ownership two failed on me both times leaving me stranded.  Are these still on the 6.7 version?

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) MegaDork
4/12/21 10:00 p.m.
wawazat said:

My 5.9 ISB was solid except for the fuel control actuator, a N/C solenoid valve in the fuel line.  During my 190k miles of ownership two failed on me both times leaving me stranded.  Are these still on the 6.7 version?

Nope.  All common rail injection.  Works actually more like a modern gas EFI.  Electric lift pump supplies a belt-driven pump which sends about 30,000 psi to the fuel rail.

On your old 5.9, the injections came from a hydraulic pump and the only way to kill the engine was to physically block the fuel flow.  Now, much like gas EFI, once you kill the power to the ECM, the injectors stop opening.

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