Looking at bus engines for the first time.

[wrenchtech]

I am on the verge of buying my first bus. I am going to look at a 2003 Freightliner with five windows (28 - 32 passengers?). It has 5.9 Cummins and an auto trans (Allison 565?). I am gathering that the Cummins is not a popular engine in this forum because of its small displacement. I thought some advantages to the Cummins might be that more shops and mechanics are familiar with it than with any other diesel meaning that it would be easier and less costly to find parts and service than with a DT466 or a Cat 3126. The online knowledgebase for the Cummins is pretty fantastic too, especially when it comes to squeezing more power out of it. Of course, the little engine us up against the old axiom that says that there is “no replacement for displacement”. On the other hand, there is a pretty large community out there of folks swapping the 1.9 Volkswagen TDI into Toyotas and Ford Rangers that are pretty happy with the results they are getting. A Cummins 5.9 with the p-pump mechanical injection system can easily make 300hp and 800lbs/ft with minimal modification. Just going by the numbers it seem like that would make a good powerplant for the kind of bus I am talking about.

[WARGEAR]

The 5.9 Cummins is a durable and tough motor. Being that in this case it’s in a five window it should be fine as a power plant.

[cadillackid]

in a short bus it shoul;d be fine... year 2003 you may very well have the allison 2000... 545s were i ntheir last year at that time.. is your shifter D-4-2-1. or D-3-2-1?

[wrenchtech]

Originally Posted by cadillackid

in a short bus it shoul;d be fine... year 2003 you may very well have the allison 2000... 545s were i ntheir last year at that time.. is your shifter D-4-2-1. or D-3-2-1?

I'm going to go look at it for the first time tomorrow. Now I know what to look for when I see the shifter. Thanks for that! I will be happy if it has the Allison 2000.

[o1marc]

It's not that the 5.9 is a bad motor, it's just that 95% of them are backed with the Allison 545 transmission which make it the least desirable drivetrain available limiting your travel options. A 5.9/2000 would not be a bad set up.

[wrenchtech]

Originally Posted by o1marc

It's not that the 5.9 is a bad motor, it's just that 95% of them are backed with the Allison 545 transmission which make it the least desirable drivetrain available limiting your travel options. A 5.9/2000 would not be a bad set up.

I've been hearing that the 545 is undesirable because the torque converter slips a lot, or at least slips too much for highway travel. I am guessing that it is a 4-speed with a 1:1 top gear.

[o1marc]

Originally Posted by wrenchtech

I've been hearing that the 545 is undesirable because the torque converter slips a lot, or at least slips too much for highway travel. I am guessing that it is a 4-speed with a 1:1 top gear.

Yes, the issue is the trans does not have a locking torque converter, so it is always working against the fluid , heating it up on high speed or mountain pass roads. You don't have the option of using engine backpressure to slow you down going down hills.