Cummins 5.9 with MD3060

Badaxis · 10-01-2019, 11:42 PM

Is this combination any good?

o1marc · 10-02-2019, 12:10 AM

Bottom end motor, Mated to the best tranny. May be under powered on steeper grades in a full size bus, but be able to slow down on the back side,

SolomonEagle · 10-02-2019, 12:14 AM

Quote:

Originally Posted by o1marc

Bottom end motor, Mated to the best tranny. May be under powered on steeper grades in a full size bus, but be able to slow down on the back side,

Come now.. the 5.9 certainly isn't the holey Grail but still far from the bottom end in my opinion. It's just small.my¢2

Badaxis · 10-02-2019, 12:18 AM

Possible to upgrade engine?

o1marc · 10-02-2019, 12:22 AM

Quote:

Originally Posted by Badaxis

Possible to upgrade engine?

Possible, Yes. Cheaper to find a bus with the motor and trans combo you want to start with. I wouldn't be happy with "it does the job, but I wished I had a ......"

Badaxis · 10-02-2019, 12:35 AM

I already bought it just wondering if there are upgrades I should budget for the motor I was told it was an 8.3 and did not know

SolomonEagle · 10-02-2019, 01:11 AM

Quote:

Originally Posted by Badaxis

I already bought it just wondering if there are upgrades I should budget for the motor I was told it was an 8.3 and did not know

I learned that way aswell. I was told I was buying a dt466 but found out it was a dt360(5.9l). Not what I wanted but not a total loss by any means. What year is your bus? Some of the 24v engines benefit from a lift pump upgrade depending on year

Sehnsucht · 10-02-2019, 04:56 AM

I drove a Thomas RE with a 5.9/3060 and was underwhelmed on flat land so I walked away. Here in the flat Midwest they can get away with it by deep gearing the differential at the expense of top end speed but that's not going to cut it in the second life as a wandering skoolie. Others have said they find it acceptable but I'm unsure where they roam or how fast.

Basically I've never heard a skoolie owner say they regret buying a bigger engine or wish they'd bought a smaller one. If you're already stuck with it go ahead and make the most of it - as mentioned already there a number of things you can do to maximize it. But if in the end you just want more then if it were me I would run it until it dies and while doing so save up for an engine swap.

Badaxis · 10-02-2019, 06:17 AM

It’s a 2002 Thomas flat nose puller

EastCoastCB · 10-02-2019, 06:30 AM

Quote:

Originally Posted by Badaxis

Is this combination any good?

Its a very nice combo. The 5.9 isn't the most powerful but it'll get the job done. Especially mated to that transmission.

cadillackid · 10-02-2019, 07:38 AM

what year is your bus? rear gearing has a lot to do with it too.. in my opinion the 5.9 is a good engine even if its a little small.. parts are everywhere for it as well as aftermarket support even for the medium duty (bus / truck / RV) versions..

if its a mechanical 6BT then theres all kinds of mechanical tweaks to get a little more HP out of it.. if its a 24 valve (most likely since its paired to an MD3060).. then there are tuners available.. fewer than for pickup trucks but there are mods to be made to get a few more ponies out of it if you need them..

-Christopher

Badaxis · 10-02-2019, 08:04 AM

I don’t know if it is a 6BT but it is a 37 foot bus

Badaxis · 10-02-2019, 08:04 AM

I don’t know if it is a 6BT but it is a 37 foot bus and yes it is 24 valve

brokedown · 10-02-2019, 09:56 AM

Hi!

There's a bunch of opinions in here from people who don't own that combination. So here's an opinion from someone who does. I recently purchased a 37 foot 2003 BBAA readr engine with the ISB 5.9 and MD3060 and drove it 1200 miles home over a combination of flats, small hills, and long steep climbs with slow truck lanes.

The 24 valve 5.9 is the ISB. The 6BT was the designation of the mechanical 12 valve version that goofballs call the holy grail. .. The ISB typically makes more power than the 6BT as well.. but shares a lot mechanically.

OK, so brass tacks, how does it work? Well that depends on your gearing. i've got a 5.38:1 rear axle and 5 gears enabled on the transmission, and I can roll 70mph down the highway with room to go more if I wanted to. I'd say my comfortable cruising speed is 65-68, a cull 10mph higher than my previous bus with 6BT and AT545.

Now, I'm not going to lie, if you get a more powerful motor, you end up with... a more powerful motor. The 8.3 ISC is a great engine too and makes more power everywhere. GIven the choice between the two I'd choose the ISC. But I won't punch my face to spite my nose, I'm quite happy with the capability of my ISB, and I got it for a song.

Ultimately, I'm happy with the power I have. It's responsive, starts on the first crank, and as I've said many times, the transmission and gearing are typically more important than the engine.

If you have any specific questions feel free to ask.

Badaxis · 10-02-2019, 11:58 AM

Nice I wish mine was a rear engine I got it from a local pastor that has been the only driver that has 46,000 miles but unfortunately it is a puller not a pusher

2po2watch · 10-21-2019, 07:15 AM

Be sure to upgrade the lift pump. It is the life of the (expensive) injection pump. A set of RV 275 injectors is a relatively cheap and easy upgrade. The pickup I used to have actually got better fuel mileage after installing them. I got them new for $225.

MacC · 10-21-2019, 08:11 AM

I live in the Midwest. EVERY small farming town has a shop that can tweak your 5.9 It cam be done without all the DELETE nonsense. No it won't make it 8.3. One question for anyone willing to answer. What is the big hurry everyone is in?

EastCoastCB · 10-21-2019, 08:14 AM

Quote:

Originally Posted by MacC

I live in the Midwest. EVERY small farming town has a shop that can tweak your 5.9 It cam be done without all the DELETE nonsense. No it won't make it 8.3. One question for anyone willing to answer. What is the big hurry everyone is in?

I dont' think anyone's in a hurry, its just that pickup truck engines barely move a bus and its more efficient to get a bigger more highway capable setup.
Buses are pretty cheap to buy so its usually easiest just to get a good one rather than try to tart up a plain vanilla one.

EastCoastCB · 10-21-2019, 08:15 AM

Quote:

Originally Posted by Badaxis

Is this combination any good?

Yes its a good combo. I'd take one if the deal was right. Usually the 5.9's mate to 3060's are higher rated too!

cadillackid · 10-21-2019, 08:27 AM

Quote:

Originally Posted by EastCoastCB

I dont' think anyone's in a hurry, its just that pickup truck engines barely move a bus and its more efficient to get a bigger more highway capable setup.
Buses are pretty cheap to buy so its usually easiest just to get a good one rather than try to tart up a plain vanilla one.

my bus with a ""Pickup truck"" engine Hauls Ass

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