Good Enough Bus?

TakinCareOfBusness · 02-27-2020, 01:21 AM

Hi all,

Would love some input on a bus I'm looking at. Haven't gone to see it yet, but it's not too terribly far away.
DISCLAIMER: Wife is not currently sold on the idea. This may go nowhere. If it looks like it's not going to be doable (yet), I'll be glad to pass along info.

94 Bluebird 40 foot, non-school school bus with coach seating and rv or coach style windows. 5.9 pusher with an MT643 transmission. Under 100k miles reported, but also an engine rebuild (wonder what happened there? Dowel pin?). 4.44 rear axle ratio. I think it will have the newer mechanical fuel pump if I'm correct on when they made the change. Under bus storage on one side, and I *think* maybe basement air? Easy decal removal/repaint.

So...it checks a lot of boxes for me. What I'm curious about:

1. What's it like living with a full sized bus with a 5.9? I would guess fuel mileage with that rear axle ratio would be relatively good, but I wonder about it being gutless. I'm not in a hurry, but I want to be able to get out of my own way, more or less. So far this is my only main concern considering I haven't seen the bus.

2. Might have a/c duct work tied into luggage racks? Any thoughts on mods to utilize these if the racks come out?

Let me know your thoughts if you're so inclined, and thanks!

WIbluebird · 02-27-2020, 05:40 AM

Make sure it actually has a 5.9. Some people don't realize what they have and incorrectly list an 8.3 bus as a 5.9. There is a chance its an 8.3 especially if its a 40 ft pusher with AC.

I had the AC system that you mentioned. It was ducted thru the luggage racks and extremely bulky. Also given the fact that it didn't work factored into my decision to remove the entire system.

Truthseeker4449 · 02-27-2020, 06:35 AM

Got any pictures?

brokedown · 02-27-2020, 06:42 AM

I've got a 38 ft A3RE with 5.9 (isb-260) and MD3060 trans. It's got plenty of punch. it helps that I have a double overdrive so it can use a relatively tall (5.38:1) rear axle and still get good highway RPM.

With that said, the 6BT is also likely to be substantially lower power config that what I have in mine, Obviously it works and nobody expects a skoolie to haul ass up hills, with that gearing I would expect it to be great on flat ground and no worse than any of these other jokers with AT545s in the hills.

Sehnsucht · 02-27-2020, 09:31 AM

Not speaking from ownership experience, only test drives. Here in Flatiana they get away with a 38-40-footer being pushed by a 5.9 because A) they configure the differential so deep that a team of gerbils could move it and B) there's no hills to climb and C) no one's expecting to do over 55mph on daily bus routes anyways. Then the school district may get one or two trip buses that have taller gears and the HP to actually move it down the road. So any time I've tested a 5.9 pusher it felt like a dog and was probably programmed to be such. That being said, others here have said they get good speed and reasonable economy from a 5.9 so you might search those threads and follow up with them to confirm their assertion.

Edit: just realized Brokedown just said what I said and I'd trust him.

I'm also a big picture-ist and if your coach has luggage and AC then either it's an 8.3 or a tweaked 5.9, not the constipated one. As for living with a 5.9, I think it all depends on what you're expecting. If you plan to be on the move every day and just parking overnights then it might be underwhelming. If you plan to climb mountains or tow an SUV, ditto. If however you plan to park, setup up camp and relax in one spot for a few days at a time, then take up roots and leisurely amble on to a new spot, then I see no reason a 5.9 won't serve you quite well and you can enjoy the sights along the way.

brokedown · 02-27-2020, 09:39 AM

Just to refine things, a 5.9 bus with mt643 and 4.44:1 axle on 11R 22.5 tires will have better gearing for highway travel than most. 65mph cruising, maybe 70. The most common bus will have an AT545 and 4.78:1 axle and you're wringing its neck trying to hit 62.

TakinCareOfBusness · 02-27-2020, 10:05 AM

I had plugged in the VIN info into the Vantage site, but it didn't confirm the engine size. 7th position of the VIN is an S; I take that to confirm the 5.9 (5.9TA). I'll RTFF (Read the Fine Forum) to look for info on how to distinguish between power specs for the same block. The rear gearing & tranny combo is in fact a couple of the big plusses for me.

Regarding the 8.3: I did see an ad awhile back for a bookmobile with an 8.3 front engine with a bad fuel pump. If it had been an operable bus I would have loved to explore that...that could have been a veritable hot rod.

WIbluebird · 02-27-2020, 11:18 AM

Quote:

Originally Posted by TakinCareOfBusness

I had plugged in the VIN info into the Vantage site, but it didn't confirm the engine size. 7th position of the VIN is an S; I take that to confirm the 5.9 (5.9TA). I'll RTFF (Read the Fine Forum) to look for info on how to distinguish between power specs for the same block. The rear gearing & tranny combo is in fact a couple of the big plusses for me.

Regarding the 8.3: I did see an ad awhile back for a bookmobile with an 8.3 front engine with a bad fuel pump. If it had been an operable bus I would have loved to explore that...that could have been a veritable hot rod.

The 8.3 doesn't necessarily make them faster, just means more torque and the engine doesn't have to work as hard to get up to crusing speed. The extra grunt is also noticeable on big hill climbs and/or pulling extra weight.

I can see why the 8.3 doesn't show up in Midwestern buses very often. Driving mine around here seems like overkill most of the time (at least with an empty pre-converted bus).

Seems to practically idle at 65 mph on flat ground whereas a 6.7 or 5.9 Cummins is screaming at 2300 RPM and using every bit of torque it has to get that bus down the road.

brokedown · 02-27-2020, 11:36 AM

If your 5.9 is screaming at 65 and your 8.3 isn't, it isn't because of the motor. The unfortunate fact is that a lot of buses have poor rear axle ratios, and all the torque in the world doesn't matter if you just can't spin any faster.

TakinCareOfBusness · 02-27-2020, 11:53 AM

No disagreement...by hot rod I mean acceleration. Would have been interesting to know what the final drive ratio was on that unit.

Sehnsucht · 02-27-2020, 04:10 PM

Quote:

Originally Posted by brokedown

If your 5.9 is screaming at 65 and your 8.3 isn't, it isn't because of the motor. The unfortunate fact is that a lot of buses have poor rear axle ratios, and all the torque in the world doesn't matter if you just can't spin any faster.

Like I said about our Midwestern buses, they get away with less engine torque by deepening the gearing because most school buses don't habitually run 65. Taller gears without added engine torque now you have a bus that can't get out of its own way from a dead stop. The two factors work together. Ultimately this seems like an issue we all face because we're taking one type of vehicle and asking to be another. School buses like metro city buses are all stop and go whereas tour and Intercity coaches are about speed and hauling.

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