Looking at MC5C

[lostagain]

I am considering buying a very well maintained 5C with a very nice BCI Coachworks conversion. Originally in San Diego, CA, converted in '93. No rust. 60 000 miles on new (in '93), crate 6V92TA w/ HT740 Allison. I had it out for a drive a few days ago. Everything is nice and tight. The PO had it meticulously maintained. It is not very fast up the hills, (at least compared to the hockey team's bus that has a S60 w/ 7 speed manual). Top speed is about 70mph at 2200rpm.

What do you guys think of the 6v92TA, (mechanical, no electronics) w/ HT740? It has MC9 12 inch blowers with recently re-cored rads, plus a 3rd rad on right hand side engine door, with 2 electric fans for extra cooling when necessary. It was sure nice and easy to drive compared to a stick, which is all I have ever driven in a bus.

What kind of transmission is a HT740? in terms of does it lock up? What torque is it rated for? All I know is that it is a 4 speed. I couldn't find anything on the Allison site.

Thank you,

JC

[Timkar]

Sounds like a nice cruiser.
Here is some info I found...HTH...Tim

http://www.allisontransmission.com/publications/servicesupport_listings.jsp?ModelGrouping=ht&Model=ht740hydraulic&PublicationType=All

and from another website...

ALLISON HT 740/ HT 750 SPECIFICATIONS
•Designed for use with diesel engines up to 445 nhp (332 kW). Four forward ranges and one reverse. This transmission model is best suited for medium- and heavy-duty trucks and buses.
•Clutches are multidisc design, oil-cooled, hydraulically-operated, and self-compensating for normal wear. Spur-type planetary gears are designed for strength, quietness, and long life.
•Automatic lockup clutch, throttle-modulated for maximized fuel economy and enhanced engine braking. Automatic upshifting and downshifting within each drive range. Built-in inhibitors prevent downshifts or shifts into reverse unless vehicle speed is within an acceptable range.
•The Allison three-element torque converter provides smooth, shock-free operation. A choice of converters permits matching the HT 740 to a wide variety of engines.
•Converter-driven power takeoff drive on right side of transmission (as viewed from the rear) is standard. Design is SAE 6-bolt.
•Optional engine-driven power takeoff is available in two locations - upper right and lower left sides, as viewed from rear. Design is SAE 8-bolt.
•Provisions for neutral start switch, reverse signal switch, SAE regular-duty thread-type speedometer drive, electronic speedometer drive, and parking brake.
•7.0 inch oil pan is standard. Optional 6.0, 4.5 and 8.5 inch pans are available when ground clearance or heavy duty operation dictates their use.

General Purpose Truck Rating 
Net input power (max).............................445 hp (332 kW)
Input speed range................................1900 - 2400 rpm
Net input torque (max)......................1435 lb ft (1946 N·m)
Vehicle weight (max)............Up to 80,000 lbs (36,287 kg) GVW
and 130,000 lbs (58,967 kg) GCW
Mounting
Direct..............SAE 1 flywheel housing with flex plate drive
Remote.....Converter housing side pads, and rear housing top pad
Torque converter
Type..........................Single-stage, 3-element, polyphase
Stall torque ratio.........TC 487-1.50; TC 488-1.70; TC 497-2.72;
TC 470-2.83; TC 495-2.39; TC 496-1.78;
TC 498-2.45; TC 499-1.91
Automatic lockup clutch..........Effective in all forward ranges
or effective in 2nd through 4th ranges
– depending on model used
Gearing
Type.........................Constant mesh, spur type, planetary

Range Ratios*:
First...................................3.69:1
Second..................................2.02:1
Third...................................1.38:1
Fourth..................................1.00:1
Reverse.................................6.04:1
* Gear ratio does not include torque converter ratio.
Power takeoff provision
Converter driven (SAE 6-bolt)
Location................10 o'clock position (as viewed from rear)
Drive gear ratio............................1.00 x turbine speed
Drive gear rating.................300 lb ft (407 N·m) continuous;
400 lb ft (543 N·m) intermittent

Engine driven (optional) (SAE 8-bolt)
Location....converter housing: one at 1 o'clock position and one
at 8 o'clock position (as viewed from rear)
Drive gear ratio.......1 o'clock position – 1.35 x turbine speed;
8 o'clock position – 0.84 x turbine speed
Drive gear rating.................200 lb ft (149 N·m) continuous;
260 lb ft (194 N·m) intermittent
Oil system
Oil type..........................................Dexron II®, C4
Capacity
(excluding external circuit)...7.5 U.S. gals (28.5 liters)
(w/std. oil pan)
Filter..................................External, remote mounted
Cooler............................................Remote mounted

[bevans6]

It sounds like my ideal bus.  The 6V92 with HT740 is probably the best driveline possible for that bus, which is problematic for the short span from engine bay to drive axle.  A mechanical setup is my ideal for that pair, no need to retrofit the electronics for DDEC.  You will lose some fuel mileage compared to a more modern setup, but it's a real good pair.  The MC9 radiators are needed to accomodate the heat from the additional HP.  The trans is well matched to the engine in terms of torque, and it locks in the higher gears, and i believe can be set up to lock in all gears.  It sounds like it has a 3.73 differential.  You might have a conservate tune on it, you could probably change injectors and retime it for more power, but at it's best it probably won't run with a S60 7 speed.  It's an older technology.  The 5C has a similar stainless steel substructure to the MC-9, and is less prone to rust behind the panels.  I like the 5C as a great example of the shorter, narrower bus for those with space or access issues to deal with.  I am well pleased with mine.

You know, I was thinking the other day that I have never drive a bus (or a big truck) with an automatic.  Only standards.  Mind you the schoolies I used to drive had synchromesh...

Brian

[Chopper Scott]

Actually the 740 convertor locks up in low. It almost feels like another gear when it does. From all I've read about the 740 it is bullet proof. I took other's advise and also plumbed in a tranny cooler with a fan before it goes to the engine cooler which helped on my seven. Wish I had those bigger fans!

[lostagain]

Thank you guys, especially Timkar for the awesome info.

I always liked the 5s when I used to drive. The 5Cs were news then in the late '70s. They were really handy in tight spots like in the city, and powerfull compared to the 7s and 8s with same 8v71s and 4 speeds.

This one (6v92) has 90 injectors and smokes black like a gravel truck  when you floor it  .

We started it cold, and it only smokes for 2 seconds, then is completely clear. It is in really good shape. The PO always had it serviced every year by a professional shop, and any part that looked iffy, he ordered replaced with OEM parts.

I have an agreement with him, I am going to pick it up later this week or next. It took a while to  convince Valerie to release the funds, but she caved in when she saw it . I will post pictures once I get it. I am excited...

Now the hard part will be to sell "Lost Again", our '57 Courier 96, which I am quite attached to still...

JC

[bevans6]

Have a pair.  Early 35 footer and the last of the 35 footers.  Charge for history classes.  Conduct tours.   

Dyin' to see pictures, inside and out!

Brian

[Gary '79 5C]

JC,

Good Luck in your decision.

I like the 5C as it is a 35'er, but it feels like a 40' in that there is a flat floor frt to back.
Driver is same level as passengers, no lost space to in set floor etc.
No tags, less weight, (2) less tires, bearings, brakes to maintain etc.
You are a professional driver, I am not, I like being able to drive the 35'er in/out of places I would never attempt in a 40-45'er.
I have a 6V92TA, and it has as much power as I reasonably need. I have not ventured out west, but PO was to Denver often with toad.

Obviously I am biased, not sure why as I never have driven another bus.

Best to you,
Gary

[Timkar]

Congratulations JC.    I know we were excited when we went to get ours.
Make sure to post the pics. Is it close to home?
Tim

[Dreamscape]

I agree, keep them both. You have a very nice coach, I'm not familiar with a Courier, but I like it anyway. And with all of the work you have done, the next owner will be lucky!

Sounds like you found a gem, I'd be excited too.!

Paul

[JohnEd]

Somewhere in the past I have a foggy recollection of hearing that Th 5C had a low overhead i the engine bay and would only be fit with a side mounted turbo.  Is that true?  Not that it changes a single thing.

Glad you found a bus you are this excited about.  With your experience you must be getting a fine bus.

Happy trails,
John

[lostagain]

Thanks all.

It is in Vernon, BC, 5 hours away. I'll post pictures once it is home.

JC

[luvrbus]

JC, you can stop most of the black smoke by changing the hot housing on the turbo get rid of the 1.39 AR and go with a 1.23 AR. I wonder if you have 9G90's or 9A90's you are going to need work on that one to get 11mpg LOL


good luck

[Ed Hackenbruch]

Ahhhh, but the bigger question !!  which one are you going to bring to BUSN' USA?   

[bevans6]

If you do a side mount turbo you can keep the normal fan blower drive system.  If you keep the normal over the top turbo you have to install another type of fan drive.  ken McKarl did a hydraulic motor system for his  8V71T in his MC-5

Brian

[TomC]

Normal shift pattern is- 1C-2C-2L-3L-4L (C=Converter, L=Lockup).  For truck use, it could be programmed to be- 1C-1L-2C-2L-3C-3L-4C-4L; while you get a bit more performance, you loose some fuel mileage from the slippage in converter.  You can get lockup in 1st gear by pulling the gear shift to 1st for long hills up or down.  Great transmission-one of the toughest and most reliable.
As to the black smoke when stabbing the throttle-the engine may not have a fuel modulator on it, or it isn't adjusted correctly.  I know on my 8V-71, the adjustment is very sensitive.  There is a fine line between having it smoke a bit and perform correctly, and not having any smoke, but not accelerating well.  Good Luck, TomC