MCI7 hill climbing ability

[artvonne]

  I was going to resurect an older thread, but maybe it is better to just start over. Ive come across an MCI-7 not to far away. As many of you know, I had settled on finding a 4104 as the best compromise for my needs. One of those needs is trying to get up my bloody driveway. I think I already know the answer here, but thought I would at least ask in case I dont have the right information. IIRC, an MC7 shell is around 27,000 pounds, with most conversions running around 33-35,000 pounds. Is this correct? Im thinking the possibility of out climbing a 4104 is rediculous, but again, just checking. I might look at it anyway, maybe I could just park it somewhere else. It appears its geared more for interstate than it was two lane back roads?

 I found these gear ratios in another thread, but believe these are for an MC9, and im checking to see if these apply to an MC7;

 1st - 4.30
 2nd - 2.33
 3rd - 1.36
 4th - 1.00
 rev - 6.00
 differential - 3.70

[lostagain]

MC7s are geared quite high, especially if it still has the 4 speed. I used to drive them back when they were new, and we liked how they handled compared to the 35 foot MCIs, but with the 8V71, they were underpowered. Same power train as an MC5, but 10 000 lbs heavier... Not nice for steep hills, otherwise a nice coach.

JC

[artvonne]

  Wellllllll you know how it is, the bigger better tighter sweater thing. I just came across the Bus in a search, and went "hey, looky that". And then I went nahhhh, that sucker aint EVER coming up here unless its got a D9 cat in front it. But it never hurts to ask.

[bevans6]

Those look like Spicer 4 speed gear ratios.  If they are, reverse is  actually 4.28 even though the manuals say 6.00, just so you don't think of trying to go up backwards in a very low gear.  Reverse is a tad higher than first, in other words.  I have an open Spicer 8844 in my shop and on a slow day I went out and counted the teeth on all the reverse gears and worked out the actual ratio.  But I lost the piece of paper with all the teeth counts on it...

Your thought is pretty much correct.  First gear start-ability of an MCI with a spicer sucks.  The heavier, the worser.  If you want to get up that driveway in an MCI, a MC-5C with a 6V92 and a 740 is the best bet.  Having a 3.7 diff does help, obviously, and there may be a transit/low top speed diff ratio you could think about.

[happycamperbrat]

My thoughts are that a skooli is the 4 wheel drive back roads kinda bus and an RTS is a sports car kinda bus and a Prevost is a cadillac kind..... the MCI is more for the practicle type of person. The skoolis are the only one I am familiar with that are specifically made for going on dirt roads to pick up rural kids and stuff.....

[TomC]

Now that you're talking a T drive, rather then the V drive on the 4104, you have some options on transmissions.  I would yank that 4 spd out and install a 7spd Eaton/Spicer transmission with overdrive.  The 7spd overdrive has a 9.24 1st with a .75 overdrive.  You'll be able to get up your driveway with that.  With 3.7 gears and 485 rpm 12R-22.5 tires, your first gear top speed would be 7.6 mph @ 2100rpm-of which I'm confident you could get up to full governor speed at the bottom-even start up on the hill.  You're startability with the regular 8V-71N with this 7spd overdrive (based on 35,000lbs) would be 26.5%-that's pretty steep!  You're climbing with full torque in 1st would be (getting a running start) 35% grade. 
The nice thing about the 7spd, is that it doesn't have any air operated splitters and it is a fairly short transmission (about 3 inches longer then the 4spd).  Good Luck, TomC

[bevans6]

I wonder what would happen if you shortened the drive shaft on a MC-5C by 3 inches?  Any thoughts on that?  How does the shift linkage/mechanism on a 7 speed work?

Brian

[artvonne]

Now that you're talking a T drive, you have some options on transmissions.  I would yank that 4 spd out and install a 7spd Eaton/Spicer transmission with overdrive. (about 3 inches longer then the 4spd).  Good Luck, TomC

   Hmmmmm. I was really trying to get talked out of this, not get in deeper. How hard is it to put that gearbox in, and how hard ($$$) are they to find??

  And very seriously, what kind of fuel economy can be expected with that gearbox (overdrive) if I keep the speed down??

  Paul~

[lostagain]

I met people once with a MC7. They had put in a DD S50 in it with a 10 speed manual. Sweet.

JC

[TomC]

Two methods of shifting either the 7spd or any of the Roadranger transmissions.  You can have a single shaft that goes the entire length of the bus that both twists and goes fore and aft.  Or you can have a two shaft or two cable system that one takes care of side to side and the other fore and aft shifting.  Good Luck, TomC

[artvonne]

  Tom, any advice on those last two questions??

[Busted Knuckle]

My thoughts are that a skooli is the 4 wheel drive back roads kinda bus and an RTS is a sports car kinda bus and a Prevost is a cadillac kind..... the MCI is more for the practicle type of person. The skoolis are the only one I am familiar with that are specifically made for going on dirt roads to pick up rural kids and stuff.....

Yeah but if ya want top class then ya get a SETRA which in Germany is a step above a Mercedes!

[Tenor]

I own a MCI 7 with the spicer 4 speed.  TOTALLY empty shell was almost 23k lbs.  Super light conversion with water and generator could be as low as 27k lbs.  I need to weigh mine since I've done that kind of conversion.  First gear is a little tall, reverse is VERY tall!  I thinks Tom C has the right idea for trans.  The 871N does a fine job, at least here in flatland Michigan and as far away as Duluth MN.  Good lines, not bad interior height, well built.  I've been told they used more stainless steel in the construction than in the 8's and 9's, but I don't know that for a fact.  Anyone else have definitive knowledge about that?

Glenn

[artvonne]

I own a MCI 7 with the spicer 4 speed.  TOTALLY empty shell was almost 23k lbs.  Super light conversion with water and generator could be as low as 27k lbs.  I thinks Tom C has the right idea for trans. 
Glenn

  Thats actually pretty light considering its a 40 foot bus with a tag and all that stainless. Tom's gearbox idea is a real eye opener. Tom, I read a post you wrote a while back on the other board regarding another MC7, saying the 7 speed sucked because it was non synco and to run a 10 speed? Is the 10 speed easier to shift without clutching? Is there even enough room for an 871 with a 10 speed in an MC7? What about a 6V71? Probably a bit slow but yould have plenty of gears to play with???

I guess I need more schooling on these. I really hadnt looked at them because they just seemed too large and heavy. I didnt want to get involved in a repower either, but if its easy enough and affordable, why not?

[robertglines1]

on the 7 pick up the tags and back up the hill..rev is by far the lowest gear..Bob