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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: windtrader on April 03, 2017, 12:49:15 AM

Title: GM 4905 vs MCI 8
Post by: windtrader on April 03, 2017, 12:49:15 AM
Looking at a couple coaches. Here are a list of differences I have identified. What other practical considerations are there between these two.

Tag on MC-8
Less storage bay space.
Two more tires, higher tire costs
Turning radius less, easier turning

Stainless on MC-8
Polishes up for sides with shiny effect
Better resistance to corrosion

T drive on MC-8
Motor transmission runs length of bus, easier/worse access?
More transmission options for T drive
Motor options better on MC-8??

Coach weight
4905 is monocoque aluminum shell/frame, lighter overall weight

Parts/Service
Seems like better MCI parts availability, especially on the used market.

Styling
to each their own, not a factor in this post

Other considerations??
Are there any other practical reasons to stay with one or the other?


thanks
Title: Re: GM 4905 vs MCI 8
Post by: B_K on April 03, 2017, 07:04:37 AM
Don you pretty much have summed up the differences.
One thing though the "Motor transmission runs length of bus, easier/worse access?"
Is not entirely true. Yes the engine transmission is in a normal orientation position and not sideways in the bus, but it only runs a 1/4 of the length of the bus from the rear bumper to the drive axle.
But it has been pointed out many times that the sideways engine is easier to work on most engine transmission components as they are easier to access. However that being said it also brings up the fact that the engine also turns counter clockwise rather than clockwise.

Both buses have advantages and disadvantages.
And fans of both makes/styles could argue till the cows come home from jumping over the moon!
;D  BK  ;D
Title: Re: GM 4905 vs MCI 8
Post by: blue_goose on April 03, 2017, 07:06:00 AM
You will get lots of different answers to this question.
Both are old and will require maintenance, and parts as time goes on.
If you are going to have someone else work on it the MCI will be the best.
Jack
Title: Re: GM 4905 vs MCI 8
Post by: luvrbus on April 03, 2017, 07:25:48 AM
I have to agree with Jack,as I mention in another post brake drums on a 4905 are unobtainable now lol even Luke cannot help 
Title: Re: GM 4905 vs MCI 8
Post by: TomC on April 03, 2017, 07:58:50 AM
V-drive like the GMC is more or less restricted to Allison V-730, or VS2-8. Only 3 spds, limited startability and cruising. I have 4.56 rears on mine and can start alright on any hill (because of turbo'd 8V-71). Cruise at 60mph that is 1900rpm.
MCI has T drive, which is NOT as easy to get to the engine, but you have just about unlimited selections of engine/transmission combos.
Personally-I'd look at the MCI 102C3. 6'10" tall inside, huge windows, 102" wide. The extra 6" in width is very noticeable. Good Luck, TomC
Title: Re: GM 4905 vs MCI 8
Post by: windtrader on April 03, 2017, 08:36:51 AM
Quote from: luvrbus on April 03, 2017, 07:25:48 AM
I have to agree with Jack,as I mention in another post brake drums on a 4905 are unobtainable now lol even Luke cannot help 
That is a new one for me, certainly warrants being in the OP. Really??? Seriously, drum brakes for a 4905 are no longer available unless sourced off a donor that still has good drums? Are there interchange drums from other models that fit? 
Title: Re: GM 4905 vs MCI 8
Post by: luvrbus on April 03, 2017, 09:13:46 AM
Quote from: windtrader on April 03, 2017, 08:36:51 AM
That is a new one for me, certainly warrants being in the OP. Really??? Seriously, drum brakes for a 4905 are no longer available unless sourced off a donor that still has good drums? Are there interchange drums from other models that fit? 

No they are weird size for stopping a 40 ft bus,I understand some one is making a conversion now but no telling what it would cost to do it.lol 3 axle brakes are better for stopping the hunk of steel I would think anyways
Title: Re: GM 4905 vs MCI 8
Post by: DoubleEagle on April 03, 2017, 09:24:07 AM
Quote from: windtrader on April 03, 2017, 08:36:51 AM
That is a new one for me, certainly warrants being in the OP. Really??? Seriously, drum brakes for a 4905 are no longer available unless sourced off a donor that still has good drums? Are there interchange drums from other models that fit? 

That certainly is a factor, but on a practical basis, if the current drums are not cracked and have enough thickness to be turned once more, they might last for 20+ years of use at conversion mileage rates. Other components on the bus might be a problem sooner. The V-drive situation is the main plus or minus factor.
Title: Re: GM 4905 vs MCI 8
Post by: windtrader on April 03, 2017, 09:41:55 AM
This is a great thread. It gets into a deeper level of bus experience, understanding the differences between different coach brands and vintages and the practical issues, trials and tribulations experienced once owning one and needing to care and feed the beast.

Here is the update on the adapter kits should one be required. http://www.busconversions.com/bbs/index.php?topic=29556.0 (http://www.busconversions.com/bbs/index.php?topic=29556.0) Both Steve and JD are really cool dudes, very knowledgeable and helpful.

If all other factors are similar in selecting a GM or MCI bus conversion, it seems an MCI may be more practical, serviceable, and a slightly less painful option for a converted bus owner.

Not sure how many parts interchange between a MC-7,8,9 but production figures total about 16,000+ so clearly lots of used parts around and probably more new/nos/recon inventory as well.

Title: Re: GM 4905 vs MCI 8
Post by: luvrbus on April 03, 2017, 10:17:30 AM
It is hard to see with the engine in place but if you look at the bulk head on a GM and see bolts with floor plate bolted in place on the aluminum bulk head pass on it
Title: Re: GM 4905 vs MCI 8
Post by: uncle ned on April 03, 2017, 10:38:18 AM


Clifford  Depends on what has been done to the gm.

On my 04 it has a 1/4 inch steel plate installed on top of the old bulkhead. was attached with special bolts and a mat in between it
and the bulkhead.

Had to do this for the hole for the 730.

It takes a lot of blank engineering to keep a 65 year old coach running with the big boys.

uncle ned

PS  Clifford come east with Wayne and the eagles this May.