MC8 Muffler
 

MC8 Muffler

Started by tninov8r, August 03, 2019, 02:00:24 AM

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tninov8r

Does anyone know the correct Donaldson, or equivalent, muffler # for a MC8? Any success stories?
1961 GM 4106 Custom Coach Conversion
1967 MC5A Custom Coach Conversion
1976 MC8 Custom Coach Conversion

Gary Hatt - Publisher BCM

For what its worth, my mechanic has removed the stock MC7/8/9 mufflers on 2 buses recently and knocked the guts out of it and then welded them back up and owners have reported they run much cooler.

My Series 60 was overheating and the same mechanic removed it and replaced it with a Resonator and my bus runs much cooler too.

The stock muffler is quieter which is kind of important when you have 40 - 50 passengers on board and driving thru big cities and when the bus is relatively new, but once the radiators start getting restricted, things start heating up and a restrictive muffler works against you in a bus conversion. 

Something to think about before you order a replacement.

Or if you really want a stock muffler, you can run with your back doors open when thru Arizona in the summer like I used to do.  ;D

Gary
1999 Prevost H3-45
Gary@BusConversionMagazine.com

edvanland

Gary I am so glad Joe cut my muffler off and we put on the resonator. Our MCI 7 with 8V92 runs so much belter. Less smoke under power, doesn't bog down on hills like it used to, runs cooler and just all around better. I wish I would have known and done that 17 years ago. Thanks for introducing me to Joe
Ed Van
MCI 7
Cornville, AZ

bevans6

Donaldson style 5 is inlet and outlet on the same end, MCI is an odd size outlet 4.25" I think, I used a M120131 which is 5" in and out, resonator, with a turbo engine, the same size but a muffler is M120176.  It is significantly smaller and lighter than the stock MCI muffler but with a little fab work on the mount it works just fine, sits in the original spot.

1980 MCI MC-5C, 8V-71T from a M-110 self propelled howitzer
Allison MT-647
Tatamagouche, Nova Scotia

tninov8r

Have found a local supplier for the M120131 Donaldson MUFFLER for our MC8 - does anyone know if this muffler will work/fit in our MC5A as well? Stock ID was 8b-20-1. Thanks.  :)
1961 GM 4106 Custom Coach Conversion
1967 MC5A Custom Coach Conversion
1976 MC8 Custom Coach Conversion

Gary Hatt - Publisher BCM

Many people are tearing out their MCI mufflers and installing straight-thru Resonators instead. The stock mufflers hold back too much air causing overheating especially when engines get old. 

Others are splitting them open and cutting out all of the baffles to it can breathe better and welding them back up.

They will be a bit louder without a standard muffler but the resonator is not that loud and lets the engine breath a lot better.
1999 Prevost H3-45
Gary@BusConversionMagazine.com

TomC

I took off the giant transit bus muffler (was very quiet) and replaced it with the Donaldson 120131 10x15 oval 5" same side in and out. It is a high flow turbo muffler. If you look inside, it is empty except for the baffle that separates the right from the left. It puts out a nice tone-lets everyone know you're there, but not too loud. No need for an additional resonator. Highly recommend this muffler. I'm using the same muffler on my truck conversion. Good Luck, TomC
Tom & Donna Christman. 1985 Kenworth 40ft Super C with garage. '77 AMGeneral 10240B; 8V-71TATAIC V730.

chessie4905

Yeah...it is not very loud from 35 to 40 feet upfront.
GMC h8h 649#028 (4905)
Pennsylvania-central

Jim Eh.

"Some days it's just not worth chewing through the restraints"
Jim Eh.
1996 MC12
6V92TA / HT741D
Winnipeg, MB.

Glennman

This sounds like a great idea to help with hills and overheating. What is a resonator? is that simply a tail piece add on?

DoubleEagle

It's a muffler with a straight-thru design, usually with a perforated center tube with fiberglass stuffed around it, like the old hot rod "glass packs". It reduces the back pressure while making the exhaust sound more robust (or noisy in some ears).  ::)
Walter
Dayton, Ohio
1975 Silvereagle Model 05, 8V71, 4 speed Spicer
1982 Eagle Model 10, 6V92, 5 speed Spicer
1984 Eagle Model 10, 6V92 w/Jacobs, Allison HT740
1994 Eagle Model 15-45, Series 60 w/Jacobs, HT746

buswarrior

Great...

More old buses driving around making a hell of a racket.

And that won't cause the hobby any trouble with the authorities or public opinion?

Do we really need more attention?

If your bus overheats, fix the cooling system.

Happy coaching!
Buswarrior
Frozen North, Greater Toronto Area
new project: 1995 MCI 102D3, Cat 3176b, Eaton Autoshift

Gary Hatt - Publisher BCM

Some call it "noise".  I am a Bus Nut, I call it "music".  And to use Jakes on top of that?  WOW!  ;D

When idling thru a campground, a Resonator does not sound that much louder than a regular muffler if you keep off the throttle.

I would much rather listen to a bus than some of those "noisy" Honda cars out there with "stock" mufflers that drive me nuts.  >:(

I used to have a Harley in a previous life.  I guess people would hate me for driving that too.   ::)
1999 Prevost H3-45
Gary@BusConversionMagazine.com

chessie4905

Some of us hate you for all the noise. 🤨
GMC h8h 649#028 (4905)
Pennsylvania-central

DoubleEagle

If we have resonators we would still be much quieter than a Harley with straight pipes with the radio turned up loud so that everyone can hear it over the pipes.  :o
Walter
Dayton, Ohio
1975 Silvereagle Model 05, 8V71, 4 speed Spicer
1982 Eagle Model 10, 6V92, 5 speed Spicer
1984 Eagle Model 10, 6V92 w/Jacobs, Allison HT740
1994 Eagle Model 15-45, Series 60 w/Jacobs, HT746