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Author Topic: Re-engining an MCI8 with a Detroit Series 50  (Read 8687 times)
afryer
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« on: April 15, 2006, 01:20:04 PM »

Got an old MCI8 that we just put a slideout in, so it looks like we'll keep her for a while.  Want to re-engine now.  Thought about a Series 60 but don't want to tear out the bedroom floor.  I was wondering if anybody has had any experience with installing a Series 50?  Don't need a lot more HP but would like more torque.
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JerryH
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« Reply #1 on: April 15, 2006, 01:42:20 PM »

I've seen an MC-9, essentially the same clearances with a DD S-60 engine.  The rear had a bedroom, bed on center.  They removed the mattresses during the intall to provide a minimal hump below the bed.  The work was done by Bernhard Bus in Quakertown.  He's done several of these Mod's.  All apparently working quite well.

JerryH
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Gene 78 MC8
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« Reply #2 on: April 15, 2006, 04:14:45 PM »

I plan on installing a Series 50 in my MC8, but I have not started the project yet so I can not pass on any lessons learned yet. I have a few other projects I want to finish before I start on the Repower. Where are you located? Good luck.

Gene   78 MC8
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TomC
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« Reply #3 on: April 15, 2006, 11:41:56 PM »

Series 50 is nice since it is short, but same height as a Series 60.  Even though I'm not a Cummins fan, their ISC and ISL up to 400hp and 1200lb/ft of torque is the quietest engine now made.  Just delivered a truck with the 300hp and 860lb/ft with an Allison.  It accelerated like a car, even though it weighed around 13,000lb.  Might be an easier convert since the ISC/ISL is the same length as the Series 50 but considerably shorter.  Might also consider an International DTA466/530 and the Cat C9.  All will have enough power, will be smaller and lighter than the Series 50, and do you really need a million mile motor in your bus, when a 500,000mi engine will be more than enough?  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
Clarke Echols
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« Reply #4 on: April 16, 2006, 02:10:52 PM »

Stewart & Stevenson has re-powered hundreds of MC-9 buses with Series 50 engines from 8V92 and 6V92 configurations.  Typically, they replace the right-side radiator with a turbo air-charge cooler, then make sure there are no leaks around the radiator on the left side where air can get past it without going through the core.  The Series 50 requires proper connections to the surge/expansion tank above the radiator so it clears all air from the cooling system within the specified time limit.  The Series 50 is taller than both and longer than the 6V92 two-strokes.  You'll also need a beefed-up cradle to handle the higher torque of the S50.  One bus operator who has a fleet of MC-9s for hauling prisoners says he gets his money back from a re-power in less than a year.

It's a big job, but those who've done it love the performance.  Just make sure your S50 has DDEC-III or DDEC-IV electronics, and you can repower up to 330 or 350 HP without a lot of very expensive engine modifications.

If you can get a B-500 in the package, that's like a dream...  I took a ride around downtown Denver in an MC-11 Greyhound, courtesy of the shop general manager who was driving.  It is a very impressive package when you put those two together.  Shifting is so smooth you can't even tell it's going on.  And 330 HP on a 32,000-pound MC-9 can pull a 6% grade at close to 50 mph.  But be sure you have adequate cooling.  A 6V92 rejects about 12,000 BTU/minute into the radiator at full power.  The Series 50 is about 1/3 of that amount, but you need to make sure you keep a good air flow through the radiator.

Clarke

Got an old MCI8 that we just put a slideout in, so it looks like we'll keep her for a while.  Want to re-engine now.  Thought about a Series 60 but don't want to tear out the bedroom floor.  I was wondering if anybody has had any experience with installing a Series 50?  Don't need a lot more HP but would like more torque.
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Dallas
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« Reply #5 on: April 16, 2006, 04:27:40 PM »

I'm just kind of wondering outloud here, but if your going to repower, basically as an update, why not go to the Mercedes MBE 900 or MBE 4000?
It's the power platform that is replacing the series 50's and 60's anyway.

Dallas
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NJT5047
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« Reply #6 on: April 16, 2006, 08:12:31 PM »

Dallas, I can offer one really good reason to use an S50 rather than a Mercedes....$$!
Another reason is dealing with parts suppliers...bad as DD may be...
This project is already going to cost upwards to $30K with a used S50....what would a Mercedes add to the equation? Wink
See ya soon, JR
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JR Lynch , Charlotte, NC
87 MC9, 6V92TA DDEC, HT748R ATEC

"Every government interference in the economy consists of giving an unearned benefit, extorted by force, to some men at the expense of others.”

Ayn Rand
TomC
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« Reply #7 on: April 16, 2006, 10:44:10 PM »

If you want to run a MBE, whether it be the 900 series that is a 6.4 liter up to 260hp or a 7.2 liter up to 330hp, this engine is going to be around for the duration.  Detroit is converting what used to be the 2 stroker factory over to be producing the 900 here in the USA.  It is going to be the foundation of the medium trucks from Freightliner, Sterling, and Freightliner chassis corp.  If you could find one from a wrecked truck (they've only been out since 2002), the 7.2 liter is available up to 330hp with 1000lb/ft of torque.  That is so close to the output of the Series 50 at a max of 350hp at 1150lb/ft, that the shear size difference between the two (the 900 is a bit shorter and not as tall and weighs close to a 1000lb lighter), I'd choose the 900.  Granted it is a 500K mile engine compared to the Series 50 being a million mile engine, but then who's going to drive their conversion much over 200K miles?  Also, the 900 has an available compression and exhaust brake that combined absorbs up to 215 hp of braking.
As far as the 12.8 liter 4000 series that is available up to 450hp and 1550lb/ft of torque (1650 next year), this engine along with the Series 60 is going to be fazed out by 2010 in favor of the new line of engines that Detroit/Mercedes-Benz is going to bring out. 
As to the cost of maintenance, they are right on par with the other engines-have to be or else we couldn't sell them.  Also, after asking the mechanics at our store about the frequency of repairs of the Series 60 compared to the MBE4000, they said that the repairs on the 4000 barely exsists compared to the Series 60 that is in the shops alot.  I also would like to see an 4000 taken apart-but one hasn't come in yet in the over 5 years I've been there.  Only seen one or two heads off the engine (it has 6 cylinder heads-great design).  The 4000 also has the strongest turbo and exhaust brake-absorbing up to 600 hp at 2300 rpm.  Personally, I really like the MBE engines.  And everyone that uses them likes the fuel mileage.  We have one fleet that just took delivery of 10 Columbias with the 4000 that is used to pull bottom dump.  Compared to the Cat C12's that they had before, just the fuel savings over the Cat will pay for the truck in seven years! 
Just thought ya'all might be interested.  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
Dallas
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« Reply #8 on: April 17, 2006, 02:03:41 AM »

Thanks Tom!
I don't know from direct expeience, but people I've talked to seem to be super impressed with the Mercedes engine.
Additionally, Mercedes, since it owns Detroit Diesel and Freightliner doesn't need two Class 8 engines in it's line up.
The MBE's have been around for years in Europe and do a wonderful job.
As for cost, the idea that Mercedes is always a high dollar item simply isn't true. That idea comes from the American Automtive world where we never see the standard Mercedes cars that are built for the masses. Mercedes trucks and engines have to be competitive with all the other manufactureres or they wouldn't be around.
Dallas
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tekebird
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« Reply #9 on: April 17, 2006, 02:35:14 PM »

Why are you channging powerplants.........if it is power you are starving for perhaps your 8-71 is just tired.
Doing a major repower on an older coach is pissing your money away........unless you have alot........are looking for a huge project.........and are willing to deal with the number of different headaches that may  come with the conversion.

8-71 parts are as plentifull as they ever were.......and the things are just plain stone age simple.

the small ammount of acceleration gain.......and time saved climbing grades is minimal at best.

ex.

PA to CA trip in my Pickup vs my PD4104 (6-71) towing same truck loaded with two motorcycles.

Truck beats bus by 1.75 hours

same stopover points and times

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busnut104
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« Reply #10 on: April 17, 2006, 03:42:01 PM »

I have heard this several times, about repowering a older coach. Well if you are going to keep it and maybe the only coach you will ever own why not. We all know we will never get our money back when we sell. In my opinion it's not the age of the bus,It's how it was taken of, and what the present cond. is. I would much rather have a 30 yr. old coach in prime cond then a 10 year old which is on it's last leg. As I said just my opinion
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tekebird
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« Reply #11 on: April 17, 2006, 09:25:16 PM »

I agree with the age thing......my '59 '04 is in better shape than most MC-9's running around......

I just think it a waste to spend the time, effort, engineering and $$ to repower with a non OEM type engine.

Get yourself a new 8-71 or rebuild yours.....and it will outlast you and you will have 15k left in your bank to spend on other stuff.

and never have to deal with any screwy computer glitches

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MC7S50
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« Reply #12 on: August 12, 2006, 08:38:28 AM »

I (with much help from a very experienced buddy) have repowered my MC7 with a 1994 S 50 engine purchased from a wrecked Freightliner.  The engine had about 600K miles on it and I got it for $4500.  While were at it, we swapped out the existing RTD 10 speed with an RTO 10 speed.  The main purpose of this repower was to improve fuel economy.  The cradle was modified to accept the engine, and of course there were many other things that had to be adapted. No other chassis modifications were needed.  The engine fits like it was made for the bus.  Perhaps the most difficult part was the electrical system, with the DDEC III ICU.  It was difficult, but not insurmountable for experienced bus folks to do.  We now have the computer controlled Jakes and cruise control along with the diagnostic features of the DDEC.  We retained both radiators, and installed the intercooler in the left side engine service door. 

The job did not cost anywhere near $30K.  We have travelled about 3500 miles so far, and have had no significant problems. Our bus is in very good condition overall.

Fuel mileage is about 9.5 average including mountain climbing in CA and OR, and we have gotten as much as 11 a couple of times in the flatlands. We never got more than 6 with the old 8V71.  Torque is way more than the old motor, and there is never any smoke.  Cooling problems have all vanished, and no more hassle finding engine oil. No oil leaks except a few drops from the breather.

It was a fun challenge, and we are quite happy that we did it. I did have to learn to drive it all over again, as the engine is completely different from the 8V71.  I will be glad to share more details with anyone interested.

John

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Burgermeister
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« Reply #13 on: August 12, 2006, 01:42:40 PM »

Did you set the engine "level" or did you tilt the back end up when you adapted the mounts to the cradle?

Marc Bourget
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NJT5047
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« Reply #14 on: August 12, 2006, 08:40:28 PM »

Quote
I (with much help from a very experienced buddy) ,
The job did not cost anywhere near $30K. We have travelled about 3500 miles so far, and have had no significant problems. Our bus is in very good condition overall.
John

The $30K that I mentioned was directed at someone paying to have the conversion done...folk that can DIY can convert for the cost of an engine and transmission.   The transmission is another issue.  Your manual makes a conversion to 4 stroke much easier.    Automatics will be a bit more complicated. 
An aquaintance mated a 60 series to an HT748 and had a world of problems with communication between the engine and transmission.  I don't think it was ever completed due to that problem.  It was drivable, but plagued with irratic shifting problems.   He would have been better off converting to a "matching" transmission/ECM unit...something that was programmed to work together.  Even a old HT740 doesn't shift correctly for the low RPM 4 strokes.  Valve body can be modified for lower RPM shifts.   Yet, Jim Shepard installed an S60 into an Eagle and it's working fine.  I'll find out what he did with the trans this coming week.  He's at the FMCA rally in Charlotte.
I may be wrong, but seems as though Jim used a B500?
Ideally, if someone wanted to convert an automatic, they would find a bus with the powerplant and trans combo that suits.  Maybe find a wrecked or damaged bus and buy the whole bus and use it for a donor.
Hard to believe (I do, just hard to see it) that an MBE 6.4 L engine can make 1000 lbs of torque.   What is the difference between that engine and one of the 7 or 8 liter pickup truck engines....pickups are in the 350 HP range, but I'm not aware that they make anywhere near 1000 lbs of torque?  Maybe they do.   I'm going to look it up...tomorrow.    The smaller, lighter engine would clearly be a good choice in a motorhome.   Friend has a 8 liter Cat in an Itasca that's rated at 350 HP, and it will easily smoke my 6V92.  And he weighs within 10K (or less) of an MC9 at 28K lbs.   I've looked at those engines and they are rather smallish..and they are beginning to collect in RV junkyards.  They are not going to have the service life of an S50 or MBE, but they have matching transmissions, are very dependable, and available for reasonable prices.   Cummins also supplies a similar RV engine mated to an Allison.  Anyone using RV Cats or Cummins for repowering buses?
Both would outlive me. 
John, if you read this, please post some pix of your engine conversion in this thread...I'd like to see how your engine compartment is organized. 
Interesting subject!   JR
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JR Lynch , Charlotte, NC
87 MC9, 6V92TA DDEC, HT748R ATEC

"Every government interference in the economy consists of giving an unearned benefit, extorted by force, to some men at the expense of others.”

Ayn Rand
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