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Author Topic: MCI 8 Repower  (Read 6726 times)
NickRussell
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« on: May 04, 2009, 04:19:50 PM »

Our worn our 8V71 with Allison 740 needs replaced if we are goign to keep our bus. We have had the rack run and all the standard upgrades done, but it's just very lacking in power, and it overheats terribly climbing the grades out west. It's okay back east, but we have lived and traveled in in 8 years and it has gotten worse over time.

Both Luke at US Coach and Sam Caylor agree that it's time to either rebuild or swap it out. I was talking to Sam today about a swap, and I'm comfortable with the price of an 8V92 turbo with new radiators, etc, with him doing the labor. My question is, what kind of difference in power will I see?

To give you some examples, climbing up Jellico Mountain on I-75 southbound in Tennessee, I was down to 15 miles per hour. On I-40 eastbound between Kingman AZ and Flagstaff last month I was down to 10 MPH. Last week on the long, gentle climb into Albuquerque eastbound, before youi drop down into the valley, we were at 15 MPH. The same going north on I-17 between Phoenix and Flagstaff. A couple of years ago, on I-90 on the Idaho-Montana border we were doing about 10 MPH.
 
Has anyone driven these routes in a bus with  an 8v92 turbo and Allison 740? What kinds of speeds could you maintian?

Yes, I know a four stroke is a better option, but given the money we have available, that's not an option. 
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buswarrior
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« Reply #1 on: May 04, 2009, 04:52:41 PM »

wow, that's a tired engine!

From Detroit to Florida S/B, I only recall dropping down into 2nd gear once on I75 briefly, up towards the top of the climb and being able to run high RPM with an 8V71/HT740 270 HP set-up in an MC8.

Depends on the power settings, but you will like just about any setting in an 8V92 compared to your present predicament.

Others chime in with your power settings...

happy coaching!
buswarrior



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poppi
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mci 8 L10 ZF tranmission; helena




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« Reply #2 on: May 04, 2009, 05:13:22 PM »


 Could someone please explain to me why a 4 stroke is more than
 a 6v92............ I've seen m11 with dyno reports for under 10k


   bye the bye I drove that same idaho/montana pass at 45mph in second, 3rd was to tall
 for the slope with just one of those old L10s.

 Thanks
 Skip
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NickRussell
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« Reply #3 on: May 04, 2009, 05:26:40 PM »

Poppi,
Where do you find these engines for under $10K? I have not been able to locate one.
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poppi
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mci 8 L10 ZF tranmission; helena




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« Reply #4 on: May 04, 2009, 05:54:14 PM »


 Try here to start.

http://www.valtruck.com/search.php?part=3000

 In the pull down pick Cummins then in the next one pick M11 Celect
 then hit the search button Smiley

   There are many choices and models check them out Smiley

 Skip
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rv_safetyman
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« Reply #5 on: May 04, 2009, 06:02:57 PM »

Nick welcome to the MAK board.  I have followed you blog a bit and felt your pain as you described climbing the hills.

The 8V92 will be a great engine for you *IF* you size the radiators to cool the beast.  Be sure to use the latest fin technology and seal them very well.

The 8V92 can have up to 500 HP vs your 270-318 with comparable torque ratings.  It will have a turbo and that will make a huge difference at altitude.

Concerning the M11/ISM, the under 10K should be the norm in this market with a little searching.  Would be true with most four stroke engines.  However, the gearing with the four stroke is a huge issue and very costly to address (1400 cruise RPM for 4 stoke vs 2100 cruise with the two stroke).  

The cost of conversion with a four stroke is probably three times the two stroke.  This is especially true, since you would be converting from mechanical to electronic engine.

The M11/ISM is the ideal 4 stroke engine for your bus, but costly to do.  A great documentation was done by Brian Diehl:

http://home.earthlink.net/~diehls0792_1/BusSection10.html

Jim
« Last Edit: May 04, 2009, 06:06:09 PM by rv_safetyman » Logged

Jim Shepherd
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« Reply #6 on: May 04, 2009, 07:02:04 PM »

Nick; I have an 85 Prevost with a 8v92 and an Allison 748 .Living in AZ. I've run the Mt's many times.The worst is southbound from Camp Verde and the slowest is 35mph. I weight in at 40,000 lbs. and I pull a Toyota p/u.You should be happy with the re power to a 8v92.
   Don
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busnut104
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« Reply #7 on: May 04, 2009, 07:43:01 PM »

I did the swap that you are referring to, you will notice a great difference, and notice very little if any in millage, I bought some of my parts from Sam, from what I gather and my dealings with him he seams to be top notch and making this change before the bus co. 
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poppi
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« Reply #8 on: May 05, 2009, 06:51:53 AM »

    I don't know anything about anything so of coarse take anything I have to say as just a foolish almost old man.

  Tran. max length with a cummins M11 is around 27 1/2"
 
  from the same place you can get a allison HT747 for 2k and it might fit.    You can get bus pans and engine cradles for cummins. Hard to find but do remember MCI did have Cummins as an option engine. (so I have been told)
     at what series of MCI I do not know when they started.
  Then there are the ZF trannies (expensive to work on), new world and of course the auto standards.
 granted going with the inlines limits your tranny options and Brian's is definately one
 for the books.

    I have a stock diff on my bus.

 FWIW
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ps added tran length
« Last Edit: May 05, 2009, 07:35:21 AM by poppi » Logged

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white-eagle
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« Reply #9 on: May 05, 2009, 06:36:48 PM »

Nick, we've got an eagle with 8v92t, 740 4 spd.  if i watch what i'm doing and keep the throttle down and the turbo boost at 15-18 then i can usually maintain 70 most of the time on i-75 in either direction.  Jellico, at worst, would be 3rd gear, 50 mph.  as i said, most of the time, if i can hit the bottom at 70 with the throttle down, it will run right up the hills.  however, if i let up or hit the hill at 60-65, then i might as well let up until it hits 55, then drop to 3rd and maintain at 50mph.

We also pull a heavy Chevy Express Van at about 7000#.  Our Eagle is about 39000.
« Last Edit: May 05, 2009, 06:38:39 PM by manasst » Logged

Tom
1991 Eagle 15 and proud of it.
8V92T, 740, Fulltime working on the road.

Fran was called to a higher duty 12/16/13. I lost my life navigator.
RJ
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« Reply #10 on: May 05, 2009, 09:46:31 PM »

Nick -

Long time no see!!  Arcadia 2004, right?  Anyway. . .

I'd have to agree with Sam & Luke on this one.  There's a world of difference between an 8V71N & an 8V92TA,  plus it's a comparatively easy swap.  Since the 8V92 was an optional engine in the 9s, and your engine compartment is virtually identical, you won't have as many fabrication issues that other re-powers entail.

Except the cooling issue.  You'll definitely need this addressed, and Sam's going to be a good source on this, since he specializes in MCIs, and probably has all you'll need out in his back 40.  Larger radiator cores, well sealed.  Larger squirrel cages and a smaller drive pulley are also part of that package, as well as larger openings into the engine compartment from the blower compartment.

Highly recommend additional oil cooling for the transmission, to avoid dumping the additional heat load into the engine cooling system.

Be aware, tho, that the 92 is NOT as forgiving as the 71 when it comes to getting hot.  As long as you drive it appropriately, you'll be fine.

FWIW & HTH. . .

 Wink
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RJ Long
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« Reply #11 on: May 05, 2009, 11:02:25 PM »

Nick;

Have you thought about repowering with a Series 50 engine.   

Here is one >>  http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=180353709795QQssPageNameZMERC_VIC_RCRX_Pr2_PcY_BIN_IT&refitem=180345505046&itemcount=2&refwidgetloc=closed_view_item&usedrule1=CrossSell_LogicX&refwidgettype=cross_promot_widget&_trksid=p284.m183&_trkparms=algo%3DCRX%26its%3DS%252BI%26itu%3DUCI%252BSI%26otn%3D2
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NickRussell
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« Reply #12 on: May 06, 2009, 12:00:32 AM »

I would if I could find a good running motor and transmission, and a shop to do the work.
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TomC
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« Reply #13 on: May 06, 2009, 07:57:02 AM »

The nice thing about a 8V-92TA is that it is the same externally as the 8V-71 with the exception of the big vibration dampner (looks like a flywheel) on the front behind the pulley.  You'd have to move the engine/transmission back a couple of inches to maintain alignment with the blower pulleys, but that's about it.  Make sure you have the biggest radiators, and the fastest running blowers since the 8V-92TA is the hardest to cool truck/bus engine ever made (with the exception maybe of a 12V-71TA-but few around).  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
poppi
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« Reply #14 on: May 06, 2009, 08:48:23 AM »


Incase you are on the east coast...........http://tpa.heavytruckparts.net/detailview.php?vehicle=3376&vendor=9119842&searchnum=2282824&searchnum=2282824

   it is a ddec II for what that is worth...... still 500 hp ain't shabby

Enjoy

 Skip
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edroelle
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« Reply #15 on: May 06, 2009, 10:10:30 AM »

Nick,

You will double or triple your speed up the mountains that you describe because of the tired 8V71.

If you do the project, I would spec the job to be done completely and right the first time.   Engine cooling is marginal on the MCI 8, even with the 8V71.

1.  NEW (not used or rebuilt) "102" radiators, Part Number: 6K-1-5, as Craig Shepard shows on his site
http://www.gumpydog.com/bus/MC9_WIP/Mechanical/Radiators_And_Blowers/radiators_and_blowers.htm

2.  Large radiator blowers sealed perfectly (Sam should know the difference) and are opened at the exit so that they have basically a square opening.  Early MCI 8s had small blowers

3.  Small radiator drive pulley

4.  Good or rebuilt rear axle ring and pinion of 3.33   Yours is currently ABOUT 3.75   

5.  A good engine.  Will Sam give you a guarantee for some amount of time?

Others may see additions specs that should be added.

Ed Roelle
Flint, MI

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busnut104
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« Reply #16 on: May 06, 2009, 03:49:11 PM »

It still is a lot of work, maybe not as much as going to another make of eng. but the 8V92 is one inch longer then the 71. You will have to shorten the drive shaft, the front motor mount is different, you will have to go to a larger air cleaner and a 5" in and out exhaust. I have to make a special plate so that the 740 transmission would attach to the throttle linkage, the turbo pipes where in the road, I changed the tork convertor,  I forget the number that is need to make things perform right, And there is more but it has been several years since I did the swap and off the top of my head these are the thing that come to mind. Yes I did install two of the larger radiators and larger squirrel cage fans.  If you have Sam do the work he should have what you need. Good luck. and you will love the power
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belfert
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« Reply #17 on: May 06, 2009, 06:33:25 PM »



Interesting that this seller has both the Series 50 and a 6V92 and the 6V92 is selling for more!
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Brian Elfert - 1995 Dina Viaggio 1000 Series 60/B500 - 75% done but usable - Minneapolis, MN
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« Reply #18 on: May 06, 2009, 10:40:45 PM »

Sam said he can get me a factory rebuilt 8v92 turbo, with 100,000 mile warranty from Detroit Diesel, and with the upgraded radiators and other cooling system upgrades, exhaust, etc, my out the door price would be about $25,000 Sam has done many of these upgrades, and he has done other work for us, including upgrading our steering box, so I am comfortable with his skills.

We are fulltimers with no place to work on a job like this, and I have neither the mechanical skills or the time to take it on myself.
« Last Edit: May 07, 2009, 12:22:10 AM by NickRussell » Logged
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« Reply #19 on: May 07, 2009, 07:57:48 PM »

Two things guys..   Belfert I need to Thank You for giving me the tip on Ebay with that Delco 50dn.   I picked it up>> and a few other parts for Very reasonable prices.    The seller name is Dan, he runs a transit/city buses.    Right now they are scrapping some of there fleet.   

I talked to Dan this evening because he was putting the alternator and brackets on a pallet, along with a Series 50 and B500 for a local Charter repower.     I asked him what he would sell another package S50/B500 runner for.   He told me that he would like $5,700 for the engine and trans complete.   He would include the B500 key pad and partial wiring harness.    The engine has 290K on it and the B500 was also rebuilt.    For guys with MCI 8 and 9's and early 102 I think this is a good upgrade path.   

I don't have any financial interest in this ebay transaction other than a happy buyer.    If anyone is looking to repower, you might want to give Dan a phone call.   

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« Reply #20 on: May 08, 2009, 05:43:22 AM »

If anyone Need to re power you won't beat this price.  That is less than the core price for the engine and transmission. 
I have a series 50 in my bus and love it.  I don't get up the hills quite as quick as I did with the 8v92, but I don't over heat, burn less fuel and know if I have problems some one can work on engine. 
I don't think anything new over the road has been built in at least 15 years that used a two cycle engine.  Most of the people that can work on these are gone. 
For less than the $25,000 you could have a series 50 or 60 with a world transmission put in your bus. 
Jack
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« Reply #21 on: May 08, 2009, 09:29:09 AM »

I run a 8v92 in a Eagle never a cooling problem now a MCI maybe so
.Knowing Sam 25 grand is a lot of bucks but it will be done right.
We are getting ready to remove a 50 series from a friends bus that he has never been happy with it
.Fwiw he gets 7.5 mpg the same as my 8v92 so go with 8v92 there are people out there that can set the engine up to get good fuel mileage and power.
I have no problems with my 8v92 running with 60 series or Cummins M or I series engines with about the same fuel mileage at 70 or 75 mph.
If I ever switched engines it would be to a 3406 Cat 425 hp and not worry about the fuel mileage     good luck
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« Reply #22 on: May 08, 2009, 01:55:17 PM »

Luvrbus,  having a 8v92 and rebuilding it is one thing.   But pulling out and repowering in a MCI is a costly endeavor.    The cooling system has to be spot on.   With S50 coming down in price, and being able to MATE the B500 to it.   That alone should make one do the conversion.   Rumor has it that with the proper turbocharger and software you can get 350HP out or the Series 50.   

I have two buses, one has a 6V92 which I will replace and most likely repower with this above mentioned package.   Sell my good runner, along with the transmission,  and I might actually break even (wishful thinking)    In my other bus I have a Series 60..     I wouldn't think twice about moving into a 4 stroke with the "cost" of conversion coming down to reasonable prices.
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luvrbus
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« Reply #23 on: May 08, 2009, 04:04:47 PM »

Zero,takes more than a turbo and software to get 350 hp from series 50.A series 60 I would go for but not a obsolete series 50 that will shake the bed sheets off the bed.
Parts that don't inter change with the 60 series are getting hard to find in new parts and no one is making aftermarket parts for the series 50.John Deere doesn't make heads any longer,cranks are hard to find along with cams and balance rs.
That engine has been out of production for almost 10 years now.I am in Texas now visiting with Cole (makemine a 2 stroke) he worked for Stewart and Stevenson for 40 years and these are his comments not mine "a series 50 was the worst engine Detroit ever built".But we all do it our way    BTW he said thanks for the help with the projection TV a few months back   good luck
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