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Author Topic: What to do with the bus?  (Read 2749 times)
TrevorH
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« on: May 15, 2008, 09:27:37 PM »

So the excitment and dreams of a bus conversion is getting darker.  I have the money to convert something but dont know what to do.  The fuel economy of the bus is pretty bad in comparison to other vehicle types.  And yes I understand that it does have its advantages aswell.  So here lies where I need the opinions of others.  The bus I have is an MCI 102A3 8v92 manual 5 spd.  The motor is in perfect shape and burn only a quart of oil on the last trip I took of about 1200 miles.  I was thinking about converting it as planned and then swapping a more economic engine/tranny whenever I happened on a deal.  Or I could buy a schoolie with a large enough motor and cutting the entire body off and building a 102" wide, 7' box.  Or I could take a semi and extend the frame and build a box.  This while prob being the best is def the most work which kinda shys me away since I want to be able to make some use of it ASAP.  What you guys think?
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1987 MCI 102A3 8V92TA 5 spd MT
Tucson, AZ
luvrbus
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« Reply #1 on: May 15, 2008, 09:47:50 PM »

TrevorH,if you will go talk to Kim at AZ transmission there in Tucson the guy can tell you what he can do to get you better mileage you can accomplish it by different ways I have a 8v92 with a 740 and I lowered the horse power and changed the gearing on mine and I get 7 to 7.5  and you having a 5 speed manual you may could do it with a different transmission like a 7 speed or 10 speed.Don Fairchild on this board could also help but he is in CA   good luck
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DrivingMissLazy
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« Reply #2 on: May 16, 2008, 05:11:53 AM »

TrevorH,if you will go talk to Kim at AZ transmission there in Tucson the guy can tell you what he can do to get you better mileage you can accomplish it by different ways I have a 8v92 with a 740 and I lowered the horse power and changed the gearing on mine and I get 7 to 7.5  and you having a 5 speed manual you may could do it with a different transmission like a 7 speed or 10 speed.Don Fairchild on this board could also help but he is in CA   good luck

Be sure and get a written estimate detailing exactly what needs to be done and the cost.
I took DML there back in the 80's to get an engine swap from a 6V92 to a 8V92. The verbal estimate was $8,000. By the time I got her back, the bill was over $25,000.

Richard
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Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body. But rather to skid in sideways, chocolate in one hand, a good Reisling in the other, body thoroughly used up, totally worn out and screaming:  WOO HOO, what a ride
luvrbus
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« Reply #3 on: May 16, 2008, 06:03:47 AM »

A written estimate is a good idea for any work on a bus Richard but I told Trevor to ask him some questions to get ideas and then he could decide what to do.Richard you have to agree that the guy is sharp on DD and Allisons look how long DML has been on the road and still kicking and screaming
« Last Edit: May 16, 2008, 06:17:23 AM by luvrbus » Logged
rv_safetyman
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« Reply #4 on: May 16, 2008, 07:03:13 AM »

Clifford, this is the first time this board (and the other one) has had a positive comment about AZ transmission that I recall.  I assume you have done business with them and that you were a satisfied customer.

I don't have a dog in the hunt here, but if they are a good vendor, we need to make that clear.  A search of both boards will yield a ton of negative feedback on this vendor.  As Richard eluded to, the main complaint was horrendous bills that were sometimes more than twice the quoted price (this from memory - don't have time to do the search right now).

Please understand that I am only trying to make sure that we give this vendor a fair shake.  However, if the reported problems still exist, we need to warn new folks on this board.

Back to the question at hand.  The general consensus of the board is that you would be hard pressed to justify all of the work on the projects you mentioned to get perhaps 10-20% better mileage (probably optimistic). 

It sounds like you have a great bus and that is a good platform for a good conversion. 

Others have done a conversion to a 10 speed overdrive transmission that could make a significant improvement.  I think these transmissions are in the $1000 range or less and I think the existing shift linkage can be used since they are 5 speeds with an air splitter.  You would need to be mindful how you use the overdrive so as not to lug the two stroke.

The other great piece of advice is to have Don (or another reputable(!!!) person do a complete tune-up on your engine.  As Clifford suggests, you could have them back off a bit on the injectors (if mechanical engine) since the 8V92 has good power for your needs.

You could also think about an engine conversion.  I think an ISM/M11 will fit in your bus.  Also folks have done a Series 50 as I recall.   However, if you have someone do that conversion, you can expect to pay about $40K.

I have gotten 7.7 MPG over 41K miles on my Series 60 conversion (per the computer, which seems to be very accurate).  I figure my bus would have gotten about 5.5 MPG on the 6V92.  If those numbers are correct, I might have saved about $5000 in fuel over this since I got it running two years ago.  That covered about 25% of my conversion cost.  I did not have much of a choice about the engine conversion (6V92 spit up), but I the extra mileage is sure nice now that fuel is so high Cheesy.

BTW, my long term mileage has dropped over the last 8 months or so.  I was at 7.9 for a long time.  I have traveled in some bad winds/weather lately, but I think some of the reduction was the conversion to Ultra-low sulfur diesel.

I built my own truck chassis motorhome a few years ago.  Huge project, and it rode very rough (even with commercial air spring conversion on the back and home made air spring conversion on the front).  If you go the truck route, be sure to get a late model class 8 truck with modern suspension.  With this type of conversion you give up full width bays and loose some use of the length of the vehicle.

Just some thoughts.

Jim
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Jim Shepherd
Evergreen, CO
85 Eagle 10/Series 60/Eaton AutoShift 10 speed transmission
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jjrbus
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« Reply #5 on: May 16, 2008, 07:16:21 AM »

I feel lust in my heart, evertime I read a post on swapping engines and trannys.  With a hopped up 6V92 and an exotic transmission I could do wheelies with my 5C!!!!!
 Then there is the practical/financial side. Unless you have the shop, tools, knowledge and expertise to do it, it is a lose lose proposition. Unless you plan on driving extensively you will never recoup the cost of a repower. With the price of buses, it is much more practical to find a bus with the power plant/tranny combo you want and convert it.
 On the other hand if it just looks like fun and you want to do it even if it makes no sense. Order some new checkbooks, call the bank and raise the limit on the charge cards. Buy towing insurance and go for it!!!
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tekebird
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« Reply #6 on: May 16, 2008, 07:36:54 AM »

unless you are doing all the work for a repowere and get a huge deal on a Eng/Tranny Combo, it is not financailly worth it to repower.

this is just financailly and does not include any headaches such a project might generate.

Also, the small gain in MPG that you will realize would take decades to realize any savings on the fuel
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TomC
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« Reply #7 on: May 16, 2008, 07:51:25 AM »

This is why I'm starting on my Kenworth cabover Aerodyne conversion.  I have a Caterpillar 3406B 400hp in it with 13spd that I'm going to change to the Allison HT740-both of which are just about bullet proof and no electronics (so far RV's are exempt from smog laws in Calif.  When that changes and the rules get stricter, I'll just change out to a 425hp Cummins ISL and Allison 3000 series 6spd automatic).  With my V drive 8V-71TATAAC engine, I get 5mpg pulling my car and 6mpg without.  When I was driving my truck, once I had to bobtail (just drive the front part-the tractor) a fair distance and got 9.8 mpg-and that's with the tractor weighing 25,000lb.  So I figure I'll get around 8mpg-and since my car will be inside the truck, towing difference will not be an issue.  If you have a truck with an electronic engine, I think 10mpg would not be out of the realm of possiblity.  And if you use just a 2 axle truck, keeping the conversion lighter, 12-15mpg would be possible. Personally like the idea of a truck conversion since the engines are so easy to work on and any truck mechanic can work on them.  With my 90" cabover, I'll be able to use a 32ft box and stay right at 40ft overall with a 286" wheelbase.  I know the truck will not turn as well as the bus, but I'm used to that after 1.3 million miles of driving 68ft around all the time.  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
luvrbus
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« Reply #8 on: May 16, 2008, 07:59:17 AM »

Jim, I have never in 15 years doing business with Kim  had a problem with him on cost or what he was to do.When it comes to repair work on a bus reading these boards every one seems to have a problem with the repair shop I had one with a repair shop people recommend on this board so I don't bad mouth him I just haven't went back in 3 years and have known him for 20 years.You know me I take people from my point of veiw not what others say about them heck I even like you LOL tell Pat hi for us
« Last Edit: May 16, 2008, 09:24:54 AM by luvrbus » Logged
kyle4501
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« Reply #9 on: May 16, 2008, 09:03:35 AM »

Here is another thought to consider:
Tune your existing 8V92T to a lower HP rating & get better fuel mileage that way. My 4501 seems to have enough power & gets almost 10 mpg.

Before choosing the HP rating for the engine,
find the fuel burn v.s. HP curves
determine the rpm you need to run the engine at based on your axle ratio & tire size & desired cruise speed
etc

& use this to select a HP rating that is the best compromise.


Re powering when you have a sound engine rarely saves any money.
IF the clutch & all linkages are 'right', it is hard to beat. The mechanical (not computer controlled) automatics seem to have rude shifts that are harsh
Reevaluating how you use it & modifying some of your expectations & habits will provide maximun return.  Grin

Do you really have to be the first one up the hill? the fastest? etc
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uncle ned
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« Reply #10 on: May 16, 2008, 11:42:31 AM »



Kyle 

   From the words of several wise men. does a "7"v71 use less fuel if running on 7 cylinders. Wish you were here to help with the large tales.

From a lonely gm at genes rally

ned

ps will see you 4'th of july
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DrivingMissLazy
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« Reply #11 on: May 16, 2008, 01:57:44 PM »

A written estimate is a good idea for any work on a bus Richard but I told Trevor to ask him some questions to get ideas and then he could decide what to do.Richard you have to agree that the guy is sharp on DD and Allisons look how long DML has been on the road and still kicking and screaming

Well, I had to have the 8V overhauled within one year, and some spacers were left out of the starter and I had to replace the starter as well as get the kinks out of the radiator hose. Hopefully they are more experienced now.

Richard
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Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body. But rather to skid in sideways, chocolate in one hand, a good Reisling in the other, body thoroughly used up, totally worn out and screaming:  WOO HOO, what a ride
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« Reply #12 on: May 16, 2008, 02:00:51 PM »

Or....just keep the Bus Conversion you have.  The big 8V92 Detroits sound soossss cool, which for me would be very important and a major reason for owning the coach.  Who cares about the MPG. I have no idea what your present road gearing is, but I would assume (dangerous word!) that the factory knew what it was doing in selecting the road speed you have now.

Or....they did not and you have very short mountain gearing with a limited top speed, which would mean your mightly Detroit MIGHT be able to pull another gear.  He he he...I love a good plan.  Assuming again that you have a Fuller T905M/1105 tranny (or you could have a Spicer) you might be able to swap in an O.D. version of the T905 5 speed.

If memory serves Fuller made 3 different O.D. gear sets for the T905.  However, if we find out you have the Spicer, all of this stuff I'm writing has no point or meaning.  You do not want the tight O.D., nor do you want the big O.D. version either.  You want the middle O.D. with (I think) a 28% overdrive.  Could you Bus Conversion pull another gear?  How is your startability?

Also, if your driveline is long enough, Fuller (and Spicer) made a series of 6 and 7 speed boxes that are slightly shorter than a true 10-speed.  Your shift linkage may even work.  Anyway, what I am trying to say is that there are lots of reasons just to keep your bus the way it is, or if you really want to, there are a number of ways to make the mileage PERHAPS a little bit better.  Smiley Smiley Smiley
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DrivingMissLazy
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« Reply #13 on: May 16, 2008, 02:03:27 PM »


A written estimate is a good idea for any work on a bus Richard but I told Trevor to ask him some questions to get ideas and then he could decide what to do.Richard you have to agree that the guy is sharp on DD and Allisons look how long DML has been on the road and still kicking and screaming

Well, I had to have the 8V overhauled within one year, and some spacers were left out of the starter and I had to replace the starter as well as get the kinks out of the radiator hose. Hopefully they are more experienced now.

Richard
« Last Edit: May 16, 2008, 02:05:06 PM by DrivingMissLazy » Logged

Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body. But rather to skid in sideways, chocolate in one hand, a good Reisling in the other, body thoroughly used up, totally worn out and screaming:  WOO HOO, what a ride
luvrbus
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« Reply #14 on: May 16, 2008, 02:19:12 PM »

Richard never knew you had that problem sorry to hear about it but me owning a Eagle with a 8v92 I don't know how you could have kinks in the 3" hoses 4 inches long unless somebody threw away the metal pipes.Anyway I have never had a problem with him but have with one you like he left the bolts out of the oil pickup tube on my 8v92 and it didn't last 3 months for 14k and he said sorry not my fault   have a great day and keep up the good work   one other thing who left the vibration damper off that engine
« Last Edit: May 16, 2008, 02:47:03 PM by luvrbus » Logged
DrivingMissLazy
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« Reply #15 on: May 16, 2008, 04:17:40 PM »

Richard never knew you had that problem sorry to hear about it but me owning a Eagle with a 8v92 I don't know how you could have kinks in the 3" hoses 4 inches long unless somebody threw away the metal pipes.Anyway I have never had a problem with him but have with one you like he left the bolts out of the oil pickup tube on my 8v92 and it didn't last 3 months for 14k and he said sorry not my fault   have a great day and keep up the good work   one other thing who left the vibration damper off that engine

A different radiator was one of the added expenses that they never told me about and it was quite a bit wider than the original. The outlet hose had almost a 90 degree bend in it and it was so short that it cut most of the water flow off. Been a long time but I do not remember there being a metal pipe.

Richard
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Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body. But rather to skid in sideways, chocolate in one hand, a good Reisling in the other, body thoroughly used up, totally worn out and screaming:  WOO HOO, what a ride
TrevorH
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« Reply #16 on: May 17, 2008, 05:39:36 PM »

Well thanks for the ideas!  Sorry to have kinda stirred up a mess with the shops and whatnot.  I kinda like the idea of swapping out the tranny if it could be done affordably.  Are there any that might be syncronized?  I have gotten the shifting MOSTLY down (downshifting is a realy SOB) but it kinda locks me into having to drive since everyone else is scared of the size, let alone the shifting.  The gearing now seems pretty good and I have not run it up to the governor in top gear but got up to 78-80 and there was still some left.  It would be nice to have a tach for sure.  The last trip I believe I averaged about 6.5 mpg without using the AC for the second half the trip since it wasnt working properly.  I would be interested what it gets without using the AC at all as I think it sucked ALOT of fuel.  You guys think it would be possible to get this up to 9 mpg if driven consiously?   
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1987 MCI 102A3 8V92TA 5 spd MT
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TomC
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« Reply #17 on: May 19, 2008, 07:45:02 AM »

Nothing affects mileage more than the driver.  Depending how hard you push it, you could get 4-6 mpg-thats a 50% difference in fuel mileage.  Couple of points.  Best cruise speed is 55mph.  The faster you go the more fuel it takes-period.  When in some of the western states, like California, 55 is doable with the 55mph truck rule.  But realistically, 60 would be my choice-or with a 8V-92TA what ever speed will give you a comfortable 1600 rpm cruise, with no higher than 1800 rpm.
Also, when hitting the hills, let the bus slow down and go up the hill the same speed as the trucks are (if you're on a big highway).  Going up the hill at 35mph with your foot barely on the accelerator with engine revved up will keep it cooler, and exert less strain on everything, rather than trying to see how fast she'll do up the hill.
Most of us are on vacation when driving our bus, so just how fast do you need to go?  Last month I went to Buellton pulling my car and drove right at 55mph by my GPS, which was 1700rpm and got almost 6mpg-which is remarkable for my setup.  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
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