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Author Topic: 4107 thoughts  (Read 8428 times)
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« on: August 18, 2010, 09:03:47 PM »

Im new here so go easy, I will probably have a ton of questions. As the subject eludes, I am thinking strongly of a 4107. I like that they are only 35 foot, the large bays, and that there are no wheel wells protruding into the floor. Otherwise I would probably go with an 06. 

 
 I am leaning toward converting one myself, otherwise probably redoing an existing one. Money is tight so I have to limit my budget by doing as much as I can on my own.

  One of my main concerns are how the 4107's really handle. Ive read some about them blowing around in stiff crosswinds, can anyone offer some better comparisons? I presently run an old oshkosh bounder with a cummins 5.9 pusher, I cant imagine a 4107 blowing around as much as that, but I wounldnt know.

  Another big question is needing service out on the road. Motorhomes are actually pretty risky machines to leave home with, RV dealers wont work on the chassis, and truck shops wont generally work on motorhomes. How about a bus, will truck stops let one of those in?

  Then there are the real questions. Heating and cooling systems, power generation, etc.. I would like it to be as efficient as possible, as well as able to remain unplugged as long as possible. So RV fridge is a given. I have read some threads here discussing using the engine alternator to run roof airs, and ditching the OTR system. I would prefer a ducted a/c system in the floor, and probably in floor heat. Heat could be either diesel or propane. Generator will be diesel. Any thoughts on keeping the large OTR condensor and incorporating it into a different system???

 All thoughts and experiences are welcomed.
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« Reply #1 on: August 19, 2010, 12:09:44 AM »

Welcome to the madness!  I have an AMGeneral 40 x 102 wide transit that I love since it is 6 inches wider and has 6'10" of headroom.  With cooling, heating, stay with main stream proven technology.  For instance many like the Diesel heat of Aqua Hot (around $8,000), but also look at the maintenance on that system.  I have a propane furnace (just replaced it after 15 years), and 3 burner propane stove with oven.  Everything else is electric.  Two 10 gal electric water heaters-one feeding into the next with the final one powered through the inverter for hot water during the day when driving.  Two Shurflo Whisper water pumps plumbed in parallel for smoother flow.  3 roof top A/C's (no dash air), 10kw Diesel Generator, 130gal water, 85 gal gray, 45 gal black, 2-8D AGM house batteries, 2-31 starting batteries with solenoid to jump the two sets if need be, 6.3cu/ft Norcold refer, 2.1 cu/ft Norcold chest freezer, 20 gal chassis mount propane, 2 Fantastic Fans, etc.  Just an idea what I've done-except for replacing the propane furnace (I left it on for 2 weeks) nothing else has needed replacement in 15 years.  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
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« Reply #2 on: August 19, 2010, 01:40:17 AM »

  Thanks for the response, sounds like youve done a lot of neat work. I want to try as hard as possible to stay away from RV type heating and cooling. I want to keep the roof clear, I just dont like the clutter of a/c units and vents on the roof of a bus.

   For heat I am thinking of using a short or modified gas (LP) hot water heater and in floor heating, with a loop for hot tap water, and an engine preheat loop. For cooling I am thinking I'll use the factory a/c condensor, and plumb in a small residential A/C compressor and run duct work to floor vents. With some extra work I could possibly reverse it into a heat pump for back up heat. Thats the direction my thinking is going anyway. If I can get it insulated well, for such small space I shouldnt need a very large compressor, maybe a 1 1/2 ton compressor??? I really would like the engine alternator to be able to provide enough electrical power for cooling without taxing it too hard, and I believe this should accomplish that with power to spare.

 
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« Reply #3 on: August 19, 2010, 02:20:37 AM »

Art -

I'm in the minority here, but am also one of the few with real-world industry experience, too.  Needless to say, I hated the 4107/8s that were in the charter bus fleet when I worked that industry back in the late '70s - mid '80's.  They weren't second-hand junkers, either - they'd been bought new from GMC by a company that has a meticulous preventative maintenance program.

Loved the 4106s and the 4905s, still do.

You do mention their pluses - the large bays, the lack of wheel well "humps" and the 35' overall length.  You missed the pantograph bay doors - very handy in tight places.

You don't mention their major minuses:

~~  The stadium seating up front that takes away nearly 5' of interior space, which is critical in a 35' coach to begin with.  Sure, you can level the floor, but you end up banging your head on the vista windows in the process.  Can be remedied with a front cap covering a roof raise, but on a tight budget?  Not quite as much of an issue with a 40-foot 4905, but still lost space.

~~  The kneecap-destroying dashboard switch layout, especially if you're short and have to have the seat closer to the dash for pedal access.  Can be remedied with a Sawzall, or purchasing a 4108 instead.

~~  A lot more steel in the construction, leading to lots more corrosion repair.  Most noticeable around the two "d" windows, among other spots.

~~  The cantankerous crosswind handling.  IMHO, the 4107 and it's younger sister the 4108, both suffer the same fate.  They are far more stable than your typical stick 'n staple Winnibuggy, but for a bus chassis, they're skittish.  It's my theory that the large "sail area" presented by the taller roofline, combined with the 35' length, contribute to this behavior.  The five-foot longer 4905 does not suffer the same consequence - the longer wheelbase creates a much more stable base, not to mention a sweet ride. 

This is NOT to say that some owners don't share these same opinions, because that's all they are from an industry vet dealing with revenue-service vehicles.  In RV use, most folk park 'em when it gets really windy, so their experience is different.

If you're hooked on a 35' Buffalo, I'd suggest a 4108, due to the far better OEM dashboard if nothing else.  Harder to find, tho, due to lower production volume.


As for converting one yourself, be aware that in today's economic climate, there is NO WAY you can do a conversion for less $$$ than you can buy one already finished and ready to roll, maybe needing just a little TLC.  Think about what I just said very carefully, there are a LOT of abandoned project buses out there.

Truck stops are more than willing to let their mechanic learn all about bus systems on your dime.  OK for an oil change (bring your own oil & filters) and brake adjustment (especially if they have a pit), but for more, you need a friendly local charter bus company garage that takes on outside work.  Or one of their mechanics who moonlights.

The topic of HVAC for bus conversions can get quite entertaining, and the debate rages on.  Do a search of the archives for lots of thoughts on the subject, much of what you're thinking about has already been cussed/discussed over the years.  Use the search button in the upper LEFT for better results.  Oh, and search the archives over on BNO, too (www.busnut.com) for more entertainment.  There are a couple of busnuts on this board (Nick & Christy) who own HVAC businesses and are a wealth of knowledge, they can provide valuable assistance.

Hope that's enough to get you started thinking.  Remember that buying a bus is easy, selling a mistake is HARD!  Do your homework, and find a good BUS mechanic you can trust and work with.

FWIW & HTH. . .

 Wink
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RJ Long
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« Reply #4 on: August 19, 2010, 08:28:09 PM »

  Good information, thank you. Its valuable to have someone that has experience.

   If you could elaborate on the crosswind skittishness? As I said, I am presently pushing a 32' Bounder with a cummins. It gets buffeted in stronng crosswinds, but its nothing I cant handle. If you could better detail what your saying I would love to hear.

   I'm a mechanic, so the bus doesnt scare me mechanically, but I cant take a full workshop out on the road. If I need repairs or service to the coach away from home, im very interested as to how truck garages accept them. They downright refuse to work of "RV's". For example I wanted some brake work done when I lived in the Minneapolis area. RV dealers wouldnt work on it, and neither would truck shops. On the road ive had some minor issues, and truck stops turned me away. The few ive spoken to would not have even serviced a tire! At least a bus is heavy duty enough that if ready to roll I may never need their services. Just nice to know.

  As to the stadium seating, I really need to get back out and look at them some more, its been a while, but as I recall I will still have more floor space than I do now with this Bounder. Its 32 feet, but between the side door screwing up the floor plan and the dash and seats sitting back 5 feet taking up the whole front nose, I figure I would still get a good gain of space.


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« Reply #5 on: August 19, 2010, 08:58:08 PM »

  Another question is these busses climbing abilty and ground clearance.

  I have a very long (1/4 mile) and steep driveway with a short turn in off the highway. The bounder wont drag it butt , but it has a longer rear overhang than a bus. What about a 4107? They dont have as much overhang, but they sit much lower. I never blew up the bags on a bus as far as they could go, but does anyone know how much ground clearance could be had by fully inflating the air bags? I dont mind scraping some if im not hurting anything, but id prefer not to scrape anything at all.
 
  And how steep a grade can they go up in first gear? The initial part of the drive is nearly 30% and I dont have any run to reach any speed to make power. I need to be able to climb the drive at just a bit above idle speed.

  Ive been assuming both these questions are non issues, but we all know what assuptions cause us.
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« Reply #6 on: August 19, 2010, 10:52:57 PM »

Art, these buses will climb about 20% in first gear if they are a standard shift; try to avoid starting uphill on any steep grade.

With a three speed automatic, they will climb a steeper grade, and these will make starting on a steep grade easy. They will make a lot of heat before the converter locks up.

TomC can give you ratios and startability calculations as he is very familiar with them.

At 2100 RPM, our standard shift gives us about 20 in first, 34 in second, 57 in third and 83 in fourth. The three speed auto will cost you about 10% of the top end.

By using these forums and getting a book like Bus Garages(?), you will find there is quite a bit of help out there.

Good luck.

Tom Caffrey
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Tom Caffrey PD4106-2576
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Bill B /bus
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« Reply #7 on: August 20, 2010, 07:06:12 PM »

Art,

Steep driveway! Its a fairly tall first gear and the detroit is not a low speed torque monster.  Grin
There is almost overhang at the rear. From the rear axle its bulkhead then engine.
Air bags pressed up full will raise the bus about 4-5". I added air leveling, auto level stopped via electric valves, and I could move a corner some 8-10" with the combination of no air and opposite corner at max pressure.
First bus we had was a 4108. Loved how it drove. Somewhat sensitive to crosswinds. Come out from an underpass and watched the semi in front shift half a lane while I moved about two feet. That was a nasty wind at exactly 90 degrees to travel. One of the cures for the lower front seats is to build the floor level. The steps down must allow the tallest family member to walk down by the vista window without ducking their head. Works well. That's the penalty you pay for the tall bays.

Bill
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Bill & Lynn
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« Reply #8 on: August 21, 2010, 07:58:11 AM »

Based on a V730 with a bus weighing in at 32,000lb and with a 4.1 rear axle ratio, and 12R-22.5's, with a 65 injector 8V-71 getting 800lb/ft torque, you can expect a startability of 20.5% gradability.  That's OK, but should be higher.  I know I would have gotton stuck a few times with that setup.  On my bus at 32,000lb, 1125lb/ft torque, 4.56 rears, and 11R-24.5's, that works out to be 31.5% startability-which made last years drive over Ebitts pass on highway 4 (some 27% grades) possible.  Now my truck will be a real stump puller.  Based on what I think will be a 38,000lb truck, 1325lb/ft torque, HT740, 3.55 gears, 11R-24.5, my startability should be around 40%!  I doubt I'll ever get stuck on a hill. Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
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« Reply #9 on: August 22, 2010, 11:34:19 AM »

  Wow, lots of response, thanks guys.

  I wont be looking at a bus with an auto. I will simply accept  the bus was meant to be a manual and master it. I wont need to start out from a stop on my 20% grade drive, I have a lil bit of run at it. I was just checking to be sure I could maintain momentum once I start up. The bounder always stalls to a stop for a second or two before it gains full boost and starts moving again. I sure wouldnt want a standard trans bus to lose power there which is why I was asking.

  Secondly, I intend to keep wieght to a minimum and run it as light as possible. No granite, no heavy oak, and not bringing everything including the kitchen sink. And I wont be dragging the toad up the drive, ill drop it down below and drive up solo.

  So by what your all saying I shouldnt have any problem once the clutch is engaged, just punch it and go? Then all I have to be concerned with is clearance. When you say an additional 4-5 inches with full up bags, what are you talking for overall clearance? 12-14"? More? Thanks
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« Reply #10 on: August 22, 2010, 03:41:28 PM »

Art- before buying the bus, you must bring it home to see if will pull the driveway.  Try both a manual and an automatic bus.  I am relatively sure, you'll choose the automatic-I know I would, and I did (this after driving 1.3 million miles with a 13 spd). 

If you're on a hill with a manual, and you do slip the clutch enough to not stall the engine, that is not a guarantee that there will be enough power to keep it from stalling out.  Personally-I just don't think 4 or a 5 spd is enough gears for what we run into.  If you had at least a 6, more like a 7 spd, then I'd say OK.  Trust me when I say, you'll get your bus into situations that were not intended for a bus to be in.  And a couple of burned clutches, maybe a tow or three to get you out of the bind you're in, you could have paid for that automatic transmission.  Once again-be sure to drive both the manual and automatic transmission bus up your driveway!!  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
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« Reply #11 on: August 22, 2010, 07:27:01 PM »

Art

I have to agree with Tom C on auto vs manual. I've had both. The auto is the way to go for a conversion. I had to replace a clutch on the 4108. It is a day's job for two guys who are familiar with the GM system.
Tom's comment that we go places that buses aren't made to go is entirely correct. An auto makes it easier to recover from the error.

Regarding clearance - i would say that with one end on low air and the other on max maybe 10" change in height. Never did measure actual clearance.

Bill
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« Reply #12 on: August 22, 2010, 09:14:10 PM »



   I know an automatic makes it all easier, and I do really appreciate all the good advice. But my feeling is that fuel is going to become very expensive in the future and were going to be squeezing for every mpg we can to be able to afford to go anywhere. It seems that if a guy can keep one of these under 60 mph, 11, maybe 12 mpg and possibly a squeak more is possible. But 8 seems to be pushing it with an auto bus, and 6 to 7 seems more the norm. I get 6 and 7 now, 8 if I keep it under 65, and that adds up. Anything to gain some range will be of benefit.

  Yes,I understand there are things more important than fuel economy, but ive put 45K on this bounder now, and fuel has been the biggest operating expense. At roughly 2.80 per gallon average over the last 4 years at 7 mpg, thats cost roughly $18K in fuel. A 4 mpg increase over that same distance would have either saved me $7k, or allowed me to travel another 26000 miles. Thats a free trip around the world! Another way to look at it is that fuel could double to $6 gallon, but not really cost me anymore to operate than what im pushing now. If I do get a bus, its going to be a stick and I will have to make or break it.
 

 
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« Reply #13 on: August 22, 2010, 09:32:30 PM »

'04  will get you better milage.....but it  really won't get you up that driveway.   if you use   another driver driving the toad the toad might give you enough oooomph to get you up driveway.
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« Reply #14 on: August 22, 2010, 09:36:01 PM »

Art -

Re-reading your previous posts brings out these questions and comments:

How much of a straight run do you have at the hill before starting up?  Enough to get the coach to the governor in 1st gear?  (Approx 400 feet, give or take a little.)

If you can't get the coach to the governor in 1st before you hit the bottom of your driveway, you're gonna get lots of practice backing downhill.  Don't ask me how I know this - BTDT!

I've seen many a Muni bus in San Francisco have to stop and let passengers off the coach in order for it to get started on the hills around Candlestick Park after a ball game.  And these were 8V71 / V-730 transit buses with 5:56 rear axles - a LOT lower-geared than the 4:125:1 in the 4107s.

There is an alternative, and that's one of the (RARE) S-50/VR-731 combination, or the S-50/Voith combination powerpacks used in some mid-'90's transits.  Nimco might have a few. . .  Caveat:  These would be SMOG engines, so very de-tuned from potential, and virtually impossible to get Detroit to bump them up.  In transit service they're set for 275 hp, same as the stock 8V71 in a 4107.  330 or 350 hp for highway bus/bobtail truck operations, but NOT with the V-drive.

Not sure of the ground clearance amidships or at the back bumper, but the DA BOOK calls for 14" between the ground and the top of the bottom step at the front door.

OTOH, a later-model coach with a 400+ hp four-stroke coupled to a five-speed automatic probably wouldn't have any problems climbing your driveway.  Eh, TomC?


Added after your last post:

Hate to burst your bubble, but you'd be VERY, VERY, lucky to get 11 - 12 mpg with an 8V71-powered manual-gearbox 4107/8, most likely downhill with a strong tailwind.  The norm is 7-8, and I can show you my now-ancient logbooks to prove it.  I used to put 80,000 a year on these beasts back in my charter days, had to fuel them during or after each run, and the company insisted that the mileage and amount of fuel be listed on our logbook sheets as well as the fuel card in the coach.

A 4104 will, if driven frugally, return 10 -11 mpg, but wouldn't have the hp or torque to make it up your driveway.

Range, OTOH, is a different story.  A 4107 will easily cover 1,000 miles on a tank of fuel @ 65 mph, but it will take 125 - 135 gallons upon fillup (they have a 165 gallon tank).

Fuel will be your biggest operating expense regardless of the vehicle - even your own car.


FWIW & HTH. . .

 Wink
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RJ Long
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