There is no single kit for buses and it would be impossible to make one since a given bus manufacturer may offer 4 or 5 engine options for a given body in the same year, in addition the company who makes the bus buys engines from an engine manufacturer, the bus company knows little about the engine and the engine company knows nothing about the bus.
As an example; I built and installed a system for a $250,000 Wanderlodge bus conversion motor home fitted with a Cummins IBS engine, Cummins could tell me about the block they supplied by its serial number but noting about any ancillaries like filters, filter location, cooling system etc. Wanderlodge could tell me nothing because when a customer orders a motor home they specify an engine, they day the engine gets delivered they bolt it in and make it work with the parts they deem necessary for the project and no two are ever alike.
School buses, over the road Coaches and trucks are the same except that being commercial equipment they are often different that what we see on consumer vehicles, as an example a 94-98 Dodge diesel pick-up will be fitted with a Cummins 5.9 with the Bosch P7100 injection pump, this only became available in 1994. A 1993 40’ school bus fitted with the Cummins 5.9 will however have a P7100 injection pump. A school bus fitted with a Chevrolet 6.5TD engine may in fact have the 6.2 injection pump and intake bolted to a 6.5 block so it will fit in the vehicle.
In addition buses all have different space available for tanks, sometimes under the bus hanging from the frame, other times in the cargo bays under the bus.
That said, each bus project must be a custom system and it is up to the owner to find out exactly what engine the vehicle has been fitted with, where and what size tanks he or she wants, how they are going to go about their filtration of waste oil etc. Once we have this information and preferably a fuel system diagram, we can design and build a complete system or components of the system depending on the level of involvement you wish us to have.
We have built complete fuel systems including tanks for a several tour companies who filter their oil at the base and fill the bus before tours, built a system for Dartmouth Colleges Big Green Bus , dozens of private bus and school bus conversions ranging from systems with on-board filtration systems and huge tanks to systems where we simply custom built an in-tank exchanger for the customers tank and supplied a kit.
The first decision you need to make is how large a fuel tank you want, where it will be mounted and the size of the tank. We have a tank capacity calculator which allows you to enter dimensions and find out what the capacity of the tank will be here Tanks can be custom made by Frybrid by following the guide here or tanks can be ordered from companies like Plastic Mart, new, surplus or salvaged aluminum marine tanks or semi truck tanks are another option.
The next decision is if you will need on board filtration, again custom systems as elaborate as automated filter and dewatering tanks with coolant, 12vdc and 120vac heat, suction pumps, retracting 50’ suction lines, etc can be built or you may elect to simply build a Frybrid Still and mount it in the vehicle
Basic Bus info:
Firstly lets get some definitions and information out of the way.
School bus = A bus designed to carry children to and from school. These have been made in the classic long nose version as well as a more modern copy, they tend to have very good ground clearance (rural roads, rail crossings, etc), solid axle suspension, windows that open from the top down and are often available with manual transmissions and usually geared low (rural roads, inner city). They are not fitted with cargo compartments but often have wheel sanders. Flat front busses were also used, Gillig, Crown and bluebird were common. These tended to have higher gearing and lower ground clearance and often some storage.
Transit bus = A city bus used to carry commuters or workers, sometimes put into service as school buses. Most transit buses do not have any storage, many are not even fitted with a fuel gauge. They have lower suspensions tend to have air bags suspension offering a comfortable ride, the floor of the bus is close to the ground. They tend to be geared lower and are fitted with automatic transmissions.
Coach = A coach is a bus designed for highway travel carrying passengers and luggage. They tend to be automatics but older coaches were available with a manual. The have storage compartments which raises the floor of the passenger area, they are geared for highway use, have air suspension, low ground clearance and share much of their running gear with Semi trucks.
Coaches are commonly broken down into three classes;
Seated Coaches (people movers)
Motorhomes (converted coaches for family use)
Entertainers (converted for entertainers and tend to have bunks sleeping up to 8 or 10).
Seated coaches are still usable for commercial applications and demand higher prices. Once they have been stripped of the seats people refer to them as "Shells", you would think that a shell would cost more than a seated coach since a lot of work has been done... Wrong, although a great deal of work has been done, the market is now much smaller, only someone intending to convert thier own bus would buy it. Shells are available in all stages, I often see a stripped shell, with insulation, floor, some windows blocked off, tanks, genset, etc. all installed selling for a song because harry died or had a stroke before finishing his project and June just wants it gone. Recently there was an Eagle 10, 40' shell with all the tanks, plumbing, wiring and an onan diesel generator, all the insulation and flooring done in Oregon for $15,000.00.
Once a bus has been converted the game changes and everything depends on the skill of the converter. You see buses with old home refers in them, window AC units scabbed through the walls, regular flush toilets, plywood and lenoleum floors. You also see beautiful older motorhomes that look like yacht interiors and were often in fact built by boat builders. Hippy buses built with scrap wood and carpets, an old futon in the corner, a sink that drains into a bucket, often the same bucket that is used to flush the toilet. You see white leather and mirrored cielings, rope lights and plastic wood, the motorhome version of a 80's disco. You also see really beautiful buses, what makes the difference in all of these conversions is that unless you did it yourself, you better be sure that whoever did it left pretty good diagrams because when you have a plumbing issue or a wiring issue the builder is the only person alive or dead who knows how the darn thing went together.
Entertainer coaches are available for a song :-) and mostly in the southeast, I have seen Tammy Wynett's coach selling for $25,000 and entertainers set up to sleep a couple (or star) in a master bed and 4 musicians in bunks, talk about a perfect family rig. Google "Entertainer coach" and you will see what I mean. The details tend to be well done since the original owner paid to have the bus converted and could not afford to miss a date on tour.
Most coaches were fitted with 2 stroke Detroit Diesels the 6v71 (my first bus) and 8v71 and later the 6V92 and 8V92 bith MUI and DDEC (mechanical or electronic controlled injection) they also came as "T" or "TA" (turbo or turbo & Aftercooler) and allison transmissions although the Crown and Gillig buses tended to have the CAT or Cummins motors (Many of the Crown were mid engine).
Coaches were designed to provide 4 million miles of service, thats right 4 million miles. They are likely the best built vehicles on the road and one of the safest (when was the last ime you heard of a bus in an accident on the highway), in comparrison most RV's are built on a truck frame which is narrow making them handle like laofs of wet bread, they body is an add-on made of 1x2 wood, paneling and glued on fiberglass panels and are designed with a 5 year life expectancy if use lightly. Every wondered why a 5 or 10 year old motorhome is worth $2k? Because you can put your fist through the cieling, the floor is warped, everything is rotting and the paneling is peeling!
Common coaches are:
Eagle = They were favored by entertainers for years, have a body made with square steel stock, very strong, can be cut up without effecting structure (slide outs). Origninally built in Germany they began being built in the US in about 1974.
GMC = Most were monocoque chassis which does not wend itself to having holes cut in it. Great buses, my first bus was a 1972 GMC fishbowl transit bus fitted with a 6V71, which not designed for highway use and having no cargo space under, I lived in it for 2 years and drove it as far as Nicaragua. Not a single breakdown and I think I only changed the oil once. Everything from the old Greyhound Sceniccruiser to modern buses.
MCI = Very common and took over the US market, monocoque chassis, known corosion issues, two years ago three states dumped thier fleets for new buses flooding the market with MCI buses, for a while I was seeing them for $2k in perfect condition. Many churches and groups bought them up and they still resurface cheap here and there. Fiberglass caps are available for the front and rear which make them look just like the 2007 buses.
Gillig = Gillig built some coaches in the 70's but is almost exclusively a transit bus maker now. Some really pretty older buses, tended to be narrow and have low headroom.
Crown = 1914-1991 built fireengines, coaches, transit, school buses. Real cult following. Narrow and low, quite stylish in an antique way. Many say that a Gillig is a Crown copy.
Prevost = Based in Canada they only produce shells for entertainer and motorhome conversions, very high quality, the new standard in touring coaches.
Van hool = Belgian. MAN engines, DAF engines, and Mercedes engines used in these coaches can make finding replacement engine, transmission and drivetrain parts difficult. Some were fitted with Cummins motors, they are built on Mercedes, Volvo and Scania chassis. 3rd largest coachbuilder in the US after MCI and Prevost. Also builds transit and electric buses.
It is important that buses are easy to buy and hard to sell... Look before you leap!