but had to stop on due to Lack of Funds (which meant it was sitting in my garage with no engine when the city came around and hauled it off as a derelict vehicle) was a Biodiesel Breadloaf.
A breadloaf is a VW Bus. There are four "types" of VW Buses, labeled T1 through T4. T stands for Transporter.
T1 is the Split-Window Bus. Any Bus with a split windshield is T1. Don't convert these; they are collector's items.
T2 is the Bay-Window Bus. It has a single-piece front windshield. These offer the greatest potential for conversion; the later Vanagon and Eurovan have issues, which I will explain. Short version: the T3 (Vanagon) has no vertical room in the engine bay, and the T4 (Eurovan) is front-wheel-drive. The best years for conversion are 1974-on, because in 1974 Volkswagen put a door over the top of the engine so you could work on it. This car is air-cooled when you get it; I shall explain how to get around that.
The other advantage of the 1974 is that it contains a fuel-injected engine. FI engines have one extremely important feature: there are two hose bungs on the gas tank. All FI engines, whether gas or diesel, return fuel to the tank. Some guys get around this by dropping the tank, filling it with water and drilling a hole in the neck to accept a second bung. (The water part is to drive off any remaining gas fumes, which like to explode around heat, friction, sparks...)
T3 is the Vanagon. Converting a Vanagon is problematic because it's designed around the fuel-injected flat-four VW engine. Most successful engine swaps on the Vanagon feature a big plywood box over the engine. The Vanagon was available with a diesel engine, but the diesel available to it had 50 horsepower. Not enough! Also, the diesel engine on a Vanagon lays on its side, so it's not easy to throw the underpowered engine away and put in a nicer one--but the TDI will bolt straight up, so if you can find a wreck that contains a TDI, that's an option. Most people converting the diesel Vanagon remove the diesel, pull the oil pan, bolt said oil pan to a gasoline Rabbit engine and insert said engine into the car.
T4 is Eurovan, and if you start with one of these you're going to put a VW watercooled Four or a VR6 in it because nothing else will fit. Fortunately, one of the engines available to the Eurovan was the TDI diesel.
Okay, so you've got a bus. Next thing you want is an engine. The preferred one is the VW TDI for several reasons, not the least of which is Volkswagen's watercooled engine mounting strategy. In the aircooled days, VW made the decision to never change the engine-transmission mating area, with result that a 2002 Mexican engine bolts unmodified into the Bug Ferdinand Porsche gave Hitler. When the watercooled VW was introduced, the same rule applied. You can't directly bolt a TDI or a VR6 into the Bug Hitler had, but you can bolt those engines into the very first Rabbit ever made. So what? Go to
http://www.kennedyeng.com and you will find adapter plates for installing VW Rabbit engines into VW aircooled cars. That's what you need to make this work. There are two versions of this--laying flat and straight up. You want the straight-up one; the oil pump on a TDI is not designed to work in the laying-flat position.
There are two ways to go about getting this engine: buy one from VW, or start scouring junkyards for a TDI-engined car that was T-boned and buy the whole car when you find one. This is the way to go; with the whole car you get all the little tidbits you need to make it work, like the electronics.
After you have the donor car, the drill's pretty simple. Start by removing the radiator and mount it to the Bus. I have seen three popular places: in front, on top and in back. In back won't work. The in-back crowd replaces the engine door with the radiator, uses Buick engines with the fan flipped around backwards and blows air through the radiator all the time. This looks like shit. The guy who put it on the front disguised it as a spare tire in a Continental-style tire cover. He spent two weeks beating the fuck out of a piece of crusher mesh to make the radiator cover. If you want to see what "on top" looks like, google Roadcow. My bus was a Riviera camper and had the luggage rack in front; I had cut a hole in the front of the luggage rack and mounted a Vanagon radiator in it. Now remove the TDI engine and all its accessories and insert the engine in the Bus.