I was wondering where the money was coming from. I take it you are teaching high school. You must have some kind of budget from your school to teach with. I see you sold the engine so I see where some of it come from. Doing this work I know there is a lot more then just parts. Shop supplies like chemicals, rags, uniforms, hard ware, etc. You must need a lot of tools for a whole class to share, lost, stolen, or broken. You must have to work with all kinds, with some not knowing the difference between a chisel and a screwdriver. This all take big money. I have a customer to get mine back from. Wouldn't it be cheaper just to keep your engines and disassemble and reassemble them. It would be cleaner, need no parts and still have to get them runing. That was the way they did it when the dealership sent me to GM school.
A little more info might answer some of your questions.
I teach grade 7 - 12 Fabrication (sheet metal, wrought, aluminum, welding etc), grade 10 -12 mechanics and grade 10 - 12 Wildlife. Yes Wildlife. The province of Alberta is full of hunters, trappers, outfitters and many more peolple who use the bush for varying reasons so they developed cruuriculum around it. I'm also a Hunter Education Instructor as well as a Firearms safety Instructor (which is why I teach the course)
Back on topic, my budget is $5000 for a ten month school year. With an extra $2500 if I need to replace any big ticket items Bandsaws, drill presses etc. (The $5K budget is called consumable items but I roll my parts through this budget) it also covers, fast orange, varsol, welding rods, drill bits gasses for the oxy-acet and mig welders, plasma cutter tips, gloves, welding gear and the list goes on.
I have to be careful because I can get a pile of my budget hooked up in parts in a hurry. If I sit on the engine (or whatever it is) the other classes take a hit. My junior high classes are busy with soldering, sand casting and a bunch of other projects so as you can imagine, the budget can deep six pretty quick.
The ride on mowers I try to roll in and out with cost recovery (except consumables) and that is a grade 11 - 12 class so its a bit smaller in size and easier to track progress ( class sizes are usually 15-20)
The kids in grade 10 (class sizes are 25 to 30 as a rule) and they bring in push mowers for the most part. I have a cache of briggs and Tecumseh.......etc on hand incase they need parts. If I don't have what they need then they generally have to buy it.
The fab classes can get interesting too. I have a 24' frame off a holiday trailer and we are going to try to make a tandem, tilt deck car hauler if the frame is heavy enough. I'll have to save some money to buy axles etc..
The other option is to do custom work for fellas, but having so many kids who like you said, don't know a screwdriver from a ratchet, I can run into problems making sure every bolt and nut is snugged up.
Its always interesting down the "shop":thumbsup: