The Engines (There are at least 2)
The primary mover of our PT-40 is a Detroit Diesel 6V-92T “Red”. This is a 2-Stroke Diesel,6 cylinders in a V configuration, each cylinder is 92 cubic inch displacement (total 552 ci or around 9L.) It also has a turbo. And a supercharger. I could gush about these engines all day, they are so cool and different from almost anything else out there. I highly recommend reading more about them or watching Bus Grease Monkey videos online.
2 Stroke sexiness (not mine):
you can see the exhaust manifolds feeding the turbo, which then feeds the supercharger (needed for scavenging at idle). My engine doesn't have any of these pulleys or fan on the front. The front of the engine is actually at the rear bumper of the bus since my bus is a pusher.
The history of these engines is also fascinating, this link is extensive but a good read: http://www.dieselduck.info/historical/01%20diesel%20engine/detroit%20diesel/
Tl;dr - smart industrious guy on his yacht in the 1920s decides to build a better yacht engine. We've all been there.
These engines are pretty old school and demand special care and attention. Only Delo 100 engine oil should be used. Never overheat them. Paper air filter elements only. Extensive warm up time with an engine block heater before starting. And, of course, they run better without any effective muffler system. Our bus has some sort of spark arrestor on it to reduce noise, but to say it’s a muffler is absurd. Its loud. So very very loud. Its so loud it makes hard core Harley riders blush and then plug their ears. Climbing a mountain pass out west, the ever-present concrete road barriers reflect 100% of the side facing exhaust directly into the drivers ear drum. This needs fixing.
"Muffler" on the right. My engine compartment is usually cleaner than this...
A nice thing about this engine is most of the ancillaries are gear driven (water pump, cams, air compressor, etc.) The only belt driven component is the alternator, this is accessed through a hatch under the rear bed.
Watching Bus Grease Monkey videos shows how lots of maintenance is performed. The engine bearings can be inspected and replaced with the engine in place. You just remove on bearing cap at a time; the upper bearing can be pushed around the crank are removed for inspection, neat. Jeff at Gino’s garage actually just did a video on this: https://www.youtube.com/watch?v=JC8W8QdcLRQ (Jeff is one of the guys on Wanderlodge owners group that volunteered to help me if I had issues on my trip home, great guy!)
The engine can also be rebuilt “in frame”. Cylinder heads off, oil pan off, connecting rod caps off, push out the piston from below and then remove the cylinder liner with a puller. I might have some details wrong, but its good to know it can be done. Removing the engine for a full rebuild is best left to someone with a heavy duty forklift
The Detroit has 3 fuel filters: a Racor contaminent filter (for water / dirt / rust/etc., seen above next to the muffler), a secondary canister filter and a primary canister filter. Fuel pump is before the primary filter, its low pressure for a diesel since the camshaft activated injector provides the needed injection pressure. An old school diesel technique is to fill the filters with ATF when changing them; diesel tends to be dirty and you don’t want any debris getting into the injectors. ATF is very clean and a dinosaur like the 6V-92 will run just fine on it (at least in smaller quantities.)
The other engine is the front mounted Perkins 4.108 diesel mounted to a Kohler 12.5 kW generator. This engine also had an interesting history, but its seems somewhat boring compared to the Detroit. I love it any ways. Its mounted on a hydraulic mounted ram that pushes the engine out the front for servicing (ram doesn’t work, but will someday). This engine is also loud and stinky, so we usually carry around a 3rd engine (a much quieter Honda E2200 generator) if we don’t feel like completely smoking out our neighbors and don’t have an electric hook up. The Perkins-Kohler can run everything (AC powered) on the bus at the same time (3 air conditioners, residential water heater, engine heater, microwave, battery charger if needed). The Honda could only run one of those at most. Here are some pics of the heroic work the previous owner did on cleaning up the generator. I could eat off it!
before:
after:
