Tukukkk

It is currently the year 2059. 97 years ago, the Cuban Missile Crisis went hot, and nuclear war between the USA and USSR became a sudden reality. The people alive now are 3rd and 4th generation wastelanders, most of whom have never seen any vehicle move, aside from horse pulled carts.

In New Mexico, there are a group of paramilitary known as “The Snipers”. They task themselves with protecting the people they can in wasteland, using old world tech and some weapons they manufactured themselves. But, they also have a more ‘scholarly’ branch that tasks themselves with revamping and reusing old war technology that they can use for their cause.

Two scouts recently found an old world truck, submerged in some ancient mudslide, so intact the skeleton of the driver is still grasping the wheel. They told HQ about it, and they’ve sent their top men to try and get it moving again. They don’t have access to petroleum products, but they think they may be able to make it run on steam power.

My question is, could a modern day (or 1960s) truck be re-engineered to run on steam power?

Short answer: no.

The problem is that steam engines are bulky and heavy. They need to carry around a lot of water in addition to fuel, their fuel isn't very energy-dense compared to hydrocarbons, and they don't use it very efficiently. A steam-powered automobile would be sluggish, have a minuscule range, and not be able to carry very much weight. Not to mention you'd have to totally replace the engine and all of its related systems - it'd be not much better than starting from scratch.

You'd be better off keeping the combustion engine and retooling it to run off of a different fuel source, such as hydrogen, ethanol, methanol, propane, or natural gas (methane). All of them provide less energy density than gasoline, and hence less range, but you may find them easier to come by in the post-apocalypse. They also have the advantage of operating on the same internal combustion principles as the engine you're starting with, which should simplify the conversion.

There were some cases when coal-fired trucks were done (albeit in factory conditions) during WW2:

http://www.robertsarmory.com/gas.htm

google for "ZIS-13 gasogenerator" as well

So, first thing to get out of the way.

The engine in it's current format will not run. At all.

Every rubber part would have perished, the bores in the engine would have filled with mud and rusted. Every bearing, the timing gears, the lifters, everything would be rooted.

Even if you were to completely dismantle, sodium blast and repair all these components at great expense, you would still be missing the new parts required to make it run. Gaskets/seals, belts, hoses etc would be difficult if not impossible to come by.

If the vehicle had fallen into a tar pit or something, there may be some hope in it not rusting into oblivion. But 90 years under the mud will result in very little salvagable truck.

The main part of your question, however, is whether you can re-engineer a truck to run on steam. The answer is yes, a single-piston steam engine is a fairly simple device that could be constructed out of scavenged materials. Steam powered trucks, cars and tractors have been built around existing platforms over the years and is entirely possible.

See wikipedia for a broad run-down: https://en.wikipedia.org/wiki/Steam_wagon

Also read up about Edward Pritchard, who made a name for himself converting existing vehicles to steam power: https://en.wikipedia.org/wiki/Edward_Pritchard_(engineer)

It would be by no means easy to do in a limited resource world, but if someone happened to know how steam engines worked they could certainly build a home-brew steam vehicle.