Looking at the code, the list from more damage to least damage goes like this:
All of the have the same durability (100).
And about armors, the list goes this way, from more durable to less:
Spiked plates also deal a bit more damage when bumping something with that part.
From https://github.com/TheDarklingWolf/Cataclysm-DDA/blob/master/veh_type.h
You pretty much have to drive your vehicle to the components too heavy to pick up at all. (I’m looking at you Hard Plating with your 1800 weight)
In the case of engines, it means putting in a lesser one, and driving to the nice find, removing the old one and installing the new one.
unless you have around 30~ levels. then you can have more than one.
Makes me wonder, has anyone ever attained the mythical mechanics lv 12 required to install a second engine without the debug menu? Even at lv 8 mechanics it seems like I’m getting skill rust just as fast as I practice.
You can always disable skill rust and end up lvl 12 that way?
Yeah. Fuck skill rust. Just ruins the game for me.
I tend to turn off skill rust a lot, or at least bring it down to where it won’t take away skills you already learned. I’ve managed to get a motorcycle going with two V8 engines. Tearing through towns at 250mph is kind of fun, and if I turn off cruise control and push it to the red I can get it going up to 698. Then I hit a tree or building and die.
On a related note: do mufflers actually do anything?
Mufflers only work on gas powered engines, and yes they make them quieter.
Donno exact numbers but with static spawns off it makes a 2L engine able to enter a city without ringing the dinner bell.
Yeah, sorry but I don’t believe something that I read or learnt only a few days ago will start to degrade until I know nothing about it. Skill rust should be capped at level as default, but I generally just turn it off. I’m a newbie, I’m allowed some leeway. 
I’ve been playing the game since before it existed and I disable skill rust
We’ll replace it with something less horrible eventually.
Even whales thought skill rust sucked.
I bet he turned it off when he played Cataclysm >: (