Whats the fastest way to raise mechanics?

Trying to get mechanics 8 so I can install multiple engines, but I don’t have Internal Combustion Fundamentals and am currently at 6 (48%) skill level. Disassembled two cars over two days, and it rose by 6%. Is there a faster way to level up the skill, other than Internal Combustion Fundamentals?

Construction yields more XP, then dissembling things.

Find a job on your vehicle that’s level 6 (or nearest) that doesn’t take resources to do (such as batteries with welder) and keep doing it then undoing it.

e.g. add car seat -> remove car seat -> add car set -> repeat.

If your rifles/ranged/launchers skill is high enough you can also craft various makeshift firearms to raise your Mechanics. I once trained Mechanics from six to seven by assembling and disassembling tube 40mm launchers, they take only 6 minutes a piece and require only a pipe, a two by four and a nail to make.