Here’s the nastiness of a 30 year old ATC200. Was running OK considering some blow by and horrible leakage during leak down test. Valves, timing chain and guides were all shot. Piston was replaced with an wiseco 10.1. I intended on taking step by step pictures of the whole process but got ahead of myself and had it 3/4 assembled before realizing I forgot to. This engine was NASTY on the inside, oil rotor had around 1/4" of build up in it.
Here’s some before/after cleaning, the ultrasonic cleaner makes quick work of it.
