I worked on a lot of Cat 3306 engines in equipment. They were pretty bulletproof if properly maintained. A problem I saw more than once was dropping a valve, this in almost all case was the rear engine on scrapers. IMO this was due to almost always running at wot, overheating because of plant debris blocking airflow through the radiator cores. The rear engine only had a buzzer at alert the operator to high temps or low oil pressure and the operator couldn’t hear or feel anything unusual and if the buzzer failed you ended up with a catastrophic failure. Get the manual as suggested, keep the maintenance up to date and operate in a prudent manner and it should serve you well for years to come.