It seem that a substantial percentage of the training aircraft in the area I stay are of 1970s vintage with engines designed a lot earlier.
Most car engines of this era were pretty unreliable. (unless they were japanese). One example which springs to mind was the 1200cc Ford engine which had a life of 40000 miles before the crankshaft let go. As a youngster running cheap cars it was a challenge to find a car which did not have a rattling engine.
DO.