123 200 petrol advice

[Gerard]

Hi All,
I've been on this board for a while but mostly on the Diesel Discussion (87 300d124). However, at the weekend I saw a very nice 1982 123 200 petrol for sale, the body looks very good but the engine has a funny noise, sounds like a timing chain.
The engine starts easily and makes no smoke.I didnt go for a test drive, will do that if i look again.
Can anyone offer any advice on these engines, and how easy/difficult to service/repair.

Thanks all
Gerard
Dublin Ireland