Newb help, diag. a problem for me
 

First off, I'd like to say Hello....I've been a fan of Rotarys for a long time but have been scared away by the horror stories of apex seals blowing and constant overheating issues.....but LOVED the sound of an uncorked turbo or non-turbo 13b engine!.........so now I'm here.

Ok, my girlfriend's father has a car that I'm showing some interest in, its a Black 1991 Mazda Rx-7 13b convertable. From what he has told me he thinks the timming belt may have or is about to go out because its making loud "clattering" noises from the front of the engine. Now I'm in school for, work with, and love cars to death......I've taken my engine out of my car and rebuilt it by myself (it wasn't too hard). But my question is, should I just try to find a new engine for it (turbo or non-turbo).......or try to source out the problem?

Rotories don't have timing belts- or valves or cams.

As with diagnosing any problem it's always best to figure out what's wrong before deciding how to proceed.
Your "loud, clattering" noise could be something relatively simple to repair which would save a lot of time/money compared to an engine swap.

Or not, but at least you'd know exactly where you stand.

Yeah, find out hte problem first. ROtary rebuilds arent like cyl engines where u can rebore and put in bigger pistons if the bore is bad