The Datsun 1200's A12 is an overhead valve engine
similar to my Toyota Corolla's 4K engine.

Does any Datsun owner here have problems with
their timing chain snapping ? This is because my
Toyota's chain has been rattling for a long time and
is actually long overdue for a replacement. I'm
thinking of having it replaced these few weeks.

I have been getting conflicting opinions from
different mechanics and friends. Some say that
that the short-type double chains in OHV engines
won't ever snap and never need replacing, even
if they make a lot of noise. They add that replacing
the chain in these kind of engines is a big hassle
and is normally only done when the engine is taken
apart at overhaul intervals.

Others say it can snap. Yet others tell me that even if
the chain does not snap, the tensioner may give way,
resulting in the chain flying loose.