Changing timing belt in 131 1585 OHV - help sought

[perthling]

Okay, so the Familiare has a 131 OHV engine, and while I have the radiator out I thought I'd change the timing belt. Unfortunately all my manuals cover the twin cam only, or the OHV 124 engine with the timing chain not belt.

It looks like the belt should just slide off and the new belt slide on, but without an idler/tensioner I can't see how the tension is retained or reduced to allow the new belt on.

Any assistance gratefully received!

[So Cal Mark]

is it really an OHV engine with a belt?

[perthling]

Really truly. The belt is covered by the 'Triger'-labelled guard which I understand was a common upgrade to the chain 124 engines (and some 850 engines too). But the advice I have is that the 131 engines came like this from the factory. Parts supplier had no problem providing the correct belt to suit either.