K Series - alternator belt tension

[analog_me]

I hope this is the end of a long list of works i have to complete for fixing a series of issues that were not dealt with when the car was at a specialist's workshop,

So the left hand side engine mount (on a LHD car) was found broken all around the weld so i will give it to a skilled local technician who will reweld and reinforce it so i can reuse it and save myself the long delivery time of the new part.

So, my consequent question is:
What is the right tension for the alternator belt?
I read in a thread some time ago that anything between 1/4 to 1/8 of an inch of deflection is acceptable. That is about 3-6mm.
I was told by the mechanic that he on purpose left the belt slipping a startup otherwise if tighten more the tension will break the engine mount.
3 months later (now) my engine mount is broken so i need fix it and tighten the belt the right amount, I am therefore seeking your advice.
Thanks

[analog_me]

any hints on the alternator belt tension?

[Penelope Stopit]

6mm is good, check after putting some miles on the clock if it's a new belt

[analog_me]

thanks will stay with +6mm then