QuestionI have an MGBGT which has been modified by fitment of a supercharger and the drive for the water pump, alternator and supercharger is now by a Gates flat v-ribbed serpentine belt. Tension adjustment is by sliding clamp bolt on the alternator. My question is, what is the appropriate belt tension and how to estimate it.
AnswerThis is a question about a non-standard fitment - a supercharger. I have only ever fitted one, so I don't consider myself an expert. I suggest that you contact the manufacturer of the supercharger, or the seller of the supercharger kit, and ask them what the correct tension should be.
Moss sell supercharger kits for the MGB, so you could also try their technical people.
Checking the tension of a serpentine belt is usually done in one of two ways:
(1) Check the in-and-out movement in the middle of the longest run of belt by applying finger pressure. It should not move more than 10mm in or out.
(2) Apply a twisting action with finger and thumb. It should not rotate more than 90 degrees.
Professionals have a hand-held device that they press against the belt to check the tension, but these are expensive, and anyway you need to know what tension the manufacturer specifies.
Finally, I am concerned that the kit relies on a sliding clamp. If I had a problem such as needing regular re-tensioning, then I would make my own tensioner bracket, with a stud and nut adjustment system.
Hope this helps.
