Their instructions clearly indicate the setting for the timing belt to be 5.0 - 5.3 using the 9201 tension tool. How about the other 4 belts? Can the 9201 be used to set their tension as well? What should the readings be or where on-line can I go to find out?
Thank you,

The 9201 can't be used on the V-belts, but can be used on the poly-ribbed alternator drive belt. It goes unbelievably tight - 9.2 for a new belt, and
8.4-8.8 for a used belt.

The tension on the V-belts should allow 1/4" (0,5-1cm) deflection with firm thumb pressure in the center of the longest run.

The top and sides of the V-belts should be perfectly flat, the belts must not touch the bottom of the pulley, and there should be no cracks or missing chunks.

Wally Plumley
928 Specialists



One possible reason for low voltage is a loose alternator belt.

The "10mm with thumb pressure" check given on page 13-18 applies to the V-belts used on earlier cars.

The flat poly-rib belts used on later cars should be adjusted using Porsche Special Tool 9201 per page 13-18b.

It is worth noting that the 32-valve timing belt is set to 5 on the 9201 gauge (in whatever units that might be), while the alternator belt is set to 8.4 - 9.2 of the same units. That is so tight that the belt feels like a solid bar.

Bottom line - if you don't have access to the 9201 gauge, tighten the flat poly-rib alternator belt as tight as you dare, then a little tighter than that.
Wally Plumley
30,000+ Parts Online!
Search for 928 Parts by Your Model Type!
928 OC Charter Member