Crankshaft toothed pulley - reminder why it's a service item...

[quattrostyle]

Going by Dave this should be good: http://www.tommisbillet.com/fi/tuott...-hihnapyoeraet
Also on here: http://www.s2forum.com/forum/showpos...5&postcount=22 however I've fitted Jamil's one to my former S2 and as far as I know it did 60.000 km since then without issues.
I got another one from Jamil that I'll be using, if it does 60.000 km again I'm happy. No chance I'll ever reach that mileage in a project car within ten years and a belt is not that expensive.

I think Dave means the teeth on Jamil's sprocket are more round than the tommisbillet and OEM one and the teeth on the belt are also more square, so there is a difference.

[Error404]

This argument is bulls*it. The teeth on the OEM sprocket are not square and neither is the cam belt.
The convex shape of the bottom of the OE tooth profile gives an optical illusion that the teeth walls are square but look at them closely and they are not. So unless someone has taken the trouble to exactly model the radius of the OE sprocket tooth profile, a square cut tooth is not better a fit than Jamil's.

[UrS4boy]

...I got another one from Jamil that I'll be using, if it does 60.000 km again I'm happy. No chance I'll ever reach that mileage in a project car within ten years and a belt is not that expensive. I think Dave means the teeth on Jamil's sprocket are more round than the tommisbillet and OEM one and the teeth on the belt are also more square, so there is a difference.

I don't give a toss about the cost of the timing belt. It is the damage done when a timing belt fails and the pistons give the intake valves a Glasgow kiss.

And yes, I am attempting to suggest strongly that Jamil's short-cut to create the valleys via semi-circles in no way properly matches the profile of the teeth on the belt and therefore will stress the tooth at the point where it meets the belt, perhaps leading to premature belt failure, etc.

But that is just my opinion. I would buy one of Tommi's before I'd buy one of Jamil's.

Tommi's:

[UrS4boy]

This argument is bulls*it. The teeth on the OEM sprocket are not square and neither is the cam belt. The convex shape of the bottom of the OE tooth profile gives an optical illusion that the teeth walls are square but look at them closely and they are not. So unless someone has taken the trouble to exactly model the radius of the OE sprocket tooth profile, a square cut tooth is not better a fit than Jamil's.

Well I know I never said that the teeth were "square" cut. Trapezoidal is closer. But yes, I probably said that I preferred flat surfaces for the sides of the teeth. With the South African producer of the previous CNC'd version (with almost factory profile teeth) that EFI Express sold out of production, Tommi's (now sold through EFI Express for us in North America) is the closest thing to the factory tooth profile available. http://www.efiexpress.com/catalog/pr...products_id=23

Nice cracked pulley in that photo by the way.

[driftin jo]

Well I know I never said that the teeth were "square" cut. Trapezoidal is closer. But yes, I probably said that I preferred flat surfaces for the sides of the teeth. With the South African producer of the previous CNC'd version (with almost factory profile teeth) that EFI Express sold out of production, Tommi's (now sold through EFI Express for us in North America) is the closest thing to the factory tooth profile available. http://www.efiexpress.com/catalog/pr...products_id=23

Nice cracked pulley in that photo by the way.

They should actually be a involute profile.
This provides rolling gear mesh and reduces friction/wear.