944 turbo cam belt

[T86951]

Does anyone know for sure if the 944 turbo is an interference engine or not. I have always been told and have read that if the cam belt breaks on the turbo, the valves will not hit the pistons but one member on here had his break and all 4 cylinders are down. Now I figure it must be an interference engine am really worrying about the belt on my turbo.

[Dave951]

It is an interference engine, but only by a couple of millimeters at the top of the pistons travel. Since there is so little distance at which the engine could be interfering, it is highly improbable. However, your right, Walker944 did bend his. He was not having a good day!!! You can measure this for yourself if you have the timing belt off. Take the sparkplugs out(to make the crank easy to turn by hand), move any valve to the fully down position(you can watch an intake valve with the manifold off), then move the crank BY HAND SOFTLY until you hit the valve. Move the valve back up some and see the remaining distance that the piston travels until it hits TDC(place a small screwdriver in the spark plug hole so you can indirectly see piston travel). I did this, it was a couple of mm).

Hope this helps.

Dave

[T86951]

This really burst my bubble on not having to worry about my cam belt breaking on my turbo. I wonder if one could put a thicker head gasket on to make it non-interference. I know that would reduce HP a tad but the cars are rockets anyway and I would rather have 5hp less than bent valves. I don't know, I guess just keep an eye on the belt and change it regular. Has anyone heard how often to change the belt if terms of time as I only put about 5,000 a year on it and it will be a long time til the magic 30,000 mile mark.