906 Flywheels

[chris_seven]

I have been looking at 906 Flywheels and I have the impression that they may use a 200mm clutch rather than the 215mm used on the early 911.

I have now become completely confused as looking at California Motorsports Website saya that early 901, late 901 and 914 all use a 200mm clutch ?/

I thought that the Four Cylinder engined cars were 200mm but all the sizes were 215mm.

Does anyone know about the 906?

Thanks

[davep]

All 914 use a 215mm clutch.

[gled49]

I believe all 6 cyl engines used 215mm Pressure Plates. But the 200mm Pressure Plate from the 912 would bolt to to the 6 cyl flywheel. GLed

[66S]

This is a 906-911R flywheel. looks like 215mm

[chris_seven]

This is a 906-911R flywheel. looks like 215mm

That's what I always thought and then I tried to give a machine shop an order to make a similar but new flywheel.

I started out with some similar photographs and a drawing from the Workshop Manual






If you use the drawing as the main reference it results in a flywheel that looks more like:



If you compare this to some other views of the 906 Flywheel it looks quite different





I tried to crudely scale this from the photos and it does seem different.

I then found a picture of a 914 Flywheel advertised in Ebay which says it is for a 200mm dia clutch and became totally insecure - hence my post



I must be missing something obvious and have just cracked up.

[davep]

That 914 flywheel is anything but stock, so who is to know for sure what clutch it was designed for. It may not have even been machined from a stock flywheel.

[gled49]

The last flywheel has 6 bolt crank mounting, so it is for a 6 cyl engine. 914-4's only have 5 bolts. If you take a push type clutch flywheel for a 6 cyl engine and start carving away at it and drilling holes you will eventually end up with a 906 flywheel. Gled

[gled49]

The 906 flywheel above has had some extreme machining done. Here is a 'R' flywheel but not the greatest view. Gled

[chris_seven]

If you take a push type clutch flywheel for a 6 cyl engine and start carving away at it and drilling holes you will eventually end up with a 906 flywheel. Gled

That exactly what I thought but if you look at the sketch which shows the radial holes at the edge of the 901 flywheel photograph they are quite close to the ring gear. The 906/911R flywheel in the photographs doesn't have these holes and there is no material there. If you look at the cross section there just doesn't seem to be enough metal to make this from a 901 part ???

I have always beleieved that I could make a 906 flywheel from a 901 blank but now I am not sure and I become less and less convinced.

[andyjboy]

Chris I recently had a 901 flywheel machined/lightened to produce a 906-style flywheel: