915 Problems

[antaircooled]

I race a '74 Carrera with SC 3.0 engine and 915 gearbox which has been tired for a while so I decided to get it sorted. I have been buying bits and pieces over the last year and really nursed the Gearbox on the track while waiting for a good time to do the rebuild before it blew to pieces.

Anyway I decided to get the car into the local Porsche agent who should know what they are doing. They have come back to me with the prognosis that the diff housing is stuffed and needs replacing - only problem is the housing is not available from Porsche Germany or anywhere for that matter so I should look at acquiring a second hand gearbox

Has anyone out there had the same problem and got the diff housing machined to fix this sort of issue? I can't believe you can't fix the housing after a bearing has spun!

Any thoughts and suggestions are welcomed. Thanks

[KFJ_SC]

There are lots of options with spun bearing races - a NOS case is unlikely so you may end up with a used case with the same issue as your existing. A search will show some people have used Loctite 660 (or similar race seal products), others have had the area machined and plated, etc. Personally, I went the Loctite route - there seem to be several that have had success with this and so far (only a few hundred track miles) mine seems to be holding up.

[john walker's workshop]

http://www.wevo.com/Products/TransmissionProducts/WevoTransmissionProducts.htm

[MBEngineering]

HI antaircooled.
Depending on how worn the pinion bearing hole is worn, a oversize bearing can be fitted, like the one below.



I have used lock-tight on competition box's and the bearing will come loose as the lock-tight will not take the pressure/load on the bearing/housing, the other option is as "john" has suggested at Wevo, or a S/H box's,

regards mike

[antaircooled]

Thanks everyone - I think that I will try to get the Wevo modification done down here.