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Re: 912 outlaw project
Posted: Mon Nov 30, 2020 7:52 pm
by johnM
Hi Chris
Not sure if you know, but Tuthills sell oversized bearings to resolve this issue. I'm afraid you may find that fix is only temporary.
Kind Regards
Re: 912 outlaw project
Posted: Mon Nov 30, 2020 7:57 pm
by Gary71
Drill and tap some holes around the circumference and fit some grub screws
Re: 912 outlaw project
Posted: Mon Nov 30, 2020 8:21 pm
by Cortina
johnM wrote:Hi Chris
Not sure if you know, but Tuthills sell oversized bearings to resolve this issue. I'm afraid you may find that fix is only temporary.
Kind Regards
Hmm ........ I very much suspect you will not be able to move it without heat ! We shall watch the space and wait .
Re: 912 outlaw project
Posted: Tue Dec 01, 2020 2:51 am
by jury
Head scratch.....Tightened to 250 ft/lb and it still has play in it !
I removed the inner shaft and replaced with a spare...retightened and again has play!! The bearings are new and the outer one is now firmly in place...don’t think it’s play in the bearing. Only things I can think of are:
1- The interference fit between the inner and outer shafts with their bearing mate
2- The fit between the inner driveshaft and outer hubshaft when the are tightened and begin pull together. There is also the internal spacer sleeve
Hmmmm
Re: 912 outlaw project
Posted: Tue Dec 01, 2020 5:48 am
by coomo
only real solution imho.Find another comparable bearing, then have hub machined out few thou to assure is not oval, plus youlll get a proper interference fit. fit.An ill fitting bearing, and fifty years, may have ovalised the recess.Maybe even have a sleeve made to return to standard bearing spec.
Re: 912 outlaw project
Posted: Tue Dec 01, 2020 10:02 am
by 911hillclimber
Just talking principles here.
My 915 box when stripped by Mike Bainbridge fell apart easy. The main bearings had worn the alum case oval and a previous psecialist had 'fixed' it by the centre punch method on both bearing positions. The centre punch 'highs' had simply worn down and the play returned.
The fix was to machine round the bearing recesses, sleeve the new hole and fit new bearings. However, there is a lot of casting to machine away so you can fit a 1.5mm thick sleeve...
Here, you could get skimmed the bearing cavity IF you search out a bearing, same inside dia and width, but (say) 1mm larger dia and machine the arm recess to take the new 'large dia' bearing outer race.
You are then effectively back to Porsche design. I think you will find the arm bearing recess is oval and there is your play.
All this before it hits the road and the high loads applied. Never rated bearing fit over correctly fitting metal to metal mating interfaces.
Re: 912 outlaw project
Posted: Tue Dec 01, 2020 9:22 pm
by SeanP