Hailwoods TT motor failure.

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bobnorton
860 GT / GTS
Posts: 280
Joined: Wed Jan 16, 2008 2:18 am
Location: bromley kent

Hailwoods TT motor failure.

Post by bobnorton » Sat May 25, 2013 3:20 am

Its a well known fact that the bevel gear failed as Mike won the race. Did we ever find out what caused this?. When you consider that the Desmo set up was designed to reduce the loadings and these motors have competed in endurance racing with much success its a bit odd .Did the crank shims fail and precipitate gear failure?, Incorrect shimming by the factory, or the entrant, poor metal in the gears? Some might say it lasted just right , Its not my view though.Often wondered on this.

Peter Mille
MHR / S2
Posts: 476
Joined: Fri Aug 13, 2004 1:12 am
Location: The Netherlands, Europe.

Re: Hailwoods TT motor failure.

Post by Peter Mille » Tue May 28, 2013 11:32 am

I've been told that because of the foot injury that Mike suffered from a race car accident earlier in his career, he didn't like to shift the Duc much, so he overreved the engine during his winning race back in 1978...

bobnorton
860 GT / GTS
Posts: 280
Joined: Wed Jan 16, 2008 2:18 am
Location: bromley kent

Re: Hailwoods TT motor failure.

Post by bobnorton » Wed May 29, 2013 10:44 pm

HI Peter, I would have expected overreving to bring ring, piston, big end or rod failure, the desmo gear should have been safe to the breathing limits of the motor.

ducadini
750 Sport [BEVEL]
Posts: 201
Joined: Sat Jul 31, 2004 8:54 am
Location: Antwerpen

Re: Hailwoods TT motor failure.

Post by ducadini » Sat Jun 01, 2013 12:55 am

Those gears failed on earlier Ducati racers also, maybe due to lateral movement of the crank but it could be the complete setup of the bevelgears that is stressed to its limits with constant high revving.
The distance between the bearings of the lower bevels isn't really big, so they can get overloaded when revving.If one of the three starts to "go", the rest follows VERY fast due to sideloads on the teeth and completely wrong meshing, increasing load on teeth, messing up meshing etc etc.
Not too long after the fail in that engine, NCR adopted a special support inside on the righthandside to fit the later type of bevels, with some straight gears to get rid of the interaction between the bevels and the movement of the crankshaft.

ducadini
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Richiamo i migliori pensieri

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