Timing drive shaft damage

Yes. That is an easy fix . You tig weld on more metal on the damaged side then hand cut the woodruff keyway back into the shaft and of cousre file away the excess to match the diameter. It is easy to do with time and patience.

 

I think you need to take it off and hold it in your hand. It is a labor intensive hand skill thing and you need to be able to move it around in 3d space to make a nearly undetectable repair. If however, you are mr. golden hands maybe you can do it insitu. Some people just have freaky amazing skills.

 

Would suggest a new gear

 

If the teeth are good, a decent machine shop can spray-weld or tig weld and machine it for you (probably under $100.) A new one will cost over $500 unless you are lucky. Maranello parts have them new for £468.

 

Crikey they have gone up a bit I think I replaced both of the drive gears for less than £500

 

Yes, That's correct for the year you have. Try to get the NTN 6203LLUA1C4 bearings as they were the best available a couple of years ago (viton seals, high temp grease C4 clearance.) This is a known weak link so use the best you can find. Give the bearing to the shop as it should be quite tight (and make sure it's machined concentric!)

 

Is the pulley ok looking at state of the shaft that may also need some attention?

 

By the time you have welded this up and machined the keyway in it and machine the shaft concentric below the thread you might be cheaper getting the machine shop to make a new one. Its in such a state plus the heat of welding is not going to help to keep it straight.
The cost of a new one is worth paying . I would not waste money trying to fix that

 

I would replace if for nothing else than piece of mind. If it breaks, shears or fails, engine destruction will follow.

 

And if this fails the engine will sustain fairly serious damage. It's hard to imagine how this got so butchered.

 

Replace it if available.

 

The one thing i would say if that the present damage shows that the woodruff key has been rocking side to side a lot- the danger is in what you cannot see.
Just dont end up with the shaft shearing due to it being weak.
I could fix it up so it looked new but i would not trust it.

 

If they haven't welded yet, get them to dye-check for any cracks at the bottom of the woodruff key slot. When properly tightened, the woodruff key is for location mostly since the friction between the pulley and the locked nut on one side and the inner race on the other holds it in place. I know several people who removed pins/keys on cam pulleys without an issue. I would be more worried about the fatigue right where the shaft comes out of the bearing race so this should be properly heat treated after welding (but not the gear teeth which are probably hardened.) Are your lower pulleys aluminium? Check them for wear in the slot.

The bearings should be 6203-2RS1/C4 and preferably with high temp grease and seals.

 

These bearings run very hot so require the extra clearance (plus better grease, seals.) If your lower pulleys are aluminium, make sure they are 7075T6. The clamping force from that 17x1mm nut is 3824kg (8429lbs)