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Velocette TT winners
Top End Timing Chest Crank Cases Flywheels
Rockerbox Other Stuff Gearbox Summary

Once the cases were stripped out, I was able to remove the epoxy and survey the damage, this is when the large gap at the back of the repair became obvious. I have to say the repair seemed to hold the spindle nice and tight and the little plate was very neat. I haven't seen the plate since I took it off, if I find it I will take a photo of it.


Figure 1. The 'hole'. There is a picture of the cases with the patch still attached on another page.

After cleaning the area a repair piece was milled to fit the hole, the repair piece provides similar support for the follower spindle as the original boss, I basically copied an original boss. The area to be welded was well cleaned and angled with a burr then the patch welded in. I didn't know the coordinates for the gears, have to thank John Watson[he makes makes cases] for supplying the gear and spindle coordinates, very helpful bloke. The case was machined and all the dimensions checked, seems it wasn't effected dimensionally by the welding. The gasket face was blued to verify the timing chest seal. The one way valve for the oil system seat was re-cut, I suppose I should really check that the ball seals. I had removed the cam spindle and was tempted to replace it, there is quiet a bit of wear but where do you draw the line, so I pushed it back in.


Figure 2. Back of timing chest before the patch was welded in.

The oil pump gear and spindle had marks from being beaten to remove the pump. When I removed the pump I actually couldn't turn it by hand, the bronze worm looked more like a pointy thread form than an Acme thread! The gear was still intact so I have to presume the pump was still working! Stripping the pump showed the scavenge pump to be pretty rough, I am suprised the gears were intact after seeing the metal I removed from the oil tank. The bore for the oil pump has a deep gouge and the pump didn't seem that tight, but I think it will be OK and luckily the new pump is a thou bigger. The oil pressure valve should have a 1/4" ball, the thing in the hole looked like a bit of welding spatter;-) When I got the new crankshaft worm I realised the wrong worm had been in the engine, it had a double start worm, but the oil pump gear was for a single start worm, which explains the wear on the oil pump drive gear.


Figure 1, Not at all bad considering the metal that had been through these. These are the scavenge gears from the oil pump.

The rebuilt flywheel assembly was installed with some dummy bearings to check rod position and end float and when happy with it the new main bearings and necessary shims were installed; while the cases were warm I installed the oil pump. The cases had a smear of 3bond and the flywheel assembly was reinstalled in the cases, with the replacement crank pinion and oil pump worm. Then the cases were bolted back together. All looks sound and I am reasonably happy with it, the weld was scurfed off the top of the chest but left were it isn't visible. I forgot to take any pics at this stage, someone that called in took some pics of it I will ask for a copy.