Monday 29 September 2008

New Type 9 gearbox progress at last !

Well after breaking the old box, I have picked up the ford gearbox and apart from the crud on the outside looks like a good buy.

The crud has now been removed along with the old bellhousing. After taking a few measurements the design is underway as shown below, now the model is a work in progress and knowing me the final result will look somewhat different.


Measurements.

Old triumph box - Back of casting to centre of gearlever hole = 450mm Ford =557mm . Now that means i have to get rid of 107mm + whatever the thickness of the adapter plate ends up as to get the ford gearlever poking up in the right place.

I think i can remove 105mm from the aluminium casting. There is also a real possibility that i can gain an additional 5-10mm. I will only be able to tell once i have cut and remeasured the casting. This extra might not be worth the effort as there may need to be some additional cutting welding and machining to get these last mm's. This would change how the selector rod is sealed and bushed.

I have actually managed to take out is 99mm, 6mm short of what i really wanted as a minimum. I think i might have a later gearbox than some and with this box you cant take out as much. Still it is what it is.

I also think i can 'gain' another' 10mm or 15mm. but i will need to check with the gearbox in the car to confirm.

The adapter plate will be more complicated than other peoples designs but this will hopefully shave mm's of the thickness.

All of this might mean that the gearlever ends up just 12mm further back than the stock location. Or even possibly less. Now will be. Now more likely to be 18mm out of place






This design will be completed this week. I will then hopefully make the plate. If not i will sub it to a local toolmaker that i trust. It might have no choice but to sub it out as i only have access to a small Myford lathe.

The gearbox is in the process of being stripped, mainly because the Layshaft spindle came loose and i have lost a thrust washer in the bottom of the gearcase. Bugger i wasn't going to do that. I suppose at least i can give the box a good exam before i torture it in use. To aid this i have bought a copy of the Haynes manual to help me.

I am going to shorten the remote housing, before i do i will need to study the casting more to see where i cut it. And then the fun of welding it will come next. Again i might chicken out of this and leave it to someone with experience of welding ali.

Wednesday 24 September 2008

How to break a gearbox

Senario

Your driving up a hill, top down on what turned out to be one of the best weekends for weather this summer. Your gearbox 'jumps' out of third gear. That funny it's never done that before.

Well the picture below tells a story, it's the mainshaft from the gearbox and yes it definitely needs to be one piece to work correctly.




I examined the shaft and it apears to be a stress crack that resulted from a manufacturing fault 32 years ago. it's been waiting that long to break!

Now i know i want to put a ford 5 speed in the car but i was going to leave that for at least another month. Not now the car is disabled. However i have sourced a gearbox off ebay and will be collecting it this week. Hope it is OK.

The design work for the gearbox interface plate is underway, the details will appear here shortly.

On another note before i broke the gearbox i started to test the effect different pump unleaded fuels have on performance. It was to early to get meaningful results but Shell super unleaded does give more power. Probably what sent the gearbox over the edge.