Running in ailments

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Mucus72
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@JV - thanks for updating speedo codes. I have just updated mine to 039558 as teh 2015/55 13" Avon CR500 will be pretty much the same as the Avon ZZS of the same size.

Out of interest, my speedo was set t0 036398 which, based on how your table appears to work, would be some massive tractor tyre ;)

SM25T
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That must be horrible with gearbox touching the chassis !
revilla
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Glad you've found it.

From the pictures it looks at though part of the gearbox is actually sitting vertically on the top of the chassis rail rather than just touching the sides. Is that correct?

Surely there cannot be anything so unique about your car and this must have been seen before. Have you spoken to about it Caterham yet?

One other thought - once you do get it sorted it will probably have taken the powder coat off the chassis there. Might be worth getting some protective paint or treatment on it while it is still fresh as it is rather exposed to the elements down there.

SV VVC 170 - 170.4 bhp @ 7100 rpm - 142.4 ft.lb. @ 4900 rpm

Mucus72
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yes, it's sitting vertically, in effect the chassis tube on the LHS is acting as a shelf. 

Mucus72
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I spoke to BaT and they had not experienced this, I sent them the photos through also. I have checked the assembly guide and there are no additional spacers mentioned, although the image in the guide shows a flange that sticks out of the bottom of the box and potentially this rests on the mount. My gearbox does not have this.

I think that if I could raise the gearbox around 2-3mm then it would not be resting on the chassis...

What would be really interesting would be to see what others on the forum have done, or even see photos. 

Mucus72
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this is the bottom of the Mazda 5 speed from the assembly guide. Note that mine is flat across the bottom and this one looks like it would rest higher up.

nutty7
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On your pics it clearly shows grinder marks on the casing were the flange has been removed, i'm not familiar with this gearbox but would think that this is the obvious cause of chassis contact.

Jim 123
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Marcus to lift the box off the LH chassis rail get a couple of half nuts that will allow the 2 large fixing bolts for the gearbox to pass through without touching the bore of the half nuts (I can confirm the correct half nut size when I get back tomorrow).  The half nuts will be about 7mm thick. Use these between the underside of the box and the face of the mounting plate with the fixing bolts passed through the half nuts.  You should be able to do this by jacking up the box with the large fixing bolts removed and avoid the hassle of trying to access the cap head bolts and nylocs that fix mounting plate.

I think you'll find this can prove your theory.  After a road test if you think you have a few mm too much clearance you can get a plate fabricated.  The angle change to the driveline should be comfortable.

Jim

Mucus72
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Hi Jim, so this is great detail firstly, thank you. So you had to do exactly this on your car for the same reason? Does that make it a known issue, and your fix something that Caterham suggested, or just a hack that you have come up with?

It strikes me as odd because EVERY Mazda 5 speed installation will have exactly the same problem. Having paid a big chunk of money for the kit, I think Caterham should do something here. 

Mucus72
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and Jim, yes please for ID on the half nut size...