Running in ailments

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Mucus72
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The bolts are M14x40, so wondering if it would be better for me to use spacers, in effect fat washers like these: ebay linky

Jim 123
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Having checked the link you these might not work without modification to your washers. 

You will need washers that can sit flat on the uppermost internal face of the gearbox mounting plate.  From my notes, the max space you have in this area between the chamfered internal sides of the mount plate is 25-27mm (best leave a couple of mm wiggle space to line up all the holes).  Your spacers will centralise when you slip them in.

You might want to pop out one of the gearbox mounting bolts beforehand to check as the manual could be out of date.  From my notes, I am pretty sure that, as a proof of concept, I used 14mm half nuts that allowed the gearbox mounting bolts to pass through without engaging the threads of the half nuts.  These half nuts were 22mm across flats.

Jim

JNC
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Stop !,  let me get this straight this is a new build ? . If so what are you doing ! If it's not right get back to CC . In my opinion something is not right pls don't bodge it up get it right. seek advice from CC 

John.                                               

Mucus72
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Hi JNC, yes this is a new build. I spoke to Derek at Caterham and he suggested that giving the spacers a go is the right option. The tolerances are fine here, and Caterham have not retooled to take into account the width and shape of the Mazda 5 speed. I am going to have a go with the spacers (I also have some half nuts on the way too just in case). As a final back up I have the car booked into Book a Track, who I purchased the new kit through in mid October. If I can't get to a reasonable resolution, they as a proxy for Caterham will have to.

JNC
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Sorry Marcus, if the car was mine I would take it back ,it sounds like a right bodge up , Why is your car the odd one why isn't there a que of other cars with the same problem  ?. Some thing is not right.

John.                                               

Mucus72
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So tonight I lifted the gearbox. I took the gearbox/chassis bracket off so I could remind myself of what the inner surface looked like and to play with fitting spacers. In the end I had to trim the edges off some fat washers to get a good fit. My gearbox is now about 2mm higher than it was and therefore doesn't rest on the chassis anymore. I am still bothered by the asymmetrical nature of the box. There is loads of space on the RHS and none on the LHS. Elements of the box still stick into the heat proof foam and are therefore pressing against the car, specifically against the inner transmission tunnel skin.  

I will try and find a moment for a road test tomorrow. Hopefully vibrations will be reduced. I can't see a way to move the gearbox any further to the right. The slots in the gearbox/chassis mounts run longitudinally, so no real way to push the unit to the RHS. 

JNC
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Can the gearbox mount be turned around ? Will that make any difference 

John.                                               

Mucus72
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Hi John, the mount can't be turned around. It's an asymmetric design, short side to the left. I am rather hopeful that the work I've done tonight will cure the vibration. i will report back after a test drive tomorrow. 

JNC
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I really hope you get it sorted soon . I don't think I would be easy going, good luck 

John.                                               

Jonathan Kay
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I am still bothered by the asymmetrical nature of the box.

I can't see a way to move the gearbox any further to the right. The slots in the gearbox/chassis mounts run longitudinally, so no real way to push the unit to the RHS. 

It's an asymmetric design, short side to the left. I am rather hopeful that the work I've done tonight will cure the vibration. i will report back after a test drive tomorrow. 

Hope that fixes it. It will leave a lot of questions:

  1. Why yours and not others?
  2. When did the ability to adjust in yaw disappear?
  3. Would it be easy to restore it? By fettling the chassis or mounts? Or otherwise?
  4. Would a single spacer or replacement mount with two holes be any better than two stacks of washers for the adjustment in pitch? The latter does allow adjustment in roll.

Jonathan