360R Build - Differential Cage Touching Chassis

[Britspud]

Hi All,

One of the things I came across during my build while fitting the diff (360R SV with BMW/Titan) is that the rear diff cage comes up against the boot cross member and the front of the cage touched the non-structural metal beam running across the back of the bulkhead. Caterham build support team told me  just to bend the bulkhead beam upwards (with pliers!) to fix the problem at the front. And to put some spongey rubber between the diff cage and the boot floor cross member! Which I did do...but was slightly worried/disappointed that this is an official resolution!

Is this a common thing ? And is there a better resolution to it than the one described by the Caterham team?

Thanks.

Edited March 23 by Britspud

[simon_h]

The are very low volume cars that have a lot of hand fabricated parts fitted. If they say do it then they do it to every one they assemble there that need it. You just have to remember that at the end of the day it’s a kit car not a Porsche even if some of them cost as much 

Edited March 23 by simon_h

[Britspud]

12 minutes ago, simon_h said:

The are very low volume cars that have a lot of hand fabricated parts fitted. If they say do it then they do it to every one they assemble there that need it. You just have to remember that at the end of the day it’s a kit car not a Porsche even if some of them cost as much 

Hi Simon - yeah I do get it...but this one could have massive NVH consequences. I'd have thought the Caterham engineering team might have had a think about this if it's as common as they led me to believe.

Mainly though I was hoping someone might have a better solution. Some of the brilliant blogs that I've depended on (Purple Meanie, Chris Collins, Tigger and many others) don't seem to have mentioned it, and I presume they didn't encounter this issue. So I thought this was something unusual to my car. But I'm told that this is a usual thing. 

Cheers,
J.

Edited March 23 by Britspud

[simon_h]

NVH? Yes you’ll get lots of that. It’s probably been looked at and that’s the quick fix that does the job adequately.

[Britspud]

Thanks Simon...again, I'm hoping for people on here who may be able to comment:

a. Is this something that is normal amongst the kit builders here when they installed their Diffs on a Duratec car?

b. And if so, did they just do the above suggestion from Caterham (bend the beam/insert a spongey pad) or did they do something better/different?

Thanks,
J. 

[AlastairA]

Hi,

Yes I did encounter this (link) and chose to "notch" the non-structural cross beam that the diff was touching to try to avoid vibrations from being conducted through the chassis. My personal conclusion is that this is just an effect of the level of mechanical tolerances involved with a hand built chassis. Ultimately I just decided that it's necessary to make minor adjustments to get the parts to go together and that is one of the wonderful challenges of building one of these cars.

[aerobod - near CYYC]

I found the fuel pipe and diff clearance to the boot floor was the problem in my older R400 build, so I went for a more radical solution by removing a non-structural portion of the diff cover:

[Ainsley]

Bend it 🙂

There are lots of bits that need a small bit of bodge/persuasion/fettling.  

[Britspud]

4 hours ago, AlastairA said:

Hi,

Yes I did encounter this (link) and chose to "notch" the non-structural cross beam that the diff was touching to try to avoid vibrations from being conducted through the chassis. My personal conclusion is that this is just an effect of the level of mechanical tolerances involved with a hand built chassis. Ultimately I just decided that it's necessary to make minor adjustments to get the parts to go together and that is one of the wonderful challenges of building one of these cars.

Thanks Alastair ... I must apologise as I have studied your blog and been guided on many aspects of my build by your write-ups, but obviously failed to notice that you had covered the same issue! Interesting choice, cutting the beam. Did you also find that it was touching at the back of the Diff, up against the boot floor?

[Britspud]

3 hours ago, aerobod - near CYYC said:

I found the fuel pipe and diff clearance to the boot floor was the problem in my older R400 build, so I went for a more radical solution by removing a non-structural portion of the diff cover:

Thanks James...another interesting solution. 

[prisoner7]

I'm building a 420SV (LHD) and put soft rubber on the differential to limit the "chatter" that will happen when the cover rubs on the differential. All part of the joy.

[AlastairA]

10 hours ago, Britspud said:

Thanks Alastair ... I must apologise as I have studied your blog and been guided on many aspects of my build by your write-ups, but obviously failed to notice that you had covered the same issue! Interesting choice, cutting the beam. Did you also find that it was touching at the back of the Diff, up against the boot floor?

Yes that’s the only place it was touching so far as I could tell - just the aluminium boot floor support.

[Britspud]

1 hour ago, AlastairA said:

Yes that’s the only place it was touching so far as I could tell - just the aluminium boot floor support.

Ok thanks a lot 🙂