620 SV nosecone - fit to CSR??

[Shortshift]

Here's a conundrum.  Does anyone know if a 620SV (wide body) nose cone will fit to a CSR?

James

[7 wonders of the world]

this might help James

https://www.caterhamlotus7.club/forum/techtalk/2009-sigma-sv-nose-cone-doesnt-fit

 

 

[Shortshift]

Thanks Neil - but to be frank I can't get my mind around that!  Might take a bit of unraveling...

James

[7 wonders of the world]

This was the interesting bit in #3

After speaking to Caterham today, the bonnet design changed about four years ago as did the nose cone. You cannot buy a 2009 SV nose cone as advertised on the Caterham website, it will be a design from circa 2013. It fits a CSR perfectly as I established earlier at Blue7's.

 

So assuming its a new SV nose your using it should fit albeit with a little reworking around the lower mounts which I believe a different to normal ones - same for anyone using a 620 nose on an S3.

ISTR the 620 does not use the 2 lower tabs with dzus fasteners from underneath sure a 620 owner will be along soon to confirm this

[Shortshift]

Ah - thanks for decoding that, Neil.

It does sound promising, then.

James

[mic]

The 620 SV nose will not fit a CSR unless you either modify the cowling at the front or fit the 620 radiator and pipework.

[Shortshift]

"The 620 SV nose will not fit a CSR unless you either modify the cowling at the front or fit the 620 radiator and pipework."

Thanks Mic.  So the 620 SV nose will fit to the CSR body shape (thinking in terms of the shape at the mating interface, body sides, bonnet curvature, etc)?  But that it's the packaging of the cooling system (rad, pipework, etc) that would interfere, unless modified?

Just checking I've got that straight!

James

[mic]

Yes, that's about right. The 620 nose has cutouts for the anti roll bar too. You will need the brackets for the lower fixings.

[Shortshift]

Thank you Mic. 

James

[Shortshift]

Making progress.  New (secondhand) nosecone now sitting in the hallway and the lower mounting brackets purchased.  Just need the car, now, to see what fettling of the CSR radiator mounting and cowling arrangements is needed to make it fit. 

Biggest risk might be getting a perfect paint match - but I'd imagine that Tony at TSK will be up for that challenge when we get to it.

James

[Shortshift]

Right - some five or six months on, an update (for anyone who picks up on this in the future).

Well, the good news is that a 620SV nosecone fits snugly but well around the CSR radiator and cowling structure.  So no problems in that area at all - all good.

However, two small issues to be aware of.

Firstly (and, dohh - of course!) a CSR is built on an imperial chassis whereas a 620 SV is a metric chassis beast and it seems there are slight (millimetric) differences in body width and profile around the area where the nosecone sits on the body sides in the area that extends forward of the nosecone rear/upper mounting points.  Nothing serious but a very slight gapping in the areas where the cone and front body sides meet.  Hard to describe and, I should say, not a show-stopper but something to be aware of.

And secondly - well... there seems to be a difference in profile of the trailing edge of the cone/leading edge of the bonnet between CSR and SV620 models.  To attempt to describe it: the CSR nosecone is more 'rounded' (in the vertical plane) across the bonnet joint line than the 620 SV cone, and actually rises to a point on centreline of car that is around 8mm higher that the 'flatter' SV 620 cone.  Who knew - the CSR 2.3 engine is (of course!) a little taller than the 2.0 litre unit in the 620 SV and it's obvious, in retrospect, that the CSR bonnet and nosecone profiles are slightly raised, slightly more rounded, to accommodate this.  This is fixable - a modest lift at the rear of the SV 620 nosecone of 4 or 5 mm (on the rear mounting Dxus fasteners) was enough to provide clearance to the top of the CSR engine but this also then contributes to a slight further degradation of 'fit' around the front end.  Just a mm or two and probably invisible to most but I am very fussy and ultimately whether you can live with that will depend on your OCD levels!

So there you are.  No show-stoppers but a bit of fettling required and, after that, be prepared for a slight amount of gapping around the front end fit areas which you may, or may not, find acceptable.

James

 

 

[Shortshift]

To illustrate the difference in curvature and peak bonnet height, here is an image of a CSR bonnet (orange), profiled to give a working clearance to the taller 2.3 litre Cosworth/Duratec engine, nestled up against a mounting height-unadjusted SV 620 nose cone (red).  About seven or eight millimeters difference on centreline of car..

James

[Shortshift]

And to finish off, here's some images of a nearly-finished fit of the 620SV nosecone on a 2015 CSR.  The last of the three images shows the slight gapping around the front-side panels.

Actually, maybe I over-emphasised the fit challenges; with a bit of fettling and adjustment, it ended up just fine - just go into it with your eyes open!

James