bendy bonnet
bendy bonnet
Author
Discussion

350matt

Original Poster:

3,896 posts

308 months

Tuesday 21st March 2006
quotequote all
Chaps

I noticed a while ago that the bonnet on mine flexs quite an amount when travelling 'at speed' shall we say. Indicating the pressure underbonnet is quite high, as it rises up to meet the curve of the wing which is about 10-15mm above it when the car is at rest. Now I've got visions of the whole thing tearing away from the bonnet mounts and sailing over my head can anyone else reassure me that this is normal?

Oh and the fact that the bonnet doesn't tear off would also be nice to know

I'm planning on fitting a spoiler underneath which doesn't get torn off by speed humps ( special sprung loading method) but haven't got round to making it yet, fitting this would obviously help reduce the underbonnet pressure and probably engine bay temps as well.

Matt

Tyre Smoke

23,018 posts

290 months

Tuesday 21st March 2006
quotequote all
TADTS.

Worse on a Chimaera - only one catch!

It's front hinged so the worse you'll get is a rather disconcerting rear edge of the bonnet obscuring your view the faster you go - I don't recommend you try it, but I have often forgotten to secure the bonnet after removing the Accumate only to discover a lovely view of the underside of my bonnet at 80mph on the M5!

budaholic

1,516 posts

264 months

Tuesday 21st March 2006
quotequote all
Tyre Smoke said:
I don't recommend you try it, but I have often forgotten to secure the bonnet after removing the Accumate only to discover a lovely view of the underside of my bonnet at 80mph on the M5!



Been there, done that. but I was on the A10,

Bud

robertjp

2,281 posts

254 months

Tuesday 21st March 2006
quotequote all
budaholic said:
Tyre Smoke said:
I don't recommend you try it, but I have often forgotten to secure the bonnet after removing the Accumate only to discover a lovely view of the underside of my bonnet at 80mph on the M5!



Been there, done that. but I was on the A10,

Bud


I have nightmares about doing it...nearly happened twice. Not sure i would like to see the underside of my bonnet at any speed never mind 80!!!!

spartacus

2,878 posts

299 months

Tuesday 21st March 2006
quotequote all
350matt said:
Chaps

I'm planning on fitting a spoiler underneath which doesn't get torn off by speed humps ( special sprung loading method) but haven't got round to making it yet, fitting this would obviously help reduce the underbonnet pressure and probably engine bay temps as well.

Matt


Matt, very interested to hear how you get on with the spoiler, intennd to do the same myself, keep us posted!

david smith

716 posts

277 months

Tuesday 21st March 2006
quotequote all
I never seem to learn ... my bonnnet is up so many times
wastes time locking it down!

managed to leave it unlatched for my first run at santa pod...

and again in high speed run at cream!

stoopid boy is me!

mine now flexes alarmingly at speed even when latched .. investigation has
shown one of the ally rods has broken and quite a bit of freeplay in the whole area.

have reinforced the ally rod and chemical metalled the whole lot back together and
stuck chenks of runner around the resting point to tighten it all up ... havnt done a high speed run to test out yet
but it seems a lot tighter!

jesfirth

1,743 posts

271 months

Tuesday 21st March 2006
quotequote all
Matt,

mine bounces around alot as well. I wouldnt worry

350matt

Original Poster:

3,896 posts

308 months

Tuesday 21st March 2006
quotequote all
Thanks for that, I'll post on here when I've got a working sprung spolier

Matt

paul.a

270 posts

274 months

Tuesday 21st March 2006
quotequote all
mine decided to break on the high speed run at cream was willing it to get to 170 before braking and the bonnet pins broke off it only came up about 8 inches still had to change trousers. The plastic on the pins seemed very hard and brittle and i presumed thats why they broke the new ones i replaced them with seemed softer plastic.

nick cooper

139 posts

248 months

Wednesday 22nd March 2006
quotequote all
Mine does the same thing. Found it to be the fibreglass mounting at the front is cracking around the hinges, Ian at Middlewich says he has seen it before,think he said cookys is dooing the same thing but has a bloke who will fit new bit for about £100?, but i might try some chemical metal for a start as it needs some driveshaft boots shockers and tyres,just had it serviced new throtle pots so etc so after 2 months of ownership i can see why people say it WILL cost 2-3k per year to run.

Rob Dance

200 posts

268 months

Wednesday 22nd March 2006
quotequote all
The "hinges" holding the bonet front are a pair of (small) rose type joints bonded into the bonet, and attached to (small) brackets that bolt verticaly to the cars front panel.a short 10mm spanner is required, and and lacerated fingers result in removing said brackets.

Age and use will see the bonding work loose ( especialy if the front of the car has had a nudge from the collection of old bags that frequent our local car parks ..... they don`t call Dorset `God`s waiting room without good reason)

I re - bonded both rod ends back into the bonet when it was off to change the water pipes, and also tidied up the brackets, which ( surprise surprise) had their coating flaking off !!

complete job took an hour or so , and £10 of GRP

simonsparrow

1,599 posts

291 months

Thursday 23rd March 2006
quotequote all
Some Cerbera bonnets have been modified with a big vent for the radiator - does this reduce under bonnet pressure?

spartacus

2,878 posts

299 months

Thursday 23rd March 2006
quotequote all
simonsparrow said:
Some Cerbera bonnets have been modified with a big vent for the radiator - does this reduce under bonnet pressure?


Where is the vent?

simonsparrow

1,599 posts

291 months

Thursday 23rd March 2006
quotequote all
spartacus said:
simonsparrow said:
Some Cerbera bonnets have been modified with a big vent for the radiator - does this reduce under bonnet pressure?


Where is the vent?


Like Dean's one here www.theratpac.com/members/dean/deano_tvr.shtml or variations on this theme.

350matt

Original Poster:

3,896 posts

308 months

Thursday 23rd March 2006
quotequote all
should do the job, can't say I'm a fan of the look tho'

Matt

simonsparrow

1,599 posts

291 months

Thursday 23rd March 2006
quotequote all
The speed twelve has some long skinny oval shaped vents on the bonnet - maybe a better look?

dean_ratpac

1,582 posts

307 months

Thursday 23rd March 2006
quotequote all
350matt said:
should do the job, can't say I'm a fan of the look tho'

Matt

I’m with you on this too - not keen all the time on it - I’m currently looking for a spare bonnet if anyone has one going? Other benefits I’ve been told that it keeps the front down too at higher speeds. It certainly runs A LOT cooler in summer. There are also some other variations - more towards the Tuscan sloping mould. I saw this at Duxford in 2002

GreenV8S

31,017 posts

313 months

Thursday 23rd March 2006
quotequote all
If you want decent bonnet vents, it looks as if there is plenty of space for long vents down the side of the bonnet similar to mine? Agree the large hole between the headlights is a bit of an acquired taste. Putting a splitter or air dam in front of the engine bay lower opening would help reduce the under-bonnet pressure too.