Bonnet rattle ?

[Mark Coomber]

After a test drive with the bonnet removed, I can only conclude that the mystery rattle that I can hear (proportionate in frequency to engine revs when in gear) is coming from the bonnet vibrating against something somewhere.  I now just need to establish where.

 

It doesn’t happen when in neutral.

 

Has anybody else with a K-series VVC engined car experienced something similar ?

 

( It doesn’t appear to be the bonnet clips ) 

[Wrightpayne]

The throttle cable touches on some cars - any witness marks on the underside of the bonnet?

[SM25T]

I have put a strip of self adhesive foam on top of the aluminium plenum on my VVC to stop it contacting the bonnet

[Jonathan Kay]

7 hours ago, Mark Coomber said:

It doesn’t happen when in neutral.

And that's when it's hot and revved?

As well as the possible sources suggested upthread I'd check the engine and gearbox mounts.

Jonathan

[Mark Coomber]

Thank you to all those that have responded; these suggestions give me a list of things to check/do this weekend. 
 

( Just after I return from the Dartford factory ‘jumble sale’ ! )

[Wrightpayne]

Just spotted on a Caterham for sale a couple of O rings on each of the bonnet springs - could be there to stop rubbing or rattling? 
 

Edited April 20 by Wrightpayne

[wjw]

Mine did this when new in 2001,  catching on the plenum. The factory gently reshaped the bonnet so it no longer touched.