Spitfire Six Bonnet Fit

[Stratton Jimmer]

The Sixfire has a fibreglass bonnet and had been fitted with twin gas struts which made raising or lowering the bonnet an absolute doddle. Only snag is that there was no gap between the bonnet and car when it was lowered. Removed the covers and found the adjuster was fully back. Slackened them off and tried to move the bonnet but it just moved back. In essence, the twin struts were too powerful for the adjuster. I took one of the struts off leaving just the nearside one on and hey presto, the bonnet is now adjusted with a nice panel gap. Be wary if fitting twin gas struts!

[Pete Lewis]

with the bonnet tube there is a risk it gives a bit under the load of the struts  

one good reason triumph never used the lever and spring idea of the H & V cars 

Pete

[Badwolf]

I got a pair of gas struts for the spit ages ago (don't tell Kevin, he hates them) ready for when I finished my steel bonnet....ok, stop laughing at the back!!! I didn't put them on the glass fibre bonnet in case they ripped it to bits. Maybe I should give them it a try.

[Neil Clark]

Just for interests sake, is the fibreglass bonnet very much lighter than the steel?  And does it flex as much when lifting it from one side, as we must?

[Pete Lewis]

last time i lifted a FG bonnet i needed extra  shreaded wheat   it was very heavy 

but lb for lb i have no idea about the bonnet weights 

you really need one lifter each side to prevent stresses 

pete

 

[Badwolf]

My MkIV spitfire fibreglass bonnet is very wibbly, wobbly when lifting. Fairly solid when latched down. Like a sail when vertical. I much prefer the steel but, as followers of my restoration trivia stuff know, we don't talk about that!!

[Stratton Jimmer]

I am going to investigate what the spec is for the gas struts as fitted. They are obviously too strong for the FG bonnet so ideally a pair of weaker struts should do the job. I will post more as my investigations continue. In the meantime, one strut does seem to do the job reasonably well.

[Badwolf]

Might give single lift as go then, maybe on the opposite side to the side that I normally lift from, which is the side of the standard support thingie.

[Stratton Jimmer]

The single strut has been working really well so I have decided to stick with it. The struts as fitted were Metrol Springs NS-FF-8-300 rated at 360 Newtons. I looked on their web site and they don't actually list a 360N one but do list a 350N. The part number indicates that it is an 8mm rod with 30cm travel. https://motioncontrol.metrol.com/fixed-force-gas-strut-ns-ff-8-300-s.html These are clearly too strong for the fibreglass bonnet and as one does a good job (albeit asymmetrically as per the original bonnet support) I will suggest that a force rating of 150N should be perfectly adequate if using a pair.