14 replies to this topic

[fvracer72]

Before I spend too much time on this......Has anyone tried an external bonnet hinge? Maybe something similar to the Hillman IMP.....I was thinking of trying to adapt some early door hinges.  My goal is to be able to open the bonnet all the way back to the windscreen, 

[nicklouse]

Just wait for the Minivation ones to come back into production.

 

if I remember correctly pivots above the bonnet don’t work due to the shape of the rear of the bonnet.

 

you can get quick release bonnet hinges. And you could always just pin it. 

[stuart bowes]

I'm always happy to be proven wrong but I'm not convinced it's possible to have the bonnet open 'right back to the window'

 

for a start, even if you could make hinges to achieve it, the back edge of the bonnet would hit wipers first without some really clever thought put in

 

The geometry of the hinge arms is the awkward part, I got about halfway to success with these (the result of many hours of adjustments in a solid works assembly)

 

 

 

as you can see the open angle is decent.  The tricky bit in getting that right was the left and right back corners of the bonnet hitting wings, and then opening it from the closed position required a push from underneath at the back edge which obviously isn't what you would call success exactly.  it's possible with some experimentation you might be able to tweak it to work (at least the general principle is reasonably sound, not that I can take credit, I basically copied the bonnet hinges off a porsche boxster) 

 

in the end I went with this instead:

 

 

what you normally get:

 

 

and what you get with the springs stretched out

 

 

The limit of the up position will be provided by gas strut full extension, to protect the wipers and back edge of the bonnet

 

spring strength is critical though to not droop at the back while lifting up

 

there is a flange which physically stops it opening the other way, i.e bobbling up and down at the back edge while you're driving along

 

I would point out, though it does work nicely it is as yet untested with the wiper motor in situ (still got my fingers crossed on that)

 

I can't see how you would make an external hinge work due to the shape of the panels, also it would look terrible IMO

 

one thing is for sure the OG hinges are totally rubbish lol

Edited by stuart bowes, 25 September 2024 - 05:37 PM.

[Spider]

That's a nice option Stuart.

 

 

,,,,.Has anyone tried an external bonnet hinge? Maybe something similar to the Hillman IMP.....I was thinking of trying to adapt some early door hinges.  My goal is to be able to open the bonnet all the way back to the windscreen, 

 

If you do something like this, the Pivot Point needs to be high and probably forward of the scuttle panel so that the bonnet arcs far enough away from the body to the back corners to clear and also so it can clear the wiper spindles.

 

[stuart bowes]

Well that's the problem so far as I could tell the height of that needs to be up right where the bonnet is almost, but you have the drainage edge with all the spot welds sticking out in the way so the bracket needs to be stepped outwards to clear that

The two arms worked well in that one can lift up to provide the higher pivot point and the other steers the back edge of the bonnet

I was sure that if I'd spent a couple of months on it making a few, and slowly getting closer to the right geometry I would get there

But the added bonus of the second design is you can remove the bonnet just undoing two clevis pins and refit without having to mess about with alignment every time

[stuart bowes]

Just realised you were talking about the external hinges, d'oh

[Mr.greenPullover]

Have a look at the early prototypes: https://www.aronline...ototypes/ado15/

They also seams to have external hinges until 1958...
 

[stuart bowes]

It makes sense that the internal hinges may have been an afterthought when someone in the design department said no I want cleaner lines, put the hinges inside

On my build thread when it was discussed I did point out one other alternative, make new hinge arms with a deeper dip and cut some slots in the bulkhead so they can recess in. Would be simple to box that in on the inside or maybe just have a sort of rubber boot on the inside to stop water etc

Edited by stuart bowes, 26 September 2024 - 08:12 AM.

[Ethel]

They already do open that far, including on the motorway at 60mph 

[Lplus]

A long time ago I fitted a full glassfibre front using boot hinges at the back of the "bonnet" .  The spacing was decided by the need to get the hinges to line up to prevent distortion  The whole front would lay back on the drip rail above the screen.  The front didn't have the downstand lip of a metal bonnet, so that might have made it easier.

[Ethel]

I think there was at least one topic on creative hinging fibre fronts, piccies might not have survived though. Pretty sure transit bonnet hinges got a mention.

[fvracer72]

A long time ago I fitted a full glassfibre front using boot hinges at the back of the "bonnet" .  The spacing was decided by the need to get the hinges to line up to prevent distortion  The whole front would lay back on the drip rail above the screen.  The front didn't have the downstand lip of a metal bonnet, so that might have made it easier.

this is the sort of thing i'm thinking about....

[fvracer72]

Have a look at the early prototypes: https://www.aronline...ototypes/ado15/

They also seams to have external hinges until 1958...
 

those photos show exactly what im trying to replicate.....

im probably going to make a mock up during the winter

[stuart bowes]

the problem you might have is that the bonnet curves over so especially if the hinges are far apart they won't be coaxial (or concentric viewed from the side if you prefer)

 

it could be angling of a base plate underneath I guess

 

I wonder if whilst building it, it might be worth using one long rod as the pin for both to keep them in line and to gauge how they should be fitted, but maybe just some trial and error would get you there

Edited by stuart bowes, 26 September 2024 - 01:04 PM.

[Lplus]

the problem you might have is that the bonnet curves over so especially if the hinges are far apart they won't be coaxial (or concentric viewed from the side if you prefer)

 

it could be angling of a base plate underneath I guess

 

I wonder if whilst building it, it might be worth using one long rod as the pin for both to keep them in line and to gauge how they should be fitted, but maybe just some trial and error would get you there

That's why boot hinges are a help, the back of the mini curves at about the same radius.