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MG Midget and Sprite Technical - Frogeye Bonnet

Frogeye bonnets are notorious for biting the back of one's head for the unwarey. I also know some people have altered theirs to hinge at the front rather than the back which gives better engine bay access. Photos online show a fairly simple looking bracket and hinge arrangement for this, though I don't have actual measurements.

Is it a worthwhile task though? I would wonder about fit with the weight of the bonnet and also about getting a good fit with whatever fastenings would be needed to hold the bonnet shut at the rear lower corners of the wings.
GuyW

Being frugal (read "cheap") I used the original front locking mechanism. I just undid the hinges, set the bonnet down and closed the latch. I then added some latches from a Marcos/Spitfire/Herald, a slightly modified to fit Spitfire bonnet support and a connector spliced into the wiring harness. To remove the bonnet I unplug the connector, undo the support lower the bonnet and turn the latch. It's worked for about 40 years.
Martin

You can buy a kit in the States to do it. Quite expensive. I find it's not the headbanging that's the issue but lifting the bonnet weight and then working bent double (although the two make be connected!). My bonnet has a heavyweight underseal layer which I really need to remove.
Graeme Williams

Guy

DIY front bonnet hinge fabrication instructions:
http://www.ahsdc.org/Files/Tech_Information/Tech_Information_Bonnet_Hinge.pdf

More info from another builder: http://www.spritespot.com/phpBB3/viewtopic.php?f=3&t=213

Ready made to buy:
https://www.petermayengineering.com/product/bonnet-hinge/ (for GRO fronts)

http://www.gerardsgarage.com/Garage/Tech/tilthinge/tilthingeWS.htm (Gerard is retired, but might be worth asking if he still has these for sale - think I may have current contact details)

Cheers
Mike

PS have you seen these seat belt installation instructions for early cars: http://www.gerardsgarage.com/Garage/Tech/SeatBeltWS.htm
M Wood

Thanks Mike. You must have an amazing filing system - or memory? - to find all this stuff!

I had seen Gerards's garage version before and it seems pretty much the same as in all the various other examples. Your other link adds detailed dimensions for making the brackets - l like that !

A while ago l read an article about a rather more complex system which involved an arrangement with a moving pivot point that slid forwards on a piston arrangement as the bonnet was lifted. It may have been to give better clearance for cars fitted with a front bumper.

I added seat belt anchor points at an earlier stage of rebuilding the body, but thanks!
GuyW

A couple of things to ponder on. What provision will you have for a safety catch - and how will you lift and close it bearing in mind it weighs close to 100lbs? I had an untethered fiberglass one lift at surprisingly low speed and it was a pretty scary experience,so I think some kind of safety catch should be included.Screwing on Harry Moss rubber straps will look awful and even modified Herald will be wrong if you want the Frog to look original.This leaves you to engineer some kind of internal release operated via a bowden cable - not impossible but more work,especially if the front has already been painted.Then opening and closing the bonnet with fingers could be interesting. It's a struggle on a fiberglass bonnet - simply impossible on a steel one. Again not insurmountable but you might need to look at springs to help with initial opening, together with correctly weighted struts to assist a controlled closing.
f pollock

...not to mention some sort of back-up in case the release cable fails.
Dave O'Neill 2

Hi
I understand where you are coming from, having banged my head many times under my bonnet.
As a result, these days when I am doing a job under the bonnet, I simply jack the car up nice and high onto axle stands, and it is surprising how much easier it is on the head wounds (and the back!)

Graham
Graham V

Yes, I have decided to stay with the standard rear-hinged bonnet arrangement. At least for now.

Good tip Graham, about jacking it up to a more comfortable working height. Maybe a pair of car ramps would be easier!
GuyW

I've got a skullcap-shaped piece of football, which I insert into the back of my beanie. Haven't needed it for a few years, but heading for Spridget 60 now. I know just where it is.
Nick and Cherry Scoop

So here's a crazy idea. Someone must surely have thought of it but what about adding a simple link to the existing hinge to allow the bonnet to swing higher. On paper it seems to work - you add a pivot to allow the bonnet another 200mm or so as in the drawing. If you have your bonnet off and the hinges attached at the bulkhead, a few minutes spent with scissors and templates would establish if it would work or not. If it does you have a pleasurable afternoon ahead of you cutting, welding and drilling a pair of sacrificial hinges to make up some articulated ones. Bonnet stays would need extending of course, but I think the loom would be OK.


f pollock

I think that an articulated hinge would allow the bonnet to bounce up and down.
Dave O'Neill 2

This thread was discussed between 23/12/2017 and 16/01/2018

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