Bonnet Pins

[JasonR]

Hi Guys, looking to take out my bonnet hinge etc to lighten the car a bit for the track.

I guess some one has done this before, so could you give me some tips? How did you do yours?

Thanks in advance

[djs325]

The best way to install bonnet pins is to keep the factory hinge and rear guide plates; that way you can still raise the bonnet and work on the car easily. But it deletes the shi**y cable operated interior bonnet release, which makes life easier and safer (quicker for marshals to get the fire-extinguisher in there).

I just installed a set of pins of the British Patent type (see image below) on a mate's E30 Racing Car; pretty easy to do providing you take it gently, and have the right tools:
-Drill
-Drill bits (small pilot drills, large finishers (10mm, 15mm etc)
-Hole saw bit (approx 25mm)
-Flat & round files, preferably fine
-Spanners for pin nuts
-Pliers to hold pins in correct orientation
-Screwdriver/bits for clip-pin screws

Have a look at the top of the radiator support panel, there should be 2 adjustable rubber stoppers that the bonnet rests on. Remove these (they unscrew), and you have a ready made hole for your bonnet pins. You'll need to use large (e.g 40mm OD) washers between the nuts on the pins.

Install the pins in the hole, and adjust them so that just enough sticks out to touch the inside frame of the bonnet. Adjust them up a fraction more, then push the bonnet down hard to leave a dent mark on the frame. This is where you will drill the pilot hole for your hole saw.

Cut the holes in the frame with the hole saw, but do it GENTLY so that you don't penetrate into the outer skin. Adjust the pins up further if necessary, and then push the bonnet down to leave a dent in the outer skin. This is where you will drill the pilot hole for the big drill bits.

Drill (and file if necessary) a hole just larger in diameter than the widest part of the pin top, from memory ~16mm. You should be able to push the bonnet down over the pins fairly easily. Now grab the clip-pins (the bits that mount on the bonnet), and connect them to the pins in the usual fashion.

Line them up the way that you want them (would recommend pull towards front of car to disengage; less chance of them coming undone and also more ergonomic-ish), and then drill the screws into place, mounting the clip-pin on the bonnet.

If you install the pins so that the wide top is installed east-west in the car, i.e. perpendicular to the crankshaft, I recommend to file the backside of the pin top, to create a sloping surface that won't foul the hole in the clip-pin bracket that it has to maneuver through).

Then you get to play with the final fiddling of alignment, slightly bending the radiator support panel, file off all the sharp edges on the underside of the bonnet...

And grab some rubber hose that is the right ID to slip over the pin, and cut 2 short pieces to suit. These will act as your bonnet bumpers, and will mean that to close the bonnet, you will need to apply a light downward pressure (to compress the hose), slide the clip-pin into the pin, and then release the bonnet, which will then have some residual spring from the hose holding it up against the clip-pin.

I'm afraid I don't have pictures to show the install, but this keeps your bonnet mounted in the factory location, no chance of flying off, makes it easy to work on (you can still keep the factory gas-strut), and easy for the marshals and scrutineers to open/inspect/secure/extinguisher the contents.

[Theo]

I would use some aerocatches instead, they have several benefits.

They don't rust
They're road legal
They look alot better

They're £35-£40 a pair but well worth the expense.

[JasonR]

DJS, thanks for the info, however i'm looking to remove the brackets etc to reduce weight. I was hoping to make use of the guides at the back of the bonnet and use pins at the front.
Theo are you saying normal pins aren't road legal? As i also use my car on the road.

[cragles]

there are some pictures on our race car build here

http://www.team156.co.uk/pbmw_build_photos_005.asp

and here

http://www.team156.co.uk/pbmw_build_photos_002.asp

which show the bonnet pins, hope this helps![/img]

[djs325]

If you're worried about rust, you can get anodised aluminium versions (but I would HIGHLY recommend the steel version). We use the Aerocatch system on our R56 MINI Challenge Cars; they are nice, but harder to fit with that huge hole to cut in the bonnet, plus the 6 bolt holes. In a serious accident they just snap off and the panel can just fly off.

Since when did people care what was road legal or not? It's a TRACK car!

The bonnet I modified looks almost identical to the one in this picture from Team 156:

[furbster]

I would use some aerocatches instead, they have several benefits.

They don't rust
They're road legal
They look alot better

They're £35-£40 a pair but well worth the expense.

If you're planning on taking it to the Nurburgring you NEED the aerocatches........ They have a new rule this year and will not allow you on to the circuit with normal bonnet pins!

Luckily I found this out before I went and refitted my original bonnet temporarily (didn't have time to get aerocatches) but did see a few people stopped by the marshals! That's a long way to go to be denied access for the sake of £80!!

[JasonR]

Cheers for the heads up furbster! I picked up a set of cheap bonnet pins (very similar to team 156) that i will fit for now. When i get around to going the the Nurburg ill sort some aerocatches.

[JWaller360]

Bonnet pins are road legal, though I didn't know about the 'ring! Luckily we've just got a set of free aero catches for the rally car