Alfa Romeo SZ Technical Page

Extended Bonnet Prop (18/05/10)

The SZ comes equipped with a very small bonnet prop which will cause some problems for me as a six footer! This is my solution...

  Obtain a length of tube. I judged the maximum length to be about 1300mm and cut accordingly.

Just make sure it's strong enough to take the bonnet weight!

The tube I used is 14mm o/d with 10mm i/d.


The idea is to form two hooks to match the original prop and insert them into each end of the tube.

Some 10mm steel bar was needed, but without turning down some much thicker stock, all I had was some rusty old 150mm bolts!

  The bolt head had to be removed.
  A 40mm length was turned to fit inside the tube, then the rest was reduced to around 8mm; which is the same thickness as the original bonnet prop.
  One finished....
  Two finished.

Now to bending.

Two old 155 rear arm bolts become a former when held tightly in a vice.

  Using the remaining tube helps with leverage and cold bending the first shape.
  Compared with the original...
  ...and cut to size.

On to the next bend, which is a bit tighter, I used a piece of flat stock to form the first bend and applied heat from a blowtorch.

No idea if it helped but the bend is close enough!

  The main radius was cold bent around a 12mm bolt.
  Compared with the original and cut to size.
  Both bends completed.

These are the rivets I decided to use, to avoid welding and allow for replacement if necessary.

They are 5mm in diameter and usually for leather, but ideal for this purpose!

  So a 5mm hole was drilled through the tube and 10mm part of the hooks.
  Rivet inserted and hammered into close contact with the tube to avoid sharp edges...this is why the soft copper rivet was ideal, but still strong enough to hold the bonnet weight.
  ...and of course, it needed the protective plastic modification to safeguard the precious SZ bodywork!
  Finished item, measuring around 1400mm
  SZ bonnet open with the standard prop in place.
  A mere 700mm clearance.
  SZ bonnet open with the extended bonnet prop in place.
  A more generous 1300mm of clearance with massively increased access and lighter engine bay.
To further demonstrate the point...side views show the bonnet angle approaching ninety degrees to give full access!

As you can see, an extremely useful tool when working on the SZ's engine.

Another slight adaptation I'm considering is cutting the bonnet prop in half and sleeving the joint so the two halves can be stored easily (perhaps in the car?) and assembled when needed.


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