mikealdren wrote:Here it is:
The problems is that the tubular bar is too long so it won't go between the bobbins and close enough to the front edge. In a previous life, it was riveted where it is loosely shown in the photo
I've now tried the bonnet off my other plus 2 130/5 and that has a much shorter front bar.
The adjustment I and referring to is the small bracket off the front of the bar which can be adjusted to abut to the front fibreglass of the bonnet to stop it sagging.
I think I'll cut the bar off, shorten it and get it welded back, if that fails I'll buy a replacement bar from SJ Sportscars
when they become available.
The next challenge is getting the bonnet to fit accurately to the profile of the front wings and fitting new bobbins into the bodywork. Neither bonnet fits very well! Has anyone tried altering the curve of the rear end of the bonnet by adjusting the bolts on the reinforcing bar?
Yes, I can see it now !
Several problems here.
First of all, whoever fabricated the front bar ( tube ) assembly seems to have had no idea what its function(s) are relative to the bonnet design.
The side strips reinforce the side flanges, but also serve to support the front pivots bolts, avoiding a "single shear" mode of support. ( Which is probably why you need to repair the bobbins ! ) See pic.
The main function is of course to strengthen and support the bonnet across its full width.
The "adjustment" bar you mention is not an "adjustment" bar. It was meant to attach a pair of springs which would assist the bonnet lifting, see drawing. As such, the end of the bar would need to be located in front of the pivot axis, and as far forward as possible in order to maximize the leverage.
IMHO the bonnet is light enough not to need spring assistance !
To get the curve of the bonnet front right, I used a small timber block with a semicircular cut-out to sit between the tube and the bonnet, and a small timber wedge glued in place. See pic.
I moved the bar( tube ) on my bonnet to a position to the rear of the pivots in order to allow the front of the bonnet to clear the top of my dry sump oil tank. I also had to cut away a section of the front flange. I found it easier to braze rather than weld the tube, it's quite thin walled.
Another thing I did was to replace the nut on the pin at the top end of the bonnet strut with a small spring locking pin.
I made up a spring bolt to replace the rhs pivot pin. See pics. I still have normal bonnet operation using the locking strut, but I can also now remove the complete bonnet in less than 20 seconds.
Regarding the mating of the rear end of the bonnet with the scuttle, I did not refit the reinforcing bar with the bonnet catches. What I did was cut a couple of small "vees" in the rear flange, and refibreglass the flange with the correct curvature, using a temporary timber supporting cross bar and wedges.