I can certainly appreciate the hard work and do diligence in trying to bring a Bugeye bonnet back to pristine condition. Buyer bewares, you must be cautious of EBay sellers calming the quality of pristine bonnets. The bonnet that I purchase off of eBay was a nice bonnet and it had some great quality’s, especially how the original grill fit, I was very impress of how well it molded into the grille opening, I don’t believe I’ve seen one fit so perfect. But if that bonnet had not been damage by Greyhound I would have never discovered one of the problems designs that BMC had done.
As we all know during that time BMC had a very poor rust prevention with this car as well it was one of the first unitized bodied cars to go to market. BMC wanted it cheep enough to draw the younger generation in that could afford the car where by the big Healey’s were for someone that was more of the middle age professional type buyer.
BMC used raw unprotected steel between the underside of the bonnet stiffener and wing stiffeners. The bonnet stiffener has two oval openings, primer and paint can easily be applied, but not under the stiffeners, a perfect environment for rust to start. What is taking place is corrosion can not be seen or address due to the inability to reach this area because the stiffeners are press tight against the unprotected skin of the bonnet. What eventually happens is the rust start working its way through from the underside towards the surface, potentially destroying the bonnet from the underside. To prevent this, I sand blasted this area and then POR-15 both bonnet and stiffeners then installed the new protected stiffeners to the protected bonnet. Here’s a photo of what you will find under the stiffeners.
I guess the reason they lasted so long was BMC uses American steel due to the shortage of raw steel in the UK after the war.