Hi folks, In another forum I was requested to post the following here. More than two decades ago I had head gasket problems with my Sebring, which did not cure with assistance of "specialists", so that I had to go an own way. I first had the rubber part made (that surrounds the engine housing), wherein a metal layer was laminated between two rubber layers. This made all these strange tiny spheres superfluous, you will know what I am talking about. These spheres and the corresponding holes in the original (simple) rubber gasket design are constructional weak points, obviously. I had three rubber gaskets made, then took the actual thickness (slightly different from my specification). Then I calculated the compression of the rubber components and therefrom the matching thickness of the bronze "fire-rings". I turned these myself on a precision lathe in a clients workshop, who let me have fun there over a weekend. Making these from tube material is far from easy since they are thin. The tube needed to be turned for the inner and outer diameters first, and then cut-turned for thickness just slightly before coming completely through. The rest done with a knife and the remaining burr removed by hand. Thickness tolerance was less than 0,01 mm. And it worked out, no problems anymore thereafter. I believe that in the meanwhile conventional composite head gaskets are distrubuted, wherein the fire rings are conventional as well. But I am not sure, whether this design is really suitable for the open deck design of this engine. You might discuss this. I have plenty of the bronze tube material left, from which I turned the "classical" fire rings. It collects spider webs and is of no use for me. Anyone interested can have it for the shipping costs and I would ony suggest to "pay" for the actual material by way of a donation, 50/50 to this forum and the Vintage Lamborghini Garage forum. Anyone interested give me a notice. The bronze alloy is specified for exactly this fire ring purpose. Cheers, Bernhard P.S.: No rubber gasket is left, I gave the two spare ones with the car, when selling it.
There is an article on the 3500 and service thereof in the newest issue of the German magazine "Motor Klassik". No really useful details, as usual. But interesting that Guiseppe Candini made bad experiences with the "modern" composite gaskets, therewith confirming my concerns. And that he makes the fire rings individually as well. But sticks to this rubber gasket / metal sphere setup, although this becomes even more prone to failure, if the head needs to be been planed, thereby reducing (or even removing) the grooves at the edge of the head sealing face. Cheers, Bernhard P.S.: If no one needs the semi-manufactured material for making the fire rings, I will presumably bring it to a scrapyard and spend what they give for a few pizzas .
