David Kirkham, thank you for your kind words and your more then generous offer. This just keeps reinforcing with me that there is absolutely no doubt that you are the one and only Cobra guy to deal with.
Detroit Bill thank you for your apology I sincerly appreciate that.
Barry R, while I understand your comments that the valve does not rotate there still remains questions on my motor and what I believe is a valve that has both rotated during its operation and also at the same time been subjected to continuing valve to piston interference.
This is a photo that I have zoomed into and cropped of one of the 4 exhaust valves on the right hand bank of the engine.
And this is the corresponding piston notch.
It is pretty obvious that a continual rotation of the valve has occured whilst also contacting the piston. If you zoom right in on the valve photo you can also see the exact contact points which were the final contact when the chain broke.
I can't in my mind come up with any logical explaination as to why the valves are witnessed a full 360 degrees if 1. The valves do not rotate during operation. And 2. They are witnessed a full 360 degrees which would mean full time contact during operation.
I'm happy to be corrected on my thinking if a logical explaination can be given, but several well known engine builders and drag racers that I am friends with here in Australia have looked at these things with me and all are of the same opinion.
As far as these heads are concerned the leaks are directly as a result of machining out into water jackets and then welding them to repair and hand smoothing the port when finished. As my engineer said in his email the wall thickness is less about 40 thou. This ain't enough meat to ensure they don't crack like they have.
I know these can be repaired my guys have fixed way worse then this before BUT there is an equation of cost v's effort that I have considered and the potential for that effort and cost to be frivolous if the repair doesn't last.
The simple fact of the matter is if I wanted this sort of hassle I would have bought 2nd hand equipment and rolled the dice.
I didn't I bought new equipment from someone that is supposed to be well regarded, the parts have failed and there has been little to no offer of assistance from this engine builder for warranty even though I all I have requested is parts.