As I just know that Chris is on the verge of winning the Power Ball lotto, so based upon the potential of unlimited funds that will then be available, have you ever thought about making a 3/4 inch (19mm) thick dry deck plate that would separate the head from the block but most importantly provide a place where you could make some good 1/4 wide counter bores that you could then shrink the new aluminum sleeves into, plus it would strengthen the block and eliminate the somewhat minimalist head from having to do some structural work that it appears less than able to do.
Rex
Rex, I was SO CLOSE on the PB yesterday. Had 5 numbers been completely different, I'd by writing this post on a jet to Fiji.
I'm just trying to think which eye I want poked out at this time.
My recent thought was maybe whip up some aluminum jugs similar to the drawing I put together, weld them into place top and bottom, mill the top and bore it for iron liners.
If we can get by with a .010 cleanup in the casting bore, we pick up .25 mm surface on the liner boss, then we can take the B dimension up to 90.25, which would exceed the top diameter of the much of the casting boss for the liners - they're oblong (
) - but we lose our additional support at the lip of the jug, which would also need to be taken to 90.25.
At 79 mm depth into an albeit thin aluminum cast boss with the interference fit of an iron sleeve having a 4.375 mm wall thickness, I'm thinking now that in conjunction with O-rings on the combustion chamber, lateral stability and sheer shouldn't be an issue.
I do want to have as much of this ready to discuss intelligently with Darton - or whomever - before we place an order. Ideally, I'd like to put together a print that only needs to be clarified with the shop. Darton's engineering services are costly, but still cheaper than screwing it up, so biting the bullet looks like my most cost effective and risk-averse bet.