A14force wrote:
Long time no posts Marcus!
I often wondered how you were getting on. I think if you're going to go that far oversize in the bore and run boost then you're going to need to at least partly fill the water jackets. So long as you don't go overboard, the engine will still be useable.
I did read somewhere that large overbores (Albeit on big old 6's) the wall gets too thin, and actually alows it to deflect. This allows more blowby to get passed the rings, and results in less power than the same engine with a smaller bore would make. Add boost to the equation, and one would tend to think that such a problem would be exacerbated.(spelling?)
That said also, they were including in that analogy the reduction in bore thickness resulting from corrision. Given you get pretty harsh winters it'd be safe to assume that not many motors get used for extended periods without Antifreeze (?) unlike can (and does) happen in warmer climates.

Lemonhead wrote:
The block that I have had bored to suit 82mm pistons has had a sleeve put in numbers 1 and 4 cylinders and 2 and 3 bored in original material.

This would work, but I am not happy with the arrangement of the bores, no.'s 1 and 4 have been moved to the front and rear of the block and 2 and 3 closer to the centre a bit. This has not given me the bore spacing/combustion chamber alignment that I wanted for the twin cam head nor a A-series head.

So, what I am doing now hopefully is what I originally wanted and that was a full wet sleeve block, I say hopefully because I have a dummy block at my machinist shop to see if we can do it, he's a 'can do' type of bloke and he can't see why we couldn't do it.

With the type of sleeves we are planning on using we can incorporate a raised ring around the bore (about 1mm high) to act as an O ring type of arrangement, with the sleeve thickness, 82mm is just the beginning of bore sizes, it will be interesting to see what size I can go to, coupled with the 88mm stroke crank I should be able to get some good capacity out of a little ol' 1400 block, 88mm x 85mm is 1997cc

I have recently acquired Feral's A13 raised port race head to intially put on the motor while I keep working on the twin cam, I have literally worn out my huge race head which is currently on rally car.

So if the wet sleeving does work, even with a 82mm stroke crank some good capacity can be achieved and to answer the theme of the thread - yes be perfect for high boost applications.

I will keep you posted.

D - From the other thread, I can build you whatever combination you desire

Marcus - I ran a 79mm n/a motor for a long time with no problems, had the block sonic tested and bored to suit, I like your signature, I guess I'm building honest 200hp n/a A-series motor.

ddgonzal wrote:
The other 200HP A-series are not strokers, but are running high RPM (excess of 10,000 RPM) with highly modified heads with raised/fabricated ports.

ddgonzal wrote: -- use a sonic tester to locate the thinnest portion of the wall and then bore accordingly. That's what they do with early A12 engines when doing large overbores (early engines have thinner cylinder walls).