late reply but the d5 conrods mean from my understanding you can gain 2.5mm in stroke
from your crankpins from 45mm to 40mm in resizing. That will give your a15 an 84.5mm
stroke which with 77.5mm is 1594cc with enough meat for boost.

clive.. did u fix the crank ?? how it goes..

I don't have my notebook handy, what are the factory measurements compared to the ones you're talking about D?

A14force how about stroking it with the knife edge and use mazda d5 conrods
which have 40mm crankpins and around 130mm c-c

I guess, when we're dealing with so little HP in reality, every little bit counts if your going for performance,
the engine was designed with maximum drivability/efficiency when it was designed, we take many compromises when we make performance,

if your going for maximum, it's a must, if you can afford it, why not..

The cost is not an issue. My old man has been turning on lathes since the mid 60's. I'm just gonna give it to him, and tell him, "I bet you can't knife edge this as good as this guy did!" (Insert photo of Gary's crank) The old reverse psychology can work wonders (at times) and he'll make a sweet job of it for zero dollars. (apart from maybe $20 for electricity, since his big lathe is at my mums house)
If I was paying for it, then yeah, I wouldn't be so gung ho about wanting to do it. If I was loaded, I'd prolly run a dry sump set up, and the scavange pump helps to cut down the fog too. But thats well outside my means, so I wont be doing that.

A14force.

I'd like to offer something productive to what you have just said but I'm not of the capacity at the moment.

Tell me one thing though, are you serious about the 'fog'? We are talking about push rod engines, if you are considering oil 'fog'-drag to be a hinderence on pushrod, block-cam engines, then I suggest you might want to consider increasing performance on other aspects of the engine.

Getting stuck up on crank knife edging is dangerous (and very costly). If you have the big ideas and big cash, then spend the money..... other wise cut the weight, do your best in shaping what you have left after the cut. And then drive the bloody thing knowing that you did what you could afford.

my understanding is, that it's not so much the crank dipping into the oil laying oin the sump, but more to reduce drag as the crank moves through the oil "fog" in the crankcase. with the cranksaft spinning at high velocity through the engine, and oil seeping out both sides of all 9 bearings, a tremdous amount of fog is created. The drag on the crank must be quite a bit. how much difference does less wind resistance make to a car? Imagine that same drag full of droplets of oil.
The reduction in weight also doesn't hurt none.

I would say most of the knife edging has more to do with lightening the crank, the L18 on my bench the counterweights only protrude 15-20mm from the bottom of the block and doesn't sit in the oil when i made my sump. Making some sort of windage tray is also important so that the oil is kept where it is meant to be ready for the pickup to take it to the oil pump, same goes with baffling around the pickup. A crank scraper would also be of benefit to reduce the amount of oil rotating around with the crank.

I have one question about cranks and oil levels I'm not quite sure about, happy to be pointed in the right direction.

My way of thinking is that when the engine/vehicle is stationary the crankshaft is not actually sitting in oil, (I went through this when I made a winged/baffled sump) , if you measure a block with the dipstick in and compare the dipstick levels with the sump levels (obvious this is a 'bench' test) I'm pretty sure the crank in not sitting in oil, if so not by very much.

So my point is the only time the crank has oil splash on it is on movement i.e cornering, acceleration and stopping, even then it is limited, so at idle the crank has sweet f.a. 'cutting through the oil' action and it's made worse by knife edging.

Maybe if someone has a block on the bench and do the dipstick level test, and pour four litres of water in the pan to simulate oil level i'd be interested to know your findings.