So as clearly I was bored yesterday I tried an A15 crank in an A12 block and there are issues.

First the block in question was a 73.75mm bore. My intent was to use 75mm Honda Pistons in my A12A block

I used the standard A12 rod and piston (knowing th piston was going to stick up 2.5mm), the connecting rod fouls the bore. I didn't measure but the top of the rod bolt contacts the bore so I'd say it needs at least 5mm more clearance.

Next I pulled the rod and piston off the crank; the crank throw contacts the block about a 1/3 of the way along the surface of the throw.

So a couple of things; an A14 crank may fit without these issues given the shorter stroke, the A15 crank might clear the A12A 75mm bore block but I doubt it so I won't be trying it.

MX5 / Miata

I'm trying to use off the shelf parts hence cast pistons

My A15 blocks, with 76.5mm bores are scored so I need to go out to 76.75 or 77mm

I may use either 76.75 A14 pistons in my A12A block or try the 75mm Honda piston with either A14 or A15 crank in A12A block.

I'm just trying to get my car back to the 90-100whp range because the current 75whp is painful

I'm looking for 77mm pistons for an A15. I don't want to the usual mix and match or milling of pistons.

SW Motorsports lists them on there site; made an inquiry but haven't got a response back yet.

Any leads would be appreciated.

David the plan would be to use the A14 crank in conjunction with the Honda pistons as a 30mm pin height is what's needed for the 77mm stroke. I've yet to try an A15 crank in an A12 block, there is a Honda piston with a 27mm pin height which would be .4 proud of the deck, not an issue one could in theory mill the piston top.

D the Honda pistons are only 45mm long meaning there is no need to clearance the crank throws on against the pistons.

Sleeving the block would cost more than simply ordering custom pistons for my A15 block.

I'm trying to build up stuff using off the shelf parts; Honda pistons & rings are $75 for the set plus $40 to have the machine shop sit them on to the A12A rods.

So back to our regular programing; anyone have an A14 crank?

A 10K motor; probably about 6 hours of run time, the engine life is indeed directly related to the kind of revs the motor is pulling. Keeping the motor to 8K means you can probably get 100 hours out of a race motor.

The reason why I'm looking for an A14 crank is I can use 75mm Honda pistons. 86-87 Acura Integra pistons come in a flat top with a 30mm pin height. The Honda/Acura pistons have 15mm shorter skirts so they woot foul the crank. I have a A12A short block that was freshly rebuilt I'm trying to put together a "in the mean time" motor while I decide what it is I actually want to do long term.

Anyone willing to swap me an A14 crank for one of my A15 crankshafts?

I'm up to some evil planning again: looking to put A14 crank into A12A block in conjunction with Acura pistons.

I have to ask a friend who races a 510 as I don't know the value of Lseries stuff but the shipping may well be a deal breaker.

I'm in Las Vegas Nevada