Has anyone stroked an A15 via the crankpins?

Im thinking of an alternative to the E16 crank
for a stroker. This is to cut the costs & use either

mazda d15 133mm rods w/ 40mm BE journals RSR = 1.547
or
Early 4age 135mm rods w/40mm journals RSR = 1.57
and 133mm length.

48 --> 40mm crankpins should allow 4mm stroke?

Therefore 77mm bores and 86mm stroke = 1602cc

Mazda could be better so you can bore for Mazda pistons too, capacity, and stroke... End up with a lillte more than 1608cc ;) with only mode to crank end of rids and a bore

There was a lad here who had an alleged stroker
But he wasn't sure himself... I think Mike ended up with the block but never pulled it down

And if you offset grind the crank like they do with 308 strokers with hemo rods , or Cadillac 500 cubes into 540 cube with BBC rods.. .you'll get more stroke
Just need to balance the rod/piston combo

the mazda rods are definitely an option
however the longer and stronger 4age rods
also allow some good pistons straight off
the bat, eg. gemini, mitsubishi and honda.

Whatever will be easier to have as few mods as possible, if you only have to mod piston at crank not gudgeon pin- easier for piston replacements later if need be.

if grinding big ends u can grind 1mm one side
and 7mm other side ending up with a longer stroke
if rods and piston are available to suit combo
would need to check for clearence in block

It's not a datto but here is a good article about offset grinding cranks and increasing displacement via the longer strokes.

Obviously you'll get to a point that the head (no matter how well it is ported) just won'tbe able to flow enough to support more power, so in race setups, you eventually get to a point where it won't make more power (on mini A series engines, for example, you can get a 1275 all the way out to near 1600cc but they actually make more power at around 1440-1480cc becaue there's less friction from shorter stroke (vs 1600cc) and the worse rod to stroke ratio that long stroke brings (which increases rod angularity and side thrust/friction). They also make a little les power because by the time you go that far oversize, the bore walls are thin to the point they flex and the ring seal is compromised.

Having said all that, I reckon an a series would still be quite useful at 1600cc. It might not make more power outright than a std stroke a15, (it probably would, but even if it didn't) but you _could_ run a well ported head, and a slightly larger cam than you'd get away with n a street a15, - since the larger the capacity the more it 'tames' the cam's effect on low-mid range rpms. SO you could basically get closer to race engine power on a street setup with longer stroke.

I'd say at a guess that you wouldn't want to try and go up around or beyond 1700cc (and I don't know for sure if that is even possible, I haven't done the math, based on offset grinding, crank/rod clearance in the block and bore wall thickness) even for a streeter.

Of course I'll throw in my 'usual' comment - that a supercharged a15 (even a very modest low buck combo) will have more midrange torque than any NA race a15, and more power than a NA street motor - it'll behave like a stroker on steroids - the sort of torque you'd expect from a 2 litre NA engine or better potentially.

How about 1600 and supercharged? :)

I figure 77mm bores leaves plenty of meat on the a15
and 86mm stroke is only 4mm more with 2mm longer rods
should be quite peppy down low with still decent rod
stroke ratio to keep it reliable.

Lemonhead has already done an e16 88mm stroke crank into
an A series with sleeved outer bores and final bore of
82mm with 25mm comp height pistons.

Im thinking 86mm stroke with 4age rods and isuzu 27mm
comp height pistons (originally 27.2mm) will be just
what the doctor ordered with 8psi.

with that sort of bore and stroke - have you had a look at the dish volume (if any) of the isuzu pistons- and what the static comp ratio will end up with with all that extra capacity. That might be the hidden obstacle here. On minis (sorry for repeated referalls to inferior engines) with 1275s it's not too hard to get around 9.75:1-10:1 compression with dished pistons in modest oversizes (mind you, the 'listed' comp ratios on hepolite brand pistons for the 1275s are almost always WAY off the actual real world calculated results) - anyhoo - by the time you get our to more than 40thou oversize (let alone with really big bores and offset ground stroker cranks) - it can be a real challenge to get the comp ratio UNDER 11.5:1 - no kidding.

Have you done the math on this theoretical combo (and I'm not asking this by way of some sort of criticism, I'm actually very curious to know just what sorr of comp ratio you are able to achieve with such a combo) - and if so, what were the results?

I only used the Ozdat engine calc and put in all the
figures we know from this site. eg 29cc chamber volume
on h89 head, 205.1mm block height and all the rest.
So far the comp goes up a smidgen with 1mm bigger slugs
and it doesnt change as long as I adjust the piston
compression height to suit. Ill be better off with the
1.547 rod stroke ratio using mazda 133mm rods and isuzu
27.2mm comp height pistons this gives me lower comp
ratio than standard or can raise comp to 9.5 to 1 with
135mm 4age conrods or similar.
It will have to be a real world trial if I go this way
but will like to see what issues I should consider
eg. re-hardening crankpins etc.