KA Stroker

[Tatanko]

I was thinking of ways to increase the displacement cheaper than boring out the block and paying tons of money for oversized pistons. But of course we all know the KA only comes in one displacement. So I started looking around at other Nissan engines with the same bore to see what their stroke was and if I could potentially use that to increase the KA's stroke. Well, the only match is the QR25DE. This increases the stroke from 96.00 to 100.00. My question is, would it be possible to use the QR's crankshaft and rods (pistons also?) in the KA to create a stroker engine? The only concern I have is that you might have to limit your redline like another 500 RPM's or so due to the increased stroke, plus the fact that the bore and stroke are so far apart. SO...does anyone have any input?

[PSI240SX]

why undertake such a huge project? Just slap some pistons and rods in there and have at it. I pushed 30psi through my motor without failure and made 412rwhp and 412.1rwtq. I assure you that you can have all the fun you would ever need with that much power.

[Tatanko]

Well "huge" is a matter of opinion. I honestly don't think you read past the title. "Slap some pistons and rods in there"...well, if I'm going to rip apart the engine to do that, how would swapping a crankshaft while I'm at it be any bigger of a project? As to why...well, for one, to be different. Anyone can slap on a turbo and up the boost.

[Chingon]

someone in the forum has a stroked 2.5ka already...you may ask the guy...(he'll probably chime in).

[Tatanko]

Wow...really? Awesome...was it using the idea I had or how did he accomplish the 2.5L?

EDIT: I just found threads about his 2.5L. However, he accomplished the .1L through boring out the block and using larger pistons...exactly the opposite of what I'm trying to accomplish.

[im two techno]

Are you looking to make the KA have more stroke? Why not just go turbo diesel?

The KA block has very large pistons in it stock. 91mill is about as far as Nissan says you can go. Changing the crank would be a challenge or machining the crank would take the use of a machine shop and this would only lower your rev and cause the motor to vibrate more. If anything use a Z22 truck crank from a 85 Hard body and go with a 2.2 liter Turbo of corse.

The QR25DE crank will not work well....i guess anything will work for the right amount of money

[hamsturbation]

just a thought, but you could have the crank offset ground, then use oversized rod bearings..i dont know how much diffrence that would make, but it would be diffrent for sure...

[Def]

A different crank will require custom rods unless the deck height is the same on the QR25DE(highly doubt that).

This wouldn't be cheap, and you're talking about only gaining a few percentages of torque, and probably losing some HP due to the higher piston speeds. Just spend that money putting a turbo on it and making it bulletproof.

...there's a reason no one's done it before - it'd be an utter waste of money.