Stroke The 20 Or Destroke The 25?

[driftjunke]

OK, so here's what we have, a 25 with 2 bent valves, and a 20 with slight knock on #6. So here's what I was thinking, we can take the 25 crank and rods, and swap them into the 20 with 1mm overbore forgies in the 20, hence making it a 2.3, from what I have read, needs machine work of course. Next option, take the 20 crank and rods and drop them into the 25, destroke the 25 to have the big bore, and smaller stroke, like a F1 motor, high displacement and shorter stroke. Build the 25 head to make it stable at 12k rpm, but push it to 10k.

So my issue is, I have only seen the 2.4 ever doen in magazines, but has anyone ever tried this really? I am sure the 20 crank will fit in the 25 with no mods, the 25 nto the 20 my have some clearance issue, like the 26. Looking at specs though the 25 has only a 2mm longer stroke than the 20, so would that make much of a difference? We are gonna go from a 78mm bore to a 79mm with the forged pistons. And possibly see if we could find some 9 to 1 compression pistons possibly.

Any ideas?

Let me know what ya'll think, I wanna do a frankenstein motor, I've done 26's 25's and 20's, and we're in the process of a 30, but we still want something different.

E

[GTRsean]

If ya got time and money I think it'd be a first.

[R31Nismoid]

this has come up before.. a while ago

26 crank - 2.4

25 crank - 2.3

as u know. Try searching a bit... using 2.3* etc.

Not sure what it will return... it was a LONG time ago all this came up