donaldmejr

Are all s2000 cranks the same?


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MM3Kwolik

No. F20 cranks differ from the F22 cranks.

donaldmejr

Could you tell me by how? Different stroke? Will it change my CR or drop the displacement down to a 2.0? Sent from my C811 4G using Tapatalk

MM3Kwolik

The strokes are different. An AP2 crank in combination with AP2 rods and pistons is what increases the displacement. This has been covered over and over. A simple search would've yielded you your answer. AP1 pistons are domed, while AP2 are flat on top. AP1 rods are 153mm while AP2 rods are 149.65mm.

donaldmejr

for someone that has no idea what that means can you explain it a little...

I did find this:

AP1:
Bore: 87mm
Stroke: 84mm
Compression: 11:1
Pistons Domed
Rod Length: 153mm

AP2:.
Bore: 87mm
Stroke: 90.7mm
Compression: 11:1
Pistons: Flat
Rod Length: 149.65mm

If I pair all the correct parts together what could my results be? Less/more displacement? Higher/Lower CR? or just completely screwed up motor? The reason I ask is my motor has crank walk and just the crank was damaged. I have been able to find a used AP1 shortblock.

Also If im reading things correctly if you use AP1 Crank and rods with AP2 Pistons then the CR will drop. But if you use AP2 crank and rods and AP1 pistons then the CR will increase to ~12:1.

Slowcrash_101

AP1 Stroke + Rod length = 237 mm
AP2 Stroke + Rod length = 240.35 mm

S2000 combustion chamber ~ 53.6 cc

AP1 Intake Valve lift = 12.15mm
AP2 Intake Valve lift ~ 12mm

AP1 Exhaust Valve lift = 11.10mm
AP2 Exhaust Valve lift ~ 10.6mm

AP1 piston dome = +2cc
AP2 piston dome = +0cc

Yes your CR will go up but so will the likelihood of striking a valve with the piston. OEM pistons are very expensive, I'd rather get aftermarket pistons, there are a couple that are compatible with FRM sleeves and they tend to be lighter than OEM plus you can pick your CR, and keep your stroke and rod length smaller and with lower piston speeds(better reliability).

donaldmejr

Well my 08 ap2 has 14k miles and just a bad crank. The ap1 short block is in good condition with 50k so my choices are good. Sent from my C811 4G using Tapatalk

MM3Kwolik

If it only has 14K miles and only the crank is bad, why even bother with anything other than finding a good AP2 crank? Messing with a motor that low in milage is foolish IMO.

donaldmejr

By all means thats my plan by 500 bucks for a good local short block is hard to pass up over a sight unseen crank shipping to me.

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_brandon

Curious on how you destroyed a crank at 14,000 miles. Even more curious on how you destroyed a honda crankshaft period