Someone please tell me if this will even work without the pistons smacking the head or valves. Factory h22a4 is 10 to 1 compression, so what will it be with the f23a crank and rods shoving the piston up higher out of the hole.

Any thoughts on boring the F23a past its recommended service limit? 86mm is 3.3858 inch. Honda maks pistons that are .5 mm oversize which is 3.4055 inch

Would it really hurt to bore out to 87mm which is only 3.4251

Thats only about .020 more and really only about .010 on each side of the wall since its round.

I'm considering doing the G23aVTEC but I don't have funds to boost it now and I would hate to lose power by dropping my compression when using the H22a head on the F block. I have OEM h23a and h22a pistons here that I can use if I over bore the block. So if the H22a pistons will raise the CR too high or smack the head, maybe the H23a ones will do the trick. I really don't want to raise my compression any higher than prelude type s pistons in H22a (11 to 1)

 

If you plan on turboing it later on down the road dont ever bother with the F23 crank and rods and or F23 block.

 

Ok, I'll tell you: It will work, with modifications or a thick HG (see pirate's G23 thread, the F22 VTEC thread, search, etc.). The compression will depend on your exact modifications, but would probably be in the 11-12 range.

My thoughs on boring F23 to 87: experimental, but seems to work. I don't think I would want to boost on it further than walking distance. Boost a stock F22 block if you want (again, see the threads where this is covered...)

H23 pistons will give a lower compression and slightly lower compression height, but they are not floating pin (i.e. more modifications).

 

Cylinder pressure is already a haunting factor with the horrible r/s ratio the F23 crank and rod combo yield. That teamed with a thin sleve and boost is going to go boom fairly soon.

A sleeved H22 block with the 90.7mm stroke and 5.630 rod is your best bet.

You dont need stroke with boost.

 

ya, so there.

 

Didn't like the answer I gave in the F22/H22 Hybrid thread huh? You will find very few people here running what you are asking about... just talk about cup-holders, "Mugen" thermostats and Eclipse Turbo ECU possibilities...

If you want more compression but not stratospheric, you can use RSX base model pistons in an F23 block, with a 50cc head (F22/F23/H23) you'll get 11:1CR with a 53.8cc head (H22) you'll get 10.38:1 CR. You can mill either to get more compression. BTW more compression is not necessarily good for boost either. The RSX pistons will not stick out of the block but the H22's valves may contact pistons with aggressive milling or cams. So be sure to clay your motor before final assembly for that extra assurance.

AND to curb comments from rick... an H22 head has a larger diameter bore than the F23 block and is generally thought to be a NoNo amongst most performance engine builders. So you should consider taking steps against it. If you want to know more about this issue be sure to PM rick, he would love to tell you.

Pirate