hondamark35

from some info i've gathered this seems to be a possibility... it would need different or custom rods for sure.

crank journal diameter: same
main journal width: same
rod journals: same
deck height: same

most notable difference- F23 has 97mm stroke, F20B has 88mm stroke.

has anyone tried running this? any reasons it wouldn't work?

the idea of a high reving F with parts that are easy to find and "cheap" would be nice...

jr_deleon

iTrader: (1)

First off i dont think anyone has tried this Second You need F20B rods or rods the same size as an F20B (which do not exist within the Honda or aftermarket family unless somewhere buried deep in Japan they do) as this is based off of the F23/F20B having the same deck heights but you might wanna check the comp height of whatever pistons you planned to use Maybe if you could hook up a good set of pistons on them you'll be golden. You could use the F23 rod bolts and pins. If you dont have F20B rods let me know i have a set

Are you using the SOHC head still? you may want to check out the head CC size as well

ej6.sean

i have f20 pistons crank and rods if u need

hondamark35

i did some rough math... the F23A pistons would be out of the bore 0.50mm due to the compression height. since they're dished there's plenty of margin to be safely milled down to clearance. one of the concerns was the size of the "snout" at the end of the crank where the timing cog and pulley fits. i read, for instance that a D17 crank will bolt into a D16 block but the pulleys won't fit. anything like that in the 'F' world?

EDIT: rough math was wrong (or gathered info was). no piston work needed unless using K20A pistons.

really i'm happy keeping my F23A crank as i'm going for a low rev, torquey motor. i just came across the numbers and began wondering what the possibilities for the future could be...

..say i drop the F23A in and a after several thousand miles of fun, i spin a bearing... if i already knew i could drop in a F20B crank and rods and retune, that would be handy.

Turbowa

If it helps any on high reving, my F23 bottom end revs to and makes power till 8000rpm. If you need to go higher, You may want to look at a diff. motor.

V8 Eater

wow turning a sohc into a dohc,making a minimum extra 50hp and spinning a 97mm stroke 2.3 4 banger to 8k that has to rough for the engine! Iam sure revving it that high on an engine like that is equal the amount of torture of a 10k b16.

^^^^ what kinda numbers did this engine make? any dyno sheets?

hondamark35

that's where the idea of putting the F20B crank in... to reduce the torture. it would also remain a single cam (...if i were really planing on doing this. maybe one day, but not yet)

i'll find out how to make power one way or the other, but i know my ears like that 6k-9k rpm sound!! a better R/S ratio would help out on the wear and tear side of things. help reduce the chance of putting the rod through the block..

V8 Eater

so let me get this straight your going to go from a 2.3 to a 2lt so in other words reduce dissplacement by 13% (f22 I think is 160 so the reduction would bring you down to about 140hp or more like 120 at the wheels) just so you can rev high? and on a sohc setup?

dont get me wrong but I have to say this setup is bound to fail!

your best bet would be to use the f20b head(dohc you know that right?),the f23 block ,get the block bored .25 over with oversized k20 pistons then youd be making that nice sound/noise/note your after,only this time it would actually have power(easily over 200whp with bolt-ons)

hondamark35

i know it can do it- the bottom end rev like that and still make power. that's not my issue with the setup. my thought is high and happy reving (including makeing power up there, otherwise it's near worthless...) but with longevity and reliability still in the picture. this is where the R/S ratio comes into play.

that's all this is.. a practice in adjusting geometry of the internals. it's the same thing honda engineers do everyday.

they say "good power, small engine, no turbo... rev it high!" looking at the equation for power it's almost a no-brainer. hp=(torque*rpm)/5252. you either increase torque (forced induction, reduce losses, increase available air/fuel...) or you increase rpm.

F22A is about 145 at the flywheel... but we're talking F23A1. 150hp/154ft-lb. then concidering F20B internals with 13% less displacement (and 21% more rpm range...) makes near 200hp and about 140ft-lb. a little help from improved flow... nothing a good set of bolt-ons and valve train work can't solve.

...but you say better to source an F20B head (why not H22 with cams...?) over-bore the block to remove the nice sturdy, reliable stock liners and put in pricey pistons in need of machine work all for 200whp? and still far less than ideal R/S ratio...?

if my goal were numbers and spending money, i would never have posted a query about changing up the internals... i would have just grabbed some forged stuff, a big turbo and the rest of the "kit". done.

alterdcreations

you will lose power if you do this. reving a f23a head into the 9000 rpms isn't going to happen.....there is too much mass in the valvetrain componets.......

hondamark35

wasn't planning on it (so goes the whole thread, just theoretical discussion really...) but i don't dissagree. F23A has a heafty valvetrain!

V8 Eater

sorry to burst your bubble I think your a little off here, your stating you have an f23,then your saying your going to put an f20b crank and rod/pistons to get 200hp then you say you dont want to spend money on a bore or pistons but in reality the f20b crank wont even get you close to the number you expect with a louzzzzy f23 head,youll be lucky to get 150whp REALLY!

plus why buy an f23(you can sell it if already have one) then buy an f20b crank and rods and pistons when you can just buy an f20b full longblock that hasnt been butchard,choped and put together and has a great r/s and can rev and makes 200hp in the first place? you do realize the blue top f20b is going for dirt cheap nowadays right? I found one for 1000 canadian and the guy said he would let it go for 800 without a warranty or reciept,800 canadian= around 700 U.S and that was from an importer! why bother with all your plans,your trying to reengineer what honda already has available for you and for cheaper than you can ever come close too

here you go my friend http://www.torontojdm.com/lite/cart....d=101&pageID=2

and here http://www.torontojdm.com/lite/cart....ategory_id=101

I would like to see you build your setup for cheaper,more reliable and more powerfull than that

thehatchninja

He's using an F22A head. The F23 is actually pretty decent also. Check out this ported F23, it flows 307/224 cfm. http://www.**********.com/naturally-...-na-build.html

I appreciate that you're trying to help, but you need to know what you're talking about before you try to give advice.

I think a 10k 2.0 F22A would be amazing for an extensively built race motor. Bisi actually used a F18 crank for a while (maybe still does, but I think it's custom) . However for a simple budget setup, I think you should just keep the F23 crank, and not have to rev as high. It will still be a beastly motor.

spoonInspired

why not put a 98+ h22a4 crank in the f23 with forged rods and pistons. the h22 from 98+ has 55mm mains like the f23, even the stock h22 rods would be better then the f23a's. not saying it works but do want to know for my project. so if someone does it or knows hook up the info

alterdcreations

If you were building a engine with a size restriction then i could understand.
honestly a 88mm stroke long rod 90mm bore f23block with a ported f22a head and custom 550+ lift cam with a external oil pump at 10k would be great....or buy a bisi's race engine