is it possible to bore an f20b to 87mm. i've been offered a h22 head with some goodies in, the initial plan was to remove the parts and run in my head, but i'm now thinking of using the complete head and building my bottom end to match. i'll need bigger bores to go with the larger valves in the h22 head,

also does anyone make pistons for the f20b? will be wanting to up the cr to go with the cams.

 

yes it is possible the f20b has iron sleeves and any aftermarket piston manufacturer from the likes of wiseco, cp, je all make pistons for the h22a and can be used in the f20b after boring the cylinders to 87mm.

 

No he's wrong you can't bore it to 87mm without having to put sleeves the material is too thin at 87mm. Safe bore for this motor is at 86mm. I mean thats what i know about this motor with the cast iron sleeves and its 85mm bore like accord f22a1,b1,b2. taking off that much will leave you with a thin wall which is not good.

 

ok cheers mate, i've got some 12.5 cr 85mm (stock bore) cp pistons on the way now,

 

wow thats gonna do some damage out on the road, what else you plan on doing to it????
oh and the bore shouldn't really matter being that the head is 87mm thats like an h22 head on an accord block, its the same concept.
i got myself right now a g series, f20b head f22a1 block in a 4dr civic and boy does she move. the block is high mileage but its ok ima rebuild it has about 240xxx miles and it pulls so hard lol

 

hi. its actually in my dirt oval racer, going to stick with the f20b head so that head matches the bore, will be running some roller rockers with vtec delete cams. planning on a high end tri-y header and running 52mm twm itb's. 210 - 220 @ wheels and maybe 165 - 170 ftlb would be nice

 

You sir are incorrect i have the likes of h22a, f20b and f22a1 and have honed the f20b to 87mm and use wiseco 87mm pistons. The sleeves are thick enough so i wouldn't go off of assumptions if i were u.

 

once again your wrong there's a reason that f20b head has a smaller valve than the h22a head since the f20b has a smaller cylinder bore, hence if u use the h22a head with the f20b stock bore your gonna run into valve to cylinder clearence issues.

 

And you sir are probably correct about the overbore of the f20b but it has the same bore as an f22a1 which is 85mm, and they state on Helms manual that safe block bore limits are 86mm which which by the way has an open deck block like the f20b and the walls are thin with 87mm. How long has the block lasted you with that setup? Are you a professional engine re-builder cause if you are then you know about f22a1 overboring also if your right than you have corrected me.

And by the way h22a head only has a bigger intake valve (35mm) and is 1mm bigger. My point on putting an h22 head on a f22a1 block without issues is doable I've seen it with me own eyes running and all no tapping or no valve to piston issues unless your using high comp pistons.

 

The car has been running for over a year now with no problems. There are people who use to say that u can't run high compression and turbo together, and that didn't stop people from doing it. I'm not a professional engine builder but my machinist is and is one of the best out there by far.

 

I see dam you definitely proved that it can be done i guess i need a little more info on that.
I've heard of it being done with little info but it must be the tune that factors its reliability plus since the f20b has an 88mm stroke the piston travel really doesn't stress the rods that much.

I had an f20b and i found out it has no oil squirters when pulling the motor apart that was new to me and i used to beat it like there was no tomorrow and it still had life for 2 1/2 years untill i hit a puddle lol. Those motors are very good, btw how much power you pushing out to the wheels?

 

The car is not my car it's a customers and it made 245whp.