Would they work? and what would the compression be with a set of dc5 or K20a2 pistons? I already have steel H-beam rods so the floating wrist pins will not be a problem and my F22b Dohc head machined for 86mm bore.

 

they may need to be ran backwards.

Check out this guys thread. He used 87mm weisco k-series ones though.
https://honda-tech.com/forums/hybrid-engine-swaps-18/my-f23-h22-87x97mm-h2b-build-2252451/

 

things to match up..

-bore (sounds like you've got that taken care of)
-compression height (wrist pin center to flat, top edge of piston)
-wrist pin diameter
-wrist pin offset (like Gold DA9 said, K20 pistons must be turned around because the offset is opposite that of the F22... CW=K20 CCW=F22)

these are the main things to check before deciding if any piston is a fesible option. of course valve to piston clearance and compression are factors as well, but to some degree can be "corrected."

 

So the f22 and f23 both have offset wrist pins? Is it the same?

 

hmm... im not sure. But i have heard many people saying the k20 pistons fit perfectly of f23 rods.

 

all engines have offsets for the wrist pin (the hole in the piston is not centered) to my knowledge. they would wear out quickly otherwise. i think they are the same or close enough to not matter.

i've got a set of these on the work bench right now! K20 pistons and K20 wrist pins with F23 rods, like they were made for it..

 

k20 pistons do not fit F22 rods, I found otu the hard way. I couldn't even get the machine shop to make it work.

 

my mind completely jumped over that... F22 was there but i was thinking K20...

 

Why wouldnt they fit? im using aftermarket rods not stock. heres a pic. Or are the rods too wide?

 

They won't fit on stock F22 rods with press fit wrist pins. It's not worth it to bore and bush the the PE of a stock F22 rod to fit floating wrist pins. Yes they will fit aftermarket rods that use a 0.866(22mm) BE made for floating wrist pins.

Isn't the whole wrist pin offset problem, not about the fact that all pistons have offset. But the fact that the K20 engine happens to have a reverse rotation to the F series. This puts the offset to the opposite side. I think that is why people recommend turning the piston 180°.

 

right, you also have to take into account the difference in valve geometry once it's turned. the exhaust valve reliefs will now be on the intake side and vice versa. intake valves are larger (and depending on the setup, may have higher lift) than the exhuast. therefore the reliefs theoretically need enlarging. i say theoretically because i haven't clayed the motor yet to find out for sure...

 

2 year bump for more info.

 

What kind of info, anything specific that your looking for?

 

i would like to find out why a machine shop couldnt make them work. wouldnt the 21 mm small end of the f22 need to be bored out to the 22mm wrist pin of the k20 piston? also is it safe to bore the f22 block to accept the 86 mm bore of the k20. i looks promising on paper. i just started getting interested in h/f series this week due to a ton of these parts around the shop. just doing my homework.

 

A machine shop probably could make it work if they were wiling to bore the PE out further than 22mm. It would need to be bored out further than 22mm so that you could install a brass bushing. You could try and use a floating wrist pin without a bushing. However, odds are it won't last as long. Buy a set of H23/B20A/F22A-B aftermarket rods and they are already 22mm with bushings. Ready for slip fit wrist pins.

Yes the F22 block can be safely bored out to match an 86mm piston.

 

my bad bro. f22a pistons already came with 22mm not 21mm wrist pin. just noticed what i wrote. i have f22a rods and k20 type s pistons at the shop. ill check it out and post pics tonight.

 

Ghost so tell me if i am thinking right then, if this would work

Aft Mkt f22 rods
K20 pistons rotated 180*
F22 crank
stock h22 vtec head and/or stock f22b1 or b2 head

would this work ok?

 

Would it work.... sure it will work. Will it be reliable.... depends on the clearances and how well it's put together.

 

ok might be an understatement.

oops. top part got cut off. my print screen isnt working so this is the best i got. anywaya i simply pluged in f22 block, head rods.... and the k20 type s pistons and it gives you .020 p2d clearance and cr of 11.30. sounds too good to be true.

question. can pistons with floating wrist pins be mounted on stock rods? i thought they could. im gonna have to pull a piston and rod from the f22a tomorrow.

 

i know this is a old post but I did it. F22b2 with rsx type s pistons and a h22 head. Machine shop matches my rod to my f23 rod and bored the hole for the wrist pin.