Building the f22 have a question or two

[Dragon_lowrider]

Ok so I'm going to be rebuilding my f22, I know it stock bore is 85 mm and stroke is 95 mm, I was wondering if I could get away with running h22 pistons that are 87 mm on the stock block with no sleeves and will it give me a higher compression ratio? I've tried searching this but keep running into dead ends, and if that wont work what would you suggest to raise the compression ratio a tad from stock, any help is great full, and thanks in advance

[Jarrett]

I've never seen anyone be able to fully bore, install and run an F22A/B with H22A pistons. Theoretically, your compression ratio and displacement would increase, but if it can't be done it doesn't matter.

Raising your compression ratio via other alternatives is an option, though. The aftermarket has a few options for you and there are some OEM options as well. Rebushing your rods and running RSX-S pistons would be a sizeable boost also requiring a rebore. Higher compression will also really open up the potential of aftermarket camshafts.

Keep in mind, it will need to be retuned to run properly.

Edit*

I wanted to add more to my post to help out for those searching. One post should NEVER be a one stop shop for deciding your build, but the more helpful it can be, the better.

The K20A2 pistons are 86mm and because of the pin offset to cope with the opposite direction that the K-series spins, will need to be rotated 180 degrees inside the bore. It is a floating pin design and your rods are a press-fit pin design. You'll need to have the rods rebushed to support the 22mm floating pin. The pistons are 30mm tall instead of 30.5~.55 that your pistons are. That will obviously drop them in the bores by .5mm which seems counter-intuitive. However the 4.25cc dome they use will more than make up for the loss. You'll sit at around 11.5:1 with those.

If you decided the $100 you would spend on rebushing the rods could be better used toward new rods then the cheap forged rods on eBay would be perfect. They are 141.75mm long (OEM F22A/B and H23A1 is 141.5mm) center-to-center so that will raise the piston a little, but not beyond streetable. Using an off-brand headgasket is an easy way to bring it back down a little as they usually spec out at around .045" compared to the factory .026". It's all up to your goals.

As of this writing you have 3 posts. I ave absolutely no idea what your mechanical abilities are, what tools you have, your budget or the amount of free time you have at your disposal. In the past few minutes I've just advised you to use parts not originally intended for your engine inside your engine. I have also suggested that it's okay to use non-OEM parts such as your headgasket in the reassembly of your engine. Keep in mind that your own knowledge and capabilities are necessary to achieve any type of build or modification. I could have told you all OEM parts and that still doesn't prevent you from having the ability to mess it up. Just something to keep in mind. Do more research...always.

[stunin92_accord]

installing an 87mm piston in to your 85mm cylinder will have some problems in your cylinder walls.eventually scaring will accure,damage rings and piston to wall grind..so,boring your walls isrequired .oh and you cant use h22 piston because they are design for fiber reinforced metal like the one in a h22 block.

[Jarrett]

Hold up there. It's a foregone conclusion that anytime you increase the size of a piston in an engine that you need to bore the walls. Not simply because 87mm is past the limits of acceptable increase. You need to overboard even for a 85.5mm piston.

The FRM-compatible pistons are okay to use in non-FRM applications. They are made out of a better aluminum that expands slower and are coated with silicon to reduce friction. They are backwards compatible.

[Dragon_lowrider]

Well rebuilding an engine is cake walk, I'm a mechanic with proper training, I was jus wondering the tolerance on the cylinder walls, ive built many stock f22's, h22's, d series b series, trying trying to get a little more bang for my buck, I also plan on running the vtec obd1 head aswell, so what you are saying from your last post is that if the tolerance is capible, that the pistons would be ok to use from an h22 into a f22 block? And the 86mm pistons is not to far out of reach either, but with that being said should I run a different rod, or would stock rod lengths be ok?

[Jarrett]

No, my first sentence in my first post was to say that it likely can't be done. I won't say definitively because a veteran member of this site has invested a lot of his time and money into a build to essentially see if it could be done. He made a toque plate out of a junk head and mostly has it done but is busy with too many other projects to devote much more time to it. Other than the potential for him to have success using a torque plate and a ton of luck, I don't see it being anywhere close to a viable possibility.

The rod choices I think I made pretty clear. Use your factory ones and rebush them for floating pins which would keep the same 141.5mm length...

...or get the cheap forged rods off of eBay for the added insurance and to avoid the machine shop costs of rebushing the rods. I also explained that they usually spec in at 141.75mm which would bump the compression ratio a bit, with everything else constant.

It's all up to you and your preferences. Even 11.5:1 may be more than what you're looking for.

Also, I forgot to emphasize how much any of these options, even beyond the two scenarios I mentioned, will all need extensive tuning.