jdm92_accorn : 1992 Accord LX

[P5ylance]

Hey jdm, I was wondering, since my block is gonna be a high mileage block, should I move from 85mm to 85.5 oversized pistons or find some 86mm oem cast pistons? I'm trying not to go to forged internals or change my rods out so I was wondering what my options may be.perhaps just some oversize f22 pistons would suffice? I'm not trying to open pandoras box and exceed my budget, but if there's an option that's a real easy switch, id consider it

[jdm92_accorn]

If you're interested I have a set of billet steel light weight I-beam rods for sale right now. Then you could use any full floating 22mm wristpin piston including f23 and k-series pistons. They are also slightly longer at 141.73mm vs oem141.5mm. Here is them in a f22 block with f23 and k20a pistons.
F23A pistons with .010" shaved off the block and .020" off the head. I strongly suggest an adjustable cam gear.

K20A2 pistons

Just pm about the rods.

[P5ylance]

It seems like cb pistons are the only ones that mount like they do... are all other worthwhile oem piston floating wrist pin then, as in if I want to change my pistons, f22 rods are not good for much else? For sure I want to avoid forged because of their expansion poperties. Also, althougha cam gear is useful for tuning, is it because the rod length is changed that it becomes a necessary item? Ca has strict laws and even adjustable cam gears aren't allowed.. though I know me building a motor isn't allowed either lol, just trying to find a balance if possible.

[Jarrett]

The only OEM pistons that will work with your current rods are all 87mm.

The adjustable cam gear is needed because of the change in deck height if you were to mill like he suggested. It's also a decent tuning tool when compression has changed significantly.

Why can't you just put the timing cover back on to avoid trouble?

[P5ylance]

oh hey, what's up Jarrett! I actually just read one of your responses to this thread

http://www.cb7tuner.com/vbb/showthread.php?t=195240

It's possible to rebush the f22a oem rods to use the k20a2 pistons?

I also read from Jdm92's other posts that the compression bump I'm seeking (between 9 to 10) might not be too noticeable either. but the k20a2 compression looks tasty, but i know with higher compression theres a need for premium gas, yeah?

I've looked up some threads about the effects of the cam gears, and most of the threads that came up showed the cam gear didn't deviate from center much for a mild build, though IIRC most of those didn't have pistons.

I would like to limit my changes to deck height, only whats needed to resurface the head and block.

As far as not using the cam gear, carlos mentioned modding the cover so it would fit, but if i could avoid it that would be ideal... I know my requirements are probably not possible either! in all honesty, i'm entertaining the possibility of somewhat building my bottom end a bit, but because of my budget i'm content with just a head build as well. I just wanted to be able to see if there was one more thing I could add to the motor for benefits without opening up a bunch of other things that need to accompany it. :\

[P5ylance]

Though again, since i will be bringing in my car sometime late this week, there will probably be no more time for me to even get the remaining stuff, so i'll be safe and most likely stick with a stock rebuilt bottom end. I'm interested in learning about this stuff because it's important to know about engines, i think.

I'd like to thank you Jarrett and JDM92 for helping me out a lot with all my questions! I'll let you know when things have been all put together

[jdm92_accorn]

I'm only asking $300 for the rods shipped and oem replacement f23a pistons are roughly $200-$250 with rings and wristpins and decking the block .010" and the head .020 is nothing plus it will give you a true flat mating surface. The cam gear is to correct the offset from the change in deck/head height. A bump from 8.8 to 9.5 will wake up the cam, peak power won't change much (roughly 2% increase) but the area under the curve will be greater. The 51cc increase in displacement from the 1mm over bore will help aswell (roughly another 2%). The additional displacement, compression and refresh along with a tighter valve adjustment should make it more eager to pull and rev quicker. Low compression makes naturally aspirated engines act like tired old dogs, lol. Funny enough, too much compression and having to take timing out to accommodate the compression or dome being to high has the same effect. For the price of having oem rods modified to use full floating wristpins you can buy a cheap set of rods and they will be much stronger. I asked about bushing my rods and the local machine shop said they wouldn't do it unless I shotpeened the rods after and that was going to cost $450 total. It might be cheaper where you are but for me I felt more piece of mind buying $650 billet steel rods.

[P5ylance]

Thanks for replying!

How about this option, if i forego my original fear of forged parts?

I'm looking at the Bisimoto 10.5:1 CR pistons now... would they pair up well with your rods? If I don't do anything except enough to resurface the head and block, would this combo be fine without a cam gear, or does any resurfacing lead to a need for an adjustable cam gear? I want to avoid extra tolerances or possible chances of slipping which is why I like the fixed design of the stock cam gear.

for some reason I'm really deadset on not having to use a cam gear if i can help it.

what is there to do to make Bisi 10.5:1 pistons work? bore to 86mm, rods designed for floating wrist pin, etc.?

The f23a1 pistons are designed to give a 9.3:1 CR? I feel like I'm missing some info in between

theres probably a few more questions lingering in my head right now, but i'd like to hear the responses to these ones before i keep asking

[P5ylance]

okay, i just tried the zeal calculator to try and calculate it and I kinda see where your numbers came from now. the milling number you called, .030, is that the typical amount of material that gets removed during a resurfacing?

[Jarrett]

Milling 0.030" is quite a bit and done so only when someone wants a bump in compression. A resurface is usually around 0.004-0.008".

The F23A pistons don't achieve the same compression because of the lower compression height. Their numbers with a 97mm stroke and 141mm rod are not what they would be with a 95mm stroke and 141.5mm rod.

At this point, some of these questions are best asked in your own separate thread.

[P5ylance]

alrighty, sorry to ask to much! I'll probably stick with my stock f22 block setup and be happy with it. its a lot of uncertainty with little time so i'd rather not leave my motor's life to my inexperience. I may just ask the shop if they could grab some oversize F22 pistons and be good with it. using the zeal calc and having 85.5mm OS F22 pistons and an average resurfacing amount (.006, value taken from this thread: http://forums.evolutionm.net/evo-eng...resurface.html) and using stock rod length, I was able to calculate an 8.99:1 CR. almost +.2 and within my understanding haha/

thanks again jdm92!

[P5ylance]

Milling 0.030" is quite a bit and done so only when someone wants a bump in compression. A resurface is usually around 0.004-0.008".

The F23A pistons don't achieve the same compression because of the lower compression height. Their numbers with a 97mm stroke and 141mm rod are not what they would be with a 95mm stroke and 141.5mm rod.

At this point, some of these questions are best asked in your own separate thread.

I noticed that too when using the Zeal calc, so I figured it wasn't worth doing all the stuff necessary to switch to f23a1 pistons, and k20a2 piston CR is too high for my liking.

Yeah, I apologize, which is why i'm gonna stop here.

Thank you again as well Jarrett, it was fun!

[jdm92_accorn]

Just pm me and ill help you out when you need it. On another note it might be worth it to just go my route and use a F23A rebuilt short block. That way there is no guess work and you can get a nice bump in compression and displacement. With your car being an auto that added stroke will bump low rpm torque enough to help it not feel so sluggish down low. I've actually been contemplating selling my whole setup trans, engine ecu and all around next April. Do it as a turn key 200whp f23a non vtec swap. I really want to go k20 in my dd and built f22 in my dx coupe.

[Jarrett]

I'd swap an F23A1 short block in place of rebuilding an F22A any day of the week. It will be a lot cheaper than having yours rebuilt in addition to the added performance benefits. You'll be replacing all of the same seals anyway.

[jdm92_accorn]

My sentiment exactly. And with the f23 you bore out to 87mm and use tsx pistons for a budget 11:1 compression true 2.3 liter.