myaccord1993

So I have an h22a jdm block and head. I'm going to be running the stock h23 crank, forged rods, and pistons. trying to reach 12:1. as far as rods its pretty simple. but the part that confuses me is the pistons. normally on non forged h22a type s piston which are 11:1 or something close. So in my head I'm thinking i need h22a type s forged pistons.... BUT..... When i go looking and i go to select stroke and length.. i assume it needs to be 95mm for stroke and 141.5 for length which is the stroke of the crank I'm using and the legnth of the forged rods i would be using. and the only option i believe is that of those specs for the h22 rods and h22 crank. so i guess my question is. do i need to be looking for h23 forged pistons or is it the extra length and stroke what bumps the 11.0:1 to 12:1. i just dont want to order wrong parts.. also ill be on race gas and probably bottle tuned. 100-150 wet. block is also sleeved with darton 300-018 flanged iron sleeves. trying to get 350 to the wheels.

GhostAccord

What year block is it? I'm not 100% on the JDM blocks if they are all 50mm or not. The H22 came with 2 different main journal diameters. 50mm and 55mm the H23/F22 Crank has a 50mm main journal diameter. Should make sure you have the H22 block with the same size mains. Some of the later H22 blocks had 55mm.

As far as parts goes, crank stroke, rod length, piston diameter, dome and compression height all contribute to your final compression ratio.

H23 Stroke = 95.00mm
H23 Rod = 141.50mm

Piston H22 Type - S
Compression Height = 31.00mm
Dome displacement = 3.90cc

This setup would net you approximately 12.11 compression ratio.

If you want to use aftermarket parts you can mix and match your rods and pistons a bit more. You are definitely going to want to go with forged pistons.

myaccord1993

The block and head were both pulled from a 96 prelude. obd2 no mobi. well i believe i was looking at some arias pistons and before you order them they ask you the following.

ex.

Arias Forged Pistons H22 H22A H22A1

bore: 87.5mm (+0.020) << should i leave it 87mm?
compression ratio: 11.0:1
stroke: 90.7mm
rod length: 143mm

Are the h22 type s pistons other then the bore, these specs?

also I may just be dumb but why are the asking the stroke and rod length when purchasing. are they doing some of the math for you? my main concerns is clearance. I'm pushing it as it it is. But would i buy the pistons as if they were going on h22 rods and h22 crank. because the fact that there not. is why im getting 12:1?

GhostAccord

The reason they ask for the stroke and rod length is so that they can calculate the location of the wrist pin in the piston in order to keep the proper piston to deck clearance. AKA keep the piston from popping out of the cylinder and/or kissing the cylinder head, this also maintains the piston to valve clearances. In these interference engines that is a big deal. The measurement between the wrist pin center line and the shoulder of the piston top is known as the piston compression height.

You mention in your original post that you are using an H23 crank. If you are using an H23 crank and H22 rods you will need to have the piston compression height changed from 31mm to 29.08mm to keep it at the stock piston to deck height. I know this is a lot to take in all at once but it is all part of the overall compression of the engine. Any measurement that you change in the bottom end affects the compression ratio. Even the diameter of your piston/cylinder bore.

If you are using the stock H22 crank and rods then you would just purchase a set of off the shelf forged pistons for a 12:1 H22. They are sold in different bores and compression ratios straight off the shelf. No need to do any math, they have done it all for you.

myaccord1993

have you personally looked into the "strokers" h22a. Where they run
h23 crank
h23 rods
h22a type s pistons.

they say to run a thicker head gasket for clearance. because its real close.
those are my intentions but with forged rods and pistons. and spray. what ever the final specs are for the non forged build is what im trying to put together. but with forged internals. maybe i need to just stare at the numbers longer. and it will come to me. ive arleady found my h beams. i just need a forged piston with the specs of the type s pistons. and i havnt even begun with the head yet.. wont be stock.... lol

and if i try todo the h22 forged piston there is not option for the stroke and length im running. only the normal h22 stroke and length.

GhostAccord

That would get you right in the 12:1 range. The stock piston is in the hole 0.152mm and with your set up it will be out of the hole 0.508mm. That is a 0.660mm difference from stock. so a head gasket that is +0.5mm will be more than safe. However adding that 0.5mm thickness to the head gasket will drop your compression to approx. 11.4:1.

I am currently building a similar engine build, however, I went with all forged internals.

Mark Chappell's 2.4L 96 GhostAccord ITB Induction Build: Engine + Drivetrain

F22 block with Darton M.I.D sleeves
95mm Stroke - F22/H23 Crank
89mm Bore - Forged Wiseco pistons, w/0.6cc dome and 29.08 comp height
12:1 CR with stock head gasket.

myaccord1993

with all that being said, do i order h23 pistons with my h23 rods and crank or do i order h22 pistons? when i try to order h22's they do not sell them with my size rods and stroke. and am i able to make the clearance else where? with out giving up compression? maybe with a different type of piston style? and ive already looked at your build im very impressed all tho it dosnt mean much.
my idea was

h23 crank
h23 h beam forged.
and there Arias Forged Pistons H22 H22A H22A1 11:1

Also my sleeves came in today.. very happy! darton 300-018


and what math did you do to figure out the stock pistons sits in the hole 0.152mm

GhostAccord

Have you talked to anyone at Arias to see if they have a stoker piston that you can buy?

I deal with the boys at Race Engineering and they always set me up with what I need. My custom 89mm slipper skirt Wiseco's were $500 shipped. Not a bad price to pay for a piston that doesn't require thicker head gaskets or modification of any other part to reach your target compression ratio.

If you want to stick with ordering OEM spec pistons online without talking to anyone about what you are trying to achieve. You simply put in your rod and stroke numbers as H22 specs.

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That deck clearance of 0.006 (0.152mm) is for a stock H22 with stock internals.

Here is how to calculate piston to deck clearance, in this equation an answer of 0 = piston shoulder is level with the blocks deck surface. A (-) number indicated that the piston rises above the cylinder hole. While a (+) number has the piston sitting below the deck surface.

Divide Stroke by 2, then add rod length and piston compression height. Then subtract that number from the engines deck height.

Here is an example of your H22 block H23 crank and rods w/H22 Type S pistons

H23 Crank = 95mm stroke
H23 Rod = 141.50mm
H22 Type S compression height = 31.00
H22 block deck height = 219.50mm (Stock or New Part) if your block has been decked or planed this number will change.

95 / 2 + 141.5 + 31 = 220.00mm
219.50 - 220.00mm = - 0.5mm

If you want to calculate how to order a custom piston with a stock piston to deck clearance of 0.1524mm (0.006"). You can use a similar formula

Divide Stroke by 2, then add rod length and your desired piston to deck clearance, then subtract that number from the engines deck height. I like to maintain Honda's stock piston to deck clearance. It leaves room for heat expansion and rod stretch.

Or if you want the quick and easy way to get some approximate numbers you can use an online calculator - Honda H-Series and F-Series Compression Calculator by ZealAutowerks

myaccord1993

Thank you for the equation. and no i havn't made any phone calls. but it would be nice to find a piston that allows normal thickness in head gasket obviously it is possible i just need to have a talk with these companies and see what they can do. I truly didnt think talking to them would be any help. I figured it would be like talking to the parts guy at the parts store. But you have showed me other wise. so that is my next step. Also as for the equation thank you oh so much... i knew there had to be one....... could not figure it out and wasnt sure what to search... kept showing me people micing the diffrence... i wanted to crunch the numbers to find my clearance. this engine building seems to be a lot of math... i need to go read a damn book. also what is your ETA on the motor build?

GhostAccord

I am currently working on finding a local shop to install my Darton M.I.D sleeves. I don't really want to ship it across the boarder if I don't have to. Once i find a shop then they will tell me the ETA of the machine work, then I can put everything together over a weekend..

myaccord1993

been awhile but quick update. Going a different route. Ive actually been looking threw the forum trying to find a similar build. so everything we talking about for bottom end im going to do... which with a thicker head gasket will but me at about 11.4 else if no clearance issue. 12.1:1. But im going to turbo on e85 and see what happens. my main objective was to try to use as little assistance as possible but i feel like with this setup. the e85 will let me force some more boost into it. now i feel like the car could be near the 500fwhp mark. suggestion? opinions?

myaccord1993

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