Rick Solis

Ive seen quite a few people post up incorrect compression ratio guestimates in regards to H23 VTEC motors... The deck clearance between the H22 and H23 is the same but only after you take into consideration that the H23 pistons have a shorter compression height of 1.203 vs the H22 piston at 1.222

When using the H22 (US/JDM/Type S) piston in a H23 blockyou have to factor the fact that the H22 pistons will sit .019 higher in the hole than the H23, so you will have to subtract .019 from the stock H22/23 deck clearance...

Compression is going to be quite a bit higher than what has been previously calculated on this and other boards... Id like to get this all resolved with actual compression numbers instead of far off guestimates...

To calculate each combination I will need...

The cc volume of each dome to calculate the CR's...

I need the cc volume of the H23, H22 US, H22 JDM and Type S pistons

Ill also need the stock deck clearance for the H22 and H23 blocks,,,

Once I have that info Ill clear it up for everyone

fastludeh22

iTrader: (1)

would it be the same as if you used .019 smaller head gasket on h22? that would raise the compression 1 point over what the pistons are rated.

Rick Solis

you could subtract the .019 from the gasket or the deck... either would net the same results when calculating compression

93H22ACX

keep me inform

Rick Solis

Hmmm... This gets more and more interesting as we go...

I just calculated the deck clearance to be .0175 on the H22 and .0113 on the H23 (I could be wrong)

I know the pistons dont raise above the deck, Jeffs sat close to but definitely not above the deck...

does anyone know the deck clearance listed in the helms manual for either of the 2 motors (H22/23)?

Who knows, I could be wrong, everyone could be wrong... but thats what this thread is about... clearing it up for everyone...


Modified by Rick Solis at 5:47 PM 6/16/2004

93H22ACX

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Rick Solis &raquo;</TD></TR><TR><TD CLASS="quote">Hmmm... This gets more and more interesting as we go...

I just calculated the deck clearance to be .0175 on the H22 and .0113 on the H23 (I could be wrong)

I know the pistons dont raise above the deck, Jeffs sat close to but definitely not above the deck...

does anyone know the deck clearance listed in the helms manual for either of the 2 motors (H22/23)?</TD></TR></TABLE>

So the piston to deck is 0.0175?

Rick Solis

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93H22ACX &raquo;</TD></TR><TR><TD CLASS="quote">

So the piston to deck is 0.0175?</TD></TR></TABLE>

Not 100% sure to be honest... Thats just what I came up with by doing a little math... Thats not an actual measurement...

A more precise method would be actually measuring the deck clearance...

What does Helms list the stock deck clearance at?

Wiseco lists it as .015 -.038

Im not sure if thats intirely acurate though

Speedra500

.0175 sounds a little to low to me, I will be claying my motor today, so we'll see what kind of numbers I get

93H22ACX

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Speedra500 &raquo;</TD></TR><TR><TD CLASS="quote">.0175 sounds a little to low to me, I will be claying my motor today, so we'll see what kind of numbers I get</TD></TR></TABLE>

H22 motor? Good let me know what the piston to deck is

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rick solis &raquo;</TD></TR><TR><TD CLASS="quote">Wiseco lists it as .015 -.038

Im not sure if thats intirely acurate though
</TD></TR></TABLE>

thats what they told me too...but its too close to the deck to be right....and i know its less than a 0.003" (didnt have a measuring tool only used a feeler gauge )

Rick Solis

well, find out what you can... Im out for the day... Ill be back later tonight with, hopefully... a little more to add to the topic

93 VTEC

As long as you are using a H22 head, the only compression increase you will see will be the result of the increased stroke of the H23 crank/rods. If you are using stock H22 pistons and a stock H22 head the piston dome and cc volume won't change.

fastludeh22

iTrader: (1)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Rick Solis &raquo;</TD></TR><TR><TD CLASS="quote">you could subtract the .019 from the gasket or the deck... either would net the same results when calculating compression</TD></TR></TABLE>

so wouldnt that mean that usdm h22 pistons in h23vtec would be 11:1.

what are compression test #'s?

LudeyKrus

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fastludeh22 &raquo;</TD></TR><TR><TD CLASS="quote">
what are compression test #'s?</TD></TR></TABLE>

I'll tell ya in about an hour

PirateMcFred

arias Pistons:

h22a1 piston to deck height: 0.005"
h23a1 piston to deck height: 0.005"
H22a1 compression height: 1.200"
h23a1 compression height: 1.200"

http://ariaspistons.com/sportcompact.pdf ~10Mb

page 16.

Rick Solis

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PirateMcFred &raquo;</TD></TR><TR><TD CLASS="quote">arias Pistons:

h22a1 piston to deck height: 0.005"
h23a1 piston to deck height: 0.005"
H22a1 compression height: 1.200"
h23a1 compression height: 1.200"

http://ariaspistons.com/sportcompact.pdf ~10Mb

page 16.</TD></TR></TABLE>


You get different info everywhere you go... lol, gotta love the H series... Nothing is ever easy

Going by Arias' specs and the 8.655 H22 deck height youd be in the hole.015 for the H23 and .045 for the H22

that cant be right???




Modified by Rick Solis at 11:25 PM 6/16/2004

satan_srv

Rick, where did you get this compression height information from? Did you actually measure it or what? For reference my endyn H22a pistons had a 1.218 comp height

edit: also wiseco pistons here are 1.219 https://honda-tech.com/zerothread?id=419227

Rick Solis

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by satan_srv &raquo;</TD></TR><TR><TD CLASS="quote">Rick, where did you get this compression height information from? Did you actually measure it or what? For reference my endyn H22a pistons had a 1.218 comp height

edit: also wiseco pistons here are 1.219 https://honda-tech.com/zerothread?id=419227</TD></TR></TABLE>

No, I didnt personally measure it... A friend of mine did when he built his H23 VTEC motor...

I think maybe Arias had patterned their piston after the H23 piston assuming the 2 (H23 and H22) were the same... Youd have to deck the block a considerable amount to get to the .005 deck thats listed in their catalog

The ENDYN and wiseco pistons are both obvious H22 pistons but as you can see when used in a H23 block they will stick out of the hole a few thou...

Id really like to get a H22 and a H23 piston in my hands to measure them for my damn self... Im also confused as to the actual deck clearances for each of the H blocks with both the H22 and H23 internals


Modified by Rick Solis at 4:51 PM 6/17/2004

satan_srv

yeah and you thought that was weird, let me throw you another wrench.

H22a deck height is 219.52mm = 8.643" not the 8.655 you're using.

I got it straight out of the helms, I finally found it.

I'm beginning to think possibly the H23 block has a different deck height.

Rick Solis

scratch my calculations... according to Crower the H23 rods are 5.580 not 5.570...

blah, Ill have to go and recalc' all the H23 **** ...

Im too tired right now, ill do it later I guess...

Rick Solis

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by satan_srv &raquo;</TD></TR><TR><TD CLASS="quote">yeah and you thought that was weird, let me throw you another wrench.

H22a deck height is 219.52mm = 8.643" not the 8.655 you're using.

I got it straight out of the helms, I finally found it.

I'm beginning to think possibly the H23 block has a different deck height.</TD></TR></TABLE>

Funny, 8.655 is what basicly ever piston manufafturer has listed as deck height for the H22...

lol... yeah, thats what i was trying to tell you from the get go... the Deck height is different and thats why the compression will be a lot higher than what was previously calculated...

still trying to get all the specs together to figure out EXACTLY what compression ratios with various H pistons will be...

93H22ACX

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Rick Solis &raquo;</TD></TR><TR><TD CLASS="quote">

<U>Wiseco pistons:</U>

H22 - 1.780 + 5.630 + 1.219 = 8.629

.026 in the hole
</TD></TR></TABLE>

What is the 1.780 number measuring?

PirateMcFred

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93H22ACX &raquo;</TD></TR><TR><TD CLASS="quote">What is the 1.780 number measuring?</TD></TR></TABLE>

this the stock h22 stroke in inches divided by two. To figure piston to deck height you add the crank offset from the crank bore center line (one half of the stroke), the rod length, and the compression height of the piston and then compare that number to the block deck height and that will tell you about how much it is in or out of the hole.

the Pirate

PirateMcFred

That brings me to another point Rick, you need to carry out the mm to SAE conversion out more significant digits to more accurately calculate PtoD height and subsequently the compression (if you're gonna be a stickler about it).

H22
90.7 mm = 3.5709"
3.5709/2 = 1.7855" not 1.780

use 1.7855 inches for the crank offset. That should account for another .006" PtoD height.

H23
95.0 mm = 3.7402"
3.7402/2 = 1.8701"

HTH the Pirate

PirateMcFred

Also I have h22A1 rods/pistons and H23A1 rods pistons so you can get both stock compression height and rod length measurements. I just don't have the proper tools to measure accurately. I could be convinced to ship them somewhere for measurement as long as I get them back (or some other form of compensation ).

the Pirate

prelittlelude

yes joel is right, the deck height is 8.643 as listed in the helms,

i did a quick look around , and all the info is king of close, but not, its weird, hope we get this figured out.

cp pistons has h22 specs at 1.220 compresion height
wiseco pistons has h22 specs at 1.219 compresion height
je pistons has h22 specs at 1.220 compresion height
je piston has h23 specs at 1.204 compresion height

h22 rods
je list as 5.630
eagle rods 5.630
crower 5.636
pauter 5.636.
Carrillo 5.636
Manley 5.636
Oliver Racing 5.630
Probe Connecting 5.630


h23
je lists as 5.571
Probe Connecting 5.580
crower 5.580
pauter 5.571