h23 piston problem - Honda Prelude Forum

tenzola · 10-03-2003, 10:41 PM

boring of the engine...

h23

i know i need to bore the engine out something like .10 or .20 over.. (due to very deep scratches on the cylinder walls) i have not measured the bore yet and don't knwo the extent of the taper... what i need to know is.. are there any pistons that are a lil bigger then stock "b" pistons in the h23 from honda... i don't want anything high performance .. just want to rebuild back to stock specs

thank you for any input... i'll get measurments by monday or tuesday

=)

Satan_SRV · 10-03-2003, 11:55 PM

I have H22A4 pistons that are 87.25mm overbore USDM. Standard overbore for honda is .25mm like .010" You can't go beyond 87.25 or you're out of FRM material to use.

You could use those and conveniently an H22a piston in an H23 wil give you 11:1 compression

Yes you can use them on H23 rods you just need the rods to be rebushed for floating wristpins. It's in the for sale forum if you're interested

tenzola · 10-04-2003, 10:19 AM

so the pistons aren't stock right... they oversized pistons meant for a bigger bore then on a stock block

=)

Satan_SRV · 10-04-2003, 10:46 AM

Yes that's right, here's some info

H22A spec:

Cylinder size A 87.010-87.020 Service limit 87.070
Cylinder size B 87.000-87.010 Service limit 87.070

A piston set diameter (no letter): 86-990-87.003
B piston set diameter : 86.980 - 86.993

piston to cylinder clearance in new H22as: .007 - .030 service limit .040

So max clyinder bore after re-hone to retain stock clearance
for a: 87.020 - 87.033
for b: 87.010 - 87.023

so for your 87.01 use a regular size b pistons
for anything 87.25 and over use size A standard pistons

Anyone have a probem with running 11:1 on an H23? I know someone locally doing it, I'd recommend a S-AFC and some dyno time just to make sure the fuel is right.

Preyluder · 10-04-2003, 03:38 PM

Joel nailed it. Use the A pistons on the cylinders you're boring. There's another thread on this subject elsewhere in the forum.

tenzola · 10-05-2003, 05:34 PM

i was told that i need to get all teh cylinders bored in order to keep the power distribution between the cylinders even

wouldn't i want to anyways becuase one cylinder is goign to be at 11:1 and the other 3 at 9.6:1

plus i plan on spraying the engine.. so .. i think it would be best to bored all the cylinders out to the same spec

=)

oh satan... the block is a h23 and so i don't know if it differes that much from the h22 block

so the specs on the h23 may be different then the specs on the h22

Satan_SRV · 10-05-2003, 05:49 PM

H23a and h22a cylinder specs are the same, as they are both FRM 87mm bores, hence the piston compatibility.

tenzola · 10-05-2003, 10:02 PM

i c says the blind man

=)

RacingGasLude · 10-05-2008, 11:39 AM

Quote:

Originally Posted by Satan_SRV

I have H22A4 pistons that are 87.25mm overbore USDM. Standard overbore for honda is .25mm like .010" You can't go beyond 87.25 or you're out of FRM material to use.

You could use those and conveniently an H22a piston in an H23 wil give you 11:1 compression

Yes you can use them on H23 rods you just need the rods to be rebushed for floating wristpins. It's in the for sale forum if you're interested

what happens if you bore over .10 .25 ? what does FRM stand for ?
I was looking at WISECO .40 overbored pistons....

RacingGasLude · 10-05-2008, 11:44 AM

I am looking at Honda Prelude H23 .40 Wiseco Pistons

Bore Size = 88.00 / 3.464
Special Commets : To be Run w/ .030 piston to head minimum (Requires a .040 gasket at least!)
Over Size = .40
Comp. Ratio = 9.0

What do these numbers mean ?
88.00 is the cylinder bore
what is 3.464 the piston height ?

Can i bore out my h23 cylinder walls to accomodating the size difference of 87.00 to 88.00 without jeapordizing the strength of the motor ?