I'm in the process of assembling an engine for a customer and his old set-up had scarred cylinder walls so I am running 88mm wiseco's on the new engine.

I noticed after installing one piston that the piston to deck height was extremely high. So I started doing some research and it turns out that wiseco lists the piston "Prelude H23-To be run w/ .030 piston to head minimum (requires .040 gasket at least!). "

I know in the past I tried to find a thicker headgasket for the h23a and nobody manufactured them. I would have tried to had this settled via wiseco but they are currently closed. So have any of you guys ran into this and if so what did you end up doing?

 

Here is your answer:

Wiseco h23a1 88's are the exact same as the h22a's. Since the h23's are the same as the h22's the piston sticks out of the block by .025". This is unacceptable in my opinion.

Therefore you have 3 options:

1) Double stack a head gasket - NOBODY makes a thicker h23a1 headgasket. Period. Cometic will make a copper one custom but will require an o-ringed block for proper sealing. Member 'XES' gave me the stock number for a steel one they made for him years ago but cometic will not and can no longer manufacture these.

2) Remove .020-.025 from the piston and flycut .020-.025 from the valve reliefs. .025" is the threshold for the amount of material you can remove from the valve pockets though.

3) Return the wiseco's and have custom CP's made.


I went with option 3 since I have had CP's custom make me them before in the past.

Wiseco h22a 88mm's will work fine with an h22a engine, but DO NOT run the wiseco h23a 88mm's otherwise you'll run into the same issue I am. Wiseco did not properly design the h23a's. They are simply h22's marked as h23's.

 

could've just hit it with some sandpaper

so are the valve reliefs even different on the h23 and h22 wieseo slugs? or are they the same exact size. i am assumign an h23 has smaller valves, nto sure, cuz i never opened one up.

 

The wiseco h23 piston IS a h22a piston. There is no difference whatsoever. Period.

 

interesting......

thanks for the info

 

About the only "fix" I see is going w/ a H22 crank..

 

Thats how Arias does it as well.

Is the H22 gasket that much different? I havent messed with the h23 in a long time.

 

you might wanna tell brian nutter @wiseco to change the shelf h23 piston and reduce the compression height by 0.025" and tell him about this post would be good.

also my intent here is not oo peddle parts, but sometime ago, cometic made some 0.078" thick gaskets for both the closed deck h22a h22a1 and the open deck h22a/h222a4,5,7 so on so forth..........no longer made.
these were made to lower the compression by 1.0 point from 10.0:1 to 9:1 or 10.6:1 to 9.6:1
i know it's thicker than you need.
I do so happen to have a limited number of these gaskets available. 87 and 88mm


hope this helps

 

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also my intent here is not oo peddle parts, but sometime ago, cometic made some 0.078" thick gaskets for both the closed deck h22a h22a1 and the open deck h22a/h222a4,5,7 so on so forth..........no longer made.
these were made to lower the compression by 1.0 point from 10.0:1 to 9:1 or 10.6:1 to 9.6:1
i know it's thicker than you need.
I do so happen to have a limited number of these gaskets available. 87 and 88mm


H22's wont work with the h23's unfortunately.

hope this helps
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