boostdeliquent

Has anyone done a H23 build where they used Crower Stage 3 Cams, Type S pistons, and 1mm oversized valves w/ a Cometic .030 head gasket? If so did you have any problems w/ the piston to valve clearance? I know there is a difference in the compression height of 0.019 between H22 and H23 pistons but claying is unreliable at best and I'd like to get a clear answer before I proceed. Not to mention I can't find numbers for the compression height of Type S pistons.

my9thtry

wheres pirate

PirateMcFred

You can have issues with the stock exhaust valves when retarding the exhaust cam. The valve reliefs don't line up on the exhaust side real well. Otherwise you have a LOT of room on the intake side. At 0,0 you will be fine though.

You might have more to be concerned about with the pistons and head meeting. The Type-S compression height is the same as the other H22s. They will stick out a significant amount in the H23 application. This is not a problem with an h22 head since the combustion chambers are recessed around the periphery a good amount but the H23's combustion chambers seem pretty flush sort of like the P72 head versus the PR3 but not as much or as clean. The solution to this is to cut the chamber out a little to allow for clearance or to run a thicker headgasket. It's not that much of a concern but a healthy dose of paranoia is cheaper than rebuilding an engine. Just use quality tools to measure clearance and adjust the headgasket accordingly.

Also with a H23 and those pistons you'll be over 12.5:1 compression. If you can tune for it then hey great.

Oh and you will probably want to remove the starting air valve in the IM when you install those cams.

Pirate

N.Y.C.E.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boostdeliquent &raquo;</TD></TR><TR><TD CLASS="quote"> I know there is a difference in the compression height of 0.019 between H22 and H23 pistons but claying is unreliable at best and I'd like to get a clear answer before I proceed. </TD></TR></TABLE>
why is claying unreliable

boostdeliquent

Thanks for the info Pirate. Regarding the modification to the combustion chamber, is there an amount you'd recommend I have it machined? Would it be the same as in your F/H hybrid?

As for claying being unreliable, I'm refering to me not trusting my skill level to do it properly and obtain accurate measurments. I'm going to be doing this build myself, under the guidance of a good friend of mine that knows his **** but I'd like to avoid unnecessary variables. I also found a pretty good link on google that covers another method for finding the clearance and fixing it where necessary. What do ya'll think of this?

http://www.fordmuscle.com/fund...shtml

Thanks everyone for the info so far. I have alot of the parts bought already and will post it up once I am done.


Modified by boostdeliquent at 1:34 AM 2/2/2007

boostdeliquent

Pirate, one more thing, do you think the 1mm oversized valves will be that big of a deal or will I need to grind out the valve reliefs a bit for it to fit?


Modified by boostdeliquent at 1:35 AM 2/2/2007

PirateMcFred

Okay. Again this is back to the paranoia thing. With the stock headgasket I am sure that the pistons will have no clearance issues at idle. But at 7000+ rpm things stretch and can cause contact as the clearance is taken up. You want .030"-.040" minimum clearance between the head and piston. Here's what I would do.

Build the shortblock.

Take your bare H23 head and install it on the block without the headgasket. Just snug the headbolts you won't need to torque them. You're going to just get a feel for what comes into contact with what. Removing the head gasket is like milling the head .026" and it effectively tightens the clearances between the piston and the combustion chamber.

Carefully turn the crank over until a piston is around TDC. If there's contact between the piston and head then take it apart. Take the rivets out of your old headgasket to expose the 3 separate layers.

Install one layer at a time and repeat the procedure to see if there's piston to head contact. When there's no more contact issues measure how thick the gasket material was. If it took all three layers, and it shouldn't BTW, then that is .026". The layers are not all the same thickness so beg, borrow or steal a micrometer to take the measurements. That measurement is the amount of "interference" that there is. Subtract that measurement from the headgasket thickness you will be using for final assembly. If there's .010" "interference" then you need a .040" headgasket to achieve your .030" minimum clearance. Understand?

Custom thickness headgaskets are easier to use than hogging out the combustion chamber like I did. I chopped the chambers on my builds since there's not a lot of custom thickness F23 HGs out there. You should have no problems with H22/23 headgaskets. If you have to go super thick on the HG then be sure to adjust your cam timing to get it back to 0,0.

As far as "How To" claying articles this one is Honda specific and is "prettier" FWIW.
http://www.c-speedracing.com/h...y.php

The H23 chamber is not symetrical like the H22's. The exhaust valves do not line up with the H22 relief pockets. If you break a timing belt you will have some nice big dings in the middle of the EX side quench pad of the H22 piston. You should have no issues with the intake side unless you go nuts on the Intake cam advance. Just be careful and test cam timing settings that you will never use like +10˚, -10˚ on your gears. If you do your clearance tests without the headgasket then when you complete your final assembly then you have that extra HG thickness as insurance.

Pirate

boostdeliquent

Excellent. Thanks for the info and taking time to write it all out. That helped clarify alot. All that is left now is to wait for the parts to arrive and begine my build. This should be fun considering I'm swapping this into a 88 CRX HF.