The head on an h22a4, if i have it ported & polished, new valve springs, retainers and cams can't i increase the compression simply by milling the bottom of the head itself ? I believe they call it " milling the deck height". I was also wondering what the stock compression is and how far i could raise it thanks

 

The stock compression is 10.6:1, or maybe 10:1, im not sure for the h22a4....

Yes you can mill the head to raise the compression, but i dont think you can go that that much because you will start having the pistons come too close to the head....

i know someone on here knows exactly how far you can go, but i would say, get some type s pistons and then mill it just a little to get about 11.5:1....

 

exactly what is a type s piston and where would 1 buy 1?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by texx &raquo;</TD></TR><TR><TD CLASS="quote">exactly what is a type s piston and where would 1 buy 1?</TD></TR></TABLE>


It's a Honda Prelude Type S from Japan. and you can find them https://honda-tech.com/zerosearch and here http://www.google.com

 

check out http://www.hmotorsonline.com

they have sets for 200 bucks, which is a very good deal...go under the jdm honda section or something....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by texx &raquo;</TD></TR><TR><TD CLASS="quote">The head on an h22a4, if i have it ported & polished, new valve springs, retainers and cams can't i increase the compression simply by milling the bottom of the head itself ? I believe they call it " milling the deck height". I was also wondering what the stock compression is and how far i could raise it thanks </TD></TR></TABLE>

mmlling the deck height is when you cut some material off the top of the block where the head meets it, milling the head is what you are doing...both do the same thing. its just the surface that you cut is the surfaced that is getting "milled"

 

compression on the h22a4 is 10 to 1

 

You can only mill the head and/or deck the block about .030" IIRC because you will start throwing off the timing of the cams w/ the crank.

Use the higher compression pistons, as mentioned above.

 

Can't he get a different head gasket or oversized valves to increase compression?

 

Taking out the middle layer of the headgasket MAY bump it .5 a point, and the valves my do a little less than that.

Plus pistons may be cheaper than buying all new valves...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">they have sets for 200 bucks, which is a very good deal...go under the jdm honda section or something....</TD></TR></TABLE>
Try $550

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by delLudeVTEC &raquo;</TD></TR><TR><TD CLASS="quote">
Try $550</TD></TR></TABLE>

That's a horrible price or is wrong.

IIRC, they're about $300.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by delLudeVTEC &raquo;</TD></TR><TR><TD CLASS="quote">Try $550</TD></TR></TABLE>

stop smoking crack

10026 - BB6 Prelude TypeS Pistons
JDM Prelude Pistons
$ 200.00 Shipped

 

yall act like crack is so bad!

 

Check https://honda-tech.com/zerothread?id=1126888 for general over view of compression, see bottom of my post for a few good links.

H22a4 specs:
Displacement 2.156 l, 131.601ci

Bore: 3.425", 87.00mm
Stroke 3.571" , 90.7034mm
Rod Length: 5.630", 143.002mm
Compression Height 1.220" 30.988mm
Compression height is the distace from center of wrist pin to the top of the piston (not considering a dish or a domed center, so from the outer ring of the top)
Rod to Stroke ratio 1.58
Valve size 35mm/30mm
Gasket: .028", .7112mm, volume 4.227cc (per cylinder)
Head Volume cc: 53.8cc, 3.2830ci
Deck Clearance .005" .127mm, volume 0.0460cc
Compression displacement 32.892 ci, 539cc per cylinder

A big issue with taking a little off the top of the block and/or a little off the bottom of the head is the valve to piston clearance. These motors have tight clearances anyways and messing with this system could cause the valve to "kiss" the top of the piston at high rpm if this isnt done properly.

Hands down the best way to increase compression is with a set of pistons. That way the valve conserns were already figured out by somone in a possition to know. I mean if you have to take the engine out and break it down anyway why not to it the right way?

Now i dont know how much you could reasonably take off by decking, but say LudeyKrus is right with .030". THat means you'd only be taking out about .75cc per cylinder - hardly 1% of the compressed volume. That would result in even less gain in net compression when you consider that by deckin off 1% of the compressed volume, about .01% also comes off the uncompressed volume as well.

If the head or block matting surfaces aren't perfectly flat then it would be worth having it milled flat while the engine is appart for new pistons, but in dont know if it would be worth decking especially considering the effects on timing as well.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by delLudeVTEC &raquo;</TD></TR><TR><TD CLASS="quote">
Try $550</TD></TR></TABLE>

10025 - BB6 Prelude TypeS Camshafts
Brand new cams!
$ 550.00 Shipped

10026 - BB6 Prelude TypeS Pistons
JDM Prelude Pistons
$ 200.00 Shipped

Try Reading!