sorry if this is a repost... We are doing the b18c swap into 99 civic si. My friend got the b18c head already, and we were told that the USD GSR, and the JDM GSR have basically the same block. I wanted to verify this. was wondering if theres any difference on pistons, crank, walls, etc... any help is great!

 

no CKF on the oil pump of the JDM GSR...also, something makes for a higher static compression ratio (us vs. jdm), so either the combustion chamber is different or the pistons are different. i'm not entirely sure because i'm new to dohc but i just put a b18c into my 97 hatch.

 

The get the compresison bump from a very slight difference in the piston.

 

Pistons are not part of the block, blocks are exactly the same.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slomofo &raquo;</TD></TR><TR><TD CLASS="quote">Pistons are not part of the block, blocks are exactly the same. </TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hndacord02 &raquo;</TD></TR><TR><TD CLASS="quote"> I wanted to verify this. was wondering if theres any difference on pistons, crank, walls, etc... any help is great! </TD></TR></TABLE>

 

so we would see slightly better gains and performance with jdm gsr bottom as opposed to the us?.... how about if we took the us block and put the jdm pistons in? would that work then?

 

You take the pistons and switch them but honestly thats allot of work for not a whole lot. If you want more compresison out of the motor then I would leave the bottom end alone and do headwork. You can raise the compression by replacing the headgasket with a thinner one along with some flat valves and you would raise a USDM GSR motor to around 10.6-1 which is fine on a street car.

If you were going to replace the pistons then i would either use P30 from a B16 of JDM ITR pistons.

 

so id be fine with the jdm head, and us bottom? my friend plans on doing cams and the valvetrain to as well. Would you suggest putting in higher compression aftermarket pistons or no? thanks for the help guys!

 

Or since I hydrolocked my db8 today and may have to use my other block as a replacement.

You can buy my P30 pistons/wristpins. They are brand new I got them from HMO.

PM me if interested and we can take this off the board.

Tech wise I would not rely on a headgasket to boost compression. Flat faced valves are maybe .3 to .4 of a bump and a headgasket maybe another .2 or so.

even ITR blocks are 11.0:1 or better. P30's in a straight gsr would give you roughly 11.2 or 11.3 maybe.

 

yea, that would be good, how about if we take the pistons out of the b16a2 that comes with the car? there we go! anybody got a gsr block forsale?