ok well i know that the usdm itr has a 10.6:1 compression and the jdm has 11:1...why is this if i could ask? i am getting ready to rebuild my b18c5 and trying to pick certain routes to go? the head gasket is different i believe is that the possible difference or is it the actual pistons? the p73's are the 11.1 cr pistons and if i went with the .25 overbore p73's what else needs to be done besides a hone? thats a factory overbore right? oh and for your info the bottom end is getting rebuilt because of bad piston ring so a hone will be done anyway. and clearance should be fine on the head with new jdm pistons right? any ways thanks in advance for you help/answers/suggestions.

 

The actual pistons are different. Yes, the clearance should be totally fine with the head...and I'm 99.99% sure that a USDM B18C5 headgasket is the same as a JDM B18C-R headgasket. (I could be wrong, I've just never heard mention of it being different.)
The JDM motors in general tend to run higher compression than their USDM counterparts. B16's and GSR motors are the same way. More power/different emissions regulations/different fuel available I really don't know why to be honest. I'll leave that to the more knowledgeable. Good luck!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AltimaXX &raquo;</TD></TR><TR><TD CLASS="quote">The actual pistons are different. Yes, the clearance should be totally fine with the head...and I'm 99.99% sure that a USDM B18C5 headgasket is the same as a JDM B18C-R headgasket. (I could be wrong, I've just never heard mention of it being different.)
The JDM motors in general tend to run higher compression than their USDM counterparts. B16's and GSR motors are the same way. More power/different emissions regulations/different fuel available I really don't know why to be honest. I'll leave that to the more knowledgeable. Good luck!</TD></TR></TABLE>

well i am sure that the jdm p73's are going to be the route i am going i will post pics when i start this project in two weeks when i get back from vegas&lt; hell yeah maybe i will win some money and change the whole set up and go turbo ha anyways yeah i cant find a difference in the gasket just wondering cause i thought the jdm might be a 2 layer and the usdm 3 but anyways

 

definitely get the jdm ITR overbore pistons since you're going to be tearing into the block anyhow... and of course get the appropriate rings. stick with OEM pistons or ones that are reputable. RS Machine pistons seem to have a good reputation. if not the jdm ITR pistons, the P30 (JDM B16) pistons provide even a slightly greater bump

 

so the SIR p30's with the .25 overbore going to be my best setup then??? what rings are recomended if not the oem ones that come with it? with the p30's the cr should be somewhere around 11.3:1 - 11.4:1 right and still would not have a clearance problem??? and what is the difference between the PCT's (Civic Type R) pistons and the P30"s? And to help anyone out here is the current setup


2000 usdm itr motor
Skunk 2 stage 2 cams
spoon cam gears
brain crower valve train
rc 310 injectors
aem ruel rail
B&M fuel pressure regulater
blox type r intake manifold
spoon 70 mm throttle body
j's racing (whale dick) carbon fiber intake
toda racing header
spoon n1 muffler
ctr crank pulley
walbro 255
nkg wires and plugs
buddy club grounding kit
tuned on the s200

oh and stock 10.6:1 bottom end

 

The PCT pistons have a larger dome and higher compression height. In a stock ITR (no mill/no deck/OE 3 layer HG) they'll give you around 12.5-12:6:1 compression.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by iheartmyctr &raquo;</TD></TR><TR><TD CLASS="quote">so the SIR p30's with the .25 overbore going to be my best setup then??? what rings are recomended if not the oem ones that come with it? with the p30's the cr should be somewhere around 11.3:1 - 11.4:1 right and still would not have a clearance problem??? and what is the difference between the PCT's (Civic Type R) pistons and the P30"s? And to help anyone out here is the current setup


2000 usdm itr motor
Skunk 2 stage 2 cams
spoon cam gears
brain crower valve train
rc 310 injectors
aem ruel rail
B&M fuel pressure regulater
blox type r intake manifold
spoon 70 mm throttle body
j's racing (whale dick) carbon fiber intake
toda racing header
spoon n1 muffler
ctr crank pulley
walbro 255
nkg wires and plugs
buddy club grounding kit
tuned on the s200

oh and stock 10.6:1 bottom end</TD></TR></TABLE>

that seems like a good setup to me. good luck finding p30 pistons... that are overbored. standard p30 pistons are hard to come by already. my comment about appropriate rings referred to just getting new rings (OEM would be great) when you change the pistons as opposed to say, reusing rings. your clearance will be fine with the p30s if you can find them. if not, the JDM p73 pistons are great. when i did my rebuild, i just used http://www.zealautowerks.com or whatever to help me calculate compression, etc. personally, i'd steer clear of the PCT pistons as the dome height is really too high for my taste.

 

The reason why was back in the day Japan had higher octane premium than we got here and could bump the compression a few points. And no, honeing is one machining operation, boring is another. Boring is cutting the hole or bore, honing creates a uniform surface in the bore.


Modified by The Dude at 5:35 PM 7/2/2008

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by The Dude &raquo;</TD></TR><TR><TD CLASS="quote">The reason why was back in the day Japan had higher octane premium than we got here and could bump the compression a few points. And no, honeing is one machining operation, boring is another. Boring is cutting the hole or bore, honing creates a uniform surface in the bore.


Modified by The Dude at 5:35 PM 7/2/2008</TD></TR></TABLE>

right but who said anything about boring the motor...everything that was said is keeping stock bore only honeing the stock bore because of bad piston ring and will have the block ripped apart anyway only makes since to do it before installing new ones.... and aslo the new setup will most likely get a stand alone system not sure wich one yet and allready have TWM ITB's for it so cant wait to hear this...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by iheartmyctr &raquo;</TD></TR><TR><TD CLASS="quote"> if i went with the .25 overbore p73's what else needs to be done besides a hone? thats a factory overbore right? oh and for your info the bottom end is getting rebuilt because of bad piston ring so a hone will be done anyway. </TD></TR></TABLE>


YOU DID!


He was just explaining the difference.

 

oh yeah but with only going .25 over doesnt require sleeves correct????

 

Should be fine with .25 over. Thats what i am at.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by iheartmyctr &raquo;</TD></TR><TR><TD CLASS="quote">oh yeah but with only going .25 over doesnt require sleeves correct????</TD></TR></TABLE>

Sleeves, no...

However if your going to .025 OVERBORE, you will need to bore the block to meet those specs. Honing is a process of basically cleaning up the cylinder walls for a better "seal" of the rings. (in cases where there are little to no knicks in the cylinder walls, but this needs to be measured by a machine shop) If your going with STD pistons (stock bore) then you will only need to hone the block. If your going with .025 OVERBORE pistons, then you will need to bore the block.

As for the rings/pistons... I run the P30's in mine, STD bore. I also used OEM B-series rings. No issues thus far.

 

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


YOU DID!


He was just explaining the difference. </TD></TR></TABLE>
LOL! And a for you.

 

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

Sleeves, no...

However if your going to .025 OVERBORE, you will need to bore the block to meet those specs. Honing is a process of basically cleaning up the cylinder walls for a better "seal" of the rings. (in cases where there are little to no knicks in the cylinder walls, but this needs to be measured by a machine shop) If your going with STD pistons (stock bore) then you will only need to hone the block. If your going with .025 OVERBORE pistons, then you will need to bore the block.

As for the rings/pistons... I run the P30's in mine, STD bore. I also used OEM B-series rings. No issues thus far.</TD></TR></TABLE>

well the plan was to take the old ones out and see if the walls are ok then i hone would be done and if they were [freak]ed then a bore will be done......
as for the p30's what is your cr and is it you daily