the right compression, suggestion please
 

Currently I have a B18c5 USDM. I am about to build it at this moment and ready for the up-coming summer

I've purchased Skunk2 Pro1 + valvetrain + High CP valves + milled head but very little, maybe 0.10 or , 0.20

I might decide not to install those valves because I heard people have/had diffculties to make them to fit properly.

My concern is, should I install JDM B16 pistons or B16B pistons for the right compression to run those cams properly or any other suggestion for this build.

if you're head is milled .020" then your CR is already about 11.4:1.
Why put different pistons in?
With p30s you'll be close to 12:1 which IMO is high enough for a street car. With CTRs your CR will be through the roof and too high for a street car IMO.

What ever you decide to do, make sure to use at least 1 step colder of a spark plug and make sure the tuning is really solid.

From what i hear from friends who have S2P1's you might not like the idle, especially before it fully warms up. But they make nice power through out the rpms.

ok thank you, I've calculated, my CP with B16 JDM should be around 11.8:1, should I guess it should be fine?

and what do you mean make sure to use at least 1 step colder of a spark plug, Im sorry still a Noob.

you'll want a colder spark plug, stock is BKR6E, so you'll want BKR7E (NGK's part number for the BKR7E is #6097)

ok, thanks very much, I will also change some APR rod bolts and bearings as well...anymore suggestion?

make sure to have the big ends of the rods resized after installing the ARP rod bolts.
And if you're buying new pistons, get oversized pistons and bore/hone. I'd go 81.50mm personally.

I won't be taking out the block, so...I don't think I will be bore/hone out.

oh, well i feel sorry for the person who has to do the assembly, b/c plastiguaging bearing clearances with the engine in the car would be almost impossible. And thats a step that i would definately NOT skip.
I'm not saying swapping pistons with the block in the car is impossible, but definately a lot harder than when its out of the car.

Ic, ok, If the block is out, u will definitly bore/hone and install oversize pistons right
how much does it usually cost and how long does it usually take

bore/hone at the machine shop i use is $120. Its usually ready next day.

very nice, can you please give me a hand on that? let me know which shop so I can send the block to them?

its a shop here in hamilton called athenia machine.
I'm pretty sure thats close to the standard rate at most machine shops. I'm sure theres a machine shop closer to you (i'm assuming you're in the GTA), Gord Bush comes to mind, give him a call and see what his bore/hone rate is.

120 bore/hone is a good price. GB quoted me 250 - bore/hone and decking.

GB is definitely one of your choice when it comes to machine work.

$120 for a bore and hone? wow...we used to charge $200 for a bore and fit, extra for a pro finish. do they bore off the mains or off the oil pan? thats damn cheap.

they bore off the mains torqued down.

I figure i've found a jem of a machine shop, and its local, like 10 minutes from my house....he's got great prices, fast and reliable work. I've been using him over gord bush for a while now, i almost crapped myself when he told me how much it'd be to balance the rotating assembly.
Only thing he's missing is a flow bench.....hurry up and get urs done steve...lol.

ya that is in the near future...

the big primaries of the P1 will bleed off a bit of that calculated compression. i honestly believe a smaller cam is better for 1.8L. actually, 90% of the cams we've used over the last 2-3 years are all too big. i've recently divorced my P1's for Jun3. i personally prefer Blox B's, Crower stg2, Jun3 & BC4. and even then, those are probably all too big for a 1.8, but, they are my personal favourites. all of the cams (with the exception of the Crower) need 12.5/1 c.r for optimum performance. lastly PCT's are the worst piston in the Honda line up.

did you put the Jun3's in yet?
How does it feel compared to the S2P1's?

I agree about the CTR pistons, i'd never personally use them in an engine i build.

not, yet. but, i can tell you this, the Jun3 power from 6-9K with the right compression and set up is very, very hard to beat. especially in a 1.8. BC4, is essentially an improved version of the Jun3's...but, i have yet to see a cam lose very small amounts of hp from 8-9K like the Jun's. but to be honesst, i'm only changing because i've always wanted Jun3's and P1's are overratted in my opinion. its a very good profile, that maintains a Kansas flat torque curve from 3-8K, but, its idling characteristics suck ****. its not a tuner/driver friendly cam. i converted from non vtec for the simple fact that back in 95' my Gude ls cam was choppy as hell. well, these cams (P1's) brought back those terrible memories. they make power, but they are not for me. lastly, as of late, companies are just making big ass cams. P1's are basically a stg3-4 cam, P2's 5, P3's 6. for a 1.8L the original S1 & S2 profiles are excellent. but, everybody wants the new ****, you know. kinda like the mistake i made with my last cam choice. now i have Brian Crower 2's and Jun3's. i'm at a cross roads, because i know the Crowers are underratted..... and, i'm not even touching on my recent F.I addiction. its true man...decisions, decisions