I have a b18c-r block with the stock p73 pistons.I'm building a hich compression motor and I'm using my ported b16a2 head from my previous build,only problem is it's been skimmed about 0.040".I'm running Brian crower stage 3 cams with 12.6mm lift.Now If i use an oem headgasket this will give me the desired compression of 12.5:1,but with that skim,there's no way the valves will clear the pistons...Only option is to get a thicker headgasket.Cometic sell a 0.050 headgasket,with which I think my piston to valve clearance will be okay.But the compression is going to drop down significantly.I thought about using the PCT piston,but then the compression goes over 13:1.What are my options here? Maybe some b16a pistons,with flat faced valves or a 11.5:1 aftermarket pistons ? I don't want to ditch my ported head,but I also don't want to spend 600 $ on a set of pistons,I'm trying to keep it a budget build.Also I can't really test things out,becouse I'm not from the usa,and the parts mentioned cannot be bought here,so I'll have to buy them from the US,import them and hope to get it all right the first try.
To sum things up I want a 12.5:1 compression ratio,without the possibilliy of piston to valve damage.
The stock engine has 11.1:1 comp ratio.I tried using the zeal compression calculator,but I couldn't figure out a solution.

 

ive build an b18c6 with pctx pistons. with oem 3layer gasket and not resurcaed head. 12.8:1..with skunk2 pro 2 camshaft and skunk2 alpha springs. pulls 241 hp and 202whp runs very fine

 

So basicly a stock b18c6 (which has the same compression as the b18c-r) + some PCT pistons with stock headgasket,bumped the comp from 11.1 to 12.8,which is around what I'm looking for.But will be close to 13:1 with my skimmed head.I was wondering,can I get the pistons mashined to make the dome a little smaller ?

 

I would get a set of 12.5-13:1 wisecos w/ a flatter dome.

 

But If I get a 12.5 pistons and I use the 0.050 cometic headgasket I'll still have over 13:1 compression ?

 

Not with a GSR crank and rods

Check this part number....

K593M81AP

 

I'm using my stock b18c-R crank and rods,I'm not changing them for a GSR...
B18C

std.
3.433 inch
5.433 inch
1.185 inch
41.5
8.25cc
12.5-13.2:1
.827 inch
This is what comes up when I check the part number.
What If I stay with the p73 pistons and leave the head as is and put a 0.029 headgasket.This will give me the desired compression,only question is will there be a p2v clearance problem ?

 

GSR and B18C-R are the same crank and rods.......... -_-

 

Same stroke and lengh,yes.I'm sorry I was a bit confusing.I ment I already have the same stroke and lenght cam and rods.But still the compression is way too high.

 

I'm not following you.

You say you want 12.5:1 compression right? These pistons will give you that w/ a STOCK HG. If you use a .050 gasket the compression will be LOWER. Where am I mis-communicating my point?

 

Did you read the thread ? My head is skimmed 0.040.That + 12.5 pistons + stock head gasket = 13+++ compression.So I need 12.5:1 and my 0.040 head skim gets me there,but I'm not too sure about the p2v clearance.My question is- is it okay to leave it like that or is it best to get a high comp piston with a 0.050 headgasket.

 

I must not have comprehended this properly. Now I see where you are coming from. I apparently can't read early in the AM. My apologies.

If it were me, I would put it together and clay the motor as is to see if the P2V is ok. I would only run the thicker HG if it were necessary. That is my .02. I like to have hard proof it is safe and not guess. Plus I don't like band-aid fixes (thicker HG) unless it is a last resort.

 

buy an another head. or use a thicker headgasket + flat valves