Hi Guys i have a B16B head from a ek9 that i am looking to stick on my jdm b16a2 bottom end, now the question i have is how do i up the compression to the 10:8:1 like a B16B runs on from 10:4:1 that the b16a2 runs on think that's the exact compressions

option 1: a thinner head gasket(0.47mm or 0.50mm) would it up it enough and with that would i run the risk of piston and valve touching

option 2: just change the pistons to the B16B pistons but are these not prone to hot spots and will they up the compression to the said above with the head

All help and views appreciated

 

I highly doubt you will have piston valve contact with a thin head gasket, people use thing HG on b16b which have huge dome's in there pistons with no problems.

 

cool thanks blinx

 

Hey wait a minute, i know you

 

That is correct about the CTR pistons and thinner h/g not having valve to piston contact. There's plenty of safe clearances left when running CTR slugs in a B16 w/thinner h/g.

Your best bet in raising compression IS by going with a CTR piston set, and to avoid hot spotting on the CTR pistons, have the piston's sharp edges sanded down.

If you don't want to deal with swapping out pistons you could always mill the head about 35-40 thousandths and raise compression that way. you'll want to run a set of adjustable cam sprockets to possibly correct timing, although I believe 35-40thousandths won't mess with the crank and cam timing offset too much..

 

The last time I got my engine tuned, which was after a rebuild of a B16a2, where I added CTR pistons, milling the head did make a difference. The tuner could immediately tell without me advising the head was milled and the cam gears I am running were used more for correcting timing then for using them as an advantage with timing over-lap. I later went back to the reciept and found it was milled .003. He said he when this is done it appears to be at TDC when engine is assembled, but is slightly off. Hope this helps.