Well me and cedric at modern prefornace are about to do a sick ass port and polish to this b16 head i have and my question is what is the best size valves? i know they make stainless .5mm and 1mm over size but how does the +1mm sit in the vavle seat? It looks like it will be ok but i want to make sure before buying valves and all that shit.I also am wondering if anyone had clearence issues with the valves in the combustion chambers.I know we can work it out no matter what but i would like to know what i am getting into before starting it all.. I am not going turbo or anything but i will have one of the sickest all motor sprayed b series around by next year so be on the look out..I am looking to go all motor FORGED/sleeved b18c with S2 stage 2 cams or maybe even some jun's. I am just trying to get some input...any info helps..Please do not reply unless you know what you are talking about..thanks guys..

 

I talked to Cedric at modern performance on the phone, and asked him about the oversized valves, he told me not to do it?? Im sure if you asked him, he would know what to tell you...Good luck on your build. Im gonna have my fully built NA D-series on the street soon, all work done by modern performance also..

 

ya,i had a long talk with him in person the other day when i picked up a block.He said the valves will make a huge differance sence we are opening up the chambers so much.We just want to make sure the valve seat will be ok.We kinda mic'd it some and they look fine but you know how it goes when you are actually getting into it. CEDRIC is the man..he has done tons of motors for me and they always turn out GREAT ! One of the best machine guys around if you ask me..He has never built a motor for me but the machine work is always the best ..

 

Anyone seen the new ferrea Super flow valves? they reduced the stem size some to move more air but dam they are like twice the cost..I doubt its worth it..

 

one BIG thing to check with ove sized valves is contact with eachother like useing them with a larger lift cam can be bad,and not timed perfect can be bad..when i go bigger i only use larger exhust valves and only have the exhust side ported..but that was on my gsr motor other then that i say no use in over sizeing valves

 

I would do the clay test for piston clearance.
As diameter increases, valves get closer to the piston.

I would do a temporary test fitting in a head from the junkyard
to check for interference with valves next to each other.

Unless you open the ports all the way down to the valve seat,
you might not be helping yourself that much for what it costs.
Look around an see if this is sold ready-made by anyone.
If not, then maybe people don't do it; for a reason......-Bob

 

ya,I just want to over sized valves cause i want to go all out race head. I never drive my shit but for fun.i have put 14 miles on this set up i have now in 2 years..We are realy going to open up the chambers alot.1MM is only 40 thousandth of an inch so that would only be 20 on each side of the valve and it looks like i have that much room all day.I just realy want to make sure it does not effect the valve seat. I can not beleave no one on here has done this before.I am going to do some more checking around.Maybe i will just stay stock size valve but stainless..Anyone ever heard of 21-an stainless ?? they say they have a 1650 degree temp ratting..

 

stock size are fine. If you do the oversized, make sure the person doing your head work knows what they are doing. The valve job on a oversized valve will make or break the motor.

 

You can go +.5mm on the stock seat but if you go +1mm you need oversized seats.

 

THATS WHAT I NEEDED TO KNOW !!! Thanks kj your the man..