Engine:B16A1
What are the advantages in going 1mm over for the valves, is it worth the investment?

I'm wanting to push 15+ PSI, I'll also be redoing the entire top & bottom end, sleves etc.
(Will post questions for advice later on that)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by WVTURBOCRX &raquo;</TD></TR><TR><TD CLASS="quote">Engine:B16A1
What are the advantages in going 1mm over for the valves, is it worth the investment?
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More air in and out of your motor..

According to Earl(This guy knows his ****) A 0.5mm oversized valve is good for about 10 cfm more flow over the stock size when everything else remains equal.

 

1mm larger on both sides will PROBABLY not have enough clicking clearance with just about any cam. itd be especially dangerous with a slipping cam gear or belt

 

So it sounds like a .5mm over would be better and safer. I have not seen many reviews on what would be the best and worst. Now that does mean going .5mm over on all 16 correct?
Did mike mean that you can just do 1mm only on one side. The bore will be on a CNC machine.

 

i think if you dont have a flowbench, and your combo isnt some very big bore or even worse, ultra stroke monster, that youre best sticking to stock sizes or .5 over on one side. maybe 1mm and .5 will clear.. i dunno. oversized valves is often a great way to make a great head not so great.

 

Over size valves are not a good ideal on most b series motors. Unless you have a beast of a motor. The "additional" flow is off-set by altering the combustion chamber geomtry.

 

Also, the stock 33mm intake and 28mm exhaust valves are VERY generously sized for a 1.6 liter motor.