BigC-ivic

can someone explain this like I am an idiot.

if you get larger valves, what exactly does that mean?

Does the head have to be PP'd to fit larger valves or what?

any info is helpful....

Fook_me_honda

Larger valves is just larger valves, if you know wat a valve is? its the holes in yur head (no not yur real head, yur honda head) that open and close to let air in and CO2 out, porting and polishing lets in air smoother, and i think by milling the head (if people actually do that to honda heads) u can get a greater amount of air inside yur cylinders increasing air volume.

Kendall

Larger valves means that the actual valve relief is slightly bored out and new valve reliefs are formed so that more air is allowed into the combustion chamber.

blah13

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kendall &raquo;</TD></TR><TR><TD CLASS="quote">Larger valves means that the actual valve relief is slightly bored out and new valve reliefs are formed so that more air is allowed into the combustion chamber.</TD></TR></TABLE>

Not only does it allow more air in but the motor also breathes a little easier too, however on lower rpms your velocity may be less but were talking so marginal that you wont notice but its nice to know.

BigC-ivic

these are valves, right



and then those valves fit into the holes in your head

so I'm still not sure what a larger valve is? Is it longer?
Cuz if it was wider (atthe bottom) then wouldn't the holes in the head need to be larger?

Here's a little diagram just for kicks

BigC-ivic

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kendall &raquo;</TD></TR><TR><TD CLASS="quote">Larger valves means that the actual valve relief is slightly bored out and new valve reliefs are formed so that more air is allowed into the combustion chamber.</TD></TR></TABLE>

to be obnoxious, what is the "valve relief"?

PrettyLude

vavle reliefs are the indentions on the pistons

kur0ryu

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Fook_me_honda &raquo;</TD></TR><TR><TD CLASS="quote">... and i think by milling the head (if people actually do that to honda heads) u can get a greater amount of air inside yur cylinders increasing air volume.</TD></TR></TABLE>

Milling does not allow a greater amount of air, it decreases the volume of the cylinder. It will increase compression ratio though.

kur0ryu

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BigC-ivic &raquo;</TD></TR><TR><TD CLASS="quote">these are valves, right

and then those valves fit into the holes in your head

so I'm still not sure what a larger valve is? Is it longer?
Cuz if it was wider (atthe bottom) then wouldn't the holes in the head need to be larger?
</TD></TR></TABLE>

Larger valves mean they're wider at the bottom, so yes, the valve ports would need to be widened as well.

Wes V

Think of valves as the "doors" that open and allow the engine to suck in air. If the door is larger, then it's easier to suck in more air.

A larger" valve is has a larger diameter at the head.

Where this comes in contact with the head, the head has to be opened up to match. On an almost all heads, this is a circular hardened steel insert called a seat. If the valves are significantly larger, then a larger seat needs to be installed.

One thing has to be known about how engines work! As the pistons go downward (during an "intake" stroke), a low pressure area is formed and it sucks in air. At no time during this phase of a four stroke engine is the pressure within the cylinder the same as what is in the intake manifold. The air just can't be sucked in past the valve that fast.

That's what turbos and superchargers are all about. They "force" the air into the compression chamber.

Wes

BigC-ivic

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Wes V &raquo;</TD></TR><TR><TD CLASS="quote">Think of valves as the "doors" that open and allow the engine to suck in air. If the door is larger, then it's easier to suck in more air.

A larger" valve is has a larger diameter at the head.

Where this comes in contact with the head, the head has to be opened up to match. On an almost all heads, this is a circular hardened steel insert called a seat. If the valves are significantly larger, then a larger seat needs to be installed.

One thing has to be known about how engines work! As the pistons go downward (during an "intake" stroke), a low pressure area is formed and it sucks in air. At no time during this phase of a four stroke engine is the pressure within the cylinder the same as what is in the intake manifold. The air just can't be sucked in past the valve that fast.

That's what turbos and superchargers are all about. They "force" the air into the compression chamber.

Wes </TD></TR></TABLE>

thanks Wes

So you can't have larger valves without larger holes in the head

So in reality, its not really that people want larger valves, they want the larger holes, to flow more air, and just NEED the larger valves to ensure proper opening and closing

blah13

You catch on quick grasshopper, you'll learn a lot here.