So I was reading before about flat faced valves and dished valves and im wondering what everyone knows about them,

We know that flat faced valves will bump compression and usually weigh more then a dished valve, but what other effects do they have vs dished valves.

How do the flat faced valves help during combustion?

I've herd that dished valves create a swirl effect?

I would think that the flat face valves would be able to flow a larger amount of air possibly at a larger velocity because of the flat face compared to the dished?

Any legit info post it up

 

What are you plans for your build?

 

I've heard time and time again that the oe dished vlaves outflow the flat faced. Not to mention what you've already pointed out that they are more mass and generally weigh more.

 

On the intake side, in theory, having flat faced exhaust valves will allow more flow

and a member had weighed oem exhaust valves vs supertech flat faced valves and found the weigh difference to be miniscule

 

I don't have any plans for a build I was just thinking about valves today and what the difference would be and figured I'd get everyone's input on them.

Do the flat face valves help dissipate heat better?

 

If you don't plan on doing anything with it than keep it stock

 

There is a lot of speculation on this topic and several threads already. A couple of the theories I have heard is that particularly on the intake side, a dished valve will help flow because it creates a low pressure underneath the valve, helping draw air in around it. There are some interesting theories about using flat faced valves on the exhaust side only as it should be easier for the air to be pushed around it compared to a dished valve. There is also the whole other topic of what is happening during the combustion cycle, not just when air is moving in and out, and I think this is where not very many people (including myself) have a clue what effects valve design might or might not have. Generally I think people go flat-faced when they want the extra compression, otherwise stick with dished. In response to the heat question, I would think that a flat-faced valve would actually hold more heat since there is more material inside and marginally less surface area than a dished valve.

 

the material of a valve has more of an effect on heat than its shape, the difference heat dissipation between a dished and flat face valve of the same material will be miniscule.

People look more into aftermarket guides for heat dissapation (bronze, etc)

It will be a lot easier to give the OP advice if we knew exactly what his intentions with the car are

I would not recommend using valves to up the compression on a build unless your trying to get the most out of a stock block or somethin

 

My Crower flat faced valves actually way less than the stock b16 valves.

OEM b16a
Intake 45g
Exhaust 41g

Crower
Intake 44g
Exhaust 37g

The b16a valves had a little carbon on them so they would probably weigh a little less if cleaned. The Crower valves are new.

 

which material crower valves do you have? I'm not familiar with too many of their products

 

The Crower catalog says stainless steel. Mine are black so I guess the have a coating on them.

 

hey N/A i have all skunk2 pro series valvetrain. im building the head but keeping the block stock (01 jdm b18cr) so i got the stock size hi comp valves but i was wondering if i should get bronze valve guides or stick with stock?



sorry dnt mean to thread jack but i think this info can be useful aswell...thanks

 

Are the valves you have nitride coated? What do you do with the car?(daily,weekend/seasonal racing)

 

im not doing anything to my motor im just trying to gather information that I otherwise wouldn't know on my own. And I had read about the lower pressure theory with the dished valves on the intake.

Open to any other theory's or facts..

 

yes they are...car is a weekend/"track" car

 

If the car is only a weekend track car id say try out the brass guides.
The only concern with them is wear so if its not id daily id say try them out.
Brass guides are a good way to dissipate heat