Competition valve job?

[Eccool]

Please pardon me for asking such a rookie question, but what exactly is a competition valve job?  I know what porting & polishing is, but I see some porters have competition valve jobs listed on their site for quite a bit less money.  Does a comp valve job improve flow (and if so, by how much?)  Or is the advantage simply that you are replacing stock valves, guides, etc with premium aftermarket parts?  I've heard the term "competition valve job" forever but don't know what it it.

[Don D]

It's a funny term, similar to what we used to call "3/4 race cam". The factory uses 3 angles on seats and some are even radiused. So the factory is doing a "competition" valve job then right??
Well many porters including myself go to great lengths and choose seat and valve profiles with multiple angles and \ or radius angles to get the best flow possible and other features. Plus all valves and seats are ground concentric.

I typically see seats on factory heads that are up to .006 out. They actually do no valve job, the seats and guides are CNC ground and installed into the CNC machined head and are suprisingly pretty square with proper stack heights, all things cosidered, well if .006 seat runout OK.

[aharp]

According to some on here Don all we're doing is rebuilding back to stock specs 

[hrdtail78]

I think it's a buzz word that sounds good for marketing.  To get what it actually intales you would have to call the guy using it and ask them.

http://www.allbookstores.com/Build-Modify-Chevrolet-Small-Block/9780879385477

This is a pretty decent book that shows a step by step cut on the seats and back cutting valves.  He flows between each step and shows the benefit of each step that is performed.  There are different ways the skin this cat, and I have no input into which one is the best.

[prodrag1320]

a competition valve job is a valve job that will perform better than stock,seats matched to ports,narrowed (.040 45 degree)& raduised cut seats.some guys will use different cutters to get as many angles below the seat as possible,while other use one piece cutters to cut the seat & radiuses in one step(we use a SEDRI 100 seat & guide machine)you can see in the pics how the seats do not match the ports,a competition valve job will fix the proplem.in our case anyway,it is not a "marketing buzz word" at all,and im sure not with the rest of reputable porters either
http://s125.photobucket.com/albums/p79/veetwin1/100_6012.jpg
http://s125.photobucket.com/albums/p79/veetwin1/100_6088.jpg
http://s125.photobucket.com/albums/p79/veetwin1/100_6089.jpg
http://s125.photobucket.com/albums/p79/veetwin1/100_6090.jpg
http://s125.photobucket.com/albums/p79/veetwin1/000_0005.jpg

[mayor]

Kirby, if you use the IMG code the picture will be posted in your post:


you can use the quote button to see what the IMG code for this picture is, but you should be able to see it listed in your photobucket account for each picture as well. 

[02roadcling]

The 3 spoke steering wheel looks cool. Reminds me of driving old farm machinery, lol.

[prodrag1320]

thinking about getting a chrome,deep dish chain st. wheel!!

[Don D]

Well Kirby we are on the same page, my point is there are valve jobs then there are some that even though they have multiple angles (yes they market using the term "competition") they may not be any better than stock and some cases worse.
Tell them about cutting seats with Neways

[sbcharlie]

we use a NEWEN machine to cut valve seat profiles. these are a CNC machine where you can program any angle or raduis you desire. go to NEWEN.com to see one run. all of the Nascar and top cylinder head shops use these machines. i see talk about air flow. according to most on this forum it really not a factor. the safety porter from AZ. short block charlie

[ultraswede]

To me "competition" anything raises a warning flag.

Do I want competition reliability or life span for a street bike...NO.

I understand what you head guys are saying, all good stuff with no down side,
but the word "competition" to me is a poor marketing word for street use stuff.

[Tsani]

True, but it is like saying "Chrome!" to some!

[ultraswede]

but it is like saying "Chrome!" to some!

So very true...

[prodrag1320]

To me "competition" anything raises a warning flag.

Do I want competition reliability or life span for a street bike...NO.

I understand what you head guys are saying, all good stuff with no down side,
but the word "competition" to me is a poor marketing word for street use stuff.

stock valve jobs are not very concentric,so just by that(even though theres many differences) makes our,and most other,"competition" valves jobs much better & more reliable than stock

[ultraswede]

stock valve jobs are not very concentric,so just by that(even though theres many differences) makes our,and most other,"competition" valves jobs much better & more reliable than stock

I have no doubt, not at all!

On the other hand, I would NOT like to have the cyl heads of off this bike on my touring bike. 

To me THIS is racing.....nothing you'd want on a bagger going on a long trip.

Source; http://www.veetwinperformance.com/gallerymenu.php

[prodrag1320]

sheeeet!! would do you mean,we put about 8 miles a year on it,whats YOUR idea on "hi milage!!LOL

[billbuilds]

     Well let's see... We have two very reputable head porters stating that their version of a competition valve job is an enhancement to the stock heads. I don't know about you, Ultraswede, but I'm not planning on drag racing my 99 RK.  If these guys  can get a little more air to move by using slightly bigger valves and re-radiousing the seats and yet still retain the necessary velocity to make my little mouse cam perform well then I'm all for it.  Sounds like money well sent for me.  Bill
     
     

[Don D]

Different parts of the port have higher opportunity for flow enhancement and resulting performance / torque gain. The valve seat happens to be the highest IMO. Call it whatever you want Competition, Street XXXX, Stage XYZ or whatever...
I just call it properly seating the valves and I have see a minimum of 5% gain in flow without touching a grinder, plus the added benefit of 100% seal and no side thrust on valves that hit seats with runout. Use whatever machine works for ya steering wheel or not. Just get it done right and be sure the guides are properly sized and fit to the valves.

[Admiral Akbar]

If these guys  can get a little more air to move by using slightly bigger valves and re-radiousing the seats and yet still retain the necessary velocity to make my little mouse cam perform well then I'm all for it.

fixed

Not picking on anyone, but it's to see numbers, even if they are only sampled..

Max