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VALVE JOBS AND FLOW (THE TRUTH)

The past few months I have spent a lot of time flow benching different types of valve jobs on the B16, GSR, LS, D16, K20A2 and S2000 head. This is just the Honda Camp. I have noticed that this is one area that is often taken for granted. The reason being is many racing head shops out there use SERDI or SUNNEN carbide inserts with a typical 30,45, 70 or 30, 45, and a radius. This is the bible to them and use them on everything from a Chevy to a Honda head because they dont know otherwise. On the Honda S2000 head, using these typical angles will result in a loss of flow in the .050-.350 valve lift range. 2-3% to be exact. Ive even tested a 5 angle seat (this is also a no no,) with less than stock flow results through the entire lift range. Angles are very important producing venturi effects essential at certain valve lifts. On Old American Iron Heads or non performance factory heads the 30,45,70 may see gains only because the head is so bad to begin with.

We here at ALANIZ never guess at what we do. On our S2000 inner workings project we have over 25 individual seat and valve angle tests which were performed on a flow bench. It was very difficult to improve the factory valve job. The reason we know this is because we flow tested a Virgin new head with factory seat and valve angles. After all this testing we found something that works. Playing with valve widths made the biggest improvement. We saw about a .5-1% increase in flow at low lifts (.050-.150) and about .5% on high lift numbers (.350-.500). A Honda will see at max about .510 valve lift on after market hot cams so trying to improve flow at .700 valve lift makes no sense. This is Ford and Chevy territory. Valve profiling is very important also. Matching correct seat angles to valve angles will result in a good breathing combination.

Another thing that is overlooked is valve sealing. To make power a head has to flow well but it also has to seal. Valve sealing is something that is over looked quite often. On many brand new "production off the shelf" race heads, I find leaky valve jobs. How do I know??? I simply pour solvent down the ports.If it leaks liquid its going to leak air. Even a dummy knows air is thinner than water and any one who tells you the combustion pressure will seal the valves is someone who you probably shouldnt be dealing with. An off center or just plain bad valve job means your bending or deforming the valve to make it shut. An engine is not designed to function in this manner.

In my honest opinion I feel everything boils down to time and $$$. I dont do $125.00 valve jobs. I know how long things take to do them correctly and I price them accordingly.

After all this said and done.....I hope I have shed some light on this subject and hope it will help you make the right decisions when choosing a company to perform you valve job.

JOE ALANIZ