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The Final Lap - May. 09 Vol. 1

Cylinder Headwork, Valve Jobs, etc...What do I choose??
The Final Lap - May. 2009 Newsletter ver. 1.0

To all of our patrons and supporters,

For this month's "May Newsletter", I will touch on the subject of Cylinder Headwork. Cylinder headwork is a very important step in the modification process of your build. It is the step that goes hand in hand with the new pair of camshafts you just purchased. It also ties into everything else and is needed to complete the recipe...or is it?

How do you know what type of headwork is right for your application? Nice, clean and shiny ports, opened up, valve guides cut down, the works! Bigger is better and it'll flow a lot more volume! Shiny sells as they say. This is what many shops will tell you is necessary for a power gain from headwork. When performing headwork, one thing to remember is that you cannot estimate a horsepower number gain. There are too many variables to take into consideration. For this, we at Inline Four can gaurantee that the cylinder head will "flow" as expected, but you must have the parts to complete the recipe and to achieve the "gain" you are striving for.

Getting a little side-tracked, I wanted to make a quick point in relation to dyno numbers and expectations before continuing on about cylinder headwork. Your engine is going to put out whatever it will make. Down to the nitty-gritty, it is what it is. So, regardless if you expected to see 200whp and you only made 185whp, but your roll-in baseline was 150whp?? That is awesome and a step in the right direction. All dyno's read differently and some utilize a SAE correction factor. So don't be stressed out on the "number" or "peak horsepower output". Be concerned that you have achieved "useable" horsepower, good driveability and an overall increase in relation to what your baseline number was.

Going back to the cylinder heads, Honda has designed some of the best cylinder heads and have done a superb job in the way they are cast and the numbers they flow. For most of the Honda motors that have the usual intake, header, exhaust (with a stock bottom-end and stock camshafts) and want to explore headwork, a competition 3-angle valve job will suit them well. If they plan to explore the realm of aggressive camshafts and upgraded valvetrain, then I suggest the "Street Master" or commonly known "Street" headwork package. Occasionally, I will suggest the "Competition" headwork. The competition headwork is typically set aside for motors with compression levels of 12.5:1 and higher, displacement of 2.0 liters and above and intake systems like ITB's or Forced Induction/Nitrous applications. Last, but not least, the "Outlaw" headwork is purely race and more or less drag racing only.

The Street Master is hands down, the best flow improvement per dollar spent. This headwork also applies to 90% of the street tuner demographic. Many customers will skip the Street Master and hop onto the Competition Headwork, but realistically, the gain they expierence is from the work performed at the Street Master level. Bigger, is not always better and all the rest is just cosmetic at that point. Like I said earlier...Shiny sells!

The Street Master headwork is basically a bowl port (throat section) on the intake and exhaust ports (like a Civic Type-R head). Gasket port match about 1 inch into the runners on the intake side. Polish, deburr and deshroud combustion chambers and a 3 angle, competition valve job. Add a 2 layer headgasket to the mix and a nice set of camshafts and you are ready to rumble. Street Master headwork is $900.00 and takes anywhere from 1-2 weeks at the most.

On other Honda cylinder heads such as the K-series and S2000 F-series heads, there is little to no improvement when actually performing any type of "major port work". The only gains we have seen were from the Street Master and competition 3 angle valvejobs. A competition 3 angle valve job is $325.00 and takes about 3-4 days to complete. Competition 3 angle valve jobs are perfect if you've just purchased a used cylinder head and aren't quite sure of the condition or how it was run in the past. Once the valve job is complete, you can rest assured that it will seal perfectly and perform as expected.

Getting a little more in-depth on the "valve job" in general, I, along with Joe Alaniz 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. We've 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 Inline Four and Alaniz Technologies never guess at what we do. On Joe's 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, we find leaky valve jobs. How do we know??? We 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 anyone 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 money. We at Inline Four DO NOT do $125.00 valve jobs. We know how long things take to do them correctly and with precision.

I hope I have shed some light on this subject and hope it will help you make the right decisions when choosing the cylinder headwork needed to take you to the next level and keep you in the winner's circle.


The Final Lap -*- il4.tfl.newsletter.may.2009 -*- Cylinder Headwork, Valve Jobs, etc...What do I choose??

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