This is Micheal Bird's head, a forum member building a stout 700whp monster Evo

His build thread is here https://www.evolutionm.net/forums/ev...-one-mine.html


The chamber stock has a lot of potential, but it also has a lot of potential hot spots. The sharp edges need to be contoured and blended. Doing this is also a necessary act when the customer picks a ported head from us because the valve job is so aggressive and takes out so much material around the valve seat it not only disrupts flow, it leaves the potential for hot spot for detonation, to combat this we we blend it into the valve job.


TOOLS

Of course not every head porter will have the same equipment. Our chosen grinder of choice is a hand held, front exhaust grinder made by Cleco. It is a $500 grinder that came into effect during my tenor at Pat Musi Racing Engines. This grinder has the torque to rip trees down, and with the right burr on the end takes out metal mercilessly. We use front exhaust because it will blow the metal away from the piece your working on, and away from you.



There is 2 cast iron burrs in this pic, for finishing and one for getting into the tight spots. Roughing sanding rolls, 60 grit and we finish with a 120 grit roll(small ones)




Speaking of bad *** carbide burrs..this is a favorite at HeadGames..high helix..it leaves a trail of metal in it's wake!



another very important tool is modifying valves to protect the valve seat. We take a valve, and put them on our valve refacer and make the margin of the valve razor sharp so it sits flush with the valve seat..



as seen here...this is the exhaust side facing the intake part of the chamber. You are looking at it from the valves perspective. Notice how the valve is flat on the seat and you just see a tiny bit of the top cut from the valve job.


it's much more pronounced from the intake side...

The Works

Carving out combustion chambers is not for everyone..it's not easy. And we have seen heads come threw here done by "professionals" that actually look like Stevie Wonder was a fill in that day. Not a straight line in the thing!

I learned how to do combustion chamber design at School of Automotive Machinists and really learned how to carve them out from Charlie Kulp at Pat Musi's. And think of all the things you can do with a cylinder head, besides making a short turn a actual turn..chambers are the hardest.

this is how they start out...



and after some careful grinding..they are roughed out, and starting to take shape



a close up of how the chamber valves we make help blend right into the top cut of the valve job


next up..sanding

We take a 60 grit cartridge roll and rough blend the grinding marks into the chamber..smoothing them per say. There is still some shaping taking place during this process, as you are still moving material around. Just slower and less precise.






here you can see how it is sanded into the valvejob and everything is blending nicely. If you scroll up you can really see the difference in shape on the back side of the valve.



Semi-finished



a close up



and lastly..the finished product!!

stock size Ferrea 6000 series valve give that chamber some bling!

 

I dont like how you do your chambers. May be one of the reasons some of your customers have seen no gains with your head work. Removing that margin above valve and blending it into the seat is a bad idea. It is there for a reason from the factory. It prevents exhaust reversion when both valves are slightly open during overlap period. would be hard for you to see the results since you make improvements is other areas of the head work. two steps forward on step back sorta thing.

You are also removing the contours in the chamber bowls as well. All those little shapes are all there for a reason. its best to leave them there and polish only.

 

I like the cut down valves to protect the seats. If I ever port another head, I'll be using that little piece of advice.

Every time I get done porting a head, I say I'll never do it again...yet it seems like I keep doing them anyway.

With regards to what 94AWDcoupe said though, I think it's hard to prove either way. Stuff like small ridges to prevent reversion probably works under lower airflow conditions and probably was designed for that purpose. But it seems like at WOT on a high powered motor, it's all about getting the clean air in and keeping heat from building up anywhere. The best way to do both is make everything smooth and continuous.

Do you cc match each combustion chamber?
Do you take the chamber out to the HG opening size?
Do you lap the HG surface?

 

also what is the finished chamber volume of a head like that?

 

Although we do not agree with anything you say, we can appreciate your thinking..our heads have had zero issues in the making horsepower department. When we do, that maybe the time to think outside our box. You should take notice that almost every head offered to the EVO has a combustion chamber that is pretty similar..we could all be wrong, but it's doubtful. We deal with a great deal of shops, and talented tuners, with amazing feedback.


Glad we could aid you in porting! The valves will make your life so much better, and the head come out much cleaner..now you can do the chambers after the valve job! Another tid bit for you, is oversize valves work best for stock size valve chamber work..when you take the 45 out to the margin, sometimes the valve will only cover the 45 and you will lose the top cut with the same size valve the head is machined for...hope that makes sense.

totally agree on your thinking of the chamber design...

We do not CC every chamber of every head...we do check them as some heads have been milled before, so it keeps us safe and the customer aware. But, honestly being a pro..if you can not grind a chamber within a CC or less...you should put the grinder down. A novice should though! That is how we learned how to be accurate.

We do not lap any cylinder head..something like that is needed when it is milled on a broach, or wet grinder(stone) and used with a metal gasket.. we have one of the best milling machines on the market..DCM makes it, and most of the cup shops switched to it years ago. You would be hurting it by touching the deck. I can post pics tomorrow.

 

Nice write up! Ive been waiting for you to get this thread up. I couldn't be more happy with the finished product. The quality and time put into the head is top of the line. I appreciate everything! Ill have some dyno numbers hopefully in less than a month!

 

headgames, you dont know everything about head porting. your reaction to my tip is just what i would expect. That info originated from one of our local porters who is flown all around the world to do porting. He flies to puerto rico on a regular basis. he is a wiz at getting results, not making it look pretty. There are several threads on this very board about your heads not working like you taught them too. I could pull them up and start crap but what would be the point?

you posted your work on a public forum. if you cant take the criticism maybe you should do it? good head porters dont usually post their work. they dont want to expose their secrets.

 

Dave, all ofthe heads that you have done for me in the past on multiple platforms ALL made SICK power!

You need to expect haters on this forum and it's funny given all the records that have been set using your heads... Haha

 

94AWDcoupe Your making yourself look bad by rudely coming in this thread and basically from what i see hating on Dave... He is nice enough to make a thread showing what he does to a chamber and u go off on some rant saying his heads don't work "which i personally know is BS" and then go on to try and teach HIM what to do on a cylinder head which i got a nice out of. Can we say rude and uncalled for??

I was referred for what i was wanting done to my head to Dave by a very knowledgeable person that i have personally known for YEARS that drives the highest HP EVO in the country that held the 1/4 mile world record for quit some time until the owner of the car "i guess" just lost interest and they stopped taking the car to the strip or im very confident it would hold the record again.... And it did all this on a Head Games head BTW. And when you take into account that the best of the best in this industry were trying there butts off to do better at the time and couldn't do it!! ENOUGH SAID!!

I just got the valve job he does and some guides and valves and i couldn't be more happy with the results, the customer service and turn around time when i needed my head back with the quickness. When i called i got an answer and Dave was always willing to lmk anything i wanted to know and then some. Customer service like this is few and far between in this industry of people that think there above everyone else and think they don't have to take care of there customers that are putting there hard earned $ in there pocket anymore. I see this ALL too much!! What i received in the end was exactly what i had expected and will continue to use Dave from now on due to my experience!!

Dave how about you post those results of the comparison you told me about?? Might shed some more light on how you know a little something about what your doing. I know i was very impressed but i will of course leave that up to you if you want to let that cat out of the bag or not. Until then my lips are sealed

BTW Dave you will be getting a PM from me here in a bit.

 

I can definitely see that being true. I have always had a hard time dealing with core shift. I can get a shape all worked out on one chamber, then go to the next chamber and realize that shape isn't going to happen because of core shift. I'm sure hundreds of hours on the grinding bench makes it easy to identify what is going to work on all the chambers and that keeps volume in a very small range.

 

Great looking CC OP. Sorry to hijack, but Jerry always seems angry for no reason. Like whenever someone posts something that may be different from his views it's like they have just insulted his mother. He is a smart guy but has absolutely no tact...

 

I think this is an interesting discussion. I linked a pic of the combustion chamber from Headway Performance and see it is much different. It says it is from the EVO so I assume this is how they shape out. Why is this shape so much different then what Head Games is posting?

 

its nice to see a writeup,most shops dont like to disclose their "tricks of the trade"...p.s. my headgames head is working great for me!!

 

thats a cool chamber,im just wondering if all the sharp edges in there might promote detonation though...

 

240Z, that's a very interesting picture. It looks like 1mm oversized valves (possibly 1.5mm?) are being used?

Two things hit me on that combustion chamber.
1. Are they adding material through welding?
2. Does the valve have to be modified for length?

I don't think those shapes are possible without one or the other of those things happening.

Those points where 3 contours intersect seem troublesome to me though. Pre-ignition hot spots.