Here are some cross section pictures of a KA24DE cylinder head and i wanted to here some ideas to see if i'm on the right track.

Heres the first picture.



At first sight, I want to round out more the short side of the exhaust port right above the seat around that bend. I was also thinking of some work near the long side/center coolant jacket portion of the runner.

The intake side the same thing on the short side.

Can I hear some more educated suggestions? Heres some more pics of the head. a freind had fun on the bandsaw [}]

 

I'm by no means an expert, and I'm hardly educated. Is it possible for you to smooth out where the valve guides insert into the ports? Also take down the inside radius on the intake and exhaust side. Trial and error owns.

Are you going with oversized valves?

 

take the valve guides down to be smooth with ports. Polish the intake divider. Don't go to crazy with porting it will kill your bottom end. Polish your cc dish. 3 or 5 angle valve job, maybe back cut the valves? Swirl polish intake ports. Also how much do you wanna spend?


You can always add more metal to the head. It gets complicated. I have been looking to all this latly for my head.

 

Everything is looking good, the seats look great, the guides are taipered. You may want to look at shaping your combustion chaimbers as well. www.dprracing.com..... i think.

 

this is how you do nicely designed head for flow. Shaped perfect I think. This is what i was trying to explain.

 

Heart shaped combustion chambers are optimal, like the above picture, correct? I don't see how you can do that to a KA head without adding material?

 

You have to add material. Thats why i said how much you wanna spend. I was going to have cosworth redo my head until I sent it off and got a quote. About blew my mind. 3800

 

that heart shaped head DPR did doesnt look to promote swirl at all. complete combustion occurs better in a sphere head rather than a circular head. Endyn has done alot of testing with this. and the fact that my stock head includes some of the features they mention, i tend to aggree with a nissan engineer more than a performance shop such as DPR

 

i've read from endyn's pages that this is a big no-no to modify how the valve guide is introduced into the chamber. they say you cant just remove material to the port wall, has to be a progressive ramp to the actuall valve.

i'm not going with oversized valves. I'm gonna play with S13 and S14 cam combinations to see what i like. I have a completely stock setup and she feels to die off about 5,500 rpm. but with the S13 cams i get a dip at 3,000rpm that i HATE feeling. it shows on the dyno and i can feel it on the last motor setup. dont know if it was the head or just the cams but i'll be testing.

I threw some Toulene in the gas tank 2 gallons of it. went to 10psi with 18degrees of timing on 9.5:1 compression. 10psi and 10 degrees would ping a bit.

seems the stock setup offers very complete combustion since timing cant be advanced to much. less timing means a better combustion efficiency persay. I had to run 10degrees more timing with different cams and my last ported head.

 

Try the 248/248 setup? It should shift the power band up top, and make it a little more fun above 5k. I think it should get rid of the dip you feel with the 240/248 combo.

I have yet to see a dyno comparing just cam changes on a KAT. Do it. HA.