Questions on Porting ohc heads!

[cboggs]

"square" the port floor next to the divider and make the divider more concave. Keep a small radius on the leading edge of it and otherwise do as Curtis says.

SWB, .. who's this? , .. you do know these ports.

ya know, .. this internet thing is cool and all, .. but I still like calling
people by their name, .. you guys should at least put a first name
in your profile, ..

Curtis

[PFM]

Curtis,

Been there done that, still have a block of blue wax but the seat was just never right. I plan on using a base plate of aluminium with the chamber CNC'd out and valve seats cut in as well, then add the plastic and guide around the rubber plug.

PFM

[ou812]

Thanks for all the help guys!!!! Really helped me out on this one. I flowed the old head and it did pretty good, 280 at .500 lift. Like I said, this intake port is squared at the flange. So Im working on the new head and decided to square the bottom of the intake port near the divider, made if more concave, did a 35/45/60 seat cut, opened the throat up a little, and now have 267 at .500 with the stock port opening. Check this out though, my low lift is way higher than his, at .200 my port flows 157 while the other flows 143! My port out flows it to .350 lift. At .400 my port flows 243 and the other flows 253. So...you guys think these are good numbers or am I way off. I have heard these ports can flow over 300 cfm no problem. And whats you take on making the intake port square at the flange, necessary or not????? Thanks again for all the help, seems to be working.
Brian

[MysteryMAN]

Brian,

I've done a ton of those, .. held some records & stuff, ..

What teams and records?

[cboggs]

Brian,

I've done a ton of those, .. held some records & stuff, ..

What teams and records?

MysteryMAN, .. is this Brad?

Jason Hunt & the Car Doctor stuff is one, ..

Curtis

[cboggs]

Thanks for all the help guys!!!! Really helped me out on this one. I flowed the old head and it did pretty good, 280 at .500 lift. Like I said, this intake port is squared at the flange. So Im working on the new head and decided to square the bottom of the intake port near the divider, made if more concave, did a 35/45/60 seat cut, opened the throat up a little, and now have 267 at .500 with the stock port opening. Check this out though, my low lift is way higher than his, at .200 my port flows 157 while the other flows 143! My port out flows it to .350 lift. At .400 my port flows 243 and the other flows 253. So...you guys think these are good numbers or am I way off. I have heard these ports can flow over 300 cfm no problem. And whats you take on making the intake port square at the flange, necessary or not????? Thanks again for all the help, seems to be working.
Brian

Brian,

Myself, .. I always look at the entire flow curve not just some peak number.
The 300 cfm heads are possible, .. but I think the fact that your head out flows
the other up to .350" is a good thing. It's area under the curve that's important.
If you can keep the low lift flow and "puff up" the high lift you'll have a good head.
You're getting there. Heck, .. how far do you open the valve anyway?

Make sure you don't have any turbulence at .400", .. flow at least at 28" H2o
and hit 36" H2o if the bench will do it.

The square intake, .. I don't like that myself. It makes the area in the port all wrong.
You go from the giant port area before the dividing wall to a much smaller
cross section after the dividing wall, .. I can't see a reason for it.
I've tried it, .. didn't show me anything on the flow bench, .. and can't see
why it would work on a turbo car.
Maybe some one else has some insight on this????

[ou812]

Well...were gonna run the port like it is, and see how it works. Changing the intake also, so I think by looking at the flow numbers vs. the velocity Im getting and the size of the port that its gonna fly. But there is the off chance that Im wrong. So Ill keep ya posted! Thanks again for all the help guys...much appreciated!!!!
Brian

[cboggs]

Good luck with it Brian, ..

OBTW, where are you located???

Curtis

[ou812]

Curt Im out in southern Ca, near Palm Springs. The name of my shop is IMM, were in Indio, just east of Palm Springs.
Brian

[cboggs]

Brian,

Oh for some reason I thought you where out here close to me
in Virginia, ..

You've got the better weather.

Curtis

[seth]

curtis,

got a good one what kind of velocities do you see along the short turn in a B-16 head. i have on one the bench now and i can't seem to get it to drop below 407fps at the apex of the turn. i gave up on the educated approach and took the caveman approach and just opened the port up. the flow has increased but the velocities haven't changed. i didn't know if you have seen the same.......

[cboggs]

Seth,

You're right, .. that is a good one, .. ..

I'll have to look up my velocity maps in the computer tomorrow, ..
maybe I made some notes on it, ..

I've got a question for you guys, .. anyone try a radius intake seat???
It looks good on the flow bench, .. but does it make power??????

My past experience has never shown a radius intake to make power, ..
but I've heard of guys doing it.

Curtis

[RGL]

Just wondering, what kind of head is that pictured on your site that has no chamber ?

Seth,

You're right, .. that is a good one, .. ..

I'll have to look up my velocity maps in the computer tomorrow, ..
maybe I made some notes on it, ..

I've got a question for you guys, .. anyone try a radius intake seat???
It looks good on the flow bench, .. but does it make power??????

My past experience has never shown a radius intake to make power, ..
but I've heard of guys doing it.

Curtis

[cboggs]

Just wondering, what kind of head is that pictured on your site that has no chamber ?

RGL, .. that's a Ford 4 cylinder cross flow head, .. also known as
a "kent", .. it's used in Formula Ford 1600 road racing.

Same type of car that is the RFD "shop" car shown in the Tech section
of my web site.

Funky little thing to work on, ..

Curtis

[RGL]

thanks , i guess thats one less area on the head to screw up. LOL