<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Woofer &raquo;</TD></TR><TR><TD CLASS="quote">Sounds unbiased to me.
.....and the winner would receive??
Lessons in part's swapping and religion perhaps?</TD></TR></TABLE>
lol
no reputable head porter would enter a contest like this
there would be no winners and everyone would be losers

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ImportReview &raquo;</TD></TR><TR><TD CLASS="quote">
Personally, I think so many people are scared to put their work (their neck) on the chopping block, that come time for the tournament contest, nobody would show up!

I would even conduct this contest in a totally unbiased manner. Yea, .. Right, .. just like your posts
Jeff</TD></TR></TABLE>

Jeff,

Every time a porter builds a head they put "(their neck) on the chopping block"
90% of the work I do is for professional engine builders, .. . if I'm off by 1/2 HP I get a phone call. Plus, .. it all comes down to the track, .. it's gotta go faster.

Now enought of the silly talk, .. can we get back to the tech talk on this thread and avoid having it hijacked.

Woofer, .. .. did you see me earlier post with the flow numbers and ratio?????
I'd LOVE to get your thoughts on the flow ratio, .. exhaust to intake flow persentage, ...
and discuss dealing with a round port.

Although the head I posted the topic about isn't a Honda, .. the discussion will apply.

Curtis

 

Sorry I missed it (somehow) in all the talk that had nothing to do with nothing. As for flow ratios, I opt to get all the exhaust flow possible, assuming the cross section of the valve and port are still small enough to produce torque. Many of my head have exhaust ports that out-flow intakes, and we choose to balance the flow by shortening the exhaust event, which helps us keep cylinder pressure captive a bit longer, as well as closing the valve a little earlier. Typically, I'll do anything possible to limit both lift and duration, as they each combine to make life more difficult on the valves, springs, and giudes.
80-85% is stil la reasonable ratio for most applications, but as you're aware, rules sometime limit what's achievable, so you have to work with both intake and exhaust lobes to "fix" what can't be achieved in the porting.
BTW, I used to do a lot of formula Ford heads back in the mid eighties when we were doing all the (competitive) mini-Indy VW Rabbit heads....and I used to use Swiss files to hand-configure the seat radii to achieve equal flow all the way around the exhaust valves, when doing vector analysis of the flow approaching the seat from the camber-side. Since the valve isn't centered in the chamber and the port isn't (straight), the seat radii have to be different all the way around, so simply machining won't cut it.
We stil do this on Honda heads..both intake and exhaust to maximize efficiency regardless of the valve's proximity to the cylinder.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Woofer &raquo;</TD></TR><TR><TD CLASS="quote">Sounds unbiased to me.
.....and the winner would receive??
Lessons in part's swapping and religion perhaps?


Modified by Woofer at 3:00 PM 5/23/2003</TD></TR></TABLE>
Umm so wtf you trying to say here?
If your implying that I know anyone or that I am in league with anyone in what I said in my post, your very wrong. I do not know or have ever talked to Jeff. I have used his IB spec pistons in motor builds before and if I built the same engine IB spec vs JE vs CTr the ib came out on top. IMO best piston I have used. I actually have a set of ur pistons ready to go in a d series turbo setup. Just got done notching the block to fit the eagle rods.
On another note I think very highly of your work and your site also. I printed the block notching off your website. I have been doing alot of head porting and learning as much as possible as I go along. I started doing it from tech articles on your site on my own and with the power I was making others soon wanted it done. I am also very excited to use your pistons in this next build, see how they are.
All this being said, am I now in leagues with you or am I cronie riding your bandwagon.....**** no...and I'm not riding his either. I have respect for what you both do and have done. I would love to see how my head work measures up to all the great head porters and head porting philosiphers on this thread. That is all I was implying and the fact that I like IB spec pistons.


Modified by DohcVtecCrx at 2:27 PM 5/23/2003

 

Woofer,

You used to do Formula Ford heads, .. what haven't you done??? That's very cool. So you know all to well what I'm up against.

The Peirce aluminum casting is now legal in FF. The problem is you may have one great exhaust port, .. and a few crappy ones, .. .. core shift. I know about the radious under the exhaust seat.
I use a 30 top .030" wide, a 45 and a radious that starts at 60 and goes into the port to 90.

Since you know this stuff, .. I've tried cutting the short turn side of the valve job flatter to remove some of that radious, .. and I've tried leaving it in and cutting on the bowl side. The problem is with a core shift in the casting it didn't give me a difinitive answer as to what the port likes. Your thoughts???

As you said, because the port isn't strait and the valve isn't centered it tends to push the flow through one side of the valve and force it to the roof of the port. Do you have any ideas how to deal with this?? The high lift ( .250" to .350" ) really starts to die off.

Back to my original question, .. flow ratio. I've always been afraid to go too much over 85% to 90% and at low lift where there my be some overlap in the valve events, .. I'm afraid it may pull some intake charge out of the exhaust.

We are dealing with a stock cam, .. but the engine builders tend to retard the cam to get the engine to run up around 6000 to 6200 RPM.

Thanks,

Curtis

 

It's illegal, but have you considered welding the bowls some to "correct" the core shift. I have torches small enough to actually get in there and do it. If you remove the guides and seats before welding, then normalize the head and re-heat-treat the casting before machining the seat registers for seat inserts that are .002" larger in diameter, you can get away with it, but you'll need to be sneaky and leave some casting (lines) in a few areas of the bowls so there'll stil lbe evidence that all's "stock".
This will allow you to make all the ports a little more (equal), so specific output will be a little higher across the board.
We also used to really get after the intake manifolds for those engines, converting manifold heat chambers into additional plenum volume. I don't know what manifold rules are anymore for the class either nowadays.
For all those who don't "know" these Ford heads...I'll suggest that when you spend the time (and you can spend years) working with them, your knowledge of how to detail ports (on any engine) will be broad.
I owe much of what I apply to Honda (and other heads) to programs like FF, Ford's awful V8 heads, and course, the old MG-B's.
I have some programs that will allow you to compare piston speed at any crank angle with valve motion. This will allow you to find the areas in the lift cycle where breathing enhancements will net the greatest benefits. Let me know if you'd like to give it a try, as it'll also allow you to calculate all the loads on pistons and other reciprocating components at any given rpm point.

 

Woofer,

yes I have concidered welding the bowls, .. but I have gotten the foundry to pick through castings to try to eliminate the problem. The head I'm working now, .. not a "choice" casting has one port 11 cfm better then the other slugs.

You're right, .. these heads are a bear. Question, .. if the area in the back of the bowl is the problem as we know it is, .. would a smaller radious under the seat in that area help???

I tried taking the radious out on the short turn side, .. it did nothing but cause a slight bit of turbulence. I've also found these ports do not like flat, wide floors, .. odd.

As for the manifold, .. nope can't cut into the heat passage that much. We can fill it with Devcon and port "to" it but the Devcon showing can be no larger then a quarter.

The software that compares piston speed to valve lift would be VERY interesting.

Thanks for the help, .. it's cool of you to discuss this stuff with me, .. .. ..

Curtis

 

Curtis,
I remember those ports and the attendant core shift well. In some notes (I stillhave notebooks on all the heads I've done), I used a relatively large radius on the short-side, and a smaller radius toward the back-side, or long wall side.
I also used a very short 35 degree approach angle to the 45 degree seat. The 35 is only .010-.012" wide, so we keep the valve as high as possible in the chamber to aid low-lift and mid-lift flow numbers.
If you were "stepping" angles, the short-turn side would have a short 35, followed by the 45 seat, with a 55 that's .050" wide blended into the short-side radius. On the back wall, use the same approach (35), the same seat (of course), followed by a 55 that's only .010" wide, immediately tapering into a 65 radiused into the back wall of the bowl. You can use some artistry to "connect " the radii as you sweep around the seat. Give it a try, I think you'll like the results.
I'll also fill you in on how to examine the flow all around the exhaust valve/seat in the chamber. It's a real eye-opener when designing exhaust ports, and the chamber-side approaches to the seat.

 

Woofer,
we spoke before on getting the valve to flow evenly all the way around it by looking at the vectors and changing the angle under the seat at different points around the seat on the bowl side.......could you expound a bit on how to actually measure or look at these vectors?

 

Sometime tomorrow, if that's OK. It's past my bed time and I have to bust *** all weekend (and Monday) to stay ahead of projects here.
Larry

 

Its a deal.

It is now 9:40pm and I'm still at the damn shop prepping this stupid class 10 car for next week's race.........I thought if I worked late tonight I could have the whole weekend off...........what a sucker I am!
I still have to be here tomorrow!

 

Larry,

Dude you are a welth of knowlege, .. thank you for sharing.
I'm doing very similar things, .. I was incorrect in my earlier discription of the valve seat.
35 top .025" wide, 45 .055" wide, 60 . 030" wide, radious 60 to 90. I've kept a fairly large venturi under the seat.

I'm going to hit the bench today and try working the radious at the back of the bowl.
The frustrating thing as I'm sure you know, .. what works on one port may not help another, .. damn core shift. I'll post before & after flow numbers for everyone tonight.

Measuring the flow on the chamber side will be a real eye opener I'm sure. Now this is some REAL meat for us porters and will help with ANY head we develope.

Curtis

 

That's what lead me to using Swiss files to "tweak" the seat radii. When you work with factory castings, it's extremely difficult to make every port perform the same due to core shift. It's a shame they couldn't have made the cores a little smaller so we could "open" all of them up the same, but then the stock heads wouldn't work well with the minimal factory machine work.

Now to open your eyes a little.

Build a header flange with a 4-6" hunk of pipe that's the same size (and fit) as a header pipe in the real world. Put a flange on the open end of the pipe that you can bolt to the flow bench where the dummy cylinder normally sits. Bolt the head on the new "fixture" and bolt the dummy cylinder to the head. The dummy cylinder is now facing you and it's open to atmospheric pressure.
Turn the bench on in the intake (suction) mode, so you're pulling air out of the exhaust on the head.
Since the cylinder is now accessible, you can probe around the seat (with the valve in it of course) and determine exactly where the flow is coming from.....
This should put working exhaust ports in an entirely different light....

 

Woofer,

I'll have to try that, .. .. .. I'll make up an exhaust adaptor over the week end, .. but makes perfict sense. I had some clear bore adaptors that had acsess holes in them, .. so I could put a probe into the chamber and measure the intake velocity around the seat area, .. .. .

Now for the latest report.

First test had the short turn radious cut down a little from a previous test that showed no improvement.

I cut down the radious at the back of the valve bowl as your instruction.

Lift ---before ------- After

.100 - -- 47.1 --------- 44.9
.200 - -- 89.8 --------- 86.5
.300 -- 105.2 --------- 109.1
.400 -- 111.1 --------- 117.9

As you can see it helped the high lift number but hurt flow at the low lifts.

Sooo, .. I tried the same thing on a different port that had a large short turn radious.

Lift ---- before ----- after
.100 ---- 44.9 ------44.9
.200 ---- 88.7 ------82.1
.300 ---- 107.2 -----103.3
.400 ---- 111.1 ---- 111.1

As you can see it hurt flow through the mid lift all the way to .350" lift.

can you see why I'm confused?????????

The frustrating thing is, .. I have some ports that flow very well, .. over 10 cfm better through the mid lift and top out at 128 cfm at .350" lift. I'm yet to figgure out why

Time to make port molds, .. ..

Larry, .. your thoughts here?????

Curtis

 

Dammit Curtis,

I 'm so frustrated right now, because I've been flogging in the shop for two straight weeks trying to get this Baja race car done so I can get back on the flow bench, but there just aren't enough hours in the day!

Once this thing is outta the way next week, I'll be flogging to finish the book, and then the week after it's done is the big seminar in Tx!

After that, I'm home free and I'm dedicating the rest of the summer to porting education!

I hate watching everybody else have all the fun though! Keep it up!
-Ben

 

Man ben baja huh? My suspension guy is heading down this week to check out all the rides and than next week again for the actuall race. its gotta be kiler to be in that race with the heat, its already hot here its gotta be 100 plus down there.

By the way lots of info slinging going on around here keep it up.-pdang

 

We're just now finishing up two off-road B16's at 1.625 liters (right on the limit). These engines also are running carbs due to the rules in their classes. We've made some pretty wild pistons for them with 8.0 cc domes.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b19coupe &raquo;</TD></TR><TR><TD CLASS="quote">
I have a technical head porting type question:
GSR engine with 84mm bore-12.5:1 pistons-Intake cam w/12.9mm lift 305 degrees advertised duration, exhaust cam w/11.9mm lift & 315 degrees advertised duration, free flowing exhaust, ITR intake manifold, PR3 (B16) head casting.Looking for max torque/hp at 6,000 to 10,000 rpm. What would the ideal port configuration/valve to seat angle etc. be? Exhaust guides ground down or no? Intake guides-teardrop/ground down/untouched?</TD></TR></TABLE>

did some of u guys miss this question.... i would also like to know this ^

 

If you're stuck with doing discrete angles, you're likely best off going with the traditional 30-45-60 combination.
Our vlave jobs at Endyn are comprised of a single discrete angle (the seat angle) with variable radii above and below the seat, with those radii depending on the side of the valve seat we're addressing. Those shapes must be different all around the seat because you're dealing with differing chamber (effects), as well as the proximity of cylinder walls too.
You will need intake ports with at least 230cc's to feed the engine and I think you'll also find that a non-sectioned manifold will also cost you close to 20 HP, assuming the header and everything else is within spec. The header will need to be 17/8" minimum on primary size.
Don't ever whack the guides out of the head, taper both the intake and exhaust guides and blow the sides of the bowls out if necessary to create sufficient cross sectional area.

 

I read that question and I didn't know how to answer it.Soooo I didn't want to sound rude but I thought the question was how I would port the head for his car or how would we port the head. I don't know if you have noticed how hard the head porters in this thread work for the answer to a question like this, this is a question we ask ourselves with every time we do a head, we sacrafice our family time, sleep, health, and sometimes ourselves for the passion of knowledge, and making horsepower. So when I read this question and thought of how hard I worked to know this the only answer I could come up with was............


I would port it.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b19coupe &raquo;</TD></TR><TR><TD CLASS="quote">Come on guys lets keep it technical. No personal grudges please. There is a lot of good info in this thread, lets not let it degenerate into something else.
I have a technical head porting type question:
GSR engine with 84mm bore-12.5:1 pistons-Intake cam w/12.9mm lift 305 degrees advertised duration, exhaust cam w/11.9mm lift & 315 degrees advertised duration, free flowing exhaust, ITR intake manifold, PR3 (B16) head casting.Looking for max torque/hp at 6,000 to 10,000 rpm. What would the ideal port configuration/valve to seat angle etc. be? Exhaust guides ground down or no? Intake guides-teardrop/ground down/untouched?</TD></TR></TABLE>

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HEAD &raquo;</TD></TR><TR><TD CLASS="quote">I read that question and I didn't know how to answer it. So when I read this question and thought of how hard I worked to know this the only answer I could come up with was............


I would port it.

</TD></TR></TABLE>
Kind of the answer I was expecting, this being a public forum and all. I had the head ported by someone who most people should be familiar with, so hopefully his work will prove itself on the dyno...

 

Woofer your idea of making that fixture for the exaust side was really cool!
what do you think of doing that and cutting a 3.5 exaust pipe about 2-3 inches long and use some modeling clay to attach it to head around the chamber to simulate the bore

 

seems natural to me............I'd wanna do it to the exact bore size the engine was gonna have..............................
I can't wait to get back inn the groove and try that fixture woofer is talking about!

 

here is the set up... this is not a street car.
bottom:b18c sleeved, 85mm, JE 13:1, eagle rods, 2 layer head gasket.
head:97spec JDM ITR, erick's racing 68mm TB, Toda Ds, toda valve train, match ported ITR IM, JDM ITR header....

WestCoast racing cylinder heads is gonna do the head... they have gone real good work in the past for me and a couple of friends.
is their alot of porting needed for this setup on an ITR head? i have always heard that ITR head dont need to much porting....

 

I think you should be asking WestCoast about this, since they are the ones porting it! didn't I just say something about this kind of question?