True throat/window, low port heads

[106-1194218389]

Chris just don't call me late for dinner sorry I forgot who's thread I was looking at and boy was I tired - this is all frustrating I know, but one thing I do know is that the heads I do now are sure better than when I first did heads. You just keep learning but you still need to go racing

Larry, if I did not do port molds then I could not do "Show and Tell" - they are sure good for conversation at lunch with the guys.

John

[larrycavan]

Chris,

Don't take this the wrong way OK....

What I see when I look at the port are all those jagged edges, low spots, etc.

Looking at the top of the SSR through the port runner entrance, it looks like it could generate a lot of turbulence.

On the left side of the floor, there are low spots and jagged edges along the base of the wall....

First thing I'd do is get in there with a sharp, single cut carbide [large as will fit the radius] and spin it slow to remove all the jagged edges. Same in the roof around the guide.

Where the runner transitions into the bowl, use a double cut carbide and blend everything nice and smooth.

You might find 10CFM real quick from some clean up work like that.

[blaktopr]

Larry, I hear ya and it's been worked on. The longer burr broke and couldn't finish before I took those pics. I have cleaned it up at the time I posted the old pics and picked up a few. I am waiting on a few new burrs. The head still has turbulence issues with the more finished runner. I was wondering who would catch that!

Here are some numbers...... Flow #'s
Port length 4.8705, 175cc .100 68 .475 246.3 .575 242.3
Pinch 2.4329 with radius factored .200 135.1 .500 253.7 .600 245.5
pinch clay floor 2.295 .300 188.4 .525 239 .650 248.8
ssr at apex 2.460 .400 226.0 .550 240.7
.400 above seat at long side to ssr 2.70
calc pinch fps 252
calc ssr apex fps 250
Avarage csa 2.19
Avarage fps 278
.617 mach at 5800 rpm

[blaktopr]

Your honesty is appreciated. Here is some locals.....

P
U 286 286 261
S 298 248
H 325 248
R 325 248
O 298 234 248
D

Probe may have been acting up during this test have to clean

SSR
185 213 254
114? 254
180 290
301
359 385 385

Tested three areas through the seat and got 321,350, 290. Maybe to quick a transition into open area in cylinder. The upper left corner shows kinda dead at ssr. Port goes turbulent during time of test. Shows me how it bias to the wall side. I have to take a break and look at that some more. Liquid shows that bias also when turbulent.

[blaktopr]

Larry, you made me think back when I was really young learning. The guy I worked for found a port shape he liked that did not take him too long. He told me to try to copy it and held me to a cirtain time. This was for laughs. I ported the runner, not the best looking, and poped it on the bench. He commented on how ugly the port looked and proceeded to clean up the port with the tootsie roll. Put it back on the bench in a ready to run state.....and it flowed the same all through the curve. Scratching head time after that.

Been trying to rework the ssr with sandpaper. The port had deep cuts there and in the floor when I got them. Roof is my doing though!:p Have not held a grinder for a while and the ssr is tough to reach ya know.

[larrycavan]

[blaktopr]

Larry, I appreciate the advice. Helps me get everything back together in my brain.. It's been more studying than applying in the past few years. I even cringed myself when i saw the pics. Yes I need some more patience, but even more I need more tools. I'm going to wait until even the valve and seats are done to show any changes in runner speeds and flow. Thanks again,

Chris

[larrycavan]

[blaktopr]

Yes I have Larry. But the ones as a cylinder not to a point. Been thinking of buying one of his "kits" to add to the very small selection I have now. If my snowmobile sells on ebay and once I finish a particular side job, I may be able to spring for both Mondello kit and a valve seat grinder. If I am lucky, a valve refacer too depending on whats left after bills. we'll see.

Chris.

[larrycavan]

[blaktopr]

Finally got my hands on a seat grinder and valve refacer this weekend. Drove a total of 700 miles which included a stop at PTS headquarters. Thanks Bruce. Put new seat cuts in, 4 total, 32,45,55,68. And tried some variations on some valve cuts. I give you guys props when you fix a separation problem. I have made improvements and through testing especially with valve types and cuts, found the port keeps improving from the low lift on up. The turbulence happens when the port (ssr) reaches the same speeds. As the port improves it can go turbulent sooner in the lift range. 250 to 260 cfm. 280 runner fps, 350 ssr local fps. There is one of my valves that has a fatter head that hold out a little later in the lift range. But when it goes turbulent, it is nasty. I like the flow curve of the runner/valve that goes turbulent sooner because I am using a solid flat tappet cam and after lash is .550 lift. Gives a fatter curve during the event but goes down at .475 vs .525, .550 with the fat valve. I am going to humble myself and ask some questions with the posted test results in the next post.

[blaktopr]

I did not convert any numbers yet, so I am going to post the % numbers. Still shows the trend. Test explanations at bottom.

lift #1 #2 #3
.200 43.5 44.5 44.5
.300 59.5 61 61.5
.400 71.5 73.5 74
.475 77.5 79.5 80
.500 80 81 82.5
.525 75.5 77.5 83.5
.550 76 79.5 79.5
.575 76.5 79 79
.600 77.5 80 80

#4 #5 #6
.200 44.5 44.5 45
.300 62 62.5 63
.400 75 75.5 76.5
.475 81 82 83
.500 83 83 t 79.5
.525 79 79 79
.550 78.5 79.5 80
.575 80 80.5 80.5
.600 81 81 81

#7 #8 #9

.200 45 45 45.5
.300 62.5 63 64.5
.400 74.5 76 77
.475 81 82.5 t 78
.500 83 78 78
.525 84.5 78.5 79
.550 80 79 79
.575 80 79 79.5
.600 80 79 80

#1 is baseline where the port was no valve job, thick head valve, 45 face with 30 and 25 backcuts. 2.125 valve

#2 valve job, 32, 45, 55, 68

#3 switched from 4.120 bore to 4.185 bore

#4 Recut valve. 45 face, 32 top, 75 to 90 at margin (for wet testing). 2.100 valve

#5 Relieve bore at intake valve just like block has.

#6 Blended bottom cut into port at ssr where was extreme angle change and protrusion. Used valve from test #4

#7 Replaced valve with thick valve from test#1

#8 Tail behind guide (had no guide boss) and around guide where wet test showed dead area. Put in exact spot. Used valve from test #4

#9 Cut new valve using a stock valve. Stem all the way to head. More of a nailhead than other two valves. 2.108, 45 face 32 backcut. Redo test #8 with this valve.

Test #7 seems to be the best but I like how #8 and 9 show better throug the lower curve. You can see the turbulence trend. I would like to get rid of it all together but still have no luck. Any thoughts? What is your take on these tests so far. With test #3 and test #7 with the thick head valve which has a 30 and then 25 degree back cut seems to loose a little on the low and "hold" the port from turbulence longer. The same thick valve but with a 32 backcut and the 75 and 90 at the margin has better on the bottom but goes turbulent sooner. Wonder what would the curve look like with no turbulence. What do you guys think is going on with the turbulence differences based on the valve. Then of couse the turbulence issue in general. I still have to do baseline valve with test #8 and 9.
Chris

[blaktopr]

Just to add, the ssr speeds at the apex are high in the 415 area. Don't want to lay it back any more and not sure how much wider I can go.

[200cfm]

Number 7 has a higher overall avg than 8 or 9. Have you attached a manifold to see if that helps the turbulence issue you are seeing on the higher lifts? What about a time study where you look at the time the valve is spending at the low lifts verses the high lifts and peak lift roll over. More time is available for the flow at the upper limits I would think, and hence more time for charge to get into the cylinder.