Rember the intake port texture debates?

[pamotorman]

no one has answered my question why is the finish the same on the gasket surface as in the ports

[Caprimaniac]

no one has answered my question why is the finish the same on the gasket surface as in the ports

Is it, or is it just the light or camera angle making it appear so?


BTW; if texturing (less the turns) make the fue (air) more moveable, not klinging, in the inlet tract- I suspect making the piston tops, valve plates and Chamber textured too would help also. Jeez- even the cylinder wall.....

What do you think?

[John Wallace]

I suspect making the piston tops, valve plates and Chamber textured too would help also. Jeez- even the cylinder wall.....

I think Larry (and Chris?) texture the chamber also?

The cylinder wall? Might be technically textured by honing?


I think they are looking to get the mixture out of the head the best?
Once in the chamber/piston area it's time for spark?

[fdicrasto]

no one has answered my question why is the finish the same on the gasket surface as in the ports

Looks like a flap wheel was run down the ports to possibly knock off some of the sharp edges and left that sanded look to the gasket surfaces on entry and exit. Just a guess.

[user-9274568]

no one has answered my question why is the finish the same on the gasket surface as in the ports

It's not. I just use a 60g DA to clean the surface of the intake face, exhaust face, and ends. Just my thing, been doing it for 20 years.

[nickpohlaandp]

I'm still reading through this thread trying to make heads or tails of it. I've seen airfoils referenced a few times (in regard to an airplane wing), and that's something I'm very familiar with, so I'm going to start from the beginning before I make any kind of opinionated statement pro or con, but holy cow, this chamber just looks like an orgy of potential hot spots to invite detonation. I'm amazed at how uniform the chaos is... that takes talent, but why is what I'm trying to figure out. I'll keep reading.

[user-9274568]

Here is the last set of Engine Master heads I did for Henderson.

[statsystems]

I'm still reading through this thread trying to make heads or tails of it. I've seen airfoils referenced a few times (in regard to an airplane wing), and that's something I'm very familiar with, so I'm going to start from the beginning before I make any kind of opinionated statement pro or con, but holy cow, this chamber just looks like an orgy of potential hot spots to invite detonation. I'm amazed at how uniform the chaos is... that takes talent, but why is what I'm trying to figure out. I'll keep reading.

That uniformity is what I can't duplicate. YET! I'm going to use Larrys advice and give it a go. The guys that can repeat that finish have some talent for sure. And PATIENCE.

[statsystems]

Here is the last set of Engine Master heads I did for Henderson.

That's incredible. Thank you for kicking me in the jimmy. Again.

That's sarcasm so it's not misread.

Damn Chad. Seriously bad assed.

[GARY C]

no one has answered my question why is the finish the same on the gasket surface as in the ports

It's not. I just use a 60g DA to clean the surface of the intake face, exhaust face, and ends. Just my thing, been doing it for 20 years.

A rough intake surface in probably the best bet especially if the center divider is narrow, in the old day it was not uncommon to see small dimples drilled around the intake ports the keep the gaskets from slipping.
Years ago I started using trim to fit gaskets glued to the head with heads on the block ant intake bolted on prior to porting so that the gasket would be exact after porting, maybe over kill but it makes my brain happy knowing there is no notch or abrupt transition in the port once finished.

[user-9274568]

That's incredible. Thank you for kicking me in the jimmy. Again.

That's sarcasm so it's not misread.

Damn Chad. Seriously bad assed.

Just did this today. Double cut burr, slight wobble, Makita with a Harbor Freight controller on the slowest speed it will go. Must warn you, when I'm done with all 8 ports my hands and arms are tingling. It's a little weird..

[nickpohlaandp]

If you "trip" the boundary layer to a turbulent condition-just the boundary layer- it enhances the Coanda effect, i.e. aids attachment. That's what the little projections on plane wings do. ...

Those are called vortex generators, they’re a PITA to install. They are generally installed in front of moving control surfaces (ailerons, flaps, slats, spoilers) to “bleed off” air from the main airfoil to increase the effectiveness of the flight control.

As I understand the port texture and riblet technique is not about flow but getting the air to follow the port and atomizing fuel.

I would think it would do just the opposite and get the air to stay off the surface, or maybe we’re saying the same thing with different words?

Just occurred me to dimples/burr finish is about holding fuel or wetting the walls better for the cooling effect. Increased surface area w/o the downside of smooth wetting.

This confuses me even further. When I apply Bernoulli’s principle it would seem that the dimpling would create a higher pressure (due to the higher velocity air within each dimple) which, I would think, would repel “wetting” of the port walls.

That won’t be happening anytime soon, ESPECIALLY in the NA performance world!

Just playing devil’s advocate, but what about direct injection? If fuel were taken completely out of the intake port equation, would this have any benefit?

there has been discussion that the additional boundary layer thickness of a rough texture actually makes the port cross section seem smaller so if you have a little too much cross section maybe it makes it acts smaller

This would make sense if you look at my earlier reference to vortex generators and Bernoulli’s principle. Just spitballin’ here.

…It seems like you would need to start with 3 sets of heads, very close in size for the engine but a small, medium and large base line and then apply texture and see if they all show the same power gain...

I think this would solve the debate as a “once and for all” experiment if someone were to take three sets of identical heads from a high quality manufacture so you know they are all the same, like a Dart SBC head. Use the same shortblock and intake assembly for all three. Have one set of heads stock, one dimpled, and one rolled, and dyno them all. See what the numbers say. Those results would be hard to refute.

I’ll finish with this. I LOVE forums like this, because just when I think I actually know something, I realize I have soooo much more to learn. Thanks to everyone!

[nickpohlaandp]

...

I just checked out your website and saw you are in Abbeville!! That's not too far from where I am. PM on it's way.

[David Vizard]

jim mcfarland was doing the dimpling deal back in the day when he was with Edelbrock
intake ports and combustion chambers,its nothing new i personally like the burr finish that chad does on his cylinder heads

Yes I so remember this era. The main high profile players were Jim McFarland and the late Ken Sperling (of AFR Fame).

I was doing a 468 dry sumped BB Chevy for a really upmarket application. Had the motor just finished and about to come off the dyno when the owner came boiling into the W/S with a copy of some mag having an article on chamber dimpling in the supposed wet flow area adjacent to the spark plug. The mag tests showed that there was a decent gain in output and he wanted his chambers dimple in the same manner.

We had gone to great lengths to port the heads with as high a velocity/flow combination as possible. We had also worked with Dave Braswell on the atomization of the Dominator and other issues that would minimize problems with wet flow that the dimpling would supposedly fix (that included evening out flow and fuel distribution). I told him it would be most likely a waste of time as we had already worked hard to minimise the problems the dimpling was supposed to fix but he insisted none-the-less. We dimpled the chambers and the power dropped from 760 to 741. We cleaned up the dimples and the power went right back to 760.

Be aware of any domino effects before giving the green light to any modification!!!

As for the effects achieved by dimpling or other surface 'imperfections' I believe we still have a lot to learn. Right now where I am at is to use those course grit rolls so the ports have a roughish finish. No port polishing in my shop - but I am watching what Larry and Chad do very closely!!

DV

[GARY C]

I would think it would do just the opposite and get the air to stay off the surface, or maybe we’re saying the same thing with different words?

Yes, not so much on the surface of the port but not lost wondering around tubulant inside the port.