Intake Manifold Porting Show ‘n Tell

[steve cowan]

Do you use flapper paper, shank with slot cut in end to hold emery cloth?Do you use trans fluid to cool carbide cutters or achieve different finishing?I don't see anybody here cutting manifolds in half to easy access the ports?

I haven't used the flapper wheels. That's something I could try.

I only use a shank with slot and emery cloth for cleaning valve body bores.

I don't use any fluid. I'm not aggressive. The aluminum is soft enough, and doesn't generate any heat.

For different finishing, I'll use carbide burrs for a burr finish in the plenum into the runner, followed by 80 grit sanding cones, then finished with 120 at the port.

A good thing about the flapper is it can actually straighten the walls for you.
My opinion is rough on intake manifold.
40 - 60 grit or the burr deal .
Fuel sticks to smooth surface.
The only place I want smooth is over SSR in the head.

[steve cowan]

I keep finding things that weekend warriors and pros write on this website, and it gets me in serious trouble.. I bought a damn wind tunnel and a smoke machine in this weekend (only approx 1.3 meters long) but i blame Erland for that i have to figure out the stall thing I should practise port matching manifolds and not playing with a wind tunnel, but thats the way it goes now




-juhana

Be interesting on your opinion on smoke.
I always wondered what is going on inside the smoke that we can't see??

[steve cowan]

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I like the pin idea but I have never done it.
Hard to see in photo but I dykem and scribe intake port on head and intake. I also scribe a centreline on head and intake to line back up each time.
It is best to have engine mocked up before port matching etc.
I put 20 hrs into this Vic jnr intake.
This is start of rough in as per photo.
I get the port match correct and work back from there.

Nice work there Steve.

That's the difference between port matching and gasket matching. An intake can be prepped for a particular combination, or prepped for general use on any engine.

One thing I see done when people port match -
They grind to suit a 1206 as an example but the PRP has area total of 1.94".it not really going to help in my opinion.

[juuhanaa]

When the shape is close and you want to blend it up, the largest flap wheel that fit can do it. It is done when you see these lines or cross marks. Can also help to get all ports the same size quickly. I use a drill with this to manage the speed and direction.

[ChopperScott]

What are people's weapons of choice, electric or pneumatic?

Pros?

Cons?

I prefer pneumatic. I'm comfortable using two fingers on the lever to control speed on the die grinders. The drill has a regulator on it.

porting tools.JPG

[steve cowan]

I use the flapper to get the finishing surface, WD40 works well.
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I just cut this intake to see how it would work, I have never welded a intake manifold before.

Wow! That is wild. I definitely would not attempt that.

On one of my audio speedtalk CD
When Phil Martin was porting for nascar,he said he has around 50hrs to do one intake manifold.
They would cut in half, port,weld back together, he said they run the intake manifold approx 0.100" bigger than the head port flange.
These would of been the days when they were close to turning 10000rpm.

[steve cowan]

Darin Morgan has said some of his baddest looking ports as far as finishing goes have made most power and run good at the track.i know I spend way to much time making it look pretty, if the CSA is correct for application it will run regardless whether burr or 40 grit

[juuhanaa]

I keep finding things that weekend warriors and pros write on this website, and it gets me in serious trouble.. I bought a damn wind tunnel and a smoke machine in this weekend (only approx 1.3 meters long) but i blame Erland for that i have to figure out the stall thing I should practise port matching manifolds and not playing with a wind tunnel, but thats the way it goes now




-juhana

Be interesting on your opinion on smoke.
I always wondered what is going on inside the smoke that we can't see??

Do you remember the black and white movie where the man had glasses the size of the bottom of a bottle? I think he show stall using a smoke. I have used a thermo couple to measure differences in speeds, but i want to try a stall like in the movie, and measure if it heats up inside of it compared to the faster/straigher and colder, not necessarily air but airstream.

This is the baby, but now have to go sleep and "tomorrow" ill post a pick about my grinders

Screenshot_20221127021402.jpg

-juhana

[SpeierRacingHeads]

Here is my porting room...

[Hilton]

Can a intake manifold be to big for a certain cubic inch ? especially after porting, Thanks

[bob460]

Can a intake manifold be to big for a certain cubic inch ? especially after porting, Thanks

YEEEEEEEEEP!!!

[steve cowan]

Can a intake manifold be to big for a certain cubic inch ? especially after porting, Thanks

In my opinion it can be if we are only talking cross section area.
I have talked to guys who dyno alot and when you bandaid a to small runner in the cylinder head with a big intake runner on the manifold it rarely work out.
Obviously there would be some leeway but how much I don't know.
If one section of the intake tract is to small for rpm and application it will go into sonic choke and changing other things like spacers,cam timing, rocker ratio,lash etc won't fix this.
I spent 12 months track testing a to small pushrod pinch and it was a rpm governer at 6000rpm.
The car would cross the line at 6300rpm but testing shift points to 7000rpm made zero difference.
Just because an engine revs higher don't always means it is making usable power.

[Hilton]

I have a bowtie manifold that's only been port matched to the felpro 1206 and AFR 220 on a SBC 331 been wondering if I set out the manifold for plenum porting would I see any gains Thanks

[steve cowan]

I have a bowtie manifold that's only been port matched to the felpro 1206 and AFR 220 on a SBC 331 been wondering if I set out the manifold for plenum porting would I see any gains Thanks

What application/ rpm
A few more details if possible please, converter, gear,car and weight etc

[Hilton]

Drag Race, 66 Chevelle, 2700 lbs, 6400 converter, powerglide, 5;57 rear, 8400 RPM at finish line.