5 golden porting rules - #1 

Smokey done. Almost genius work

High performance Harley... That's an oxymoron

I wish youtube would go above 2.0x sometimes.

Intake ports are totally turbulent from idle up. There is no getting rid of it!

There is no any reason open port too much, velocity is King!

I agree with you 100%

I don't have access to proper tools so I wasn't comfortable with messing the the valve seats on my RB20DE Neo, but what I did do is polish the comb chambers up to 2000 grit completely smooth and also took off material off the short side to help with tumble. Additionally I smoothed out 95% of the entire intake plenum which should help a tiny bit as I did not like the casting on the inside. I just wish I had a proper dremel and bits so I could have gone deeper and more precise. Also lapped the valves which ended up really nice.

Is that the objective to porting a head to remove material from the intake and exhaust port to get more air in and out of the engine quicker.

He is a Gearhead lol

Sharp edges will crack easier than rounded edges.

Have patience, I'm sure he'll get around to that stuff eventually!

​@@nathanbopp6163he's not talking about shaping rough edges into a port. He's talking about casting flash and roughness in OEM ports and tracking improvement as you go on OEM stuff. Not improving already prepped heads

It won’t matter in a hundred years…. One of two things will happen. 1 …No more internal combustion engines will be in service due to technological advances and or 2- no human beings left alive to talk about it because we ported our heads out of existence over oil….destroying any chance of survival by killing our planet 🌎

Sometimes it’s better not to make any comments…. Too many sensitive people out there trying to learn how to port cylinder heads. Fact is every cylinder head is different, every performance engine build is different. Porting cylinder heads is just the tip of the iceberg for horsepower and torque. What’s your compression ratio? What’s the displacement of your engine? Are you running headers and what size? Are you running a performance camshaft and what’s the duration? Are you running a aftermarket intake manifold… which one? Where do you want your power curve for 99% of the performance fans that drive street cars .You can port a cylinder head to perfection and then use the wrong size camshaft or wrong intake manifold because the one you bought looks cool…. But what ever you gained porting and contouring your intake and exhaust ports was lost because you used a bad combination like a sheet metal intake with short runners and a cam that wouldn’t idle below 1000 rpm’s . Great I got 650 hp peak at 7000 rpm’s. But lost 60 foot pounds of torque and 50 hp where I’d prefer to be enjoying it … 2000-6000rpm Headers without considering the primary diameter for your engine displacement and static compression ratio. Lots to consider when diving into a project.

I got his 'A' series engine book. It's encyclopaedic. I spent a fortune modifying my allegro estate, and it was all worth it

Always learning something new when listen him unique knowledge how to modify ports, seats, valves and chamber. Probably he is one off the best headmaster what I know.

Percentage is metric it is based on 100. Take whatever your width is and divide it by 100 times by 91 3.g. 2.02/100 x 91 =1.83.

The main reason that the valve sizes are what they are is that the intake valve has atmospheric pressure pushing the air into the cylinder and on a naturally aspirated engine any restriction at all in the intake system generates a power loss. The exhaust valve has pressure from the piston pushing the exhaust gas out, and exhaust valve restriction mostly generates internal EGR and reduces scavenging a bit both of which creates a power loss, but not by the same amount. Intake needs to have priority in a naturally aspirated engine. In a turbocharged or supercharged engine it is possible that reversing the valve sizes might be helpful but with the exception of I think some race-prepped nailheads, I don’t think it’s a common way of doing it.

They had these things called books back then; one read them, and applied the information gained to the problem. I have as many of the greats as I can get my hands on- Smokey Yunick, Phil Irving, David of course, Carroll Smith...etc. Nowadays people watch something on YT and consider themselves instant experts. This video does nothing more than reinforce the concepts David was writing about decades ago, as he says.

Chalk one up for "rough" port finish ?? Some guys are trying to carve golfball pips in. An engine builder told me SBC heads don't need any exhaust port work for the street.

Cutting pips do help but you need to know where to put them, if you do the whole port it doesn’t work.

Built several. If I did it again I'd consider a leaf blower or 2. The best is a roots blower.

Lmao i drive 2 valve heads and tons of other people do as well

It's never too late bro

I have done a goodly number of vortec heads and I seem to remember that in most cases of aftermarket heads they do almost as well on a 1.94 intake as they do on a 2.o2 so, for cost sake, stay with what you have.

@@DavidVizard thank you sir, I appreciate the response!

CID does.

@@racerd9669 Are you referring to Competition Induction Designs?

Doesn't matter unless the CFD result is intended to produce quantitative total airflow results. The solution shows the relative velocities and overall flow distortion (pretty bad, but typical). That's sufficient information to act on.

@Mr. Moto The air speed in the port and the direction of flow won't change as the pressure delta is affected by the cyilinder filling?

@@ForceEngineering The pressure difference across the head will affect mass and volumetric flow, and velocity. It won't effect the flow field structure much. Yes, velocity change will change the Reynolds number - which can change the flowfield - but these flows are fully turbulent, so it's a weak effect. It is very important that the CFD model uses a turbulence model, and that it is operating correctly. This flow has a lot of boundary layer separation (blue regions). While the turbulence increases pressure drop, it actually suppresses the separation and helps overall. Poor turbulence simulation is one of the most common problems encountered with CFD.

Play at 4x so you won't be wasting your time.

@@hotrodray6802 hey man speed kills! But I guess that's why we're all here...

The mechanism would be too complicated and fragile and would not hold up to the stress of combustion.

Sleeve valves. They did that on piston aircraft engines. Check out the Napier Sabre and Bristol Centaurus.

Look up Knight engine - silent as a Knight, I think their slogan was.

I think there are some Indy car engines with rotary valves for max efficiency. Maybe this isn't what you're talking about

I am interested if sliding valves have been used in performance automotive engines. Anyone got a link?