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TWIRL - Swirl & Tumble DV - King David’s terminology:) I’ll try not to do Monty Phython during a ten day class:) Constitutional Peasant's & Knights of Ni Roger the Shrubbery specialist becomes a head porting technician:)

What mite be the problem when at high lift the inches of water go down say 25” to 24”

Recommend a good electric die grinder? Bought a foredom pedal speed control My old mutabos had adjustable speeds so pedals would work on them. They finally burned out though Any more info on your (model?) sonic tester? at the point I really need to start using one. Esp for imported alum heads, some areas the metal gets goofy

Nice job...really dig your finish work. Are you using any carbide here or just rolling it for the most part?

So, maybe this winter you let me put AC in your garage so it won't be an oven next summer? REAL AC, not that lil portable thingy.....

I like feeling dumb watching smart ppl figure out new ways of finding power

I don't care for having the swirl change direction during the stroke, but its probably just my prefrence and no dyno tested theory that it matters.

I left a comment already but as I said before. When you start thinking about the flow path, include the fuel path. While rotation is mixed with tumble. The fuel likes to stay over the exhaust valves. Concentrate the flow from the divider. Inside out rotation. With the fuel path. The outsides of the port slow down because of the spread. The high speed remains in the middle. Left port spin counter clockwise. Right...clockwise. Another point to think about, is timing. Not ignition, but the entire delivery timing. At 9000rpm, the tumble or swirl doesn't get a chance to complete its journey. It is ignited when it barely reaches the back side of the cylinder. Don't forget the overlap period and what the exhaust vacuum is causing to the intake charge. Straight in and Straight out. No time to tumble or swirl. Another method used to cause low rpm mix is to alter valve timing. Individual actuation of each valve can be tailored to change valve timing. Not on this application but most ohc configurations will alter valve timing on each valve. Nice white board. As I stated. Maybe I should do my next video from the shop.

Hmmm what an interesting topic ... would love to see back to back dyno tests ... thanks CS very interesting

Interesting topic. How critical is swirl/tumble when comparing port (wet intake) vs direct fuel injection? Many years ago, a pro stock engine builder commented that he preferred a more gentle swirl motion. His theory was that a slow mixture motion during combustion resulted in a more complete burn (compressed and still mixture around the spark plug) vs a fast motion, where I envision, the flame kernel swirling around creating layers of fresh to burnt mixtures within the chamber.

there the holden GM v8 that usually can only run 26 degrees of timing in there got a really flat valve angle to the pistons and they always had good torque range . they have a very iconic exhaust note over the sbc and LS even fords. they just missed the last generation change they needed before LS was used

Very interesting good stuff

Now you have me pondering😂😂😂, recently my engine suffered bent valves and the cylinder head is going to get rebuilt, an X20XEV engine, what chance you have access to a cylinder head from this engine and do an evaluation of it in terms of what came from the factory and what can be done...i'm from Trinidad and Tobago, watching DV's channel, i know he resided here late 80's to 90's, his teachings are well known by the old school mechanics here, for my X20XEV engine, not enough quantity of cylinder head valves were located locally, from luck a cross refferenced engine from the USA market was found, a A20DMS motor from a suzuki Forenza...other engine codes be X20SE, X22SE from chevrolet optra and Daewoo Nubria....looking forward to see if my request can be fulfilled

Sounds like it's time to hook up with a 3D printer.

Love the whiteboard and sound effects Charles.

If I wanted to make a poly quad engine, I'd use different sized valves, the ports would be like you suggested, the valves would be nearly parallel to take out as much of the pent roof as possible, make it almost like a diesel engine combustion chamber, and the spark plug in the middle would have a cap over the electrode with little holes drilled around the sides. Finally the piston crown would be shaped sort of like a diesel piston, but without the dish. The piston crown would be in a shape that accents the reduced pent roof chamber. With a direct injection and strong igntion system. Maseratti Nettuno engine in the MC20 uses such a combustion system, minus the offset valve sizes.

Asked Warren Johnson on DragBossgarage live chat. How important is swirl on a Pro Stock engine? He said very important and to make an efficient combustion chamber or you will have a bad one like a HEMI ! I think you have geat ideas I know you will make it work. It would be great if you were able to test that small bore some how. And yes putting the swirl port heads on my 79 350 it spark knocked and has to back the timing off.

4 valve diesels have 8 intake ports, and great attention is paid to swirl. I have several diesel heads to look at, and they all adhere to the same basic principles

Any word on when dv's polyquad ecoboost will be ready

When in doubt, just add some swumble! Lol! Great topic and food for thought!

A negative effect may use to your advantage is to let the left exhaust port have reverse flow on overlap while right hand side port is limited.

Changing the low lift flow on one of the exhaust valves would also help during overlap. Really interesting stuff to think about

I believe DV or 1 of his students called it "Twirl"

These fascinate me, is there anybody that can do this do cylinder heads? The ex pro Stock guy he has on the show in the past. They never answered the email at all, same with a DV system cam to be spec'd?

I don't know what DV calls it but I give you my permission to call it stumble.

On both my Hondas (H22-A4, K20-Z1), when not on the VTEC cam lobe, staggers the valve opening on both the intake and the exhaust lobes, opening one slightly before the othe and closing the same one slightly earlier. I assume this is to create swirl.

Nice video what's your email address to send some head image to you

Tumble is superior to swirl in my experience.

Love this video, almost no info on this topic for 4 valve engines except for DV of course. Greatly appreciate the knowledge!

Your modern 4 valve diesel head and bowl combination. Volvo does it quite well.

3 valve Hondas CVCC. They staggered the intake lobes on the cam.

Running a set of Ferrea 5000 series valves in some old Ford J code small chamber heads with minimal port work other than exhaust ports opened up with nice bowel blends, and pockets opened up. I got about 160cc intakes with 65cc exhaust ports camshaft I’m running could stand a little more compression to help with air speeds, stock A code 289 Ford with flat tops pistons, I’m right at 10-1 compression with a Isky Mega 280 cam net lift is .551 at the seat….

Hay Charles. Another live would be nice. With the hot temps outside. Record one in a comfy place.

Why were you guys saying that DV's huge milling of the head creates issues that might not be worth it? ( shorter pushrods)

Are you part of the 318 now even of the plans changed and utg is not involved ? Hope they will test all your incredible work ! Love the 318 !

⅛" Long shank carbide burrs work great on my pencil diegrinder when I'm doing little cylinder heads. You'd be surprised at the price for an assortment of 10 on Amazon.

Flow with valves in the guide backwards. Then at least you have the stem protrusion to provide some reality and seal the guides off. ❤

Thanks for your tip to use WD40 on grinding stones with alloy, I rarely using stones on alloy heads anymore unless the spot really needs it, as it drove me mad they just clog so fast. Some scientist maybe knows why?

Duct tape had me confused, untill i realized what it was in the close up.. Nice work.

🔔😎 YeeeeHaaaaw!!!!

Not to discourage your attempts, Charles, but flowing without the valve will not transfer over to the final assembly. The vacuum draw on the port without valve will migrate the vacuum reading towards the center. Especially on those short ports. Instead of focusing on the exterior swirl, reverse that idea completely. Swirl will occur from the center out. The air speeds on the port devider will travel faster with less resistance. While the outside slows down around the radius. Use the combined valve as if they were the alternate intake and exhaust valve during overlap. Treat them like a hemi with two sets in the same chamber.

I did my 4 valve 1.6 Aveo head. The bowls were terrible. I blended everything with little material removal. My buddy did a perfect valve job as usual. It accelerated better than stock and still got the same MPG maybe a little better.

Definitely a visible difference in size ..I hate you was not ab!e to use the valves during testing ...still good work regardless .

You cannot have swirl when the intake ports are symmetric about the cylinder centreline. zero or near zero. that's why diesels rotate the valves so they are not symmetric. Or the 1990 LT5 which blocked off one port at low rpm. A small engine like that can easily be 2 valve and hit 10.5k. I don't know why they make it more complicated.

It seems like you are on the right track for inducing swirl. It's a similar theory I had for four valves per cylinder heads.

The 4 valve stuff I work on still has 2” valves 😎

Is it good swiral toward to exhaust valve?

Someone on your continent should send you a Volvo 530 head for a B230 engine to develop. :)

I would like to see and hear it run and what kind of horsepower at the end of it

A+ work as usual.