Valve lift vs. port flow and cam selection

[GARY C]

So he was dumb even though he was winning EMC and developing cylinder heads but now he is smart because you found a quote that fits your belief system?

The point i'm making is i think Kaase doe's not give a S**T what the the flow numbers are.

Thats why he uses them?

[GARY C]

A Quote from Jon Kaase........"Spending a ton of time on the flow bench is a waste for me, too. I know what the port needs to look like after doing them this long. I also see guys try to match the head to the cam, and that's a load. The head doesn't care. You should be matching the cam to the engine: how big it is, how much compression it's got, what rpm it'll turn. The engine doesn't do the same thing when it's running as you might think it does".

I know Jon is very well educated and his achievements speak for themselves. My question is if you do not have any numbers to go off how do you take a educated guess on cam specs? I think what jon is saying don’t get caught up on squeaking every last cfm out of head. Get a number and as most porters will tell you when it makes the right sound your there. Doesn’t matter what the numbers say.

In one article Jon talks about picking 2 cams for an EMC build, he references them as a big cam and a small cam, both are on the same LSA, I know of one method that gets threads locked and uses valve size, engine CI and over lap for picking a cam or you can post your build here and get 5 to 10 different "educated" guesses as to what cam you need.

[bob460]

I will bet you Kaase can see the OCEAN.......... .........LOL

[GARY C]

I will bet you Kaase can see the OCEAN.......... .........LOL

My guess is you can see anything if you can get enough customers to believe your sales pitch... just ask any major mnf how they all sell the same shit that their competitor has to multiple people... Just convince them that you have something no one else does... Sold!

Now days all you need is a sales pitch and a like button.

[bob460]

I will bet you Kaase can see the OCEAN.......... .........LOL

My guess is you can see anything if you can get enough customers to believe your sales pitch... just ask any major mnf how they all sell the same shit that their competitor has to multiple people... Just convince them that you have something no one else does... Sold!

Now days all you need is a sales pitch and a like button.

Very true................same deal with the tight lash solid roller cams.

[ClassAct]

Who says

Decades of testing. That's "who says".
Welcome to the 1960's.

Way to take on small phrase out of an entire post and twist it up. I'll ask you again, who says 28 inches is the perfect number for depression?

The answer for me iss I don't care who says it is, because it isn't. When you make your data set all about what happens at 28 inches you miss too much.

I care infinitely more about the shape of the curve and how well a port flows at different pressures and at different lifts and a few other things way more than I care about flow numbers at 28 inches. I just don't care. I have heads lose some flow and make more power. It's all about the shape of the seat, the shape of the port, the shape of the runner in the intake.

BTW, IIRC Darrin Morgan has said he doesn't get excited (paraphrasing) about exhaust flow numbers. You can just keep making the exhaust port bigger and bigger and it will flow more and more and yet each time you get the port bigger than it needs to be, you are pissing power right in the toilet.

So yeah, who says all this crap is the end of everything? It sure isn't.

[GARY C]

Who says

Decades of testing. That's "who says".
Welcome to the 1960's.

Way to take on small phrase out of an entire post and twist it up. I'll ask you again, who says 28 inches is the perfect number for depression?

The answer for me iss I don't care who says it is, because it isn't. When you make your data set all about what happens at 28 inches you miss too much.

I care infinitely more about the shape of the curve and how well a port flows at different pressures and at different lifts and a few other things way more than I care about flow numbers at 28 inches. I just don't care. I have heads lose some flow and make more power. It's all about the shape of the seat, the shape of the port, the shape of the runner in the intake.

BTW, IIRC Darrin Morgan has said he doesn't get excited (paraphrasing) about exhaust flow numbers. You can just keep making the exhaust port bigger and bigger and it will flow more and more and yet each time you get the port bigger than it needs to be, you are pissing power right in the toilet.

So yeah, who says all this crap is the end of everything? It sure isn't.

Just curious, who can say it's not? Considering all of the data we use today has been derived from decades of development using 28" as a standard... Not an absolute, why do so many today want to try to pretend it has no value in everything they do?

[ClassAct]

Decades of testing. That's "who says".
Welcome to the 1960's.

Way to take on small phrase out of an entire post and twist it up. I'll ask you again, who says 28 inches is the perfect number for depression?

The answer for me iss I don't care who says it is, because it isn't. When you make your data set all about what happens at 28 inches you miss too much.

I care infinitely more about the shape of the curve and how well a port flows at different pressures and at different lifts and a few other things way more than I care about flow numbers at 28 inches. I just don't care. I have heads lose some flow and make more power. It's all about the shape of the seat, the shape of the port, the shape of the runner in the intake.

BTW, IIRC Darrin Morgan has said he doesn't get excited (paraphrasing) about exhaust flow numbers. You can just keep making the exhaust port bigger and bigger and it will flow more and more and yet each time you get the port bigger than it needs to be, you are pissing power right in the toilet.

So yeah, who says all this crap is the end of everything? It sure isn't.

Just curious, who can say it's not? Considering all of the data we use today has been derived from decades of development using 28" as a standard... Not an absolute, why do so many today want to try to pretend it has no value in everything they do?

I for one can say 28 inches is not the do all, be all, end all depression. If you don't agree I'm fine with it. If you have a flow bench, it doesn't take very long to figure out that 28 inches may be convenient as a "standard" (sort of like use the @.050 numbers on a cam) for a quick, simple method to try and compare two ports but that's all it is.

The OP is making a decision on how much lift to use based on flow numbers at 28 inches. And I'm saying put the intake on the head and flow it. I'm betting whatever break over it has will be less if not gone.

Or, maybe flow the head at say 20 inches, or 15 inches and see what you find. And then flow the port at say 42 inches and see what you get.

You can force almost any port to back up if you put enough depression to it. That's my point. So I'm saying do base your lift number on flow at 28 inches. Stick as much lift in there as your valve gear can reasonably tolerate and use a lobe that won't kill itself.

[bob460]

Just curious, who can say it's not? Considering all of the data we use today has been derived from decades of development using 28" as a standard... Not an absolute, why do so many today want to try to pretend it has no value in everything they do?

I for one can say 28 inches is not the do all, be all, end all depression. If you don't agree I'm fine with it. If you have a flow bench, it doesn't take very long to figure out that 28 inches may be convenient as a "standard" (sort of like use the @.050 numbers on a cam) for a quick, simple method to try and compare two ports but that's all it is.

The OP is making a decision on how much lift to use based on flow numbers at 28 inches. And I'm saying put the intake on the head and flow it. I'm betting whatever break over it has will be less if not gone.

Or, maybe flow the head at say 20 inches, or 15 inches and see what you find. And then flow the port at say 42 inches and see what you get.

You can force almost any port to back up if you put enough depression to it. That's my point. So I'm saying do base your lift number on flow at 28 inches. Stick as much lift in there as your valve gear can reasonably tolerate and use a lobe that won't kill itself.

What lobes are reasonably/gentle for street/strip use in the .750-.800 lift range?

[KnightEngines]

The crane .438" endurance racing lobes with 1.8 rockers will get you there.
Better spend up on lifters, springs, retainers & Ti valves tho, .750"+ lift is hard on shit no matter the lobes.
Valve train of choice for that kind of setup is 5/16" stem Ti valves, smaller dia uber $$ springs, tool steel retainers, smaller than the regular 10 deg style locks, shaft rockers, 3/8" pushrods.
The lighter it all is on the valve side the less spring you need to keep it under control, the less spring you need the easier you make life for the lifters, pushrods & rockers.
The stiffer you make it on the pushrod side the less fatigue inducing flex & the lower chance of some wierd harmonic busting shit up.
It's cheaper to spend more up front than replace busted stuff.

[CamKing]

I'll ask you again, who says 28 inches is the perfect number for depression?

No one. It's just used as a std, for comping one port to another.
The Superflow SF-1020 flow bench will flow a port at up to 65".
One thing though, if a port is turbulent at 28", it's not going to get better at 65".

To say "Put as much lift in it that rocker gear will take", without knowing if the port is going turbulent at a given lift, is horrible advice. You're helping no one with a statement like that, and you're not teaching anyone anything.

A flow benches is just a tool, and only as good as the person using it. Same could be said for micrometers, but I wouldn't advise engine builders to stop using them.

[CamKing]

The point i'm making is i think Kaase doe's not give a S**T what the the flow numbers are.

I can guarantee you, he cares if the port gets turbulent past a given lift.
I talked to him a few years ago about the 4-valve EMC engine he built, and he knew the flow numbers on those heads.

[Steve.k]

If you dont have any numbers how in the world to you even know what to grind? Keep grinding cams till hp falls off or something breaks? Seems like a wild shot to me.

[ClassAct]

If you dont have any numbers how in the world to you even know what to grind? Keep grinding cams till hp falls off or something breaks? Seems like a wild shot to me.

No one said ignore the numbers. I said don't base your lift on flow at 28 inches. Especially if you don't flow the head with the manifold and carb attached.

That's what I'm saying. Every port is turbulent. More depression will make a port more turbulent sooner.

[77cruiser]

The point i'm making is i think Kaase doe's not give a S**T what the the flow numbers are.

I can guarantee you, he cares if the port gets turbulent past a given lift.
I talked to him a few years ago about the 4-valve EMC engine he built, and he knew the flow numbers on those heads.

Would you think that people of Jon's caliber may tend to nonchalantly BS just a bit.