cast dart 165cc test head for novice

[steve cowan]

Did you put a valve in from the top to account for the stem or no valve at all?

Gary,
I turned the valve upside down, it didn't encroach past the bottom of guide, greased stem to stop leakage,

normally you want the stem to go through as if the valve is in but it eliminates the valve head influence.

Gary,
Good tip and thanks for sharing,
You are correct as well Groberts, I know this horsepower deal is a life long journey, I don't expect to learn everything over night and I don't expect you guys to tell me all the secrets, that is why I have been on speedtalk since 2011,I am here to learn and enjoy the process, great tips here all ready, using different depression to test and look at air flow, even something as simple as a piece of string on a piece of wire, very interesting, stick my finger in the Port and feel the air very interesting, it will be interesting when I have a look at the as cast runner on the bench, I am not here to chase the number, I have read enough on this forum where you guys make x horsepower with x CFM, knight engines (Tony) is in the process of rework on the alloy 215 heads, he is doing a intake, exhaust, chamber, that in itself will be a wonderful learning experience for me, looking, measuring, flow testing, visualisation of air etc, I agree getting some junk heads to grind on, I have to make a lot of mistakes to learn I spose and there will be more failures than wins but I am sort expecting all that as well,

Steve C

[GARY C]

Gary,
I turned the valve upside down, it didn't encroach past the bottom of guide, greased stem to stop leakage,

normally you want the stem to go through as if the valve is in but it eliminates the valve head influence.

Gary,
Good tip and thanks for sharing,
You are correct as well Groberts, I know this horsepower deal is a life long journey, I don't expect to learn everything over night and I don't expect you guys to tell me all the secrets, that is why I have been on speedtalk since 2011,I am here to learn and enjoy the process, great tips here all ready, using different depression to test and look at air flow, even something as simple as a piece of string on a piece of wire, very interesting, stick my finger in the Port and feel the air very interesting, it will be interesting when I have a look at the as cast runner on the bench, I am not here to chase the number, I have read enough on this forum where you guys make x horsepower with x CFM, knight engines (Tony) is in the process of rework on the alloy 215 heads, he is doing a intake, exhaust, chamber, that in itself will be a wonderful learning experience for me, looking, measuring, flow testing, visualisation of air etc, I agree getting some junk heads to grind on, I have to make a lot of mistakes to learn I spose and there will be more failures than wins but I am sort expecting all that as well,

Steve C

Documentation is your friend for learning long term trends of what works and what doesn't, I had several close friends I raced with and we all had very similar combinations so we could learn from each others data.

[groberts101]

Hypothetical calculation If you have an average port speed in a 2.2 square area of 300 fps at .200 how fast do you think the air speed is flowing past the curtain area at .200 lift = about .64 square area ? 2.2/.64=3.44 so 3.44x300 fps is 1032 fps.
1X mach speed is 1125 fps. "near or past mach speed at the seat"? Not disputing you about the radius below the seat tho.

Not here to prove someone else wrong just presenting what I understand wanting to learn if I am mistaken so don't beat me up too bad

Your math is way off here bud. Just because a 2.2" port area flows 300fps at max lift doesn't mean it flows that same speed at only .200". And if it does move air at 300fps @.200?.. then you're into some serious choking hazard when it finally hits .5 or .6. at full lift.

[steve cowan]

If you look on my screen shot with velocity it proves exactly as you say Grobs,
How fast can airspeed get at 28""??
I assume velocity will go up as depression is increasing to speed of sound if the Port can handle it, I might be way off here though, need to read more.

[randy331]

Gary,
I turned the valve upside down, it didn't encroach past the bottom of guide, greased stem to stop leakage,

normally you want the stem to go through as if the valve is in but it eliminates the valve head influence.

The valve head is in the chamber when the engine is running, it should be for any useful info from a flow bench too.

Randy

[steve cowan]

Hi randy,
Did I read a while ago you did a set of these cast dart heads for your work truck with good results??
I flowed the intake port with no valve to see what the Port potential could possibly be, again I ask if the Port will go turbulent with no valve, is this the correct procedure to test port potential? If not what is a good way to check what the Port can possibly do,
Interested in your opinion randy if you are willing to share.
Steve C

[GARY C]

Gary,
I turned the valve upside down, it didn't encroach past the bottom of guide, greased stem to stop leakage,

normally you want the stem to go through as if the valve is in but it eliminates the valve head influence.

The valve head is in the chamber when the engine is running, it should be for any useful info from a flow bench too.

Randy

I guess the theory is if it flows more without the valve head in the way then it's a chamber issue and if it doesn't then the port is the restriction, I have only tried it a few times but didn't really see a big difference.

After having an issue with flow on a test head with a 2.08 valve from .200 to .400 I learned to rough in my chambers first so it takes that out of the equation and saves you the sorrow of making the port to big when the problem is really in the chamber.

[mag2555]

Not by a long shot!
Just because you remove the valve and you flow goes up it may not be due to shrouding as the bulk of air may be taking a much different route passed the seat.
If you have a swirl meter you will see this very clearly as I have when I got loan of a buddy's meter some years ago over a noisy hot flow bench weekend!

I do agree that if your valve to chamber wall clearance as it realates to trajectory of the runner is less then your valve lift then. yes, that choke point needs to be delt with first!

[B Original]

I do agree that if your valve to chamber wall clearance as it realates to trajectory of the runner is less then your valve lift then. yes, that choke point needs to be delt with first!

Agreed but what's a choke point. Just think about it what is your choke point, what is the most restrictive part of the intake tract? It's is the valve seat. Make the valve seat area as efficient as you possibly can then you see more accurately what effect any of your other changes make. Especially blow 1/4 D. Which when the engine is running your valve lift spends half of its duration.

I don't see what benefit there is the flo a port without a valve in it?

[GARY C]

Not by a long shot!
Just because you remove the valve and you flow goes up it may not be due to shrouding as the bulk of air may be taking a much different route passed the seat.
If you have a swirl meter you will see this very clearly as I have when I got loan of a buddy's meter some years ago over a noisy hot flow bench weekend!

I do agree that if your valve to chamber wall clearance as it realates to trajectory of the runner is less then your valve lift then. yes, that choke point needs to be delt with first!

Thats why I said "The Theory" this would be a really good place for CFD if it can be mapped to actually show the difference of flow path with and with out valve even at max lift.
I hope I word this correctly but moving air creates a pressure wave in front of it but if there is nothing in front of that pressure wave then the air will act differently than if there was. Probably the wrong terminology but I think it provides the visual.

[steve cowan]

hi guys,
been tinkering with this cast head,thin down the guide slightly
i opened the Pinch from 0.980'' to 1.02''
MCSA was 1.91'' now 1.98'' did not factor in corner radius
IS CORNER RADIUS MEASURING IMPORTANT?????
layed down SSR approx 0.020'' and widened at the apex,
i found it difficult to get comfortable trying to shape SSR,i have a reverse cone carbide but struggled,i used a long shank cone shape bit then emery taped to try and shape a bit,practice yes i understand.any tips guys??
i still have not flowed the as cast port,have not flowed the exhaust yet either,hopefully on the weekend.
USING A FLOW WAND,piece of string on a piece of wire,i want to share my observations from today on the bench.
1/ At any depression and lift (.100'' - .650'' ) lift, string remains stable on the floor of the port over the SSR and past the valve into the chamber area.
2/ ROOF - ALL DEPRESSIONS
string is pushed towards the valve and does not go near the guide boss.
3/ MIDDLE OF PORT - ALL DEPRESSIONS,
divider wall-stable
pushrod side-stable
mid-port string bounces up-down,side to side it looks violent but it is not noisy.
NOW THE BIG ONE-
i have been having trouble keeping clay on the divider it gets sucked in,
i persevered and could get it to 15''
the software has parameters for correction of no radius,clay,inlet guide,intake manifold.
reflowed with no clay 216 cfm velocity 401 ft/sec at apex SSR
reflowed with clay at 5'',10'',15'' software corrects 232 cfm i did not check velocity,
the port sounded smoother,is this normal to gain from a clay radius ????
i retested 3 x times same result.
i am excited but curious any thoughts guys??
i sent an e-mail to jamesons equipment to see if they will send to australia i am looking for inlet radius guides,flow balls,valve opening tool,exhaust pipes.
any other companies worth checking out ?
thanks in advance for any feedback

steve c

[mag2555]

B original, I agree with you as to why the heck flow the port without a valve , but if in such a test it does flow more I feel much better that I might have a shot at .
1) gaining knowledge as to why that is taking place and may be working around that.
2) getting some peace of mind that all those metal chips and the time it takes to make them was worth it, lol!

[B Original]

I remember a post several years ago it may have been Fbird88. Forgive me if I'm pointing at the wrong person my memory ain't what it used to be. He talked about flow teating on a TBI head maybe a 192 casting with a water hose spray nozzle with no valve in it. I can almost see the same value and that flow test as doing one on the flow bench without a valve in it. Other than as an exercise of learning the function's of his flow bench

[B Original]

I would like to apologize and admit that I am wrong I would like to retract any criticism I had for flow on a cylinder head without a valve. I talked to Mentor that I have much respect for. He explain to me they was a small benefit of testing the flow without a valve head. As long as you had the valve stem protruding from the port. To the effect of port potential flow at infinite lift.

[randy331]

I talked to Mentor that I have much respect for.

Hey, GVX, would you share who that was ?

Randy