Head flow testing.

comnoz

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hobot said:
Do your shop's strange noises get noticed outside?

No doubt about that, but I am not in the city so there is no noise ordinance.
 
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If a Norton motor is redlining in Jim's garage and nobody is around to hear it, does it make a sound?
 
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Dam right it does but not as loud as Peel's 2-1> open megaphone on stuck throttle beyond tach registering. Didn't not miss a power beat but shed sounded like orchestra dropped through the roof as engine stopped. There's got to be something to this sound tuning thing but don't know if louder or softer better intake wise or exhaust sounds of flow. People shoot at this and that pretty routinely out here, way more than car horns or dogs barking at nothing. Ok now get back to making more power loads for us Jim.
 

comnoz

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Well I got a new mark for an RH10 head. 3mm oversized valve.
I had some new seats made with the new angles already cut and spent a few hours getting them just right.
Here is the before and after graphs. Still using the 30mm port diameter with a radius to match a 32mm velocity stack. Jim

Knuthead003_zpsd920fc24.jpg
 

comnoz

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Since the parts to finish my new billet motor are being slow to get here I decided if I was going to get some riding in I better do something else. So I cleaned up the head from my old motor that I blew up last fall and plan on installing it on the 914 cc stroker motor that I started a couple years ago. I had wanted to try it as a "twingle" but decided a few other parts like the clutch and trans were not up to it -so I installed a conventional cam.

Anyway I put the head on the flowbench just to see how it compared to what I have been doing recently. This head is an RH4 with inserts in the intake ports that make the shape similar to a Fullauto. It was one of the heads I used when developing the porting in the Fullauto head. The ports start out at 32mm and drop to around 30mm before they open back up to a 1.5mm oversized intake valve. The guides have not been re-angled but smaller seats have been installed for the 1mm smaller exhaust valves so I could get enough valve to valve clearance. With 880ccs and a custom cam pretty close to a Webcam 12a it made a peak of 68 horse at 6800 rpm in street trim.

Here is the head on the bench.

Fueliehead006_zps6513401b.jpg


Fueliehead007_zps0d008ac2.jpg


Here is the flow graph. The blue line is my Fuelie head. The light violet line that is right about the same is a fully ported Fullauto head with a 1.5mm oversized intake valve. The green line is a stock Combat head and the red line is a stock rh4 head.

Fueliehead010_zps0a2fa494.jpg
 
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Jim,
How many Norton (or other) heads have you reworked over the years, to get to this level of knowledge? As not every step is a step forward it must get frustrating at times.
Martyn.
 

comnoz

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Matchless said:
Jim,
How many Norton (or other) heads have you reworked over the years, to get to this level of knowledge? As not every step is a step forward it must get frustrating at times.
Martyn.

That's a good question. I bet if I had a dollar for each head I could about buy a round for the whole list. I do remember my first "port job" was on my Honda Super 65 about 45 years ago. It got a bigger intake valve from a Briggs and Stratton. Jim
 

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Jim, one of these days, I assure you, I will send you my Dreer/Baisley 880 head.

I'm getting VERY curious. I'd love to see it graphed against those four!
 
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Jim

I am not sure what the advantage of the twingle motor would be. I guess more traction is the idea. I sure don't like the idea of it for the Norton. It would be pretty hard to kick over! I have a 75 Ducati 900ss. The previous owner had converted this machine to a Twingle. I didn't realize this when I bought it. There was a bit more vibration and something didn't quite feel right. The sound was different. The think is with the Duc though the two firing inpulses were still 90 degrees apart. I was able to put it back to standard in about an hour by removing the front head and turning the engine over a few times to get all the dots lined up as they were originally intended.

I am sure your Norton engines are putting out more power than this 900ss. Apparently they put out about 68 HP at around 7500 RPM

Nigel
 

comnoz

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Matchless said:
Jim,
As not every step is a step forward it must get frustrating at times.
Martyn.

Martyn,
Here is yours. Big seats, porting measures out good and ready for cut down guides.

Martynshead008_zps92bac0e8.jpg


And here it is with the seats cut and ready for 3mm oversized valves.

Martynshead010_zps6c4421bb.jpg


Now to the flowbench.

Martynshead014_zpsfd680b3f.jpg


And here is what you get when something isn't quite right. Yours is the blue line along with three of the heads I posted yesterday . Time to go back to the porting bench and figure out what is wrong. Jim

Martynshead013_zpsfe2b7be0.jpg
 

comnoz

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tricatcent said:
Jim

I am not sure what the advantage of the twingle motor would be. I guess more traction is the idea. I sure don't like the idea of it for the Norton. It would be pretty hard to kick over! I have a 75 Ducati 900ss. The previous owner had converted this machine to a Twingle. I didn't realize this when I bought it. There was a bit more vibration and something didn't quite feel right. The sound was different. The think is with the Duc though the two firing inpulses were still 90 degrees apart. I was able to put it back to standard in about an hour by removing the front head and turning the engine over a few times to get all the dots lined up as they were originally intended.

I am sure your Norton engines are putting out more power than this 900ss. Apparently they put out about 68 HP at around 7500 RPM

Nigel

Nigel,
I don't know what the advantage would be either other than I always liked the sound of a big single cruising down the highway. The idea was an experiment to see what happens. With the quick change cam it would be easy to switch back to a 360 degree twin. I really doubt that the trans would be able to handle the torque coming in big hits so until I can do something better for a trans I will be staying as a twin. Jim
 
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Why not down size the twingle's jug sizes to up the rpm & gearing to a tolerable deep thumping Commando one of a kind hoot. Might need a heavier flywheel to work nice.
 
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comnoz said:
And here is what you get when something isn't quite right. Yours is the blue line along with three of the heads I posted yesterday . Time to go back to the porting bench and figure out what is wrong. Jim

Whack those valve guides flush with the port roof and hog them things out to 39mm - hell yeah I know how to port! :twisted:
 
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hobot said:
Why not down size the twingle's jug sizes to up the rpm & gearing to a tolerable deep thumping Commando one of a kind hoot. Might need a heavier flywheel to work nice.

Wrong, wrong, wrong. Twingle needs to be 1,007cc, aluminum flywheel and Drouin supercharger. Be a helluva statement bike.
 

comnoz

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Well all it took was a little messaging to keep the air from lifting off the short side radius and what a difference. Now all I have to do is make both ports flow the same. Jim

Martynshead015_zps9b863a8b.jpg
 
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Jim,
I'm as excited as a child who has just got a new bicycle for Christmas. Can't wait to try it out!
Looks like 158cfm. I can't make out the top figure.
Martyn.
 

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Jim,
I've just read this entire thread for the 3rd or 4th time (my Missus really thinks I've lost it!) and our email exchanges, and I'm sad to say, I'm still not really clear on a few things!

It seems that for hot street use there are a few 'choice' options:

1. A stock FA head: this compared very favourably with some good heads, in particular with regards to inlet velocity, which you said is key if you want a wide powerband.

2. A ported FA head with stock valve sizes: this just performed better at everything over the stock head.

3. A RH10 with re-angled 3mm oversized valves and your new 'cut' to the seats and valve: gave brilliant flow results (despite you previously thinking it would not) but you didn't post velocity figures.

Due to the cost / benefit, it seems that a FA head with the full oversized valve work to be for serious racers and / big engines only.

So Jim, by way of a summary, or conclusion, could you please post a graph for flow, and a graph for velocity, to compare the 3 heads described above? And perhaps a stock RH10 as well, just by way of comparison?

It would really help me decide my next course of action, and I imagine there are others in the same boat as me!
 

comnoz

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Fast Eddie said:
Jim,
I've just read this entire thread for the 3rd or 4th time (my Missus really thinks I've lost it!) and our email exchanges, and I'm sad to say, I'm still not really clear on a few things!

It seems that for hot street use there are a few 'choice' options:

1. A stock FA head: this compared very favourably with some good heads, in particular with regards to inlet velocity, which you said is key if you want a wide powerband.

2. A ported FA head with stock valve sizes: this just performed better at everything over the stock head.

3. A RH10 with re-angled 3mm oversized valves and your new 'cut' to the seats and valve: gave brilliant flow results (despite you previously thinking it would not) but you didn't post velocity figures.

>the velocity is down some in comparison to the Fullauto head. The port cross section must be larger to slow the air so it will make the turn into the valve pocket. The metal simply is not there in the rh10 head to get the velocity you can with a Fullauto. Also the exhaust port is inferior<

Fast Eddie said:
Due to the cost / benefit, it seems that a FA head with the full oversized valve work to be for serious racers and / big engines only.
>generally yes<

Fast Eddie said:
So Jim, by way of a summary, or conclusion, could you please post a graph for flow, and a graph for velocity, to compare the 3 heads described above? And perhaps a stock RH10 as well, just by way of comparison?

>when I get some time I will see what I can post together. The information is spread over a few different hard drives so it makes it a bit tougher<

>for a street hot rod with a 850 or smaller motor is is hard to beat a Fullauto with a bit of port cleanup. For a bigger motor or a race motor where you are looking for every little bit then big valves are necessary to get there<

Fast Eddie said:
It would really help me decide my next course of action, and I imagine there are others in the same boat as me!
 
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