Head flow testing.

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Jim,
I am watching this with interest. Are these the mods. you will be doing to my head?
Martyn.
 
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Jim, I gotta ask. Are you making these modifications to the heads via a CNC program or by hand or some other magic? If CNC, how about a pic of the setup? Very curious how one goes about doing this and getting repeatable results. (I guess that's the engineer in me...)

Thanks! David
 

comnoz

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napanorton said:
Jim, I gotta ask. Are you making these modifications to the heads via a CNC program or by hand or some other magic? If CNC, how about a pic of the setup? Very curious how one goes about doing this and getting repeatable results. (I guess that's the engineer in me...)

Thanks! David

I use the CNC to cut the seat recess and guide hole and a few basic cuts to guide the porting tool.

The porting is done by hand and the seats and bowls are cut with Neway cutters and a couple of custom cutters I use on the Neway pilots.
When I happen on a design that works I will make a mold of the port and a template of the floor along with measurements.

The latest cutter is something I tried after looking at some Mercedes Benz ports that flowed particularly well for the valve size. The modification is really subtle and not something I expected to work as well as it does. If I showed you a picture of it you wouldn't even notice anything different. Jim
 

comnoz

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Dances with Shrapnel said:
Jim,

Would you mind showing one or more of the above plots with that Herb Becker head that went on the 1,007cc engine of mine? :D


I am sure I have a graph of it somewhere.
Of course it would be comparing apples and oranges as the Becker head's big valves wouldn't fit on anything but a 1007. Jim
 
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"OK Bill, you will like this."

You are right Jim. I like this very much. Great work.

Bill G
 

comnoz

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Dances with Shrapnel said:
Jim,

Would you mind showing one or more of the above plots with that Herb Becker head that went on the 1,007cc engine of mine? :D

Here ya go.

bigheadf_zps3bc32a3e.jpg
 

comnoz

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worntorn said:
Jim, do you have velocity numbers for this last group?

Glen

I do, but they have not been graphed. The port diameter was the same through all the the tests so the velocity went up with each increase in flow. I will get some velocity graphs done -they just take a bit more time. Jim
 
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In that case it seems there is no downside to the modfied shape for either the fullauto head or the RH10. Might this new shape become he standard shape for Fullauto heads in the future?
I guess that would mean at least some pattern work and expense there.

Glen
 

comnoz

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worntorn said:
In that case it seems there is no downside to the modfied shape for either the fullauto head or the RH10. Might this new shape become he standard shape for Fullauto heads in the future?
I guess that would mean at least some pattern work and expense there.

Glen

I am sure it will only be the standard shape for a Comstock ported Fullauto head. Jim
 
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comnoz said:
I am sure it will only be the standard shape for a Comstock ported Fullauto head. Jim

Given the countless hours you have spent to get here, that seems right.

Got me looking for a good RH10 to send off to you. Actually, I have found one but it has a bike attached :D

Glen
 

Kvinnhering

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I'm very impressed how you've got RH10 to perform so well Jim.
I'm pleased to see the great improvement of the Fullauto too. :D

I hope this work will be done on the cylinder head going to Norway also :D. Can't wait to test this on my bike :D :D
 

comnoz

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Knut,
This will be done on your rh10. I know exactly how to get there now.

rh10004_zps26766678.jpg


Here is is your head just as it came.
rh10005_zpscaf318cb.jpg


The porting is untouched. It is the blue line.

The green line just under it is a stage 2 -rh 10 head from a well known tuner about 25 years ago. It has the intake port opened to 32 mm with a slow taper to the guide. Then the rear of the bowl is opened up a bit. [to help direct the air down into the chamber?] This shows what happens when you don't get it right. With the port opened up and no increase to the flow the velocity fell seriously.

The yellow line is the rh10 I just finished. That is what the mold came from. Jim
rh10002_zps0afb0439.jpg
 

Brooking 850

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Jim , regret not getting flow figures for my RH10 on the race bike before bolting it up, any hints on doing that in situ?
Regards Mike
 

comnoz

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Brooking 850 said:
Jim , regret not getting flow figures for my RH10 on the race bike before bolting it up, any hints on doing that in situ?
Regards Mike

That would be pretty tough.
But if you want to send it over i will be glad to test it. Jim :D
 

Brooking 850

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Hi Jim, if i need to take it off and have another to replace it (thinking FullAuto???) I will think on that one.
I will check here to see if I can get it done.
Thanks for the offer
Regards Mike
 
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