Head flow testing.

mdt-son

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

Hey Jim,

It appears there are at least two norwegians waiting in anticipatuion for a performing head :)
Were you referring to my cylinder head or Kvinnhering's in your recent posting ?
Anyway, bottom end rebuild featuring JS parts is well underway .... a trick crankshaft and an enlarged oil pump will be fitted.
To maximize torque, the standard stroke engine will be have a true 850cc displacement.
I look forward to dynometer test results which will be posted here along with pictures.

-Knut
 
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rh10004_zps26766678.jpg


Jim,

Any chance we can get a another view or two of the above cast (roll it 90 degrees on the port axis). Interested if one can see how you transitioned past the guide.

Can you also provide a few comments on (in port) guide profiles as compared to stock. You know how at least one other builder treats this (short stubby guides down to nearly no guise in the port) and we understand the down side to that approach. This could probably be another thread but still intertwined with head flow.

Also, what are you using to make the cast. I have used Blue Sil in the past.
 

comnoz

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mdt-son said:
comnoz said:
Knut,
This will be done on your rh10. I know exactly how to get there now.

Hey Jim,

It appears there are at least two norwegians waiting in anticipatuion for a performing head :)
Were you referring to my cylinder head or Kvinnhering's in your recent posting ?
Anyway, bottom end rebuild featuring JS parts is well underway .... a trick crankshaft and an enlarged oil pump will be fitted.
To maximize torque, the standard stroke engine will be have a true 850cc displacement.
I look forward to dynometer test results which will be posted here along with pictures.

-Knut

Knut,
I was referring to your head. The slightly rough rh10 from Alec.

Kvinnhering's head is a Fullauto if I recall correctly.

They both receive the same bowl cut if they are getting a big valve conversion. Jim
 
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The charts look really nice. As a guy with an RH10 on his stock 850, I'm curious what rpm (all?!) you'd feel those excellent flow numbers?
 

comnoz

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I really don't like raising the powerband of a Norton motor. It is really about as high as is practical on a longstroke motor as it is.

The big valve conversion will be felt throughout the same powerband that you had before, if it is a stock or mild can then mainly from 4 to 6000 rpm. The cam and exhaust system will do more to influence the rpm range than the valve size will as long as the intake port diameter is not changed. Jim
 
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comnoz said:
. The cam and exhaust system will do more to influence the rpm range than the valve size will as long as the intake port diameter is not changed. Jim

Nice work Jim,

With the stock RH10 head and valves, could the new shape add something ?

Cheers

Mark
 

SteveA

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mdt-son said:
Anyway, bottom end rebuild featuring JS parts is well underway .... a trick crankshaft and an enlarged oil pump will be fitted.
To maximize torque, the standard stroke engine will be have a true 850cc displacement.
I look forward to dynometer test results which will be posted here along with pictures.

-Knut

Knut, in another thread if you like, but do you wanna tell us some more about this oil pump?
 

mdt-son

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Steve,
There will be a presentation once the pump has passed initial testing early next year.

Knut
 

comnoz

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Nortiboy said:
comnoz said:
. The cam and exhaust system will do more to influence the rpm range than the valve size will as long as the intake port diameter is not changed. Jim

Nice work Jim,

With the stock RH10 head and valves, could the new shape add something ?

Cheers

Mark

I don't think there is enough material in a stock rh10 head to create the shape, but I have not tried it. The cutter I made will not fit a stock sized bowl. Jim
 
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comnoz said:
I really don't like raising the powerband of a Norton motor. It is really about as high as is practical on a longstroke motor as it is.

The big valve conversion will be felt throughout the same powerband that you had before, if it is a stock or mild can then mainly from 4 to 6000 rpm. The cam and exhaust system will do more to influence the rpm range than the valve size will as long as the intake port diameter is not changed. Jim

That sounds attractive. I don't ride a Norton for high-rpm power, either. My head is low-mileage but the stem seals are toast so it burns a fair amount of oil. This and a thin head gasket might pep things up nicely.

I think we all appreciate your work, even if it doesn't actually reach our motorcycles. Although I'm still enjoying the benefits of the screw-in sump breather.
 

comnoz

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Dances with Shrapnel said:
rh10004_zps26766678.jpg


Jim,

Any chance we can get a another view or two of the above cast (roll it 90 degrees on the port axis). Interested if one can see how you transitioned past the guide.

Can you also provide a few comments on (in port) guide profiles as compared to stock. You know how at least one other builder treats this (short stubby guides down to nearly no guise in the port) and we understand the down side to that approach. This could probably be another thread but still intertwined with head flow.

Also, what are you using to make the cast. I have used Blue Sil in the past.

DWC,
I use Ferris flexible mold compound for casting a port.

I machine the guide just like a stock 750 guide in the port. I have never seen any change in the flowbench readings when experimenting with shortened guides and could not tell a difference on the track. One thing I did find was the engine lost it's edge after a weekend of racing with cut off guides. The valves got off center on the seats and they wore badly.

Here are a couple more shots of the port mold. Jim

crank051_zps7b72ed33.jpg


crank050_zps003313a3.jpg
 

comnoz

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Here is a RH1 head I finished today. It got a three angle valve job and a street performance port job. Standard size Black Diamond valves and KW guides.
About 2 1/2 hours worth of work in the bowl and guide area in the intake and exhaust and here is the result. The entrance is radiused to mount a 32mm manifold on the 29 mm port.

LaPierrehead002_zps4c3d6f7f.jpg


Green is before and blue is after.

LaPierrehead005_zps64882152.jpg


LaPierreportvelocity_zps6c99e30d.png


LaPierrereport_zpsf0dc778d.png
 

comnoz

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I believe it was Fasteddie that asked how much flow was needed for a Norton. I spent a little time with my engine building software and got a few numbers that might interest you.

For a 750 cc Norton motor
-130 cfm @ 28 in. can produce 66.8 HP at 6910 RPM
-140 cfm @ 28 in.can produce 72.8 HP at 7441 RPM

For an 823cc motor
-130 cfm @ 28 in. can produce 66.8 HP at 6194 RPM
-140 cfm @ 28 in. can produce 72.8 HP at 6670 RPM

These figures are for intake flow with carbs and manifolds installed.
They are about what can be expected if all tuning aspects [cam,exhaust,ect.] are optimized at the peak power RPM's shown. Jim
 

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Jim, if you are still accepting heads to test at no charge, I'd like to send you my Baisley (Dreer VR880) head.

Pm or e-mail with ship-to address and I'll get it out in the next few days. One of each valve, no springs, right?
 

comnoz

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grandpaul said:
Jim, if you are still accepting heads to test at no charge, I'd like to send you my Baisley (Dreer VR880) head.

Pm or e-mail with ship-to address and I'll get it out in the next few days. One of each valve, no springs, right?

I like to see what others have done. So yes, send it, PM sent. Jim
 

Fast Eddie

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comnoz said:
I believe it was Fasteddie that asked how much flow was needed for a Norton. I spent a little time with my engine building software and got a few numbers that might interest you.

For a 750 cc Norton motor
-130 cfm @ 28 in. can produce 66.8 HP at 6910 RPM
-140 cfm @ 28 in.can produce 72.8 HP at 7441 RPM

For an 823cc motor
-130 cfm @ 28 in. can produce 66.8 HP at 6194 RPM
-140 cfm @ 28 in. can produce 72.8 HP at 6670 RPM

These figures are for intake flow with carbs and manifolds installed.
They are about what can be expected if all tuning aspects [cam,exhaust,ect.] are optimized at the peak power RPM's shown. Jim

Indeed Jim, it was I that asked.

And that is a very precise answer, thank you!
 
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Jim, do your figures imply that a good Norton twin has ~70% volumetric efficiency? Most references state it takes 140-150 cfm per 100 hp. i know 1st one VE is related to size of engine per amount inhaled per stroke while the other is how much mixture to heat up for 100 hp work on shaft.
 

comnoz

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hobot said:
Jim, do your figures imply that a good Norton twin has ~70% volumetric efficiency? Most references state it takes 140-150 cfm per 100 hp. i know 1st one VE is related to size of engine per amount inhaled per stroke while the other is how much mixture to heat up for 100 hp work on shaft.

{At maximum horsepower yes. At maximum torque it would be considerably higher.} Jim

Edit.
The above statement is not correct. Hobot was referring to total airflow and I was referring to port flow capability.
Actually a well tuned Norton is likely to have a Ve over 100% at maximum or it would never produce the HP it does. Jim
 
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Ok that answered a point of confusion to me. Do your shop's strange noises get noticed outside?
 
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