Welcome to the Access Norton Forum. Login as a VIP member to remove the advertising banners.


Head flow testing.

Classic Norton Commando Motorcycles.

Re: Head flow testing.

Postby WZ507 » Fri Feb 19, 2016 5:05 pm

Dances with Shrapnel wrote:
comnoz wrote:It looks like Dan Gurney has had luck with port design similar to my findings.

http://www.gizmag.com/dan-gurney-moment ... ult-widget


Interesting stuff. More details here for those willing to trudge through patent language.

https://www.google.com.ar/patents/US9103277

This is apparently an over square motor. It looks like they use variable cam timing.

Using the above Google Link to access the patent I could view the text and placeholders for the images, but could not figure out how to actually view the images. If anyone encounters this same issue they may want to try this link from the USPTO where the images are visible.

http://tinyurl.com/jhcqdr3
Access Norton VIP Paying Member
WZ507
VIP MEMBER
Posts: 360
Joined: Thu Dec 26, 2013 3:54 pm

Re: Head flow testing.

Postby jseng1 » Fri Feb 19, 2016 6:37 pm

lcrken wrote:
The RH7 head starts with the same casting as the standard 850, but has the intake guide at a steeper angle (26.5 instead of 28 degrees off vertical) and has a fully sphered combustion chamber with no squish band. ...

Ken


The fully sphered RH7 combustion chamber could use fully domed piston as below.
Image
User avatar

jseng1
Posts: 1470
Joined: Thu Nov 26, 2009 11:50 pm

Re: Head flow testing.

Postby WZ507 » Fri Feb 19, 2016 8:16 pm

Comnoz, thanks for pointing out that patent.

The more I read about the MC4S engine of the subject patent the more impressed I am with it. Appears Ole Dan has brought together all of the best in this design. Large bore, generous squish area, short stroke, Nikasil coated Al cylinders, cylinders offset to crank centerline to improve rod geometry thereby reducing piston thrust, high angle tapered port design, very generous guide support with a proper caliber guide fit, counter rotating crankshafts to reduce vibration and the list goes on. They even call out the multi-layered steel head gaskets offered by Cometic (the ones we need in our Nortons as the Al head squirms while the cast iron cylinder is better behaved). And the ultimate proof might be in the performance quoted. The patent cites one preferred bore/stroke embodiment of 5”and 2.8” respectively, that as Kvinnhering points out has a displacement of 1800 cc. If this engine size is employed in all the examples, they suggest 189 HP without the novel porting system when mean piston speed is under 4200 ft/min, with the novel porting system 262 HP with mean piston speed of 4200 ft/min, and 309 HP with the novel porting system and a mean piston speed of greater than 4200 ft/min. Holy shit, that is 2.8 HP/cu in from a relatively low compression engine capable of running pump gas! A very nice package. Now, back to our favorite dinosaurs.
Access Norton VIP Paying Member
WZ507
VIP MEMBER
Posts: 360
Joined: Thu Dec 26, 2013 3:54 pm

Re: Head flow testing.

Postby comnoz » Mon Feb 29, 2016 9:06 pm

Fast Eddies RH10 head before and after a street port job with 3mm oversized intake valves.

Image
"If the facts don't fit the theory, change the facts." Einstein
You're never too old, to learn something stupid.
nortonmachineshop.com
User avatar
Access Norton VIP Paying Member
comnoz
VIP MEMBER
Posts: 5690
Joined: Wed Dec 10, 2008 10:28 pm
Location: Pueblo Co.

Re: Head flow testing.

Postby Fast Eddie » Mon Feb 29, 2016 9:49 pm

comnoz wrote:Fast Eddies RH10 head before and after a street port job with 3mm oversized intake valves.

Image


Thanks Jim!

I'll have to change my name to 'Even Faster Eddie' ...!
User avatar
Access Norton VIP Paying Member
Fast Eddie
VIP MEMBER
Posts: 3626
Joined: Fri Oct 04, 2013 12:48 am
Location: Oxford, England

Re: Head flow testing.

Postby cjandme » Mon Feb 29, 2016 9:59 pm

That's lookin' really good for you bike "Even Faster Eddie" :mrgreen:
Norton Fan by Bro w/'75MKIII
User avatar

cjandme
Posts: 1649
Joined: Sat Feb 05, 2011 3:27 pm
Location: Misawa, Japan

Re: Head flow testing.

Postby Kvinnhering » Mon Feb 29, 2016 10:22 pm

comnoz wrote:Fast Eddies RH10 head before and after a street port job with 3mm oversized intake valves.


Congratulations Fast Eddie! Will be interesting to get feedback how this works.

Jim, can you show us the graph of air velocity as well. It had been very interesting!
Roadster 750 Short Stroke MkIa -73
West coast of Norway
Access Norton VIP Paying Member
Kvinnhering
VIP MEMBER
Posts: 106
View Photo Album - Images: 2
Joined: Wed Feb 16, 2011 1:43 pm
Location: Norway, Hordaland

Re: Head flow testing.

Postby comnoz » Tue Mar 01, 2016 9:51 am

Here are the velocity numbers

Image
"If the facts don't fit the theory, change the facts." Einstein
You're never too old, to learn something stupid.
nortonmachineshop.com
User avatar
Access Norton VIP Paying Member
comnoz
VIP MEMBER
Posts: 5690
Joined: Wed Dec 10, 2008 10:28 pm
Location: Pueblo Co.

Re: Head flow testing.

Postby Fast Eddie » Tue Mar 01, 2016 12:02 pm

Thanks again Jim.

So, in summary, we have more gas entering the combustion chamber... and its travelling faster...!

For the benefit of the viewers, can you explain what has been done to achieve this?

It will certainly be very interesting to see the dyno results and correlate this with the known increases in flow and velocity.

Can't wait to get it nailed back together !!
User avatar
Access Norton VIP Paying Member
Fast Eddie
VIP MEMBER
Posts: 3626
Joined: Fri Oct 04, 2013 12:48 am
Location: Oxford, England

Re: Head flow testing.

Postby acotrel » Tue Mar 01, 2016 12:35 pm

I have long wondered what a flow bench really demonstrates. If the gas in the inlet port is in the form of a standing wave, aren't we looking at sonic effects and mass transfer of inlet charge, rather than gas flow characteristics ? If you have a look at the fuselage shapes of jet fighter aircraft, the best shape for sonic speeds is not what you would expect. With a commando engine, surely the mechanical limitations prescribe efforts should be directed at improving mid-range torque rather than top end power ? The best 350cc single cylinder fourstroke racer was the Ala D Oro Aermacchi which has tapered inlet ports. The Linto 500 was almost a competitive GP bike.
User avatar

acotrel
Posts: 5894
- Images: 0
Joined: Sat Jun 30, 2012 5:39 am
Location: Benalla, Australia

Re: Head flow testing.

Postby Fast Eddie » Tue Mar 01, 2016 12:45 pm

acotrel wrote:I have long wondered what a flow bench really demonstrates. If the gas in the inlet port is in the form of a standing wave, aren't we looking at sonic effects and mass transfer of inlet charge, rather than gas flow characteristics ? If you have a look at the fuselage shapes of jet fighter aircraft, the best shape for sonic speeds is not what you would expect. With a commando engine, surely the mechanical limitations prescribe efforts should be directed at improving mid-range torque rather than top end power ? The best 350cc single cylinder fourstroke racer was the Ala D Oro Aermacchi which has tapered inlet ports. The Linto 500 was almost a competitive GP bike.


As has been stated, we shall see what we shall see on the dyno.

Jim has put a tremendous amount of info on the entire topic of head porting on here. Please do not upset the collective learning by throwing abstract comments about.

And please do not turn this into a thread about how all Commando's should have 6 speed close ratio gearboxes, low CR, never rev above 7,000 and be fitted with E3134 cams ...
User avatar
Access Norton VIP Paying Member
Fast Eddie
VIP MEMBER
Posts: 3626
Joined: Fri Oct 04, 2013 12:48 am
Location: Oxford, England

Re: Head flow testing.

Postby comnoz » Tue Mar 01, 2016 1:00 pm

Fast Eddie wrote:Thanks again Jim.

So, in summary, we have more gas entering the combustion chamber... and its travelling faster...!

For the benefit of the viewers, can you explain what has been done to achieve this?

It will certainly be very interesting to see the dyno results and correlate this with the known increases in flow and velocity.

Can't wait to get it nailed back together !!



The main thing done was just increasing the area of the valve opening by using a larger valve. The valve open area is the circumference of the valve times the lift of the valve.

The port size was not changed from it's 30mm diameter. The bowl and guide area was reshaped to help get the air to the seat without causing separation.

Installing a larger valve is just like installing a higher lift cam without increasing the duration of the cam.

Increasing the lift of a cam without increasing the duration is difficult to do when using a pushrod valve train without causing problems with valve bounce and/or broken parts.. Jim

PS, the numbers generated by a flowbench have nothing to do with the airflow on an actual engine. They are simply used to help design a port that will flow at an increased velocity.

Many people use flow numbers to compare one cylinder head with another cylinder head. Actually the flow numbers do not usually equate to the horsepower developed. Moving air into a cylinder and then keeping it there until the valve has closed is what we want to do.
Making a port that is the correct shape to support air at a high velocity so the pressure wave in the port that is created after the piston reaches BDC is strong enough to keep the charge in the cylinder until the valve closes -and maybe even push a little extra air into the cylinder between BDC and valve closing is what we want. Jim
"If the facts don't fit the theory, change the facts." Einstein
You're never too old, to learn something stupid.
nortonmachineshop.com
User avatar
Access Norton VIP Paying Member
comnoz
VIP MEMBER
Posts: 5690
Joined: Wed Dec 10, 2008 10:28 pm
Location: Pueblo Co.

Re: Head flow testing.

Postby acotrel » Tue Mar 01, 2016 2:23 pm

Eddie - flow benches and dynos are not the same as riding the bike. To me a horsepower figure is only about bragging rights, where is the correlation between that and on-circuit performance ? When I was racing regularly, two stroke bikes were very difficult to beat. These days in Australian historic racing the four stroke bikes are faster. The power characteristics and handling of the two types of bike are vastly different.
User avatar

acotrel
Posts: 5894
- Images: 0
Joined: Sat Jun 30, 2012 5:39 am
Location: Benalla, Australia

Re: Head flow testing.

Postby acotrel » Tue Mar 01, 2016 2:41 pm

Eddie would you possibly please post a side-on photo of your bike without fairing and details of the type of gearbox you are using, and also about the types of circuit on which you mainly race ? When I'm reading about your motor, I feel I'm only getting half the story. I look at those dyno curves and I realise that an increase in horsepower probably represents an improvement, however I can't put together what it means on-circuit.
User avatar

acotrel
Posts: 5894
- Images: 0
Joined: Sat Jun 30, 2012 5:39 am
Location: Benalla, Australia

Re: Head flow testing.

Postby Snotzo » Wed Mar 02, 2016 4:34 am

Eddie
this reply has nothing to do with gearboxes, but all to do with flow potential through a port!

Jim's flow tests indicate that there is promise of a performance improvement for your engine with the valving and porting modifications he has carried out.

Another view of this is to examine the situation when the valve is lifted by 25% of the inner seat dianeter, which by and large can be considered to give a curtain area equivalent to that of the inner seat diameter, (referred hereafter as LD).

For the standard valve in conjunction with the PW3 cam, the duration through which the valve is lifted to the LD value is equivalent to the flow aperture being at optimum area for 31.25% of total duration.

Changing to a 3 mm larger valve, flow at the LD value is significantly reduced to only 15.45% of total duration.

Losses on swings outweighs gains on the roundabout (or vice-versa!).

As a matter of interest to some, of all the Commando cams I have data for, most have a LD flow potential with the 38 mm intake valve, of 30% or better, except one - the Norris RX which lags slightly at 29%.

To really maximise on the larger valve, a different cam would be required with increased duration above the LD value, but as Jim has stated, with the pushrod engine this becomes increasingly difficult to manage as a number of things begin to stack up against it. As it is, the increase in curtain area is sufficient to provide an increase in the flow potential, so the overall result is still coming out on the right side.

All will inevitably depend on how well you configure the rest of your engine to get what you want. If you are at Donnington for the Easter meeting, I will look forward to seeing you there, meantime let us all know via this forum the results of your testing.

Snotzo
Posts: 198
Joined: Tue Mar 12, 2013 3:47 am

PreviousNext

Return to Norton Commando Classic Motorcycles

Who is online

Users browsing this forum: L.E.N., Lannis, Onder and 8 guests