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nakoolMon Dec-13-04 03:14 AM
Member since Mar 18th 2009
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"Cam Timing for 16H (1947)"
Mon Dec-13-04 03:16 AM by nakool

  

          

Hello,
I am looking at technical data on Cam positions for my norton 16H. The cam wheels dont have any sort or marking on them and i got to know that the engines rotate in the opossite direction than conventional british engines, so its not everyones cup of tea. I would request if anyone can direct me to such a literature or image of the cam positions.

I got this "The inlet valve should just start to open at 35 degrees before top dead centre on the exhaust stroke and the exhaust valve should just start to open at 35 degrees before bottom dead centre on the firing stroke. You may need to fix up some kind of timing wheel on the drive side sprocket and set where top dead centre is."

But this necessarily did not help as i tried many times to set it using these guidelines. Maybe i missed somthing very important.

Please guide.

  

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andersonjTue Dec-14-04 05:53 PM

  
#1. "RE: Cam Timing for 16H (1947)"
In response to Reply # 0


  

          

Hi there,

Most people posting on this site are discussing Commandos or other twins. If you want to ask about Norton singles you might be better to look at the UK Norton owners site and contact their technical advice people. http://www.nortonownersclub.org/

Sorry dont know anything about these bikes.

John

  

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RohanTue Dec-14-04 09:43 PM

  
#2. "RE: Cam Timing for 16H (1947)"
In response to Reply # 1


  

          

16H engines rotate the same direction as almost all other british engines. Its the direction of rotation of the cams that you need to be especially careful of. As long as you watch that you are rotating the whole plot in the correct direction, the 35 degree data you describe should give you correct valve timing.

Do you have a degree wheel ?
Fixing it to the engine sprocket side is common, although you almost need 2 people then to keep an eye on everything.

Where does the valve timing go wrong when you tried it ? Always rotate the engine forward when doing the timing, and the cams will do what they need to do....

The half time engine pinion gear (the little gear on the end of the crank) often has several keyways, the one in use hopefully has a punch mark over it. Using a different keyway will often fix timing that is 10 or 15 degrees out. A few degrees out in valve timing is not too serious....

The magneto timing follows on after timing the cams, and needs to be fairly accurate, although the advance-retard lever should find a spot where it will at least start.

Can quote from a period manual on more of the procedure if required, although persistence is the main requirement here. Along with always rotating the ENGINE forwards....

hopethishelps,
Rohan.

  

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RohanSat Dec-18-04 08:48 PM

  
#3. "RE: Cam Timing for 16H (1947)"
In response to Reply # 2


  

          

P.S. the book also says that some 1946 and 1947 engines will be stamped with "Q" in the engine number and on the cams. These cams - wth quietening ramps hence Q - require a 0.017" feeler gauge between cam and lever follower when setting the cam timing. They also require the 17 thou feeler gauge still there when setting the valve clearance.

And further - if fitting new unmarked cams to any engine. Fit the cams so that the inlet cam is just opening at TDC, and the exhaust cam is just opening at BDC. Set the correct valve clearances. Then carefully advance the cams one tooth at a time - while checking the timing with a degree wheel - until the correct timing is obtained. Using the next keyway on the small gear on the end of the crank should give increments of one third of a tooth, if this is needed to get the valve timing correct.

Great pic !!

hopethishelps.

  

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nakoolMon Dec-20-04 04:37 AM
Member since Mar 18th 2009
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#4. "RE: Cam Timing for 16H (1947)"
In response to Reply # 3


  

          

Hi Rohan,

I tried to set as you said, but i dont feel its setting properly as the engine valves drop with lot of sound, which would'nt happen earlier.

Are you sure inlet valve shud open 35 degreess before TDC and exhaust value shud open 35 degrees before BDC?

Thanks for all help.

  

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nakoolMon Dec-20-04 04:48 AM
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#5. "RE: Cam Timing for 16H (1947)"
In response to Reply # 4


  

          

Hi,

Please also can u verify from thsi diagram that what i understood is correct?

Just a rogugh diagram to tell you how i think the timing shud be set.

Paresh

  

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dynodaveyMon Dec-20-04 10:24 AM

  
#6. "RE: Cam Timing for 16H (1947)"
In response to Reply # 0


  

          

I would think it likely that if the cam is very conservative for economy, since it is just post WWII era bike then the 35º may be a slightly hotter cam?
This is a late 40's bsa a-7/10 cam


and this late 40's norton model 7 cam


lobe centers still lay around 105ºBTDC for exhaust and 105ºATDC for intake though the lift/overlap AT TDC is quite small indeed.
I would feel more confident, if I was putting it together, in using the lobe center method.

my 2 cents
dave

  

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RohanMon Dec-20-04 05:09 PM

  
#7. "RE: Cam Timing for 16H (1947)"
In response to Reply # 6


  

          

Do you have the valve clearances set correctly ? Book says .004" for inlet and .006 for exhaust. Book also converts the 35 degrees to 9/32" for both settings for the 1946-47 16h.

Unless you have Q cams (Q in the engine number, and on the cams). Clearances are .010" for both valves.

Prewar Norton cams were milder, by a few degrees.

  

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yoramThu Dec-14-06 04:02 AM
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#8. "RE: Cam Timing for 16H (1947)"
In response to Reply # 0


  

          

Hey Nakool/ I shall quote the "Modern motorcycle mechanic" published 1953:

There are 3 keyways,in crankcase gear, locate piston 9/32" past top stroke, install exhoust cam meshed in timing gear so that exhoust valve is just closed, totating cam gear anty clock wise.
turn motor back so that piston is 9/32" before top stroke, and fit inlet cam so that inlet valve is just commencing ro open when cam is totated clock-wise.
revolve motor in runnong direction and recheck to note that inlet valve just commences to open. when piston is 9/32" before top of strole, and exhoust valve just completly closes when piston is the same amount past top stroke./

if timing whithin these limits can not be obtained, by variation of on toothe either way, on gear mesh, try fitting the gear pinion on either oif the other two keyways, which give a variation of a fraction of a tooth.

good luck! Yoram, Israel.

  

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yoramThu Dec-14-06 04:05 AM
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#9. "RE: Cam Timing for 16H (1947)"
In response to Reply # 8


  

          

my mail is [email protected] , if you have more questions. Yoram.

  

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