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spokesmanSun Jul-19-09 09:20 PM
Member since Jul 19th 2009
2 posts
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"dunstall camshaft?"


          

Hi I am a new member in Victoria, BC. I am rebuilding a blown up 810 Commando and need advice on the camshaft. It is marked: PD/R2 B/540 WEC and I have no idea what/where/who it came from and what timing it gives. Also it is running in caged needle rollers on both ends and has no visible means f controlling end float or operating the breather. Any advice will be very welcome. Alan

  

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dynodaveThu Jul-23-09 08:51 AM
Member since Mar 18th 2009
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#1. "RE: dunstall camshaft?"
In response to Reply # 0
Sat Aug-01-09 08:43 PM by NortonGuy

  

          

Due to the overly generous overlap, my guess is that it should be run with 3" radiused lifters.
Aproximately .130" intake lift at TDC.
It is similar to a Norton 2S combat grind.
The cam/needle roller is oiled with a feed into the old breather fitting, coming from the timing chest/rocker feed point then through a calibrated bleed oiling oriface.
You can see the profile here
http://atlanticgreen.com/camsurvey.htm
also at:
http://atlanticgreen.com/index.php?option=com_wrapper&Itemid=4

  

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spokesmanFri Jul-24-09 12:01 AM
Member since Jul 19th 2009
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#2. "RE: dunstall camshaft?"
In response to Reply # 1


          

Thanks for reply, all is coming clear now, it is running with flat followers in a Dunstall alloy cylinder. What governs camshaft end float with needle roller bearings? I can figure the pressure feed, any idea on the resricting orifice? Alan

  

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dynodaveFri Jul-24-09 06:48 AM
Member since Mar 18th 2009
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#3. "RE: dunstall camshaft?"
In response to Reply # 2


  

          

An oriface in a slug of brass abour 1/16 should be OK. and not bleed excessive oil from the rest of the system.
If you have a norton twin 20M3S or later, then the inboard tach makes the cam thrust to the right, and the end float is virtually a non issue. The 06-1084 washer would thrust on the steel cage of the roller and be OK. This is a racing configuration and is not a high mileage setup. Needle bearing are IMO inferior to the original setup.
IIRC this cam setup has an oiler hole on each of the leading edge cam ramps.
This was probably to compensate for the cam alloy which would be over stressed with the hot rod valve spring pressure against the lobe. After all this configuration started in the Model 7 500cc with tiny valves and springs right out of a ball point pen (LOL). So the cam lobes are worked quite hard and the extra oiling helped longevity that Dunstall seemed to pursue. This may be less than necessary with todays oil and lighter valves with more scientific lobe profiles to reduce loading of the surface.

  

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Norton Commando Oil Change