When I acquired my 1964 Jubilee the engine had been dismantled completely. I am now at the stage of fitting the points cam. I believe the cam is a taper fit to the end of the inlet valve cam and there seems to be no obvious positioning mark for the points cam. All I have is a diagram in the rebuild manual that shows the high point of the cam against the left hand set of points, presumably at TDC? Looking at the cam on in the diagram the 'flat' part of the cam is uppermost. What is the correct way to ensure the points cam is fitted correctly?
In time I will fit electronic ignition and a 12V upgrade but for now I want to test the engine running with mechanical points.
Attachments points-pngHello there, It is a bit f…
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Previously patrick_mullen…
Previously patrick_mullen wrote:
Hello there,
It is a bit fiddly as there are no timing marks but you can't go too far wrong. Set the engine to TDC and rotate the engine backwards 10 deg. Make sure it is on the firing stroke. Rotate the cam in a clockwise direction until the topmost pair of points just commences to open. Fit and tighten the securing bolt. Set the points gap to 12 thou. You might have to do this a few times until you are reasonably satisfied. Check spark at plugs.
Once you have it started then recheck the timing properly with a degree plate.
Patrick
You don't say if you are timing the engine for full advance or retard? As it happens turning the cam clockwise beats the advance/retard springs so you will be timing fully advanced. Don't forget fully advanced timing is crucial for your pistons, fully retarded ignition is just for convenience.
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Timing at 10 deg static wa…
Timing at 10 deg static was the method recommended by Norton for the Jubilee engine but for optimum results it pays to do some experimenting once you have the engine actually running. The settings supplied by Norton were only general guides and worked well enough for general use. The same applies to carburettor settings.
If Al is from the same generation as me he will remember the 'magic' Crypton tuner; we would rebuild the engine from our rally Cooper S and carefully set it up to factory spec on the Crypton - job done as Ed China would say.
Except then when it was back in the car and done a few laps we would alter timing and fuel (45Weber) "by ear" until it "sounded right". Engines from the fifties were not precision instruments so we could noticeably improve performance this way. Do not attempt this on your modern Mercedes AMG or BMW M5 - unless you want very expensive problems.
Patrick
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Hello there,
It is a bit fiddly as there are no timing marks but you can't go too far wrong. Set the engine to TDC and rotate the engine backwards 10 deg. Make sure it is on the firing stroke. Rotate the cam in a clockwise direction until the topmost pair of points just commences to open. Fit and tighten the securing bolt. Set the points gap to 12 thou. You might have to do this a few times until you are reasonably satisfied. Check spark at plugs.
Once you have it started then recheck the timing properly with a degree plate.
Patrick