BDR Ignition Timing, crank versus cams (we are timing on the cam sprockets NOT the crank)
Now that for the first time the timing is the same in the morning as it was the previous evening. (Dizzy clamp issue).
I am now wondering if she is too far advanced, because on the cam sprockets I have her set to about 10 degrees (1 1/3 "teeth)". The RS 1600 s/be 12 degrees at 1500 rpm. CC says 6 degrees for BDR. Either way given the crank turns twice for every one turn of the cams sprockets, I think that should be half the advance on the sprockets so that 3 deg on the cams gives 6 deg on the crank. However, oddly this is doing my head in.
Edit: ok the reason it is doing my head in is every single discussion (here and elsewhere) starts with respondents explaining that timing is ALWAYS based on the crank not the cams. However, we are setting the timing based on the cams NOT the crank, therefore compensation is (seems to be) required because the cams only turn half as fast as the crank. This is UNUSUAL and requires alternative thought. The reason for this is we have, after extensive searches, been unable to find any crank case markers to match the crank pulley markings. I am wondering if in 2012 when I knew nothing about such things I refitted the crank pulley randomly with a 33% chance of it being right and it is wrong. Also, access to view the crank pulley and any case mark is practically impossible. Also all the alleged timing markings in the book (Haynes RS 1600) are simply not present.
So whereas I have 10 deg on the cams that's 20 deg on the crank, which is too much.
I gather also that other things being optimised (mixture, air comp, tickover, carbs balance) the HC reading indicates degree of unburnt fuel so it can also indicate good or bad timing.
Mental rescue welcome
Anthony
Edited by anthony1956
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