Question about ignition timing on 2.7 engine

[teescott]

My 72s has the original engine with cylinders bored to 2.7 litre, according to the previous owner's mechanic, who's phone # I have now lost.
During my quest to solve a cold starting problem, among other things, I re-gapped the points to .014., which resulted in dwell of 34 degrees.
My question is, and this may seem redundant, but am I doing the right thing to set the timing to the 2.7 spec at idle to TDC (Z1) mark or 5 degrees ATC as in the timing for the standard 2.4s.
The problem is that I really don't know why the 2.7 calls for a different amount of advance than the 2.4, although I would guess that more cylinder volume might require more advance.
Can someone shed light on this.
Thanks
Scott

[304065]

When the engine was rebuilt as a 2,7 RS the distributor should have been recurved to the RS spec. Therefore, you should time it as though it's a 2,7, not a 2,4.

The important end of the timing range is the 6000 rpm range-- you do NOT want to be running too far advanced under load and high RPM or detonation will be the result. You may end up with idle at TDC or even slightly retarded (ATC).

The dwell measurement, while interesting, isn't super relevant to a CDI ignition car. If you were running kettering-ignition like the SWB cars, I would be concerned, but the CDI charges in a microsecond, making the point gap much less critical.

[teescott]

Thanks for responding John. This is helpful.
So as far as total advance at 6000 rpm, I should be seeing what the service manual says and that is total advance should be between 32 and 38 degrees.
Is that correct?
It's interesting about your comment on the point gap not being too critical, because it seemed as I was fooling with the gap and looking at the dwell that I could tell pretty big differences in the way the car was running when I made small changes like from .014 to .016. But if I understand what your saying, I guess that the timing would not change significantly with slightly diffferent point settings. I do see what you mean about the CDI box and how it would differ from a standard point/coil combination without CDI.

Scott