[ROVERNET - UK] general timing question

[peter king]

While we are on the topic of range of knowledge, here's one (oft =20
repeated, I'm sure) from the rank amateur:

I replaced points today and re-set dwell and timing, feeling out the =20
range again. As I was looking through the Rover manual, I wondered a =20
couple of things:

1) The timing specification located in the engine compartment for the =20=

NADA  3500s is 8 degrees ATC, running at 725-775 RPM, The manual says =20=

to make all readings at 600 RPM. The difference, I gather, is due to =20
the emission control equipment installed for this market. The manual =20
states that dwell must be checked at 600 RPM and no greater, or an =20
incorrect reading will result. I set the dwell at 26, running at 600 =20
RPM, adjusted the idle up to 750 to set timing, and checked dwell at =20
that RPM as well. Dwell was the same=9726=97 at 750RPM as it was at =20
600RPM. Should there be any difference in dwell at a higher RPM?

2) I started off timing with too much advance: close to TDC, and got =20
some pinging on acceleration, re-set to 8 degrees ATC as suggested, =20
and got an occasional skip on acceleration.  I settled on 6 degrees =20
ATC for now, with this question: somewhere in the 8 degrees of =20
separation between pinging and skipping is the sweet spot, but at =20
what point are you too far advanced for the good of the engine's =20
health? If I back off just until the pinging stops under load, is =20
that the best for performance AND engine life, or is it better for =20
the engine (not the driver) to run a bit more retarded?.

Thanks for re-running your answers.

Peter






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