Thread: When is Timing "All In" in Stock Dizzy

4K
Should be about 30-32degrees
I researched this a while ago.
How to power tune Rover V8s says max should be
34degrees for 3.9 and 30degrees for 4.6.
Regard sPhilip A

do you mean what is it normally or what do you set it to for various configurations.

its anywhere between 25 and 32 degrees depending on a few things. and I recall that max advance is about 3K for the below 30 degrees setup and about 3.5K rpm for the over.

To be more precise I quote from 'How to Power tune Rover V8s"
"Most Rover Distributors have a maximum 11 degrees of mechanical advance built in, which equates to 22degrees of crankshaft advance......"

"Another aspect of the mechanical advance mechanism is the rate at which the ignition timing advances, blah blah... The springs allowthe advance to start at about 1000RPM and full advance will be achieved at about 4500RPM"
So their recommendation is to mark the harmonic balancer at several increments and then set the initial static advance to give the figures I have listed above ie about 8-10 degrees for a 3.9 giving 30-32 total advance.
Regards Philip A

The term "all in " is not expressed in degrees only ! Its the end point of the advance Curve expressed as RPM @ Degrees of advance , So any "all in" point must have a RPM figure . These figures of 25 to34 to whatever must be qualified by the RPM number at which the centrifugal / mechanical mechanism is at. eg 32@2850 or 28@3000. Therefor all distributors that actually have a mechanical advance mechanism will have a "Advance curve" Its this advance curve that is important as is the maximum advance specified.Engines that still have a distributor (pretty rare these days) and are "EFI" usually dont have any mechanical advance mechanism as the timing or spark advance is controlled by the "EFI's" ECU as a Ignition map.therefore only a Idle/static advance is set. If your engine has a Dizzy with a mechanical advance mechanism then it will have a "advance" curve preprogrammed in by the use of those tiny low speed and high speed springs and ther stops, Most advance curves are matched to the engines Torque curve characteristics versus load application with allowance for Fuel type/octane level detonation probability.
So Cockie55 , you tell me what your engines specs are ,your cam event timing ,static and dynamic compression ratio's , driving application to set the "ramp" or load rate ,and I can specify a "Advance curve" that will give you the RPM and degrees of Advance .
So if someone says 30-32 total , thats not much good if the rpm at which this happens is not specified.
PS Not mentioning the "Vac" advance unit , that is also effecting the curve because there are so many variations by application that its to confusing to go into
Things like before or after manifold vacuum, advance and/or retard connections etc are all OEM specific and vary greatly !