28-09-2017, 11:36 PM
In making comparison with other cars the 0 40 45 15 is usually taken as gospel. Most other cars understate as often taken with extra clearance, although often not made clear. (The SAE standard used to be plus .006 over normal settings.) Even if achieved, the Seven timing 0 40 45 15, esp the inlet, is relatively staid, but is even this actually achieved?
Unless it is maker’s recommendation, setting timing from a single opening point is fraught, although accurately repeatable. One good datum is mid overlap equal lift point, 7.5 deg ATDC for stock Seven, or, for symmetric cams, mid lift determined as midway between same lift on flanks.
(On standard cars, whenever the head is off an unfamiliar engine the 7.5 point is worth a rough check to ensure no gross timing errors.)
Unless it is maker’s recommendation, setting timing from a single opening point is fraught, although accurately repeatable. One good datum is mid overlap equal lift point, 7.5 deg ATDC for stock Seven, or, for symmetric cams, mid lift determined as midway between same lift on flanks.
(On standard cars, whenever the head is off an unfamiliar engine the 7.5 point is worth a rough check to ensure no gross timing errors.)