timing marks on the fly wheel 1949 p3 75.
timing marks on the fly wheel 1949 p3 75.
Can some one enlighten this amateur what the five timing marks are used for on the fly wheel,i have a tdc and fa and what looks like three different degree marks 7 ,11 and 15 these look like factory stamped.also i have just replaced all the gaskets in the carburetor and had the engine running smoothly and by chance i placed my finger over what appears to be a fuel drain under the intake manifold and the engine dropped some revs when i removed my finger the revs picked up again is this normal.awaiting the experts replies thanking you in anticipation.regards Derrick.Smith.
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RobHomewood
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Re: timing marks on the fly wheel 1949 p3 75.
I'm not an expert but I can quote you from Pitmans The Book of the Rover 1958 which lists only 3 markings for the flywheel of 1947-9 models viz TDC, FA4 or FA6 (firing point of No1 cylinder when the octane selector is set at 40 on the sliding scale) and EP for exhaust peak (where No1 exhaust valve is fully open). However under 1950-53 models after TBC and EP it says 'the FS markings are 8 degrees and 15 degrees before TDC and should be disregarded' I dont know if 'FS' is the same as 'FA'.
I dont know if that helps or just confuses but good luck Rob
I dont know if that helps or just confuses but good luck Rob
Re: timing marks on the fly wheel 1949 p3 75.
The following is taken from V. H Watson book "Rover Cars", 1958 edition, pp 36:
"Flywheel Markings, All Models
The flywheel markings and timing pointer are visible when the inspection cover on the right-hand side of the clutch housing is removed.
The mark T.D.C. indicates when No. i and No. 4 (or No. 6) pistons are at the top of their stroke.
The mark E.P. indicates when No. i exhaust valve is at the peak of its lift (i.e., fully open).
The letters F.A-4 or F.A.6 on Group i engines indicates the Firing Point, i.e., distributor points just breaking.
The F.A. markings on all models from 1948 vary slightly to allow for higher compression ratios and the availability of high-octane petrol, and it is usual to indicate firing point by the letters F.A. followed by an indication in degrees.
Example: F.A. 10 degs., i.e., 10° before top dead centre. In some instances the marking would be 10 degs. B.T.D.C.
On later high-compression ratio engines it is necessary to time the ignition to suit the octane value of petrol normally used. For further details see page 42.
As flywheels for four-cylinder and six-cylinder engines are in many cases interchangeable, some may be found bearing both marks, take care to use the appropriate one."
"Flywheel Markings, All Models
The flywheel markings and timing pointer are visible when the inspection cover on the right-hand side of the clutch housing is removed.
The mark T.D.C. indicates when No. i and No. 4 (or No. 6) pistons are at the top of their stroke.
The mark E.P. indicates when No. i exhaust valve is at the peak of its lift (i.e., fully open).
The letters F.A-4 or F.A.6 on Group i engines indicates the Firing Point, i.e., distributor points just breaking.
The F.A. markings on all models from 1948 vary slightly to allow for higher compression ratios and the availability of high-octane petrol, and it is usual to indicate firing point by the letters F.A. followed by an indication in degrees.
Example: F.A. 10 degs., i.e., 10° before top dead centre. In some instances the marking would be 10 degs. B.T.D.C.
On later high-compression ratio engines it is necessary to time the ignition to suit the octane value of petrol normally used. For further details see page 42.
As flywheels for four-cylinder and six-cylinder engines are in many cases interchangeable, some may be found bearing both marks, take care to use the appropriate one."
Re: timing marks on the fly wheel 1949 p3 75.
A very special thanks to Rob homewood and luli for your informative advice.i have managed to get mavis running again so it will be a matter of minor adjustments to get it close to the mark.best regards Derrick.Smith