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Re: Ignition Timing and LRP

I'm still learning at this game and I would appreciate some advice. >

> I have a Morris Oxford service V 1959 1489cc (not sure if its a high > compression or low compression) > > I want to check the timing. From the Haynes Manual, the details are as > follows: > > High compression - 5 deg BTDC (fuel not specified) > > Low Compression - 3* fuel - TDC > Low Compression - 4* fuel - 10 deg BTDC >

The B series was a bit fussy about fuel it really preffered the much mourned

5 star, as for timing star at 10 deg BTDC and retard it a tiny bit at a time untl it stops pinking -- pinking is usually associated with low to medium rpm at full throttle to test for pinking warn the car up and ascend a hill in a high gear with full throttle from low(ish) RPM. If you hear a tinkling sound retard the ignition by degree increments until it just stops - then retard by an extra degree for safety.

Aviod excessively retarding the ignition as excessively retarded ignition can lead to over heating and running on due to the increase in heat rejected to the cylinder walls. Ignition timing should always be before TDC if you find the timing approaching TDC you may want to consider using an octane booster or lowering the compresion.

Reply to
AWM
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Strange considering that 5 star wasn't around when the 1500 saw the light of day. Some of the various 1600 or 1800 models, perhaps.

FWIW, I've had several 1500 versions and never had any problems with pinking on 4 star. Mind you, I usually blew them up long before they'd have needed a de-coke. ;-)

I agree about your timing method, though. Modern fuels are so different to the originals the makers timing figure can only now be regarded as a rough guide.

Reply to
Dave Plowman

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