camshaft lobe lubrication

[keri]

hi all as you are aware I'm in the middle of a pair of head replacements and noticed one of my camshaft lobes had worn quite badly so I've replaced the shaft   but i can  see the cam rotating shaft is lubricated by engine oil pressure via small holes but can see nothing for the lobes so do the rely on oil spray ect?

[Charles]

The cam shaft lobes are lubricated by oil that is sprayed from little holes at the base of each rocker.  The problem with the Gamma flat four is that the oil in the cam chamber drains back to the sump when the engine is not running and over time the lobes can loose the oil film protection.  It takes 3 - 5 seconds for oil pressure to build up at start-up and re-establish the oil film through the rocker spray holes.  So, if a long period has elapsed since the engine was last run, it is good practise to disconect the HT lead from the dizzy and turn the engine over on the starter motor until the oil pressure warning light goes out.  This re-lubricates the cam lobes and the HT lead can then be replaced and the engine started.  It is also recommended to use fully synthetic oil as the film strength is stronger (even though the oil seems thinner) although I generall use a good quality semi-synthetic for "classic" engines.
Of course, the real answer is to use your Gamma regularly!

[keri]

many thanks Charles for the answer