Are you sure you don't have a blow-by problem? How would oil get in the carbs if only the valve seals are leaking?

>You need to pressurize the cylinder with compressed air, that will keep the >valves at there highest point, in there seats.

This does not work well with old engines, as the rings/valves do not seal well and thus it's easy to accidentally push the valve down. Ie. the air pressure does not hold the valve with a lot of force.

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Csaba
1972 280SEL 4.5, silver