I'm changing the antique oil for the first time in my rajo equiped speedster. the engine has a Model A crank and a deep cast aluminum crankcase. Should I fill the crankcase to the level of the top petcock on the transmission housing as I would for a stock engine?
Ben Strain
How else would you fill it? There has to be just the right amount of oil for the crank to slice through and splash, and that does not change with a deep sump. All that changes is that you have more oil in the system, so purely theoretically the heat exchange would be improved and the contamination reduced. The latter can also be achieved by shorter oil change intervals, however.
Ben,
For any Model T engine, the oil level should be between the top petcock and the bottom petcock with the engine not running. What this means is oil should not flow out of the top but should flow out of the bottom petcock. If no oil comes out of the bottom it is too low, could be a spoon full low or empty. Same applies to the top petcock, if oil runs out it is too high, could be a spoon full high or quarts high, you cannot tell. Some like to see oil run out of the top for extra insurance but there is no way of knowing how much extra oil there is, only that there is more oil in it than Ford designed it for.
"...there is no way of knowing how much extra oil there is..."
Of course there is. You fill until oil comes out of the top petcock then stop. How else would you even do it?
You might looksee if it has an oil pump and pressure lubed bearings. With the deep sump, about anything is possible.