08-22-2016, 03:20 PM
1960s air cooled engine technology was such that fit tolerances between pistons and cylinders were a bit loose and engines burned some oil by design. Burning a detergent oil left ashy deposits that accumulated in the cylinder and eventually resulted in hot spots (which could cause pre-ignition knocking).
The reason I know anything about this is because air cooled aircraft engines have the same issue (most having been designed in the same era). Aircraft engines still don't use detergent oils for that reason. They use oils with an ashless dispersant that suspends contaminants in the oil, but doesn't leave ash deposits when burned.
I'd probably stick with the non-detergent oil that you're currently using. While the detergent packages in oil have certainly improved over the years, modern oils are designed for engines that burn little to no oil.
The reason I know anything about this is because air cooled aircraft engines have the same issue (most having been designed in the same era). Aircraft engines still don't use detergent oils for that reason. They use oils with an ashless dispersant that suspends contaminants in the oil, but doesn't leave ash deposits when burned.
I'd probably stick with the non-detergent oil that you're currently using. While the detergent packages in oil have certainly improved over the years, modern oils are designed for engines that burn little to no oil.