QuestionWhat fuel type is used in the original engine/fuel sytem of let's say, an old flathead? I know that the day of leaded is gone, so how do antiques operate in today's unleaded environment? I also heard that the difference has to do with the valve seats....can you elaborate? Thanx!
AnswerFlat head engines went out of style in the 50's, but back then the usual octane rating of fuels was very low, and in fact the compression ratios of most engines were very low also - those old cars of the 30s and 40s will run well on any gas sold today. Remember that AMOCO, amongst others, sold unleaded gas ("WHITE GAS") ONLY, way back in the 40s and 50s -and no one had problems with it.
The horror stories you hear about valve problems caused by unleaded gas are pure marketing hype, put out by the people who are trying to steal your money by selling you fake "lead substitute" additives, and by talking you into having your valve seats replaced with new technology valve seats which are designed for modern gasoline without lead.
Lead is a lubricant for the valve seats, but unless you are towing a heavy trailer across the desert at 90 MPH on a 100 degree day with the air conditioner going full blast, you don't need to worry about this at all.
Next time you have the engine apart for some other reason, if you want to spend some extra money on it, have the valve seats replaced with hardened seats, then you can tow that trailer without worry, but that is really extreme useage, much more than any of us use our old cars for, and you should just put the problem out of your mind!
Dick
