Posted by David Sherman on Monday, February 02, 2004 at 3:11PM :
In Reply to: Re: Lead/No-Lead Fuel posted by MikeC on Monday, February 02, 2004 at 2:06PM :
Lead caused a lot of problems that we've forgotten about like deposits on the valve seats making them leak, and deposits inside the head and on top of the pistons. I was pretty young when lead was still common, but even then I remember having to pull the head off the lawnmower every couple of years and scrape the lead off the valves, piston, and head. I think the white crud that builds up in old carbs is some kind of lead residue too. It seems like once they're thoroughly cleaned, they don't get crudded up again on modern gas.
On the diesel end of it, I worry about low-sulphur diesel in old engines like my cat. So far, off-road diesel is still supposed to be high-sulphur, but since it's usually the same as furnace oil and most of the market is for furnace oil which is supposed to be going to low-sulphur, I have my doubts. Again, all I know is the rumours that are going around, but supposedly old injector pumps and injectors relied on the sulphur for lubrication and they will wear quickly when run on low-sulphur diesel. This kind of makes sense because thread cutting oil is high-sulphur and the purpose of the sulphur is to prevent sticking and galling between the die and the workpiece.