The Stovebolt Site Forums The Shop Area Engine Shop Lead additive

Am I supposed to be using a lead additive in my 53 228 motor? http://community.webshots.com/user/53jimmy

Most people here say that you don't have to use it unless you are using the motor under extreme conditions. I use lead substitute just to be safe. You can get it at Walmart and probably just about anywhere else that sells auto things.

Lead substitute is relatively cheap compared to the consequences. 20 years ago we still had a lot of people farming with pre 1975 equipment. Those who did not use leaded gas or a lead substitute had lots of valve trouble. I'm not exactly sure where you draw the line between extreme conditions and casual driving.

Yep, doesn't that old saying go something like this? "Better to be safe than sorry."

I've run "leaded" engines for years on both my pre unleaded Harley and my '38. I've never had a problem. If you want to spend the money it's up to you but unless you're pulling heavy loads all day it's not necessary.

Short Answer:
I wouldn't worry about it. I'd just stick with premium and avoid gasolines with more than single digit quantites of ethanol in it.

Long answer (if you hated chemistry, skip):

Leaded gasoline contains tetraethyl lead. It's an "octane booster" that makes it easier to achieve higher compression without premature ignition (more power!). The octane rating of gasoline (87, 89, 93) is the amount of compression the gasoline can take before "knocking" when compared to isoctane gase (100). You can actually have octane ratings above 100.

Tetraethyl lead was the first widespread octane booster. It was gradually replaced by better, more environmentally-friendly alternatives (MTBE and ethanol). MTBE is falling out of favor due to groundwater contamination and is generally being replaced by ethanol in 1-5% blends. Ethanol can provide for more complete combustions, but it raises the vapor point during warm months (leading to smog) and ethanol is more corrosive to certain types of seals.

In general, just go with the highest octane gas you can find and avoid ethanol blends and you'll be fine. Unleaded gasoline will cause SLIGHTLY more erosion around the valve seats, but it will take tens of thousands of miles to show any effect.

No need for using Premuim gas, unless you've got over 9.5:1 compression. Waste of $$$ to use it in a vehicle that doesn't call for it. If you don't push it hard, regular unleaded will do fine. I've seen old pre-unleaded vehicle run on unleaded for years with no problems, and ehtanol doesn't seem to make any difference either.

Actually, tetra-ethyl lead also provides a lubricating action for the valve seats. Octane rating makes no difference until you get low enough to get into 'knock' country. Also remember, an engine can be knocking long before you can hear it.