Lead additive substitute

Ran Model A in late 1950's on both leaded & unleaded.

As Purdy remarked, with leaded, awful hard carbon build up, ruined plugs.

With unleaded, no carbon, absolutely no valve problems "ever", & plugs seemed to last forever.

Installing hardened Model A valve seats in my opinion is a big sales gimmick -- drove one Model A engine on unleaded for 10 years with no valve problems -- still have this engine.
 
Last edited:
I agree with H.L. , spark plugs didn't last very long. The best that I remember, it was recommended to replace the spark plugs every 10.000 miles. Most engines would need a overhaul at 50.000 miles. The advantage was higher octane without timing knocks. I could feel the difference or loss of power when the lead was removed. The excuse was that the lead was depleating the ozone layer. Vehicles do last longer on unleaded fuel and modern distributors adjust the spark to prevent timing knocks. I don't run my model A 's enough to worry about any damage that leaded fuel would cause. I remember the older guys talked about removing the head ever so often to remove the carbon. The carbon,lead deposits were hard to remove. Now we mostly just get a little soot in the combustion chamnbers and not much of that if the ignition is good and the spark plugs are hot enough.
 
Engines do run cleaner with unleaded. Far fewer deposits. I was working in a Ford garage in the 70's, and whenever there was an engine tear-down the difference was pretty obvious from cars of the 60's living on leaded fuel and cars from after 1974 running un-leaded.

The amazing thing is with today's engines, at least with Ford, the high performance engines are running 10:1 compression on 87 Octane gas. The owner's manual specifies it. The higher HP Coyote engines specify 92 Octane Premium, but you are in the 450 and 650 HP ranges. I'm sure Camaros and Challengers are running the same.

The elimination of lead never turned into the boogieman we all thought it would back in '75. For the most part save maybe race cars, drag cars and the like. But for the vast majority of cars it was no big deal.
 
And to add to Mr. Purdy's comments, in addition to the leaded gas heavy carbon build-up in all four of one's spark plugs, multiple layers of hard black carbon deposits created carbon damns all around the top of block valves openings & greatly altered the flow of one's fuel/air mixture into the combustion chamber.

Old timers referred to unleaded as "white gas" because it was as crystal clear as distilled water as opposed to the reddish leaded gas.

Also, when driving right after scraping carbon off of the top of one's block around valves, one could notice one's increased engine performance, better pick up, & far better gas mileage.

We bought unleaded back then from a "non-self-serve" Pan-Am filling station -- yes, they smiled & cleaned the windshield, checked the oil, & checked the tires & added air if necessary -- & yes, all attendants knew where the gas cap was located.
 
Purdy Swoft said:
... The excuse was that the lead was depleating the ozone layer. ....
Click to expand...

The ozone layer issue was with Freon. Lead is just plain toxic to living things. Its toxicity affects several organ systems--some reversibly--but effects on the central nervous system (brain) are irreversible. Exhaust gas from leaded gasoline was much more toxic than from unleaded, and it was accumulating to toxic levels in the soil and plants along roadways. Blood levels of lead have been dropping world wide since it was phased out of use in gasoline and food related applications such as solder in food cans.

Like a lot of dumb kids, I used to joke about all of that sort of thing, but not so much anymore since my Parkinsons diagnosis.

Steve
 
You must log in or register to reply here.
Back
Top