Lead fuel vs. unleaded fuel

"This worked well until the engine manufacturers started getting complaints about breaking in new valves – such as following a cylinder swap or after a major/top overhaul – on the unleaded gas that was still available at the time. Since the new valves now apparently needed some lead to prevent overheating and welding of the valves in the guides and seats, in November 1946 Continental issued a service bulletin recommending that engines with new valves should be run two to three hours on leaded gas prior to operating on unleaded. If break-in were performed in this manner, the valves should operate satisfactorily on unleaded for the remainder of its life." (Aviation Safety Magazine. "Burn, Baby, Burn." May 2003)

Here is a link to the entire article:

Link

What do you guys think?

-Tom

I covered this in another post somewhere, but cars in my day went thru valves at 45,000 and had to do an overhaul at 75,000....lived in Houston, TX....not a lot of dust....and this is with proper engine hygiene including using single weight HD oil...no multi vis then.

Today I have a 6 year old p/u that runs and looks like new. Yes the valves have a "Stellite" coating which is supposed to make them last longer, and lubricants have new additives that they didn't have then,but other than that, how is it that there is such a stark difference?

Don't know about tractors as I was a city boy then.

Mark

Now it's drive drive drive. I won't deny highway miles are good for warming up the engine and getting rid of moisture and revs are around 2000 at 70, but what I'm talking about is plain old crud....lead crud.

The other thing the oil companies are still pumping the 3000 oil change just like they did then.. I had a '80's Chev Nova I bought from a guy and had to replace the head (one of those stupid integrated heads that cracked). Car had 100k miles and you could still see the the hone marks on the cylinder walls....he changed oil every 3000 miles just like the oil company said.....who's wasting what here.

Mark

Mark

You don't suppose that lead was a CHEAP way for the petrolieum industry to get the octane to the govt. standards, now do you..... ..... ..naw.

Amazing, when the EPA or whomever started the lead whining cycle, all of a sudden, unleaded was available..... ..... ..but oh it cost more....geez, did I miss something. If all of us poor misserable wage earners believed all the crap that is crammed in our faces by all the special interest groups (from cereals to Viagra)
this country would have been gone a long time ago. Thank something or someone, we just aren't that stupid..... .yet.

Mark

Lead additive (tetraethyl lead) was discovered by a fellow name Midgely and another fellow working with him, a Mr. Charles Kettering of electric starter fame. They were trying to find ways to keep fuel from detonating. After about 20,000 formulae, they found that very small amounts of this additve did the trick allowing for higher compression and more powerful engines. This was done in GM labs so that the Army Air Corps could hop up aircraft engines in the 1920s.

Sure, prices went up when lead additive was banned. In order to attain the anti-knock rating that lead additive achieved, the refiners had to tinker with the octane/heptane polymer chain mix. This required the addition of more specialized equipment at refineries. No doubt many contracts were let to mechanical contractors to install the new equipment and to tear out the unneeded leading systems.

When I was in the 14-16 age bracket, we had a Ford flathead V8. The "bully" down at the end of the street acquired a '49 4 door Olds V8. I wanted one of those so bad because all it would do was go and boy could he spin the tires..... ..... ..... aw you never spun the tires when you were a kid did you? Well if you had a Ford like I did (mothers car) you didn't cause it wouldn't do it....Ford-o-matic among other things.
(grin).

Mark

On the other side of the coin, back in the '70s Sunoco marketed their highest octane gasoline as number '260' their commercials having the tag line "...get some 260 action!"

I pulled into a Sunoco station with my brand new Honda XL-250 back in 1973 and told the pump dude to give me some of that '260 action'. He told me it would burn up my valves. Yeah right.

1950's, I remember when you had to do a valve job at 45,000 and an overhaul at 75,000. My family religiously succombed to the crapola of 3000 mile oil change at the local Texaco "Havoline 30 HD" in summer, "Havoline 20 HD" in winter (Texas)....well pilgrims, I know additives to oil, (not the mineral oil it'self) are much better now than then but the real deal was the crap the LEAD put in your whole system (it's called friction particles which produce wear)...don't believe me, check out a piston today, vs a piston in the days of lead and wooh what happened.....all the crap is gone. While I'm at it, AMALIE Pennyslyvania crude..... where is it? Gone somewhere? Now the nearest is Mid-east oil that is Pennsylvania crude equivalent..it's called Pennyslyvania GRADE crude.....who is blowing smoke up whose rear???? Personally I have had a belly full of being lied to....sorry if if I stepped on some toes. I am 62 now and 2 years ago all the crapola just fell apart.

Wishing you the best.

Mark