Lead additive

[aero3113]

I know this has been talked about but I never really got a sure answer.Is lead additive needed in a P-20.When I bought the car the guy told me that he did not use lead and when I rebuilt the engine most of the rings were broken but the valves looked good.Would the broken rings be caused by not using lead?

[Young Ed]

No. The flatheads all had hardened valve seats right from the factory. Your broken rings are something else

[TodFitch]

I know this has been talked about but I never really got a sure answer.Is lead additive needed in a P-20.When I bought the car the guy told me that he did not use lead and when I rebuilt the engine most of the rings were broken but the valves looked good.Would the broken rings be caused by not using lead?

1. Lead was added as a cheap way of increasing octane.

2. Lead fouled up engines badly. So lead scavengers were added too to keep the lead deposits down.

3. Apparently some residual lead helped in fighting exhaust valve seat recession in 1960s engines when they were driven long distances at high speeds/high loads. Those engines typically used the cast iron block/head for their valve seating.

4. You are unlikely to be pulling a heavy trailer for hours on end at 70 MPH in your P-20.

5. Your P-20 L-6 came with hardened exhaust valve seats from the factory. So even if you decide to haul your boat to the other end of the continent using your P-20 you are covered.

Ergo, lead additive is not needed for your P-20.

Near as I can tell, the usual cause of broken rings is age/wear in the engine and the rings hitting the wear ridge at the top of the cylinder. That is unrelated to lead in the gas.

[central52]

I'm curious, too, about the lead additive question. Is it necessary to add it to today's modern gasoline. I have a 1947 Plymouth, and use 89 octane gas. Pepboys sell a lead additive bottle. Should I use it? Ed P.

[Don Coatney]

One can go to Pets-Are-Us and buy a diamond studded collar for there favorite dog. The dog could care less as the collar is not required and does nothing. But by using this collar the dogs owners boost there personal comfort level and it makes them feel good.

One can go to Pep Boys and buy lead additive or most any other liquid additive for there favorite car engine. The car engine could care less as the additive is not required and does nothing. But by using these additives the car owners boost there personal comfort level and it makes them feel good.

[TodFitch]

I'm curious, too, about the lead additive question. Is it necessary to add it to today's modern gasoline. I have a 1947 Plymouth, and use 89 octane gas. Pepboys sell a lead additive bottle. Should I use it? Ed P.

See answer below from me or one above your post from Don.

All Plymouth L-6 engines came from the factory with hardened exhaust valve seats. All the way back to 1933. Lead additive is not needed.

Unless, of course, you like the lead fouling your spark plugs and the lead acids/salts gunking up your crankcase and eating out your bearings and exhaust system. Basically, lead has always been bad. But it was a cheap octane booster. If the lead scavangers (also bad) left a little lead behind that had a side effect of reducing valve seat recession on some engines under some driving conditions, it was bad for your car in so many other ways.

[Captain Neon]

Tod-

While I am no chemist, I am a trained biologist so I took over two years worth of chemistry in college. I even did two term papers on lead (General Chemistry and Ecology). I am fascinated by your statement about lead acids eating up bearings and other components.

The only instance that I can point to any sort of a lead acid existing is plumbic acid which can only occur in a water-free (anhydrous) environment under very controlled conditions. That being said, this plumbic acid is very weak and given a choice I'll take plumbic acid over any of the other acidic compounds formed when unleaded gasoline is burnt in an internal combustion engine.

Any lead compunds that could form would actually show lead to be a good guy as it reacts with sulfuric, hydrochloric, and other acids to form a non-corrosive salt that usually serves to protect valves and have lubricating properties similar to graphite. A typical reaction involving tetraethyl lead in an internal combustion engine forms white lead (PbO2). This is what serves to help protect valves and serve as a graphite-like dry lubricant.

I will accept the argument that lead may be unnecessary, but to say that lead is detrimental to an engine that has its oil changed on a regular basis is a little hard for me to swallow. Lead may actually serve as an oil extender as it offers dry lubrication and neutralises acids formed in internal combustion.

I'd be interested in your source of information about how leaded is more detrimental than unleaded gasoline when burnt in an internal combustion engine of pre-1975 vintage. The only mechanical reasons I have ever heard for removing lead from gasoline is that it caused deposits in poorly maintained engines (long oil change intervals) and damage to catalytic converters. The air pollution argument is bogus as lead particulate from cars usually settled rapidly on to the pavement or gravel road. Unless your kids are out licking the road, lead in gasoline is the least of your worries.

Please elaborate on how lead is some how bad for old cars. I seem to remember lead (actually plumbous and plumbic oxides, red and white lead) being recommended in the Plymouth service manuals to serve as a dry lubricant on moving components. Unnecessary, perhaps. Detrimental, hardly.

[Tom Skinner]

How boot dat?

I,m all for Diamond Studded Collars and Lead Additives then!

I even grind up Chelated Zinc Tablets and throw some in my New Oil

at an Oil and Filter Change.

Use about 200mg. every Oil change and it feels sooooooo goooood.

Doc says it Keeps the Prostate flowin to.

Tom

[Captain Neon]

Perhaps the lead in the gasoline doesn't matter and I am just wasting my money. Perhaps the zinc in the oil doesn't matter and I am just wasting my money buying diesel oil. It doesn't hurt anything and that's my point. When some one tries to tell me lead is bad for my engine, I expect them to prove it. I explained my limited scientific and chemical understanding. Now you show me your information.

I expect to be driving for another 50 years and to be around 70 more years. I want my P15 to be there then so the grand nephews can drive me around.

[TodFitch]

No chemist either... And I don't remember the exact source for my broad statement.

But the first area that comes to mind are from the Gasoline FAQ at http://www.faqs.org/faqs/autos/gasoline-faq/part1/index.html

Originally, iodine was the best antiknock available, but was not a practical

gasoline additive, and was used as the benchmark. In 1919 aniline was found

to have superior antiknock ability to iodine, but also was not a practical

additive, however aniline became the benchmark antiknock, and various

compounds were compared to it. The discovery of tetra ethyl lead, and the

scavengers required to remove it from the engine were made by teams lead by

Thomas Midgley Jr. in 1922 [9,10,24]. They tried selenium oxychloride which

was an excellent antiknock, however it reacted with iron and "dissolved" the

engine. Midgley was able to predict that other organometallics would work,

and slowly focused on organoleads. They then had to remove the lead, which

would otherwise accumulate and coat the engine and exhaust system with lead.

They discovered and developed the halogenated lead scavengers that are still

used in leaded fuels. The scavengers, ( ethylene dibromide and ethylene

dichloride ), function by providing halogen atoms that react with the lead

to form volatile lead halide salts that can escape out the exhaust. The

quantity of scavengers added to the alkyl lead concentrate is calculated

according to the amount of lead present. If sufficient scavenger is added

to theoretically react with all the lead present, the amount is called one

"theory". Typically, 1.0 to 1.5 theories are used, but aviation gasolines

must only use one theory. This ensures there is no excess bromine that could

react with the engine.

So I think I "remembered" that the problem with bearings and such was due to lead when perhaps it was due to the lead scavangers. If aircraft engines are not allowed to have more than "one theory" of scavenger whilst auto gasoline had between 1.0 and 1.5 "theories" then it could be excess bromines that are the issue.

My personal experience is that spark plugs and exhaust systems last longer with unleaded fuel. Since I have always changed oil at short mileages I have not no been affected by lead deposits in the pan and engine (other than when I first got an old car in the era of leaded gas and typically found a bunch of grey/black colored muck in the engine).

In any case, I know a chemist who has an interest in lead, I guess I should consult with them before I make any more broad statements on this topic...

[central52]

My head is spinning reading all that technical stuff about lead additives for our old cars. Seems to be a standoff.

So, to use lead additive, or not to use lead additive. Ayyie, that is the question. What's the consensus out there? Who uses lead additives, who doesn't? Ed P.

[james curl]

Why? The engines in MoPar cars came with hardened exhaust seats.

[Johnny S]

Doesn't seem like a stand off from my perspective. You DON'T NEED lead additives in our vintage flathead motors. You are wasting money if you use them in our engines.

[Jim Saraceno]

So wait a minute... Let me get this straight....

Do I need to buy a diamond studded collar for my flathead engine?

I'm sorry, I'll go back to sleep now.

[Don Coatney]

So wait a minute... Let me get this straight....

Do I need to buy a diamond studded collar for my flathead engine?

I'm sorry, I'll go back to sleep now.

Jim;

The diamond studded collar will work for your engine only if it makes you feel good.

[eric wissing]

Why? The engines in MoPar cars came with hardened exhaust seats.

I like visiting another Chrysler site and they had a discussion on hardened seats. A retired Chrysler engineer chimed in that they stopped doing this sometime in the 50s? because of cost. Anyone here know this? The other site is an Imperial newsletter and is a real pain compared to this one. You have to subscribe through Yahoo and I can not respond or post because I am stupid!! Eric

[BobT-47P15]

OK....now, for a sim-u-lar but differnt qwestion......how about the use of

Marvel Mystery Oil in gas tank and/or the crankcase???? As the judge

told the jury, "what say you"?

[Don Coatney]

OK....now, for a sim-u-lar but differnt qwestion......how about the use of

Marvel Mystery Oil in gas tank and/or the crankcase???? As the judge

told the jury, "what say you"?

Bob;

If it makes you feel good use it.

[BobT-47P15]

I figure it may not help, but it probably can't hurt to use it. A little extra

lubrication from time to time.

[Captain Neon]

I like visiting another Chrysler site and they had a discussion on hardened seats. A retired Chrysler engineer chimed in that they stopped doing this sometime in the 50s? because of cost. Eric

My engine came out of a 1956 Dodge and this is why I use lead additive. I thought I had read this some where as well, but I didn't have any reference. I'm not about to tear my engine open just for a look-see.

Bob, I add 8 oz. of ATF to my gasoline at every fill-up for additional top cylinder lubrication. MMO would probably work even better. When I lived in Minnesota, I used to run about a pt. of MMO through my carburetor and stalled out the engine right before I covered her up for a long winter's nap. Smokes like a demon when starting up again in the spring, but it dissipates as the oil burns off.

[TodFitch]

My engine came out of a 1956 Dodge and this is why I use lead additive. I thought I had read this some where as well, but I didn't have any reference. I'm not about to tear my engine open just for a look-see.

Bob, I add 8 oz. of ATF to my gasoline at every fill-up for additional top cylinder lubrication. MMO would probably work even better. When I lived in Minnesota, I used to run about a pt. of MMO through my carburetor and stalled out the engine right before I covered her up for a long winter's nap. Smokes like a demon when starting up again in the spring, but it dissipates as the oil burns off.

My understanding, probably wrong, is that the L-6 engine always had the hardened exhaust valve seats. I believe that the engines designed and introduced in the 1950s and 60s did not have that feature (V-8 engines and the slant 6).

[Jim Saraceno]

A retired Chrysler engineer chimed in that they stopped doing this sometime in the 50s? because of cost. Anyone here know this?

I have a '55 engine and a '57 engine. They both have hardened valve inserts.

[Lancer]

So, would my 53 Desoto Hemi have hardened seats? Anyone know? Thanks.

[T120]

...Does Royal Triton nead a lead additive?

[Andydodge]

Don........If I learnt to bark would you buy me a diamond studded lead collar?............woof woof.........lol...........made me laugh, thanks, andyd