Lead additive

[DLK]

I come away from reading all these posts convinced that oil additives are NOT needed with a 46-52 flathead and it's hardened valve seats. Yet over the last month I looked at three cars where the owners religiously added the lead substitute with every fill up. As several people said "if it makes you feel good do it" but I am joining the group that finds it unnecessary.

It reminds me of my Dad with his first fully automatic car, a 53 Buick Dynaflow (after owning all MOPAR's). A friend at work convinced him he should always start in "L" and shift the car manually to "D" rather than let it shift itself. He went through 2 transmissions in three years.

[claybill]

for 9 years i have used regular pump gas in my plymouths....

i never thought of anything else...??? it runs fine, no pinging, starts up.

plymouths just dont need lead.!!! there is no dispute anymore after the many threads in this column over the years.

bill

[bgoose47]

I just topped off with 91Octane after coming out of storage. I did have 5 gallons of 87 with lead additive already in the tank. Anybody think I will run into problems if I stay on the staight 91 without lead in my P15?

[aero3113]

I do not think these engines need lead additives,they have hardened valve seats.

[Don Coatney]

I just topped off with 91Octane after coming out of storage. I did have 5 gallons of 87 with lead additive already in the tank. Anybody think I will run into problems if I stay on the staight 91 without lead in my P15?

If it makes you feel good do it. But it is not required.

[Plymouthy Adams]

your low compression engine is designed to run on thel ower octane gas..the additives to increase octane in todays fuel is there to PREVENT fast burn...the higer compression engines are prone to detoation due to heat and compression alone, as in a diesel engine thus require the anti burn addtives to make the fuel less volatile...you are paying more for a fuel that will not deliver you anything excess a false peace of mind...

[randroid]

Folks,

I wish I'd followed this thread earlier because in 1970 I lived in Los Angeles when a map was made of the homes where all children admitted to hospitals for lead poisoning lived. Over 95% were within two blocks of a freeway, and for me that's "nuff said".

-Randy

[Flatie46]

I always thought that they removed lead from fuel because the exaust pipes were spitting it out on the roads and when it rained it wound up in ground water. Don't know where I heard that but it's been years ago.

You know the way I look at it, we all want our very expensive old engines to last as long as possible. I think some worry a little too much. The oil you buy now has higher standards than when these cars were built. If you buy the cheapest oil on the shelves your buying better than was offered in the 40's. Also people change their oil more these days, used to alot rarely did some never did. These engines are pretty tough if you drive em right change the oil regularly they're gonna last. Look how long many on this forum have lasted without a rebuild or had been neglected by previous owners and still chug along.

[Frank Elder]

I just topped off with 91Octane after coming out of storage. I did have 5 gallons of 87 with lead additive already in the tank. Anybody think I will run into problems if I stay on the staight 91 without lead in my P15?

You didn't need lead to run this engine when it was new and you don't need it now, lead was used as a cheap octane boost...this is a low octane motor that has hardened exhaust seats already and in no way shape or form does this engine require lead additives, unless you just have a burning desire to spend money on something.:DLet it go towards 87 octane instead:)

[bgoose47]

I appreciate the many responses to my question on leaded gas and octane. The overwelming response was no lead for many good reasons.

Simple solution is "Ethyl" (now aka 87 regular).

Thanks

[aero3113]

WoW I posted this thread 4-10-08 and it is still going

[TodFitch]

I appreciate the many responses to my question on leaded gas and octane. The overwelming response was no lead for many good reasons.

Simple solution is "Ethyl" (now aka 87 regular).

Thanks

"Ethyl" was the name of the company formed to manufacture, promote and sell tetraethyl lead. "Fill it with Ethyl" was an advertising slogan to get people to buy leaded gas back in the 1930s.

So equating today's 87 octane unleaded gas with "Ethyl" is in accurate.

I did a quick search to see what typical octane numbers were for different points in automotive history but did not find a good set of numbers. I did, however, find this chart on this page http://www.daytona-sensors.com/tech_tuning.html

Looks like my 5.5:1 compression ratio requires a massive 55 octane. The 1936-48 engines will need at 70 octane gas. And the 1949-54 engines (7:1 or 7.1:1 compression ratio) will need something like 80 octane. Remember, buying higher octane gas than you need does the engine no harm. And it also does you no good. It just costs more. So buying anything higher than 87 octane is just wasted money.

[Young Ed]

Unfortunately around here the only way to get no ethanol gas is to also buy 91 premium.

[Don Coatney]

"Ethyl" was the name of the company formed to manufacture, promote and sell tetraethyl lead. "Fill it with Ethyl" was an advertising slogan to get people to buy leaded gas back in the 1930s.

So equating today's 87 octane unleaded gas with "Ethyl" is in accurate.

I did a quick search to see what typical octane numbers were for different points in automotive history but did not find a good set of numbers. I did, however, find this chart on this page http://www.daytona-sensors.com/tech_tuning.html

Looks like my 5.5:1 compression ratio requires a massive 55 octane. The 1936-48 engines will need at 70 octane gas. And the 1949-54 engines (7:1 or 7.1:1 compression ratio) will need something like 80 octane. Remember, buying higher octane gas than you need does the engine no harm. And it also does you no good. It just costs more. So buying anything higher than 87 octane is just wasted money.

Tod;

Once again you produced the correct answer with documentation to back it up. Thanks for your great response.