Lead Fuel Additives

SwampThing

SwampThing

Petty Officer 2nd Class
Joined
Nov 6, 2006
Messages
117
Did a search and didn't come up with any discussions on lead fuel additives.
I'm sure you've had to of had this one before.

I'm curious about the use / need for lead fuel additives for mid 80's engines and prior. The lead in leaded gasolines was originally used for valve seat lubrication. So my question is; are lead additive necessary or should I be adding it to my fuel mixtures?

I have 3 older outboards - a 1986 125hp Force which says it can use leaded or unleaded fuel. And a 1961 Johnson 75hp and a Ted Williams 4.5 hp from the 70's. Not sure of exact year, guess I should double check it.

I wondering if I should be using the lead additive. Is it "Needed"? Am I doing harm to the motors by using it or would I be doing harm to the motors by not using it. The Force literature is the only place where I've found any mention of lead verses unleaded fuels. But it only states that leaded should be my first option unless it's unavailable.

Is there a definitive answer on this topic?
 
roscoe

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,763
Re: Lead Fuel Additives

A waste of time and money to add lead or lead substitute.
Put your money into a good quality TC-W3 rated 2 cycle oil instead.

And yes, this has been discussed several times before, but the search engine is real lousy.
 
G

gss036

Commander
Joined
Jan 18, 2003
Messages
2,914
Re: Lead Fuel Additives

The lead additives were brought to market for older car/truck engines when unleaded gas was the only thing available. The older engines required lead as a valve lube, they have long since redesigned the engines and no longer required. I still have about 8 oz left on my shelf for an old 1976 Dodge engine.
As stated above you are wasting your money at this point of modern engines. Running a 2 stroke, buy the best TCW3 oil that you can afford and you will get longer life from your engines.
 
P

Paul Moir

Admiral
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Nov 5, 2002
Messages
6,847
Re: Lead Fuel Additives

Actually, the lead (TEL, tetra-ethyl-lead) additives will leave deposts in your engine which will harm it. No 2 stroke ever needed or wanted it. In fact, according to the manual on old outboards, you were to use fuel that didn't contain it if available. I have no idea why FORCE would recommend it.

TEL's primary function was as an anti-knock agent (aka octane booster). It's lubricating properties were coincedental.
 
JB

JB

Honorary Moderator Emeritus
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Mar 25, 2001
Messages
45,907
Re: Lead Fuel Additives

What Paul said, better than I could have said it.
 
D

DJ

Guest
Re: Lead Fuel Additives

Lead was strictly a combustion chamber lubricant (valves, etc.) for four cycle engines.

Lead is a complete waste of time in two strokes, along with other additives.

A good 87 octane fuel with TCW-3 oil is all you need.

Your pre '63' engines are 24:1, post '63' are 50:1.
 
M

Mdude

Cadet
Joined
Aug 22, 2004
Messages
16
Re: Lead Fuel Additives

SwampThing said:
The lead in leaded gasolines was originally used for valve seat lubrication.
Click to expand...

I was thinking that lead was originally used as a flame inhibitor as a cheap way of boosting octane. ....or at least by slowing down the flame travel, an engine could run higher compression. The valve seat lube thing was a side benefit that engine manufacturers took advantage of to cheapen their valve guides and seats. At least that's what I seemed to have dusted off in the cobweb infested part of my mind that hasn't been touched in years. So I can't remember where I got that.
 
kenmyfam

kenmyfam

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Joined
Aug 10, 2006
Messages
14,392
Re: Lead Fuel Additives

Mdude said:
SwampThing said:
The lead in leaded gasolines was originally used for valve seat lubrication.
Click to expand...

I was thinking that lead was originally used as a flame inhibitor as a cheap way of boosting octane. ....or at least by slowing down the flame travel, an engine could run higher compression. The valve seat lube thing was a side benefit that engine manufacturers took advantage of to cheapen their valve guides and seats. At least that's what I seemed to have dusted off in the cobweb infested part of my mind that hasn't been touched in years. So I can't remember where I got that.
Click to expand...
The valves and valve guides have to be much better heat treated (hardened and tempered)) with no lead fuel.
 
kenmyfam

kenmyfam

Supreme Mariner
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Aug 10, 2006
Messages
14,392
Re: Lead Fuel Additives

That is with 4 strokes only of course. No problems with 2 strokes due to lack of valves and guides !!
 
Scaaty

Scaaty

Vice Admiral
Joined
May 31, 2004
Messages
5,180
Re: Lead Fuel Additives

TEL had 2 needed properties in older motors WITH VALVES...reduction in detonation (I don't know how this happened, and know none of the effects on 2 strokes), but was needed as a cushion for the exhaust valve which some older motors had the seat cut right into the cast iron head (old Harley Sporster motors did this....not sure on old car heads, as I wrenched 2 wheel stuff). It was this cushioning effect that kept the valve from beating the hell out of the seat. Early 70's started a ban on it and they started using hardened valve seat inserts.
 
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