Anyone using lead additive on pre ‘80’s

El Capitan

Well-Known Member
Jul 9, 2014
3,828
Chicago IL./Vero Beach, Fl
Boat Info
1970 SRV 180 w 2.5L Mercruiser.
2000 Ford Expedition Eddie Bauer
Engines
120HP Mercruiser
I don’t wish to start a debate, you know, like which is the best oil…

But for our older gals w original heads/valve seats is anyone here using it?

Any observations greatly appreciated!
 
Unsure about our boat motors, but, in the early Seventies, the automotive engine manufacturers all started using induction hardening on the exhaust seats to increase their resistance to valve recession. This was driven by the fact that tetraethyl lead was being phased-out of pump gas, which used to be what allowed the exhaust valves and seats to live in relative harmony.
Once the heads were induction hardened, there was really no reason to worry about TEL additives. The only other benefit (that I know of) is an increase in the octane rating. This can be improved through a number of alternate avenues without relying on the TEL.
So, nope; no lead additives. Not even in my Norton.
 
What about Tracey?
383BFE22-E04C-4B72-B6FD-5272C1606115.jpeg
 
Marvel mystery oil is a common additive that has been used over the years.

I have a 1969 Dodge without the hardened valve seats. When I rebuilt the motor 15 years ago, the machine shop guy told me not to install the hardened valve seats. With low usage (a few 100 miles/year) and the use of marvel mystery oil, it wouldn’t be a problem.

15 years and about 8k miles later, he is right.
 
I use "Lead Substitute" in a 1971 Chevy bigblock, no big deal. It's cheap and I think it smells good. That could be more the lack of emissions gear though...:)
 
I used to. But our marina carries valvetec which purportedly has the additives needed, so I stopped.
 
There's absolutely NO reason to add lead... if your engine came from MerCruiser, OMC, or Volvo-Penta, it was either through Ford or GM Marine, in which case, they're industrial. There will be hardened valve inserts in ALL of them.
 
There's absolutely NO reason to add lead... if your engine came from MerCruiser, OMC, or Volvo-Penta, it was either through Ford or GM Marine, in which case, they're industrial. There will be hardened valve inserts in ALL of them.
I had an 88 Pachanga with twin 454’s and I had to rebuild one the engines. The engine was a 4 bolt main and had hand fitted bearings from Merc but the heads had induction harden exhaust valve seats and not actual inserts.
 
I had an 88 Pachanga with twin 454’s and I had to rebuild one the engines. The engine was a 4 bolt main and had hand fitted bearings from Merc but the heads had induction harden exhaust valve seats and not actual inserts.

Yup but it was an 1988. I’m thinking about 1974-1978 heads.
 
The induction-hardening of later heads will not have any difficultly as long as the head hasn't been machined or ground into that hardening... if the hardened area has been cut into, inserts (or a replacement head) will be required.
 
Unsure about our boat motors, but, in the early Seventies, the automotive engine manufacturers all started using induction hardening on the exhaust seats to increase their resistance to valve recession. This was driven by the fact that tetraethyl lead was being phased-out of pump gas, which used to be what allowed the exhaust valves and seats to live in relative harmony.
Once the heads were induction hardened, there was really no reason to worry about TEL additives. The only other benefit (that I know of) is an increase in the octane rating. This can be improved through a number of alternate avenues without relying on the TEL.
So, nope; no lead additives. Not even in my Norton.
I would be more worried about the alcohol that is in the fuel now especially if your running 4 stroke outboards there is an additive for that that I have used.
 
I would be more worried about the alcohol that is in the fuel now especially if your running 4 stroke outboards there is an additive for that that I have used.
After all the issues we've seen in the recent past with alcohols beating up the fuel systems, the manufacturers finally stepped-up to build systems that are "alcohol-resistant". To the best of my knowledge, anything built after the mid-2000's is able to run at least 10% ethyl alcohol without harm. I put accent on ethyl, as alcohol-blends got a bad name in the Eighties or thereabouts, because they were blending methyl alcohol. Nasty stuff! However, I still use alcohol-free in my lawn equipment, as I noticed things like plastic fuel tanks and, especially, the little primer bulbs developing hairline cracks with subsequent complete failure.
My Norton was treated to Viton fuel lines, petcock o-rings, and float needles, and now no worries with running 10% ethyl blend.
One point I failed to mention was that the alcohol has a great affinity for water. That's where most of the earlier grief came from with causing corrosion in the metal parts. Since our boats don't tend to be used on a daily basis like most cars, there's definitely an argument for not using alcohol blends, as sitting tied to the dock, the fuel will draw moisture to itself inside your fuel tank.
 
Nate, your note about water is by far the greatest concern of ethanol-mixed fuels... but it goes far beyond what most people think.

Ethanol is INTENSELY hygroscopic- it absorbs moisture like a sponge. Because our fuel tanks are vented, they will naturally WANT to absorb moisture from the air. Even if you're in an arid environment like Lake Havasu, there will be plenty of atmospheric absorption due to ethanol in the fuel.... but wait... that's not all:

Ethanol, once well-bound to water molecules, falls out of suspension, to the bottom of the tank, where you'll find engineers have placed the FUEL PICKUP. (Apparently they don't feel that having it up near the top is such a wise choice, eh?)

Take a 5-gallon can to your local gas station and get some E10... for great effect, get it about an hour after the bulk truck makes it's delivery. Take it home, Fill up a quart Mason jar to about 2/3rds full, and put on a sealing cap. Fill a second one, put a cap on, but punch a half-dozen holes in the cap. (don't use a plastic jar...). Take a permanent marker, and mark a LINE at the level in the jar.

Place them on a SAFE shelf in your well-ventilated shed, let 'em sit for several weeks, then come back and take a look at what they look like.
You'll see that the levels will change. The lighter fractions will evaporate off one jar... and moisture will find it's way IN. If you time-lapse it, you'll see the level drop over the first week... and then (depending on humidity) it'll start to climb again... as condensation occurs. You'll see the fuel layer. The clear layer on the bottom is water, then saturated ethanol... then the heavier fractions of gasoline.

Ethanol is caustic. Hydrated ethanol is worse... it's an electrolyte... like making your carbeurator bowl into a battery.

Ethanol is fine in most things AS LONG AS THERE'S NO WATER... (and that's kinda hard to do).

The best additive for running ethanol-blended fuels in anything, is a water separator, and a 'dump all remaining' policy if it's going to be stored for more than a day or two.
 
I only use non ethanol on all my vehicles including my lawnmower.
Not just due to water, but try reading the MSDS of ethanol fuel.
 
I don't know it well, but my wife used to operate a local distribution facility, was responsible for processing samples and paperwork of everything from Av gas to Asphalt... she froze diesel, and boiled gasoline... I'm certain that sheet is VERY long.

From a chemistry perspective, if one were to build an engine that was intended SPECIFICALLY to run on JUST ETHANOL... E100... then it would be a much better solution, in basically every realm, than mixing a single-compound carbohydrate fuel with a multi-compound hydrocarbon fuel blend... but that means that accomodating the nature of the fuel, especially moisture mitigation, is integral to the system in every way.

And I'm not making this comment as if nobody has done it... because they have made engines that DO run it... but from a market standpoint, they're still 'multi-fuel' engines... running strictly E means all the other unnecessary accomodations can be shed for a significant improvement in package volume and mass.
 
I don't know it well, but my wife used to operate a local distribution facility, was responsible for processing samples and paperwork of everything from Av gas to Asphalt... she froze diesel, and boiled gasoline... I'm certain that sheet is VERY long.

From a chemistry perspective, if one were to build an engine that was intended SPECIFICALLY to run on JUST ETHANOL... E100... then it would be a much better solution, in basically every realm, than mixing a single-compound carbohydrate fuel with a multi-compound hydrocarbon fuel blend... but that means that accomodating the nature of the fuel, especially moisture mitigation, is integral to the system in every way.

And I'm not making this comment as if nobody has done it... because they have made engines that DO run it... but from a market standpoint, they're still 'multi-fuel' engines... running strictly E means all the other unnecessary accomodations can be shed for a significant improvement in package volume and mass.

Yeah…uh…what he said.
 

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