Any recommendations as to a fuel additive to prevent valve seat recession on a 1972 Mopar 440 engine that was engineered for leaded fuel? The owners manual says to add an anti-wear additive if only leaded fuel is used. I am sure Mopar made an additive at the time, but that was a long time ago. Thanks for your help.
Valve seat anti-wear additive
- Thread starter Building3
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Have the heads ever been off? I know it was common for a long time to put in hardened valve seats on any engine that was out when leaded fuel was common. Once you put in the hardened valve seats there wasn't an issue. They told us all about it when I took engine rebuilding class like 15 years ago and said "you all are probably too young to have to worry about this but just in case.."
Meanwhile, if hardened seats have never been installed, keep engine speed under 3000 RPM to minimize seat wear. SAE had an article to that effect a few years back.
Originally Posted By: CR94
Meanwhile, if hardened seats have never been installed, keep engine speed under 3000 RPM to minimize seat wear. SAE had an article to that effect a few years back.
...and don't "lug" the engine and look carefully at the ignition timing and the cooling system.
This is the product I have experience with and after trying a half dozen such products back in the 70's this is what a chose. Be very careful to pour this stuff in before you start filling the tank to make sure it mixes well. Don't run a whole tank before refueling. Feuling and mixing more often will get you more consistent results.
Also use a gasoline additive with PEA and the Motor Medic lead substitute because the PEA remains active in the combustion chamber under heat and pressure unlike other fuel system additives and it's very important in your case to keep the fuel system clean including the combustion chamber and those valves and seats. This may not do much to clean up previous hard deposits but it will help delay future buildups. Use a bit more of the fuel system cleaner than specified in the directions, maybe double it.
I could not find a reasonable YouTube video on Motor Medic lead substitute but here is a good video on fuel system cleaner by a guy that appears to be better than a talking head with an ax to grind.
Meanwhile, if hardened seats have never been installed, keep engine speed under 3000 RPM to minimize seat wear. SAE had an article to that effect a few years back.
...and don't "lug" the engine and look carefully at the ignition timing and the cooling system.
This is the product I have experience with and after trying a half dozen such products back in the 70's this is what a chose. Be very careful to pour this stuff in before you start filling the tank to make sure it mixes well. Don't run a whole tank before refueling. Feuling and mixing more often will get you more consistent results.
Also use a gasoline additive with PEA and the Motor Medic lead substitute because the PEA remains active in the combustion chamber under heat and pressure unlike other fuel system additives and it's very important in your case to keep the fuel system clean including the combustion chamber and those valves and seats. This may not do much to clean up previous hard deposits but it will help delay future buildups. Use a bit more of the fuel system cleaner than specified in the directions, maybe double it.
I could not find a reasonable YouTube video on Motor Medic lead substitute but here is a good video on fuel system cleaner by a guy that appears to be better than a talking head with an ax to grind.
MolaKule
Staff member
Originally Posted By: Building3
...The owners manual says to add an anti-wear additive if only leaded fuel is used...
Huh?
The tetraethyl-lead not only increased the octane rating but also deposited a thin film of lead on the seat for valve cushioning.
...The owners manual says to add an anti-wear additive if only leaded fuel is used...
Huh?
The tetraethyl-lead not only increased the octane rating but also deposited a thin film of lead on the seat for valve cushioning.
No the heads have never been off. The engine has never been opened up. It is a low mileage (26,000) original car. The first and second owners never had it out in the rain. Same for me. So it has been well cared-for. But I want to drive it more in the spring so I am making a list of things to do. It's interesting that in the owners manual, Chrysler said that the 6-cylinder engines could run fine on unleaded, but the V8s needed the additive or leaded fuel every 4th tankful.
Run it. dont worry, unless you tow a trailer, have a tow truck or its in a motorhome. I know, i collect recessed heads ( exaust seat) that were made before hardened seats were standard . My collection is very small
. Again RUN IT.
I ran this in a 56 Packard Caribbean some years ago with good results. Don't abuse this stuff like the old Nitro 9 it can really screw things up but when used in the correct dose really stops seat recession.
http://www.wildbillscorvette.com/octanesupreme01.htm
http://www.overkillgarage.com/octane-supreme.html
http://www.wildbillscorvette.com/octanesupreme01.htm
http://www.overkillgarage.com/octane-supreme.html
I ran leaded fuel as long as it was available in a '66 Valiant slant 6. Bought it with 38K on it and it had 2 burnt valves by 90K. OTOH, the F head 6 I had in the Willys wasn't bothered at all. If it had solid tappets, set them a bit wide. Run a tad rich, timing a bit retarded. make sure the cooling system is perfect
Thanks for the replies. So it seems that if I drive cautiously I may not need to do anything, but if I want to do any "spirited" driving, I should use a lead additive to protect the valves. I only drive this car in the nice weather which is usually April through November. I put on 200 to 800 or so miles a year. Mostly to car shows and on the weekends.
I would 100% use the additive on that engine or any other that was designed for leaded fuel. Given the usage you mention you wont need much at all for the whole season.
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