Joined: Dec 25, 2016 Posts: 119 Location: Athens, Greece
Posted: Tue Mar 26, 2024 10:31 am Post subject: Lead additive, one more question.
Hi all and congratulations for our improved forum!
My M38 driver puts about 100-150 miles each year and I have always used lead fuel additive since
my engine has no hardened tvalves and seats.
I keep getting carbon deposits on my NOS sparkplugs so with other settings all as per specs, I wonder if the additive is the culprit for the deposits.
If the Redex or Wurth lead additive I'm using do foul my plugs, I wonder if I can do without them, so what is the latest consensus on this much discussed subject?
The environment that we operate these old 4 cylinder 60 and 70 HP engines is not as hostile as one tends to hear. Trying to hotrod down the street in a 1957 stock 283 on modern unleaded gas at 6,000 RPM's will create many serious problems with that engine. I do not see the harm in running a 60 HP L134 on modern unleaded gas at 2500 RPM and 45 MPH. Perhaps if you consistantly pushed the envelope by operating for hours at 3,000 RPM on freeways you may be able to cause some minor internal injuries but the only real threat in our L-134 operating environments with modern unleaded gas is damage to original equipment type fuel system rubber seals which can be easily avoided by using new production seals.
If this doesn't put your mind at ease then just start mixing your gas tank half and half: modern unleaded with old Aviation 80 to 100 octane avgas. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Joined: Oct 02, 2014 Posts: 2004 Location: South Carolina, Dorchester County
Posted: Tue Mar 26, 2024 2:10 pm Post subject:
Hi Aris,
Perhaps the best way to see if it's your lead additive causing fouled spark plugs would be to stop using it for a while?
Pretty sure no harm would be done.
150 miles a year isn't much driving.
Recommend that when you drive make sure you put enough miles on it in one trip to be at operating temp for a good while.
I think many short trips without or just reaching operating temp can also cause plug fouling.
Have you tuned your carb mixture with vacuum gauge and checked timing lately?
Might need to slightly adjust carb mixture or timing to account for your additive?
Just a thought.
Curious about your comment "congratulations for our improved forum"?
I don't see anything changed. Maybe I missed it.
What do you see as "improved"?
Good luck! _________________ Ron D.
1951 M38 Unknown Serial Number
1951 M100 Dunbar Kapple 01169903 dod 5-51
“The only good sports car that America ever made was the Jeep."
--- Enzo Ferrari
Good to know these engines are strong re std fuel.
In the U.K. we have 10% Ethenol mixed in.
I use a product which is supposed to kill the Ethenol and add lead.
Lets hope it is doing its job.
Horse. _________________ 1952 M38
Joined: Dec 25, 2016 Posts: 119 Location: Athens, Greece
Posted: Wed Mar 27, 2024 10:17 am Post subject:
wesk wrote:
The environment that we operate these old 4 cylinder 60 and 70 HP engines is not as hostile as one tends to hear. Trying to hotrod down the street in a 1957 stock 283 on modern unleaded gas at 6,000 RPM's will create many serious problems with that engine. I do not see the harm in running a 60 HP L134 on modern unleaded gas at 2500 RPM and 45 MPH. Perhaps if you consistantly pushed the envelope by operating for hours at 3,000 RPM on freeways you may be able to cause some minor internal injuries but the only real threat in our L-134 operating environments with modern unleaded gas is damage to original equipment type fuel system rubber seals which can be easily avoided by using new production seals.
If this doesn't put your mind at ease then just start mixing your gas tank half and half: modern unleaded with old Aviation 80 to 100 octane avgas.
Wes, hotrodding for me goes back some decades and you valuable expertise is great news! THANKS! _________________ Aris
Willys M38
1936 Cord Phaeton
1954 Mercury Monterey
1968 Corvette Stingray
1973 Mercedes 350SE
1974 Montesa Cota 247T
Joined: Dec 25, 2016 Posts: 119 Location: Athens, Greece
Posted: Wed Mar 27, 2024 10:37 am Post subject:
RonD2 wrote:
Hi Aris,
Perhaps the best way to see if it's your lead additive causing fouled spark plugs would be to stop using it for a while?
Pretty sure no harm would be done.
150 miles a year isn't much driving.
Recommend that when you drive make sure you put enough miles on it in one trip to be at operating temp for a good while.
I think many short trips without or just reaching operating temp can also cause plug fouling.
Have you tuned your carb mixture with vacuum gauge and checked timing lately?
Might need to slightly adjust carb mixture or timing to account for your additive?
Just a thought.
Curious about your comment "congratulations for our improved forum"?
I don't see anything changed. Maybe I missed it.
What do you see as "improved"?
Good luck!
Ron I've checked all tuneup specs many times they're OK but as u mention I mainly do short drives and I cant do much about that except try to make some longer ones in between.
But u mention operating temperature that I have overlooked so I'll remove and test the thermostat on the stove maybe that is also the cause of plug fouling.
The consensus for my M38 is no more additives!!! Thanks! _________________ Aris
Willys M38
1936 Cord Phaeton
1954 Mercury Monterey
1968 Corvette Stingray
1973 Mercedes 350SE
1974 Montesa Cota 247T
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