Tom@BearCanyon

Since I first bought my '65 Convertible with a 289, I have added Liquid Lead to every fill-up and have had no problems at all.

Now I can't find the Liquid Lead product I used at all and have been told I really don't need to add it anyway. I think this is bad advice, but would appreciate any expert's advise as to what I should do going forward.

Thanks for the time and thoughts.

mustangted

i use a lead subistute made by Red Line oil.

Jfsram

You can't easily find lead additive because it's been banned in most places. It's bad for everything, 30 years went by, find something better.

I've had 2 distinct scenarios concerning lead in an old engine.

Had a 70 Road Runner. Ran in the mid 11's with a stock iron cylinder head. Every visit to the track I lost a bit of mph. 5 mph later I took the engine apart to find most of the 8 exhaust valves were slowly, slightly sinking into their seats.
Soft seats, higher valve spring pressures and more rpm eventually sunk my seats.
I solved the problem by installing hardened seats. Some refer to them as stellite.

The other car is my wife's 1965 Plymouth Belvedere. It's a 6 cylinder that has NEVER had the engine or anything rebuilt. These seats have not sunk 1 thou. I know that because it's a solid lifter engine and checking the lash 10 years ago then again 1 year ago to find them still in factory spec is amazing. Anyways we only feed her regular 87 octane unleaded. On that note, it's has very low spring pressure, it's super gutless and it never sees high rpm.

v braaten

Putting pump gas in an old engine won't hurt anything. It's the opposite where trouble happens. Don't put lead in a modern engine.

Unleashedbeast

Can someone bring me up to speed and tell me the advantages of leaded fuels and why they used them back in the hay day. I really have never studied this.

Rubrignitz

Leaded fuel lubricated the exhaust valve seats on older heads with non-hardened valve seats. It kept the valve from sticking under high temperatures and wearing the seat down. Newer heads have hardened seats to prevent this with unleaded fuel.

Cusp

Yes but the lead was how the Octane was raised. Raw gas is about 50 Octane. It took tetraethylead blended in the fuel to raise the Octane which in turn allowed higher compression and spark timing which made big gains in engine performance possible.

Rubrignitz

Yep, I should have added that. Those engines were also typically 12.5:1 compression back in the day.