Leaded vs Unleaded

[joesmokabo]

My, soon to be 16 year old, son asked me if old cars need to be modified to run on unleaded fuel.
His step father says no but my son and his mom disagreed.
I think that it depends on the indivdual car.

Opinions please.

[tac]

joesmokabo Wrote:My, soon to be 16 year old, son asked me if old cars need to be modified to run on unleaded fuel.
His step father says no but my son and his mom disagreed.
I think that it depends on the indivdual car.

Opinions please.

The biggest difference is in the valves. The lead asted as a bit of a lubricant and helped the valve seals. Without the lead, older engines are more prone to wear on the valve seal edges and eventually have trouble keeping compression. AN engine that has been rebuilt or had a head job any time since the 80's should have newer valves that are less prone to these problems.

Anyone else want to chime in (I hope I'm not just spreading an old wive's tale with the above explanation)

[way2old]

Another thing on the valves, since there is no lead, the valves and seats should stay cleaner. So in my opinion, there is nothing that needs to be done to the engine to allow it top run on unleaded fuel.

[joesmokabo]

Not even carb adjustments?

[way2old]

The unleaded fuel has the same octane rating as the older leaded fuels. So if the octane is the same, the fuel mixture will burn the same and should not need any adjustment.

[re-tired]

hiya joe here's my opinion . I am a cert aircraft powerlant mechanic. you dont take chances with airplanes engs. Planes do not have emergency flashers. an airplane without a engine will not fly very far , it WILL get you to the crash site however. Yes lead did act in a small way to lubricate valves. It's primary function however , was to boost octane , create a smooth even flame and thus prevent detonation,piston knock , or more commonlly known ping.So I would go up a bit on octane required .If a car eng is to be used in a perfomance situation it's best to have hardened valve seats installed. In a avg high milage low compression eng there should be no problem.IMO

[joesmokabo]

I'm gonna copy and post your replies to my son.

I hope he does the right thing and admits his mistake.