Unleaded fuel in old engines... is it really bad!?

A friend bought his girlfriend a very koool '50 Buick with a straight 8-bang & I was wondering if runnin unleaded was really that bad for it?! Doubt she'll put that many miles on it & I don't have a clue but... what say you?!?

BoB

I've heard it's not so bad if you're just putting around a bit. It's the long haul at high speeds pulling hills and such that can burn valves. I bet if you put a cooler t-stat and used a lead additive from time to time you'd be OK. Another thing to consider is the engine make. I'd think and old Buick has better valves than say and mid 60's SBC but, I could be wrong.[S

Should check to see if the head has ever been done..

sometimes they do the hardened seats as routine....just a thought....[S

the new fuels?

let it set inyour weed wacker or lawnmower a little time you will not happy robertbandit merry christmas to everybody and your family hope you get what you want, and want what you get[cl[cl[cl

I think this is a larger concern with 60's and 70's engines of high compression. The Buick eight has a low CR (like 7:1 or less) and consequently, lower cylinder pressure. I'm guessing this allows the soft valve seats to survive unleaded fuels.

I have a friend with a '46 Chevy. Original untouched 216. Running unleaded for 20 years and too cheap to buy additives. Maybe he's lucky, but the head's never been off the car.

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I had a '50 plymouth and did alot of research on this. Luckily those mopar flatheads had hardened valve seats so were OK on unleaded.

The deal with lead is it acts to cool the valves & seats so they dont get super heated and soften up, which then allows them to burn out.

I've always heard its just a matter of time and how hard you drive it. Non-hardened seats will eventually burn out. If you really romp on it, you could burn them out in a weekend. Putt around and maybe they'll last years.

Additives help some. Not as good as the old "real" lead additives but certainly better than nothing.

Also, with respect to compression ratios - yes high CR will burn them out faster, but all Model As running unleaded will burn valves like crazy and they have a CR of like 4:1! Stainless valves and hardened seats are a must upgrade to run unleaded unless you are idling in parades.

According to the authorities on team buick, the Buick straight 8s have a high nickle alloy content and enough magnesium in them to make hardened seats unnecessary.

Before the addition of lead additive to boost octane in the high compression era
cars ran on unleaded fuel
The valve seats were induction hardened
I've never had bad luck just getting a good 3 angle job and taking the rotators off
i also run a little marvells

If you don't take the rotators off they can burrow the valves into the head . they were for cleaning off lead residue

Unleaded

The old buick should have hardend seats in it already, If the motor has never been apart and all cleand up, then the valves and seats have a build up of lead on them and will be fine. If you take it apart and clean everthing, then you will need new valves.

What if you soldered new lead on them XD