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Simple yes or no engine question......

2K views 11 replies 11 participants last post by  ap72 
#1 ·
If I have an engine with heads that don't have hardened valve seats, can I just put lead additive in the gas and be fine?
 
#5 ·
Jmark said:
Yes.

since there is a ten character minimum, I'll add this. What does lead have to do with anything. It was used as an anti-knock compound, not a seat protector.

Mark
Toilet seats aside, one of the side benefits of lead was that it helped prevent micro-welding between the valve and seat, principally on the exhaust side. This prevented valve recession. I have seen many times the effect of using unleaded gas with older, softer cylinder heads. Depending on vehicle, load conditions, and other factors, valve seat recession with unleaded gas and older (pre-1975) heads could range from neglible to severe (.125" recession in less than 5000 miles.

Yes, you can use a lead substitute as long as it's not in a truck hauling heavy loads.

tom

tom
 
#6 ·
machine shop tom said:
Toilet seats aside, one of the side benefits of lead was that it helped prevent micro-welding between the valve and seat, principally on the exhaust side. This prevented valve recession. I have seen many times the effect of using unleaded gas with older, softer cylinder heads. Depending on vehicle, load conditions, and other factors, valve seat recession with unleaded gas and older (pre-1975) heads could range from neglible to severe (.125" recession in less than 5000 miles.

Yes, you can use a lead substitute as long as it's not in a truck hauling heavy loads.



tom
X2 on the valve recession on extreme SEVERE duty stuff. My buddy had a fresh rebuild on a 68-70? 289/302? flat nose Ford van that was a single rear wheel mini-motorhome. After he got back fron a coast-to-coast trip, it was barely running. The valves were sunk that eighth inch or more! I think more! Never seen one that bad before, or since.
 
#10 ·
"slim chance to none"......
that those heads haven't been burning "just" unleaded for many years and miles without lead additive....

so adding lead substitute now is likely... "to little to late"....

YES you can dump it in the tank...
will it do any good....("maybe")

can using it cause other problems (like plug fouling)
yup
 
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