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Re: Leaded Gas
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Posted by MARKL on February 24, 1999 at 16:51:46:
In Reply to: Leaded Gas posted by Ryan on February 23, 1999 at 19:28:58:
Lead was used to manufactue gasoline,it raised the octane rating. An oil company could take outherwise low grade motor spirits, throw the lead to it,and make large quanities of regular grade gasoline and tractor fuel. Since it came from lower on the craker it was cheaper and plentiful,good for farmers but bad for engines. While lead increases octane it also has its drawbacks, primarily deposits that build up and erode valve& seats,to combat this problem engine manufacturers would add strong springs, steep valve angles and valve rotators. When you take an engine equiped as such and run it on UL gas under HIGH LOAD conditions it can cause valve seat recession in a very very short time . Valve springs can weaken with age,valves, sometimes can be reground to a 30 angle,but I usually rebuild mine to stock specs, and try to stay away from HL conditions,I have never used an additive or seen any sign of serious valve seat recession at teardown time,individual engines may vary.
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