Just had some work done on thief bug and the mechanic, who has worked extensively on bugs, said NOT to add lead additive to the gas tank after fillup. Any comments on that? Thanks
Bob
lead additive in gas
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Blue Baron
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hercdriver
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Lead Additive - "The Great Debate". There are no fuel additives that have real lead in them. Most additives have "syndetic" lead that is represented as doing the same thing lead originally did in fuel. Originally, the Lead was added to fuels for octane settings as well as other factors. When the EPA got involved and outlawed its use, other additives have been used in fuel for the same octane purposes. Unfortunately, none of them have the same properties as lead. One of the things lead did for older engines was lubrication for the valve and valve seat. This was important as seats were a soft metal and with ignition/heat the valve would micro weld to the seat. If you take an old engine apart you see pitting in the valve seat which is evidence of the micro welding due to being ran on unleaded fuel. The lead became the sacrificial metal that settled between the valve and the seat and was burned up with combustion.
VW starting using hardened seats in their heads with the 1300's used in the 67’s for Europe. In that the 66 had the 1300 first, one would think the US 66’s have hardened seats. I have found no way to trace which heads have hardened seats. So, there is no way I have found to know if a 66 head is “safe” running on unleaded fuels (without a synthetic lead additive that may not perform as lead did originally).
The good news is, the old style seats, softer metal, are not used at all when a machine shop rebuilds heads and replaced valve seats. So, if your engine has had a valve job anytime in its life after it was built, more than likely the valve seats were replaced with hardened ones.
If the old seats are ran on today’s fuels, you will still get between 30 – 60k miles (running conditions dependent) before you need a valve job. So it may be a while before you need to do anything.
The use of Marvel Mystery Oil provides “top lubrication” which is good because the oil tends to run back to the sump when the car sits. The Mystery Oil coats the valves and all the moving parts in the head.
So, all this to say, use what you are comfortable with in a car that is 48 years old and have fun doing it.
Motor on……….
VW starting using hardened seats in their heads with the 1300's used in the 67’s for Europe. In that the 66 had the 1300 first, one would think the US 66’s have hardened seats. I have found no way to trace which heads have hardened seats. So, there is no way I have found to know if a 66 head is “safe” running on unleaded fuels (without a synthetic lead additive that may not perform as lead did originally).
The good news is, the old style seats, softer metal, are not used at all when a machine shop rebuilds heads and replaced valve seats. So, if your engine has had a valve job anytime in its life after it was built, more than likely the valve seats were replaced with hardened ones.
If the old seats are ran on today’s fuels, you will still get between 30 – 60k miles (running conditions dependent) before you need a valve job. So it may be a while before you need to do anything.
The use of Marvel Mystery Oil provides “top lubrication” which is good because the oil tends to run back to the sump when the car sits. The Mystery Oil coats the valves and all the moving parts in the head.
So, all this to say, use what you are comfortable with in a car that is 48 years old and have fun doing it.
Motor on……….