MG Car Repair: mgb engine block # need unleaded?, valve seat recession, high octane gas

Question
I need to know if i should use lead additive in my replacement
engine. 18v884aelxxxxxx
 thanks, dave

Answer
Hi William,
Lead was added to cheap low octane gas to do two main things. One was to boost the octane rating (this way the oil companies would get more usable gasoline from a barrel of oil. The other reason was the lead acted as a lubricant for the valve face and seat in the head.

At first when lead was removed, some engines got valve seat recession (worn valve seats) So the engine manufactures started putting hardened faces on the valves and hardened seats to counteract the seat and valve face ware.

I think you will find that the unleaded gasoline today has additives to fight valve face and seat ware. Amoco "White Gas" always did. If you are worried about it you can get an additive at most any auto parts stores for upper cylinder lube.

As for octane rating, unless you know the compression ratio of your engine, you should use the high octane gas.

I can not think of any good reason to ever add lead to any gasoline for a car.

Howard