Posted for "George Braly" <gwbraly@gami.com>:

 
 AV1 was taken off the market because a lot of turbocharged engines that were
run at 200F ROP to stay cool were also operating at extended oil change
intervals (promoted by Mobil 1) and Mobil 1 was slightly less good at carrying
lead by-products than mineral oil.
 
 The result was that those engines that were using extended oil change
intervals and were being operated very very rich,  had some problems with some
sludge in some oil passages.
 
 I ran a supercharged engine at the same time,  but ran it at about peak to 50
ROP (before I knew anything about LOP operations) and my engine was clean as a
whistle when it was opened up.  I also only used 50 hour intervals.  Others
were going to 100 hours.
 
Further - - keep in mind that many of the problems blamed on
 AV-1 were, in fact,  primarily problems that were later obviously related to
the then emerging TCM premature wear problems.
 
 I still have about eight cases of Mobil 1.
 
 Regards,  George