Actually, the more i read, the more inclined i am to Aeroshell 15-50 which is a semi-synthetic. & its an AD oil.
In the early 1980s a semi-synthetic multigrade W oil for piston engines (AeroShell Oil W
15W-50) was added to the range. This grade has become very popular amongst engine
manufacturers and operators alike. In order to cater for those Lycoming engines which need
improved load-carrying (i.e. those engine models which require the addition of Lycoming
Additive LW 16702) AeroShell Oil W 15W-50 was upgraded in 1986 to include an antiwear additive
Hmmm, that would be the infamous Lycoming O320 H2AD, perhaps.
Brad Penn 20-50, another semi-synthetic has a lot of zinc - except when it does not.
reading online it sounds like it has stabilized, but the containers & packaging have changed, harder to tell what's what. I like Brad Penn way oil for price (it's made sort of locally in the old Kendall refinery), never personally used the racing oils, which were sold on the merits of the high zinc & phosphorous.
Some online posts seem to indicate that zinc levels are down in VR1.
I suppose my resistance to Amsoil was from the days it was overhyped and sometimes sold almost like a pyramid scheme. I do understand that the industry has settled out and a lot of people have excellent success with it.
It's tempting by testimonial, but by that qualifier, they all are.
I sent a note to GP a couple days ago, no response yet. The catalog only lists using 30W straight oil for engines through the 2180. Also nothing spec'd (that I saw) for the 2276.
Do the tappets in a VW rotate like in a Continental with mushroom tappets?
Aren't all popular boxer aircraft engines "flat tappet" or am i not understanding the term?
smt