Tom- how do you go from tricresyl phosphate to phosphoric acid?
Not everything with a phosphate group acts like phosphoric acid. By the logic in the quoted post, DNA (deoxyribonucleic acid) is bad because it, too, contains esters of phosphoric acid.
Do this simple test:
get 2 small pieces of 4130 plate, wash them in soap and water to remove any corrosion protection, lay them out in the weather for a couple days or until the show a light corrosion.
lay them on your work surface, using a soft cotton cloth rub one with aeroshell 15W50, and the other with a little Phillips 20W50.
come back and tell us what happens to each.
Go to the Cessna owner club and ask this simple question, "how many C-150/0-200 key start owners have had a slipping starter and what oil were you using in the engine?"
Yesterday I spent time looking thru my records to see how many starters I have changed over the years, looking back to 1995 I found 32 starter changes 14 of those were Lycoming starters they have no oil issues mostly bendix failures. the rest are Continetal starters or starter drives. starter motor failures are not an oil issue, but the drives are.
close to half of my continental customers were dedicated aeroshell users, they ranged from the old E & C series engines to the 550.
They are the ones that totally convinced me that aeroshell with TCP in the additive package is harmful to the starter clutches in these engines, because they are the ones having problems.
My continental operators using Phillips or Exon Elite have no problems, yet they are EP oils.
my 182 operator had a starter failure on the way home from buying it, he bought and installed a new starter clutch less than 50 hours later he has the same thing happen, we reviewed the logs and the aircraft had 4 starter changes in the prior 300 hours all on aeroshell, we changed to phillips and its been 4 years trouble free.
2 of the 3 C-150s that have owned came to me with slipping starter clutches, when flushed and changed to Phillips ran trouble free for the entire time I owned them.
I built 88S from the ground up and overhauled the engine using a new starter clutch and it has run on Exon Elite for 1400 hours with no starter problems.
I suggest each of you read Lycoming service bulletin 644B and see why Lycoming wanted the AD 80-04-03R2, read that also and understand the Lycoming additive is NOT to lessen friction, it is there to add protection on start up by adding cling to the oil.
Why TCP is in aeroshell is in the additive package is unknown to me. other than it does make an EP oil, I do know it is not the only ingredient to the product.
I do know when a acid is used to modify any substance it will be a corrosive by product, that is basic high school chemistry, and the bases for every metal polish on the market. (grit/cleaner makes shiney metal) and my theory of why we have so much corrosion in engines using aeroshell.
