I have the Operating Manual for the IO-550- A B C G N P & R
IPeter wrote:
It should be on the mfg’s website.
I will have to ck there.
Michael wrote:
I have the Operating Manual for the IO-550- A B C G N P & R
I have an L wonder how much different than the others.
I have an L wonder how much different than the others.
Probably enough to make a difference since the induction system and cylinders are completely different.
Has anyone heard of using specific types of car engine oil, added at about 10% to the normal oil, to clean out the aircraft engine and hopefully loosen up the oil control rings?
0W-20 has been suggested.
BTW I have been told by one specialist that you need to re-hone a cylinder only if you replace the top ring. If you replace only the oil control rings you don’t need to re-hone.
Sounds like your’e ready to try ANYTHING !
In that case, may I suggest Marvel Mystery Oil : Been around since your daddies, grand-dad and it’ll fix just about anything !
Here’s the ahem, ‘tech specs’ :
Marvel Mystery Oil is a product of the Marvel Oil Company, founded by Burt Pierce in 1923.
After World War I, the Marvel Carburetor Company (Marvel-Schebler Carburetors since 1928) produced carburetors for automobiles and aircraft. Some of these encountered problems and as a result Pierce formulated a blend of chemicals and petroleum to clean and maintain clogged jets. It is claimed without evidence to be beneficial for engines by creating a top ring seal producing higher compression, preventing blow-by on power strokes, resulting in more power. The Marvel Oil Company was purchased by Turtle Wax Inc. in 1999.
Marketing literature makes claims about lubricating qualities, cleaning and friction reduction capabilities. However, little robust evidence exists documenting these purported benefits. The product has previously been marketed for use in all kinds of engines, including aircraft engines. However, it has been implicated in one aircraft crash where an engine suffered catastrophic damage during take-off after Mystery Oil had been used as a fuel additive. The engine damage found was attributed to detonation, which would be consistent with the octane reducing effects of Mystery oil.
The product is composed of 74 percent mineral oil, 25 percent stoddard solvent, and 1 percent lard.
Me thinks it’s the 1% bacon lard that does the trick ! 
MMO has been totally debunked since they were forced to publish the constituents in the MSDS. It also contains perfume!
The idea behind specific additives is that they can loosen up the lead deposits which cause the oil control ring to stick.
Peter wrote:
The idea behind specific additives is that they can loosen up the lead deposits which cause the oil control ring to stick.
That’s what the 25% stoddard solvent in MMO is about .
At any rate, adding ANYTHING to your oil and hoping for a positive result is is just wishful thinking …
From what I have been able to find out, every Lyco engine that burns in the region of 1qt every 3-5 hours has one stuck oil control ring. With two stuck rings you burn 2x that much oil.
A freshly built engine, but bedded-in for 50-100hrs, should burn 1qt every 10-15hrs.
But a lot of engines (the majority) burn 1qt every 3-5hrs!
So stuck rings must be very common.
They don’t seen to ever cause any problems – except for the high oil consumption.
Peter wrote:
They don’t seen to ever cause any problems – except for the high oil consumption.
True, but what generally happens over time is that the other rings in that cylinder get coked-up and start to stick as well. After may hundreds of hours, ring failure is eminent.
I was/am a great fan of the venerable Lycoming -540, which can run very smoothly for hours. I overhauled mine at 2200-2400 hours, but the engines could’ve kept going. I much enjoyed the breaking in period flying low level down the west coast of France (Peter had a nice photo in the Pamplona thread) at 185 knots. I think I ran straight mineral and high power for the first 100 hours.
Once broken in I operated them at around 55-65% LOP and oil consumption settled down to around a quart every 20 hours. Never had an issue with them over ten years of operating them.
My Conti 90-8F uses a quart every 8-9 hours. Great engine but I miss the smoothness of the -540.
