Lets talk Oil.... 120W vs 25w-60 in radials & V-12's

[Ken]

I have yet to run a drop of anything but 120W in the 1340 since overhaul but I'm curious if anyting else has experience with running additives?

I, too, am familiar with those who wholly support running some amount of Marvel Mystery Oil in both their crankcase and fuel tanks. In the right circumstances and proportions my personal opinion is that it may be helpful. I'll let the experts, like Rich, chime in, but one consideration is the category of your aircraft. IIRC, unapproved additives would be a no-no in a certified Cessna 172 but okay in an experimental RV-8 ...

Ken

[Fleet16b]

I have yet to run a drop of anything but 120W in the 1340 since overhaul but I'm curious if anyting else has experience with running additives?

I, too, am familiar with those who wholly support running some amount of Marvel Mystery Oil in both their crankcase and fuel tanks. In the right circumstances and proportions my personal opinion is that it may be helpful. I'll let the experts, like Rich, chime in, but one consideration is the category of your aircraft. IIRC, unapproved additives would be a no-no in a certified Cessna 172 but okay in an experimental RV-8 ...

Ken

Ken
A good point
I dont know if MMO is actually an approved product
However it may as well be , as it has been used in all kinds of aircraft since the 1920's with no issues that I am aware of.

[Red Tail]

We have a pre-oiler on the Red Tail Mustang and wouldn't even consider going without. In my opinion cranking on the starter with the mags off until you see oil pressure is just putting needless wear on the starter. Less of an issue with the T-6 more of an issue with the Mustang...especially if you fry the clutch pack.

We ran 25-60 for a few years until I saw corrosion forming on the valve springs and retainers. After a little research and Q&A with the engine experts I switched to 120w and the problem ceased. A side effect to going with straight weight 120w from mutli vis 25-60 was we do get a bypass light on the Hinz detector for the first minute or two of operation with the 120w at cooler temps. That's proof positive the low end of the 25-60 has value if you operate in cooler climates or during the winter (Which we don't do). Without question it helps to get cold oil in a cold engine during a cold start to critical parts quicker. The solution to our light issue was simple: increase its screen size from 50 to 60 micron. We change oil every 25 to 30 hours and so far I've not seen any coloration difference in the 120w over what we saw with the 25-60. It goes in honey yellow and comes out olive green. We fly around 100 to 120 hours per year.

John

[51fixer]

We have a pre-oiler on the Red Tail Mustang and wouldn't even consider going without. In my opinion cranking on the starter with the mags off until you see oil pressure is just putting needless wear on the starter. Less of an issue with the T-6 more of an issue with the Mustang...especially if you fry the clutch pack.

We ran 25-60 for a few years until I saw corrosion forming on the valve springs and retainers. After a little research and Q&A with the engine experts I switched to 120w and the problem ceased. A side effect to going with straight weight 120w from mutli vis 25-60 was we do get a bypass light on the Hinz detector for the first minute or two of operation with the 120w at cooler temps. That's proof positive the low end of the 25-60 has value if you operate in cooler climates or during the winter (Which we don't do). Without question it helps to get cold oil in a cold engine during a cold start to critical parts quicker. The solution to our light issue was simple: increase its screen size from 50 to 60 micron. We change oil every 25 to 30 hours and so far I've not seen any coloration difference in the 120w over what we saw with the 25-60. It goes in honey yellow and comes out olive green. We fly around 100 to 120 hours per year.

John

Cranking with the starter puts a good deal of load on rod/crank bearings as well as the valve train even though the engine isn't running.
Thats the beauty of the pre oiler if it puts oil onto those parts before cranking.
If it has sat long enough that you feel you should crank to get oil flowing (but lack a pre oiler) before startup you can pull 1 set of spark plugs so that no load builds on the piston/rod bearing/crank bearing before oil circulates. The valve train will still be loaded as no way to relieve the valve spring tension. Crank as long as recommended for your starter and watch for oil pressure on the gauge.
There are also portable pre oil setups to connect to your engine per appropriate manuals or aircraft/engine guidelines.

The one P-51 here will rip the 50-60 micron screens. I don't consider it a filter but a warning device. I have 115 micron screen in it. It always has as much material on the Cuno as it does in the Hinz regardless of filter mesh size.
Our 120W is always much darker coming out. You must have a real clean insides in the engine.

[Red Tail]

We have a pre-oiler on the Red Tail Mustang and wouldn't even consider going without. In my opinion cranking on the starter with the mags off until you see oil pressure is just putting needless wear on the starter. Less of an issue with the T-6 more of an issue with the Mustang...especially if you fry the clutch pack.

We ran 25-60 for a few years until I saw corrosion forming on the valve springs and retainers. After a little research and Q&A with the engine experts I switched to 120w and the problem ceased. A side effect to going with straight weight 120w from mutli vis 25-60 was we do get a bypass light on the Hinz detector for the first minute or two of operation with the 120w at cooler temps. That's proof positive the low end of the 25-60 has value if you operate in cooler climates or during the winter (Which we don't do). Without question it helps to get cold oil in a cold engine during a cold start to critical parts quicker. The solution to our light issue was simple: increase its screen size from 50 to 60 micron. We change oil every 25 to 30 hours and so far I've not seen any coloration difference in the 120w over what we saw with the 25-60. It goes in honey yellow and comes out olive green. We fly around 100 to 120 hours per year.

John

Cranking with the starter puts a good deal of load on rod/crank bearings as well as the valve train even though the engine isn't running.
Thats the beauty of the pre oiler if it puts oil onto those parts before cranking.
If it has sat long enough that you feel you should crank to get oil flowing (but lack a pre oiler) before startup you can pull 1 set of spark plugs so that no load builds on the piston/rod bearing/crank bearing before oil circulates. The valve train will still be loaded as no way to relieve the valve spring tension. Crank as long as recommended for your starter and watch for oil pressure on the gauge.
There are also portable pre oil setups to connect to your engine per appropriate manuals or aircraft/engine guidelines.

The one P-51 here will rip the 50-60 micron screens. I don't consider it a filter but a warning device. I have 115 micron screen in it. It always has as much material on the Cuno as it does in the Hinz regardless of filter mesh size.
Our 120W is always much darker coming out. You must have a real clean insides in the engine.

We used a portable preoiler out at the museum for years. It worked great. After the Museum moved, in the Mustang I cared for we used to use a mix of 50/50 STP and 120w on the cam rack prior to fire up if the airplane sat any longer than two weeks (Which was extremely rare). Of course this didn't help the rest of the engine but we never had any issues. STP is a very good extreme pressure lube.

Correct. The Hinz detector is just that, a detector. It's not intended as a filtration system but does by default act as one. It's super important to keep the R's below 900-1000 until the oil gets some heat in it and the pressure starts to drop a bit otherwise yes, you'l get a torn screen everytime with 120w. I don't use paper filters as my primary any longer. I switched to dual Challengers on the Hovey mod filter mount and couldn't be happier. In my opinion they're way better than a Cuno for filtration and don't have the pressure drop and subsiquent near constant bypass of paper spin-ons.

The old Nixon was always squeaky clean inside even when we pulled it at 450 hours. It pained me to pull it since it ran so sweet. It never used any oil (Just leaked like a spaghetti colander which is why we pulled it). Good ring sealing (On both the oil control and compression rings) and correct jetting/mixture will have more to do with clean oil than anything else. Time will tell how the new Roush fairs on that front. I have high expectations but do expect a dirtier engine since it's jetted 10% richer.

John

[John Dupre]

Years ago a C-47 fleet operator switched from straight weight oils to ashless dispersant multi viscosity oils and began routine oil changes. As I recall before the switch they were changing 8 to 10 cylinders per engine between TBO and it took one man 4 to 6 HOURS to clean the oil filter. After the change they dropped to 1 or 2 cylinders per TBO run and it took a HALF HOUR to clean the oil filter. It depends largely on your operating style whether one oil or another is preferable but routine oil changes will do as much or more than almost anything else and should be done seasonally if your usage isn't high.