25 hours, whether you use a sreen or filter, is the recommendation from the Chemist who developed Exxon "Elite" oil for Exxon , and among other things, Camguard.

Would you show me the paper that states that? or a link.
Thanks GT

Let me throw this into the mix..
I have seen multiple studies that were done on frequencies of oil changes versus actual oil breakdown and the point it reaches diminishing return.
This was based on petroleum based oils, not synthetic oil.

Unless the oil was subjected to abuse, ie; elevated temps over 270 degrees and or high contaminate environment like dusty , off road racing etc, the oil will give good lubricating qualities to around 200 hours. + or-. This is for a automotive application and as one poster stated the airplane engine has different demands, but not enough to drastically cut into this 200 mark. The lead in 100LL is the greatest contaminate in aircraft use and that fact is born out if you guys read the oil analysis you get back from the lab. You guys do use oil analysis dont ya ? The main point of the studies is.

The potential of introducing contaminates during a oil change is higher then most people realize. For example, your filler cap/dipstick is out for an extended period of time, dirt, duct, crap can and will stick to it. The drain plug is another good source of contamination. Taking off the filter leaves the few square inches of the exposed filter base on the motor ripe for attracting dust,dirt etc. If the filter in the box is not wrapped in a protective covering then contaminates will get inside of it during storage, shipping and potentially even the manufacturing process.

I believe the reports stated that unless you changed oil in a surgical sterile setting, the chances of adding contaminates by changing oil in a car every 2000 miles you will have added the same amount wear agents, ie, dust, dirt etc as the car would pick up if you left the oil in for 5000 miles. I will try to find those studies and post the links.

Just like most things in life,, the more you fiddle with stuff the more something might go wrong. Simple statistics..

Ben

Ok i just got into the aircraft owning buisness and i had a question. the previous owner just changed the oil to 80wt for the winter in my 41' bl-65's 0-200 i was thinking for alaskan winter activity i should be running 65wt insted. there is only about an hr on the 80wt so i figure i could drain it out into a 5gal jug and save it for the spring. ive also been told as long as i preheat the engine well (which i plan on doing anyway) i wont have a problem with the 80 wt. one more thing i've been told not to use the multi vis 15-45 in the 0-200? and since i have the screen filter and plan to change my oil around every 25hrs i was wondering about oil brands. my gf's dad is an a&p and said that since im going to run oil only 25hrs i should run conventional phillips rather than semi-synthetic aeroshell since the conventional adhears better to internal engine components during times of inactivity. any thoughts
Thanks
-ATC

M6RV6 wrote:25 hours, whether you use a sreen or filter, is the recommendation from the Chemist who developed Exxon "Elite" oil for Exxon , and among other things, Camguard.

Would you show me the paper that states that? or a link.
Thanks GT

Well, yes and no.

It's information gathered from several of his, Edward Kollin, responses on the Cessna Pilot Association site. A fee based site, he owns and flies a 210. Otherwise, I would post the direct link.

Here's part of an actual reply from him regarding "Engine Oil Life span".

"Chemistry Alert

It has to do with the amount of contamination of the oil with the heaviest reactive blow-by fuel components. These components are partially oxidized fuel molecules that are polar (acidic in this case) and heavier because of the incorporation of one or more oxygen atoms. I call these deposit precursors. Their polarity provides them with an affinity for metal and preferentially hot metal, which leads to deposit formation and increased consumption. It also makes them visible and attractive to the polyamine ashless dispersant (basic). These acidic species are the ONLY things the dispersant's react with. Dispersants do not bind with lead (bromide) particles, wear metals or dirt.

There is a small amount (tablespoon) of oil that circulates around and around in the piston ring pack. It is replenished when oil is consumed. As the dispersant is consumed, polar species build up and at 20 or so hours, things begin to happen. The buildup causes both deposit formation to begin and the increase in oil consumption as the sticky species are pulled into the combustion chamber and burned,along with some innocent oil, by their polarity.

Camguard prevents the cross-linking reaction and by doing so, it prevents deposit formation. This leaves MORE deposit precursors in the oil, which consumes the dispersant a little sooner and may explain the earlier breakpoint that you are observing. A slight increase in oil consumption seems like a small price to pay for a clean engine. Every engine is different though and your mileage may vary. In my IO-520, I go 14-16 hours before I need the first quart and change my oil at 25 hours instead of adding any additional oil.

Ed"


I will add, that if you fly daily, or nearly so, then you can possibly extend the interval between changes, a little.

Hope this helps.

hotrod150 wrote:

nmflyguy wrote:.......If one is changing the oil much more often than needed, the additional cost, at roughly $90-100 per oil & filter change (for an O-360 that takes 8 quarts per change, and assuming you do it yourself and your labor is "free"), can add up to a considerable waste.....

You might wanna do some comparison shopping-- I just ordered a case of Phillips XC2050 from the local bulk plant yesterday -- $49.14 dropped off at my house. And the last 6-pack of Tempest oil filters I bought from Spruce was $88, throw in some S&H & let's call it a c-note. That comes out to about $33 for 8 qts of oil & $17 for the filter for a total cost of $50 per change.

Hotrod - I pay about $88 with tax (in Albuquerque, nearest town to where I live) for a case of Aeroshell 15/50 from the local oil company (meaning a total for oil of about just under $60 per oil change), and a Champion oil filter from Aircraft Spruce, which with shipping, runs about $28-30 each, bought 2 at a time, or about $25 each if in a 6-pack. That's the $90-100 total per oil change that I mentioned in my previous post.

I looked into offsite oil suppliers, but when you add in the cost of shipping for a relatively heavy and bulky case of oil, the net cost per quart vs. local supplies was about the same ... within a few percent.

I'm not including the value of my time or the mileage on my car to pick up the oil.

Aviation oils and filters (like everything else for airplanes) are relatively expensive, compared to automotive lube oils. I can do an oil change on my Mustang for about $15-18!

If you have a larger 6-cyl aircraft engine, like a O-540 or O-550, the oil capacity is 50% greater - meaning a dozen quarts per oil change. Meaning a total cost of around $120 just for materials.

And if you hire the local A&P to do your oil change, you're looking at something on the order of $250+ per oil & filter change.

Don't buy it in quart containers!

When I had my plane based at Lewiston, ID, Gustin's Aviation there sold aviation oil in bulk. They bought the stuff in 55 gallon drums, and I would show up with a few gallon jug and they would fill it for me. As I recall, the price was $3 a quart for Phillips 20w50 the last time I bought some, which was last fall.

WSH

It has to do with the amount of contamination of the oil with the heaviest reactive blow-by fuel components. These components are partially oxidized fuel molecules that are polar (acidic in this case) and heavier because of the incorporation of one or more oxygen atoms. I call these deposit precursors.

I'm just an old geazer and have some pretty opinionated ideas!!!
Can I interpolate from what this fellow said that if I fly lean of peak I will have less contamination from less blow-by fuel contaminates??

I try to fly WOT when I can. and when traveling long distance I try and get High enough to run at 65% or less and lean of peak.
I dump the oil at 50 hours whether it needs it or not!!! change the filter at 100 if using it alot and at 50 if over a longer time!

When we had a bunch of IO-520's flying 3000 hours a year we changed oil every 33 hours and the filter at the 100hr. only engine ever to not make it to TBO was one we lost at 120 hrs to metal screen contamination, (screen went thru engine) !

Just my $.02
GT

M6RV6 wrote:WSH
.

..........I'm just an old geazer and have some pretty opinionated ideas!!!
Can I interpolate from what this fellow said that if I fly lean of peak I will have less contamination from less blow-by fuel contaminates??

I try to fly WOT when I can. and when traveling long distance I try and get High enough to run at 65% or less and lean of peak.
I dump the oil at 50 hours whether it needs it or not!!! change the filter at 100 if using it alot and at 50 if over a longer time!J

When we had a bunch of IO-520's flying 3000 hours a year we changed oil every 33 hours and the filter at the 100hr. only engine ever to not make it to TBO was one we lost at 120 hrs to metal screen contamination, (screen went thru engine) !

Just my $.02
GT

GT

Corrosion is the big killer in GA piston engines. The more you fly them, the better off you'll be.The 25 hour suggestion is a good interval for the average person, in general.

Flying LOP helps, cleaner and cooler is almost always better. Ed flies his 210 LOP, I'm sure his 25 hour interval takes that into consideration.

Being "opinionated" is fine,however, when given a choice, I'd rather go with one based on scientific fact, observation, rather than anecdotal evidence.

Hey,I'm just passing along advice from someone who knows more about aviation oils and how they react in the engine than just about any other one single person can. If you choose to ignore it, no problem, really.

Good Luck to you.

Oil Changes any Thoughts??

Change your oil

WSH
Just opining some thoughts.
I appreciate all information that is out there, as you said it is up to each one of us to make our own decisions.
WE are responsible for them, not anyone else!!
When we do and things go haywire!?!? Thats where our opinions get set!!!
You know we all have one! (OPINIONS)
Enjoy your day and live it to the best of your ability.
GT