Oil Question

mandm

mandm

En-Route
PoA Supporter
Joined
Feb 7, 2020
Messages
2,836
Location
Chicago
Display Name
Display name:
Michael
My engine had some work done to it (2 new cylinders), so it is currently running mineral oil. I just read somewhere that mineral oil should be changed out after 10-25 hours and preferably earlier.

I thought that the break-in for cylinders was 50 hours. Would the next oil change let’s say at 25 hours go to regular oil or would it use mineral oil again? I’m also guessing the oil change hours is based off the tach time?

I am adding about 1 quart every 8 hours, but it’s possible my calculation is off as after one flight the oil dipstick was off. I have been keeping the oil around 6.5-7 quarts, and I’ve noticed some oil on the top of the cowling, which may spray onto the windscreen and also appears some oil drips under the front landing light as well, so I clean it up after each flight.

Any recommended for what oil to use for the oil change and where do you buy your oil? (Online, store?)
 
I would go with whoever provides your cylinder warranty. Changing oil early gets particulates out of the engine .Checking filter and screens and draining oil through a paint strainer can alert you to abnormal wear. Flushing the sump won’t hurt either.

Oil is cheap! Oops ! Used to be.
 
mandm said:
My engine had some work done to it (2 new cylinders), so it is currently running mineral oil. I just read somewhere that mineral oil should be changed out after 10-25 hours and preferably earlier.

I thought that the break-in for cylinders was 50 hours. Would the next oil change let’s say at 25 hours go to regular oil or would it use mineral oil again? I’m also guessing the oil change hours is based off the tach time?

I am adding about 1 quart every 8 hours, but it’s possible my calculation is off as after one flight the oil dipstick was off. I have been keeping the oil around 6.5-7 quarts, and I’ve noticed some oil on the top of the cowling, which may spray onto the windscreen and also appears some oil drips under the front landing light as well, so I clean it up after each flight.

Any recommended for what oil to use for the oil change and where do you buy your oil? (Online, store?)
Click to expand...

Which motor?
 
Check the maintenance guide for the engine - they probably have break-in procedures documented. I get my oil by the case from Aircraft Spruce (and don’t forget to order the correct filter). If it’s a typical engine you’ll have your choice of Aeroshell or Phillips. It’s a mathematical law of the universe that every A&P will strongly recommend the brand not used by the previous A&P.
 
Magman said:
I would go with whoever provides your cylinder warranty. Changing oil early gets particulates out of the engine .Checking filter and screens and draining oil through a paint strainer can alert you to abnormal wear. Flushing the sump won’t hurt either.

Oil is cheap! Oops ! Used to be.
Click to expand...

What do you mean by flushing the sump, is that taking a fuel sample or ?
 
I dump a quart of mineral spirits in the sump once in a while. When draining through a paint strainer there may be particles found. I’ve encountered a few engines that had some apparent problems with metal particles for no apparent reason. The logbook check did show that there were issues way in the past.

Flushing the sump after cylinder or starter clutch changes should get residual metal out of the system and reduce the cause for alarm down the road.
 
Last edited:
Continental tells you the break in is over when the oil consumption stabilizes. That's when I go back to W oil.
 
Magman said:
I dump a quart of mineral spirits in the sump once in a while. When draining through a paint strainer there may be particles found. I’ve encountered a few engines that had some apparent problems with metal particles for no apparent reason. The logbook check did show that there were issues way in the past.

Flushing the sump after cylinder or starter clutch changes should get residual metal out of the system and reduce the cause for alarm down the road.
Click to expand...

I'm probably not brave enough for this, who knows what you'll dislodge, or break up that you don't get out w/the mineral spirits running through that will then be moving around ( until it doesn't ) in the oil galleys.
 
It really depends on how anal you are on maintenance. I know several people who change the oil after 1 hour, then 5 hours and at 25 hours switch from mineral to regular oil. Following the manufactures recommendation is probably fine. Break in is generally complete when cylinder heads temps drop if you have engine monitoring. If not when oil consumption stabilizes. The reality is with standard cylinders that’s often in the first 30 minutes. The key to good consumption down the road is to follow the break in guidelines for power settings. If you do long ground runs or don’t follow the recommendations you will glaze the cylinders.
 
For the first 10 hours, fly it like you stole it.
;)
 
mandm said:
My engine had some work done to it (2 new cylinders), so it is currently running mineral oil. I just read somewhere that mineral oil should be changed out after 10-25 hours and preferably earlier. I thought that the break-in for cylinders was 50 hours. Would the next oil change let’s say at 25 hours go to regular oil or would it use mineral oil again? I’m also guessing the oil change hours is based off the tach time?
Click to expand...
With new cylinders, there's a lot of blowby for the first few minutes to hour of operation... and that blowby contains lots of free radicals. Free radicals react with the oil, and can also attack engine bearing surfaces, etc. Most oil guys will tell you to change the oil after 2-5 hours on a new engine, to remove the oil depleted by those free radicals, and refill with oil with a complete, non-depleted additive package to protect the engine.

Here's some non-conventional advice, but based on the science, not the aviation tradition. Go ahead an install mineral AD oil... even for the first fill. Our practice of using non-AD oil, also known as pure mineral oil, for break-in is based on some oil chemistries from the 1950's... the same chemistries that gave us the tradition of not changing brands, due to non-compatible additive packages. But that's all ancient history now. Even Lycoming, in their service information for turbocharged engines, says use AD oil for the first fill and then on. The AD oil helps manage the wear particles from break-in and prevents them from settling in the engine.

Of course, if the guy providing a warranty for your engine work wants you to use uncompounded mineral oil, OK fine... but if you use AD oil, your engine will be cleaner, and there's no downside to using AD oil always, whether during break-in or not.

The things you SHOULD avoid during break-in are higher film-strength semi-synthetic oils, AeroShell 15W50 is the only one left on the US market. You should also avoid ASL CamGuard during break-in, as it could interfere with the ring/cylinder wall wear-in. But CamGuard is a great additive after break-in (say, starting at 50 hours).

where do you buy your oil?
Click to expand...
The most cost effective place to buy aviation oil is usually your local oil jobber warehouse. Try Googling oil jobber... many have supply agreements. For instance, I buy my 20W50 Phillips aviation oil from a Chevron jobber... he also stocks Shell, and used to stock Exxon before they exited aviation oils.

Paul
 
mandm said:
My engine had some work done to it (2 new cylinders), so it is currently running mineral oil. I just read somewhere that mineral oil should be changed out after 10-25 hours and preferably earlier.

I thought that the break-in for cylinders was 50 hours. Would the next oil change let’s say at 25 hours go to regular oil or would it use mineral oil again? I’m also guessing the oil change hours is based off the tach time?

I am adding about 1 quart every 8 hours, but it’s possible my calculation is off as after one flight the oil dipstick was off. I have been keeping the oil around 6.5-7 quarts, and I’ve noticed some oil on the top of the cowling, which may spray onto the windscreen and also appears some oil drips under the front landing light as well, so I clean it up after each flight.

Any recommended for what oil to use for the oil change and where do you buy your oil? (Online, store?)
Click to expand...
Hey Paul. If done properly, the break in process of an engine should be done within the first few hours of flight. IE. flying max continuous as long as possible. Mike Busch has studies to back this one up, and your engine will start to tell you once this process has been complete. Honestly, and this well help if you have an engine monitor, once your temperatures stabilize and your oil consumption is normal (which yours should be), you are ready to do an oil change, switch to your favorite multi-viscosity oil (unless you live somewhere very warm that warrants a straight weight), run an oil analysis, check for metal, and you should be good. Also the shop should have recommendations that I would follow if they offer any sort of warranty.
 
You must log in or register to reply here.
Back
Top