Oil change methods

[carusoam]

Oil life in most cases is pretty benign…

except for the oil that gets to cool the very hot parts….

Where those hot parts are above the degradation temp of the oil itself…

The amount of contact time in those areas is important… keep the oil flowing…

The two places…

1) Exhaust valves

2) Turbo bearings

If you find chunks of carbon in the shape of a valve guide… it may be time to ream the guides… to keep the oil flowing…

 

As always…our oil survives this pretty well… when everything is working as expected…

Under most conditions… an ordinary descent and landing has cooled the oil as well as possible… no need to add an additional cool down period…. 
 

As far as lead exposure goes… I watched a video about doing body work on classic cars using molten lead… how it was much better than the modern body fillers… no mention if that was real lead, or breathing precautions, or venting the area…

Tin cans for food storage used to be welded using lead…

PP thoughts only, not a mechanic…

Best regards,

-a-

W.H.O. Thoughts on Pb in the human body….  Why it has a tendency to be around a long time…

Key facts

• Lead is a cumulative toxicant that affects multiple body systems and is particularly harmful to young children.
• Lead in the body is distributed to the brain, liver, kidney and bones. It is stored in the teeth and bones, where it accumulates over time. Human exposure is usually assessed through the measurement of lead in blood.
• Lead in bone is released into blood during pregnancy and becomes a source of exposure to the developing fetus.
• There is no level of exposure to lead that is known to be without harmful effects.
• Lead exposure is preventable.

[exM20K]

1 hour ago, carusoam said:

Lead exposure is preventable.

Indeed.  According to OSHA, most lead is not absorbed transdermally.  Unfortunately, the lead used as a fuel additive, tetraethyl lead, is.  I still use 100LL to clean the TKS panels, but I'm gloved up. 

We test employees at their hire date and semi-annually for lead levels.  Those who come back high tend to be either smokers/vapers or ammo re-loaders in their personal time.  The cure for them is all about hygiene: wash with de-lead soap and glove up when possible. ...and keep hands out of your eyes/nose/mouth.  Post -intervention, levels come down pretty quickly.

-dan

[Pinecone]

2 hours ago, A64Pilot said:

Decades ago (1988 first year) General Motors instituted GMOLS, or GM oil life system, way it works is you start with some number and every significant event some number is decremented, like a cold start for example, when the number reaches zero the change oil light comes on. I’m pretty sure GM was first.

It can go on average somewhere between 3 and 10 thousand miles, year 2000 and newer vehicles can be up to 15,000 miles between changes. Estimates are that it’s saved hundreds of millions of gallons of oil, and Lord knows how much money.

BMW did a similar system in the 90s.  It used things like cold starts, starts, etc.

They later figured out that fuel burned gives the same numbers but easier.  So the 2000s cars used fuel burned since oil change.   Base mileage was 15,525 miles, and it could go up or down based on actual fuel burned.  IIRC, it was based on 600 gallons.

But they still required oil to be changed at the 1 year mark also.

[exM20K]

1 hour ago, Pinecone said:

BMW did a similar system in the 90s.  It used things like cold starts, starts, etc.

They later figured out that fuel burned gives the same numbers but easier.  So the 2000s cars used fuel burned since oil change.   Base mileage was 15,525 miles, and it could go up or down based on actual fuel burned.  IIRC, it was based on 600 gallons.

But they still required oil to be changed at the 1 year mark also.

I wonder how the auto-shutoff at idle stuff in new cars plays into this.  It seems like a lot of wear and tear on the starter, battery, and engine for a minimal savings in fuel, but what do I know?

whenever I drive my wife’s car, that’s the first thing I disable before leaving the garage.

-dan

[carusoam]

30 minutes ago, exM20K said:

I wonder how the auto-shutoff at idle stuff in new cars plays into this.  It seems like a lot of wear and tear on the starter, battery, and engine for a minimal savings in fuel, but what do I know?

whenever I drive my wife’s car, that’s the first thing I disable before leaving the garage.

-dan

We have one in a Chevy…

Trail braking keeps the engine running as it approaches a stop sign… 

 

Does the starter have to push through the compression stroke for each start?

I imagine that it has to…

The starters must be really well built for these….

Best regards,

-a-

[EricJ]

1 hour ago, Pinecone said:

BMW did a similar system in the 90s.  It used things like cold starts, starts, etc.

They later figured out that fuel burned gives the same numbers but easier.  So the 2000s cars used fuel burned since oil change.   Base mileage was 15,525 miles, and it could go up or down based on actual fuel burned.  IIRC, it was based on 600 gallons.

But they still required oil to be changed at the 1 year mark also.

I have a Fusion hybrid and I'm curious how they sort it out for that, although I suppose fuel consumed would still be a good metric.   I know it also times out at a year, though, regardless of how much it's been driven.

I have a new (2022) Ford Ranger that seems to just go by mileage, which is probably just as good for a non-hybrid.

[Pinecone]

3 hours ago, exM20K said:

I wonder how the auto-shutoff at idle stuff in new cars plays into this.  It seems like a lot of wear and tear on the starter, battery, and engine for a minimal savings in fuel, but what do I know?

whenever I drive my wife’s car, that’s the first thing I disable before leaving the garage.

-dan

I hate those systems also.  Enough so that I would not buy a car because it had it and that it needed to be disabled every trip.

I wonder about long term battery life.

My FIL had a Tahoe.  We were doing a trip and I was driving.  I noticed low voltage.  He had OnStar, so pushed the button.  They had no answer, so made an appointment at a dealer on the way.  Stopped, talked to them, they said Hmm, took it into the shop.  Brought it out after 45 minutes to tell us that was normal.  It seems that the system shut off the alternator when the battery is fully charged, and turned it back on when the voltage got too low.  NO ONE KNEW.

[A64Pilot]

Fuel consumed is a good metric for larger especially stationary engines, but often not for automobiles. Reason is because the larger and or stationary are run very much like aircraft and boats usually they run a pretty consistent RPM and load. Automobiles are operated very differently, one guy lives 5 miles from work all city traffic, next one drives 50 miles all highway.

The reason is because a modern auto at highway speeds isn’t doing anything bad on the oil, what’s bad in oil is cold starts and short trips, neither of which uses much fuel.

Constant stops and starts apparently isn’t bad on a motor like we were taught, another old wives tale I believe.

I base that on owning a Prius for over 250,000 miles and it’s engine shut down a LOT, pretty much as soon as you took your foot off of the gas it was shut down so much that it was difficult in stop and go traffic to even get the motor up to operating temp, Toyota solved that by circulating coolant around the Catalytic convertor, because you know how hot those things get.

Initially I thought the Prius motor would wipe its bearings eventually because of all the re-starts, but it didn’t.

However a full size SUV or pickup with the stop and go motor is ridiculous, what do you get 18 mpg instead of 16?

If you want to drive a fuel guzzling Hog, so be it, but don’t play games with it like GM did years ago when the sold full size SUV’s with the word HYBRID on the sides in 12” letters.

Saw this on a car transporter as we passed the Port of Jacksonville in our sailboat. A “Solar Hybrid” ship really?

I looked it up, it had Solar panel that charged a big Lithium bank to run the crew compt AC while is port for a short time, but I guess that counts.

 

 

[Pinecone]

3 hours ago, A64Pilot said:

Fuel consumed is a good metric for larger especially stationary engines, but often not for automobiles. Reason is because the larger and or stationary are run very much like aircraft and boats usually they run a pretty consistent RPM and load. Automobiles are operated very differently, one guy lives 5 miles from work all city traffic, next one drives 50 miles all highway.

But the 5 miles in city traffic burns more fuel than similar miles on the highway.  This is what BMW found.

Run the car hard, you burn more fuel and need to change the oil more often.

Let's see, my aircraft engine which runs pretty constant RPM needs oil changed at 25 - 50 hours.  My car, under mixed city/highway needs the oil changed at over 200 hours.

[Mac80]

After short flight I did the left cowl flap release with top cover off, drain overnight, and 1 quart zip lock with couple hand towels under the filter.

No mess. Couple teaspoons oil leaked on towels. Kept filter in the bag. Took my time unscrewing filter and kept stretching the bag up over the filter mount.

Oil is too clean to read dip stick. My quick release drain is a little different. Push it in releases, push again and it backs out and shuts off. No turning to open or shut. Drain has rounded lip that secures the hose tightly.

Drain takes  internal diameter 5/8 inch clear plastic hose I got at Menards. Also put on plastic 5/8 inch connector with two males ends to hang up after it drains out to store till next time.

I appreciate the good advice.

[ArtVandelay]

Drain takes  internal diameter 5/8 inch clear plastic hose I got at Menards. Also put on plastic 5/8 inch connector with two males ends to hang up after it drains out to store till next time.
I appreciate the good advice.

I found clear plastic hose (with hot oil) loses its strength and falls off. I use black fuel hose.

[A64Pilot]

On 5/14/2023 at 9:40 PM, Pinecone said:

But the 5 miles in city traffic burns more fuel than similar miles on the highway.  This is what BMW found.

Run the car hard, you burn more fuel and need to change the oil more often.

Let's see, my aircraft engine which runs pretty constant RPM needs oil changed at 25 - 50 hours.  My car, under mixed city/highway needs the oil changed at over 200 hours.

Milage isn’t the issue, number of cold starts and time driven on cold oil is. So the guy who drives 5 miles to work each way may burn a half gallon of so of gas but has two cold starts and the whole trip is with cold oil.

Guy who drives 50 miles highway will burn 2 gls of gas but still has two cold starts and he gets the oil hot enough so that moisture is cooked off of the oil. So oil stress wise both trips are very similar, with the 5 mile guy being harder because the oil never really gets hot long enough to do any good, but he burns less than 1/4 the fuel.

Don’t get too wrapped up in the half gl vs two gl, those are just meant to be representative, but I think the number is close.

Apparently for a modern automobile once everything is stabilized temp wise, there is very little actual degradation of the oil.

A really long time ago, 1980’s I believe there was a move toward using real synthetic oil with very good high by-pass filtration and seemingly really ridiculous oil change intervals, I believe Amsoil may have led in that. Long story short, it worked, but for some reason wasn’t adopted. I think too much advertising from quickie oil change places to change your oil ever 3,000 miles maybe?

The other thing that was pushed was Pre-oiling, simple system, just a hydraulic accumulator that pressurized when the engine was running, but just before starting a solenoid would open and flush pressurized oil through the system. Theory was because everyone knew the majority of wear occurred during engine start until the engine built up oil pressure that providing the pressure first would greatly extend the engine life, by elimination that start up wear.

Except it didn’t. Seems what everyone knew, that is the majority of engine wear occurs at start up, wasn’t correct.

Now some engines, big old aircraft radials come to mind will wipe the main bearing if not pre-lubed so sometimes it is required. But apparently our automobile engines don’t.

Not saying that on average fuel consumed won’t work, on average it will, because the guy that only drives 5 miles to work  is apparently not very common at all, but GMOLS is a better system, because it takes him into account as well as the kid that runs it to redline often, and Grandma that never, ever exceeds 2,000 RPM.

 

[A64Pilot]

Oh, and our average speed in a car isn’t nearly as high as most think. Some cars, the Prius for example keep track of average speed. My wife drove the thing right at 100 miles a day for work, 90% of it highway, and it’s average speed was maybe 30 MPH, because those minutes you sit at a red light, waiting in line at the drive through, crawling through the parking lot etc really kill average speed. That’s why I bought the thing, at 100 miles a day driving her CTS-V was killing me

So if we assume an average of 30 mph and an OCI of 10,000 miles, then you put 333 hours on the oil between changes.

We just really can’t make many comparisons with our aircraft to our cars.

For example that Prius with 250,000 miles on it averaging 30 MPH meant that the engine had 8,300 hours on it, and it still didn’t burn oil, can you image an aircraft piston engine doing that?

[Pinecone]

4 hours ago, A64Pilot said:

Milage isn’t the issue, number of cold starts and time driven on cold oil is. So the guy who drives 5 miles to work each way may burn a half gallon of so of gas but has two cold starts and the whole trip is with cold oil.

Guy who drives 50 miles highway will burn 2 gls of gas but still has two cold starts and he gets the oil hot enough so that moisture is cooked off of the oil. So oil stress wise both trips are very similar, with the 5 mile guy being harder because the oil never really gets hot long enough to do any good, but he burns less than 1/4 the fuel.

Don’t get too wrapped up in the half gl vs two gl, those are just meant to be representative, but I think the number is close.

Apparently for a modern automobile once everything is stabilized temp wise, there is very little actual degradation of the oil.

A really long time ago, 1980’s I believe there was a move toward using real synthetic oil with very good high by-pass filtration and seemingly really ridiculous oil change intervals, I believe Amsoil may have led in that. Long story short, it worked, but for some reason wasn’t adopted. I think too much advertising from quickie oil change places to change your oil ever 3,000 miles maybe?

One more time.  BMW did a LOT of research.  And they started with counting all those things you state.  But, they found that simple fuel burned got them the same numbers.

Remember, a cold start on an engine burns more fuel than idling a warm engine.  So it accounts for number of cold starts.

Don't argue with me, argue with BMW.

There was a website of a guy running a Camaro and seeing how long he could go without actually changing the oil. He was running Mobil 1.  And changing the filter at something like 5,000 mile intervals, and just topping up the oil to keep the proper level.  He was pulling an oil sample every filter change to monitor.   Last time I saw the page, he was something like 60,000 miles and going strong.

[Pinecone]

3 hours ago, A64Pilot said:

Oh, and our average speed in a car isn’t nearly as high as most think. Some cars, the Prius for example keep track of average speed. My wife drove the thing right at 100 miles a day for work, 90% of it highway, and it’s average speed was maybe 30 MPH, because those minutes you sit at a red light, waiting in line at the drive through, crawling through the parking lot etc really kill average speed. That’s why I bought the thing, at 100 miles a day driving her CTS-V was killing me

So if we assume an average of 30 mph and an OCI of 10,000 miles, then you put 333 hours on the oil between changes.

We just really can’t make many comparisons with our aircraft to our cars.

For example that Prius with 250,000 miles on it averaging 30 MPH meant that the engine had 8,300 hours on it, and it still didn’t burn oil, can you image an aircraft piston engine doing that?

My Fiat has an average speed readout.  I run mid 30 MPH in average driving.  On highways over 40 MPH.   In my M3 I have averaged 85 MPH for a full tank of fuel.

But, I agree 30 - 35 MPH is where most people are.

The Fiat is an 8,000 mi OCI.  The M3 is 15,525 or less. I normally change it at 1/2 interval.  So when the indicator says about 7,700 miles, I change it.  But I do track the car at times.

[A64Pilot]

Started the Mooney yesterday after changing oil and washing it.

It seemed to take longer for oil pressure to come up than after a normal oil change. I did not time it as I didn’t think about it actually.

I’m assuming that when you blow pressurized air into the system, you completely or nearly so empty the whole system, oil pump included and of course the pump has to re-prime and fill the system before it can start building pressure.

So now I’m wondering if this is a good method or not

[A64Pilot]

On 5/17/2023 at 3:37 PM, Pinecone said:

One more time.  BMW did a LOT of research.  And they started with counting all those things you state.  But, they found that simple fuel burned got them the same numbers.

Remember, a cold start on an engine burns more fuel than idling a warm engine.  So it accounts for number of cold starts.

Don't argue with me, argue with BMW.

There was a website of a guy running a Camaro and seeing how long he could go without actually changing the oil. He was running Mobil 1.  And changing the filter at something like 5,000 mile intervals, and just topping up the oil to keep the proper level.  He was pulling an oil sample every filter change to monitor.   Last time I saw the page, he was something like 60,000 miles and going strong.

I’m betting there were legal reasons driving that change, all the work is in writing the algorithm, no additional sensors etc for GMOLS, so once BMW had it, why change?

I wouldn't be surprised if GM patented it and wanted royalties for others to use it or something similar.

Just a guess, but Toyota for example I think is making more money from selling Prius technology licenses than they make from selling Prius cars.

Thats a guess too, just a rumor I’ve heard.