Oils aint oils

[Jaydee]

How often do you change your oil, even if you don't drive it much or it's stored?
Surely 10.000 k's or six months as they say, your not going to change it every six months if it's not driven much.
JD

[Dwight]

Most Cobras in the states are driven less than 2,000 miles a year.

I always changed mine (fuel injected with conventional oil) every year in the spring. Winter weather, didn't drive it much in the winter, lots of moisture and probably condensation inside the motor thus water in the oil.
100 miles or 3,000 didn't matter. Change the oil, cheap insurance.

And those with carbs get a lot of gasoline draining into the crankcase.

Now those with newer fuel injected motors using synthetic oil have less of a problem. I would feel good about changing every 5,000 to 10,000 miles under those conditions.

[hauss]

Every 3 months 15/40 delo or 1000 miles . with new high quality filter big pan holds 2 gal. of oil. also let motor warm up !

[Treeve]

Small amounts of water in the oil gives a huge reduction in lubrications capabilities

[Gaz64]

Originally Posted by Jaydee

How often do you change your oil, even if you don't drive it much or it's stored?
Surely 10.000 k's or six months as they say, your not going to change it every six months if it's not driven much.
JD

10000km or six months, which ever occurs first.

One of my cars only does about 1500km in 6 months, oil still looks new, but analysis says other wise. Oil is cheap compared to an engine rebuild.

I've seen one engine completely ruined from acid build up, 300 miles.

Gary

[Dirty Harry]

First of April. Every year.

[patrickt]

You know, I've often wondered what owners of really extensive car collections, that all sit in climate controlled garages, do. My car sits in a climate controlled garage, and I now put a few hundred miles on it a year -- less than a thousand. Every year I send a sample off to the lab and they check for the usual wear elements, zinc & phos, and the like, plus they look for moisture, antifreeze, fuel and a TBN as well which you can compare to the TBN of your pure oil. But I don't just change it to change it -- there's just no reason to.

[Rob. Smith]

Originally Posted by Treeve

Small amounts of water in the oil gives a huge reduction in lubrications capabilities

Because the car is a "sitter" I have an accumulator to pre lube the engine before turning it over. I have also made a heater box to fit under the sump that warms the oil and reduces condensation. My engine is too valuable to be neglected.

[Treeve]

Pre heating they oil doesn’t remove entrained water - and it will still remove lubricity.
The gearboxes I look after cost a bit more than what a single car would cost... you need a desiccant / reverse osmosis filter to remove entrained oil.

[patrickt]

So I pulled my lab results from this winter's test. I last changed my oil two years ago and that was less that 2,000 miles. All wear element PPM values were well below "normal" readings. Remember that I have a solid flat tappet cam, so zinc and phosphorous are extra important. My zinc number was 1722 and my phosphorous number was 1640. Perfect. My antifreeze and water numbers were both at zero. Fuel was at a trace level. My TBN was at 8.8; my Brad Penn right out of the bottle is at 10.6 -- so I'm at 83%. A conservative change point for TBN is at 70%. There were no red, nor yellow, flags on the analysis sheet. So, why would I even think about changing my oil? That's like putting someone on a vitamin supplement when they have perfectly normal bloodwork. Nice little article on TBN and change intervals can be found here: https://www.machinerylubrication.com...terval-tan-tbn

[ront49]

I'll open up a can of worms that has been hashed and rehashed many times ... Q. What oil is recommended for a 351W stroked to 418, roller rockers, cam, 750 Holley .....

[patrickt]

Originally Posted by ront49

I'll open up a can of worms that has been hashed and rehashed many times ... Q. What oil is recommended for a 351W stroked to 418, roller rockers, cam, 750 Holley .....

If you don't have solid lifters, then the ZDDP content is not nearly as critical as if you do. That said, an old fashioned "healthy" ZDDP content is not going to hurt anything so long as you don't have a catalytic converter or other sensitive emissions equipment (which almost none of us have in these cars). That leaves you two basic choices, dyno versus synthetic, and what viscosity should you use. You will get varying opinions on both but, at least on FE engines, synthetic oil seems to "leak" a bit easier than regular oil does. Maybe that's just an old wives' tale. The best answer as to viscosity is whatever the engine builder recommends. If you're curious as to what I use, and I almost never even start the car up unless it's in the upper 50's at the very least, it's Brad Penn 15w-40 and it's a "partially synthetic" oil. I guess that's kind of like being "partially pregnant."

[Jaydee]

Thanks Patrick for a scientific answer. At the moment I'm not worried as I haven't overhauled the motor yet. It's still the donor engine. I think as long as you let the engine get hot it should evaporate out most moisture, opposed to starting it up for 1 minute and building more condensation in the engine and exhaust. I remember a customer come over for a service and only drove it 2 miles to my workshop. He complained of always rusting out his mufflers. I drill a small hole in his new muffler at the lowest point and removed a cup of water out of it. The hole was small enough not to hear the exhaust leak, and his mufflers lasted a lot longer. JD

[patrickt]

Originally Posted by Jaydee

I think as long as you let the engine get hot it should evaporate out most moisture, opposed to starting it up for 1 minute and building more condensation in the engine and exhaust.

Yep, pretty much. Another internet forum myth is that you have to get your oil up to over 212 degrees Fahrenheit to get moisture out of your engine. Because, after all, everyone knows that's the boiling point of water, right? We'll just ignore the fact that spots like the underside of the piston get way, way, way hotter than 212 degrees.

[hauss]

Originally Posted by patrickt

You know, I've often wondered what owners of really extensive car collections, that all sit in climate controlled garages, do. My car sits in a climate controlled garage, and I now put a few hundred miles on it a year -- less than a thousand. Every year I send a sample off to the lab and they check for the usual wear elements, zinc & phos, and the like, plus they look for moisture, antifreeze, fuel and a TBN as well which you can compare to the TBN of your pure oil. But I don't just change it to change it -- there's just no reason to.

One reason is peace of mind. If you change oil way before time, you will not hurt motor.Not sure what you pay for your test, but I can save that money and know I am good . {Just Saying} as my kids would say

[patrickt]

Originally Posted by hauss

One reason is peace of mind.

Wouldn't you obtain more peace of mind by knowing whether you had a significant pattern of wear, or by getting early notice of that small bit of antifreeze that is tipping you off to a gasket leak? Or just knowing how well your oil is holding up? Why would you just blindly change your oil and flush that valuable information away?

[Morris]

Originally Posted by patrickt

Yep, pretty much. Another internet forum myth is that you have to get your oil up to over 212 degrees Fahrenheit to get moisture out of your engine. Because, after all, everyone knows that's the boiling point of water, right? We'll just ignore the fact that spots like the underside of the piston get way, way, way hotter than 212 degrees.

Patrick

Not sure I understand what you are saying???

[patrickt]

Originally Posted by Morris

Patrick

Not sure I understand what you are saying???

Some car owners don't realize that some areas of your engine get much, much hotter than other areas of your engine and that the oil that comes in contact with very hot portions of your engine will be "hotter" than oil that is down in your sump where your oil thermostat pick up is sitting. They then take that misunderstanding to the next level that if my oil temperature gauge never registers more than, say, 195 degrees Fahrenheit, then no portion of my oil, anywhere, ever sees a temperature higher than that number. Then, the third step of the misunderstanding is that if no part of my oil ever gets high enough to "boil water" then I must never be getting the water out of the oil to begin with. Of course it's all not true and the automakers' SAE studies all put the "perfect temperature for low wear" (as seen on your oil gauge) down below water's boiling point and, if you just test it for yourself with oil analyses, you can confirm whether or not you're getting the moisture out of your oil by whatever driving it is that you do and whatever temperatures you happen to see on your gauge. Of course, the worst thing you can do is just start your car up in the winter, run it for a minute or two, and then shut it down and store it away for months, and then maybe do it again. But, you still, from time to time, see the statement "If you don't get your oil gauge up past 212 degrees then you never get the moisture out of your oil." Which, of course, is bunk.

[rodneym]

But is oils oils?
Or is oils ain't oils?

[patrickt]

Originally Posted by rodneym

But is oils oils?
Or is oils ain't oils?

I dunno. But I was wondering whether a 911 engine can last over 300,000 miles.... https://www.elephantracing.com/tech-...d-engine-life/