Am a bit confused by recent information suggesting that synthetic oil, compared to conventional (dino) oil, has "drain-away" issues leaving metal surfaces unprotected during dry-start conditions. The industry consensus, however, is that synthetic oil provides better wear protection at startup. Some owners report less startup noise with synthetic while others say conventional oil is quieter. Needless to say, I'm confused...
Synthetic Oil & Dry-Start Issues
- Thread starter turnbowm
- Start date
- Status
On top of all that some think that Group V synthetic oils "stick" better on shutdown than other synthetic's and therefore give better protection during start up.
And if that's not enough STP syrup fails the screwdriver test.
And if that's not enough STP syrup fails the screwdriver test.
Took apart a early Ford 240 ci six cylinder engine today that sat in a barn for 30 plus years not running. I saw it first hand: Mains and rod bearings, (and Crankshaft) had much oil still clinging to it.
Originally Posted By: turnbowm
recent information
Can you please link to this "information"? I'd sure like to see anything that's applicable to modern engines, with modern oil, utilizing any legitmate laboratory/bench test.
P.S. - The internet is full of forums that have some guy who'll tell you X or Y oil is better based upon their anecdotal observations and ingrained biases.
recent information
Can you please link to this "information"? I'd sure like to see anything that's applicable to modern engines, with modern oil, utilizing any legitmate laboratory/bench test.
P.S. - The internet is full of forums that have some guy who'll tell you X or Y oil is better based upon their anecdotal observations and ingrained biases.
I think Group 1 and Group 5 (esters) cling to metal the best as they are more polar molecules.
I believe Group 3 (HydroCracked) and Group 4 (PAO) are less polar and so cling less, and are the more common bases in typical everyday synthetics. However Group 3 & 4 have better (very) cold flow properties. than Group 1 & 2, so in that respect are better at start up than mineral oils.
So two different issues:
- metal cling on shutdown or drain away on shutdown
- cold flow properties on start-up
A Group 1 20W50 is good at staying there on shutdown, but not good at getting going on a cold winter morning (much like myself).
The ideal solution is a Group 4 & 5 synthetic, but they are rare and very expensive. I think the average semi-synthetic will work for most people.
I wouldn't be too concerned with any well developed name brand oil. I hear M1 is mostly PAO and Grp 3, but has a touch of ester added. Castrol Magnatec is designed to cling to metal parts, the silly named "intelligent molecules".
Don't forget the oil is only the first line of defence, the ZDDP should have left a protective layer on the metal regardless of base group used.
I believe Group 3 (HydroCracked) and Group 4 (PAO) are less polar and so cling less, and are the more common bases in typical everyday synthetics. However Group 3 & 4 have better (very) cold flow properties. than Group 1 & 2, so in that respect are better at start up than mineral oils.
So two different issues:
- metal cling on shutdown or drain away on shutdown
- cold flow properties on start-up
A Group 1 20W50 is good at staying there on shutdown, but not good at getting going on a cold winter morning (much like myself).
The ideal solution is a Group 4 & 5 synthetic, but they are rare and very expensive. I think the average semi-synthetic will work for most people.
I wouldn't be too concerned with any well developed name brand oil. I hear M1 is mostly PAO and Grp 3, but has a touch of ester added. Castrol Magnatec is designed to cling to metal parts, the silly named "intelligent molecules".
Don't forget the oil is only the first line of defence, the ZDDP should have left a protective layer on the metal regardless of base group used.
Originally Posted By: ShotGun429
Took apart a early Ford 240 ci six cylinder engine today that sat in a barn for 30 plus years not running. I saw it first hand: Mains and rod bearings, (and Crankshaft) had much oil still clinging to it.
You mean that you actually got oily from the oil still there due to capillary action ?
Amazing...and a story repeated hundreds of times everyone pulls one apart.
Once run, I doubt there's EVER a dry start.
Took apart a early Ford 240 ci six cylinder engine today that sat in a barn for 30 plus years not running. I saw it first hand: Mains and rod bearings, (and Crankshaft) had much oil still clinging to it.
You mean that you actually got oily from the oil still there due to capillary action ?
Amazing...and a story repeated hundreds of times everyone pulls one apart.
Once run, I doubt there's EVER a dry start.
Lots of old wives on the internet.
Ahh yes the old conventional hangs on the metal parts better. Almost forgot that one. Thanks for the free entertainment.
I guess we all need to start using Lucas!
Last edited:
It's never a dry start. There is always a permanent oil film on metal after the first minute of a motors life. IF you are hearing clicking and clacking on cold start (or maybe even rod bearing rattle if old engine) it is from lack of capillary fill. Nothing else.
An oil film is there. What MAY be happening is the so called drain-off effect. It's well known and SOME engines are susceptible to it. High mileage motors, some race motors with loose clearances, etc. New modern OEM engines should not be susceptible ... Mostly it's about engines that sit for a week or more at a time.
Dino oils are made up a various molecules. Lots of synthetics are made of of a much more restricted regimen. Dino oils exhibit better capillary fill do to higher surface tension. The downside is the higher winter grade rating of say 15W. The phenomena that allows for thinner fills and drain-off, also generates 0W and 5W winter grade ratings (lower surface tension). Can't have it both ways.
If your motor is in good shape and it calls for 0W or 5W it was built tight enough that you should not be experiencing this issue. If the motor has over 100,000 or was originally spec'd for 10W or 20W oils, it MAY exhibit this issue. If it was/is one of my hot street motors that I call "droolers", it will exhibit this issue. I build them for thicker oil and I use HV pumps. But I know you do not have one, so that is not at hand
What caused this concern? Are you hearing cold start engine noise?
An oil film is there. What MAY be happening is the so called drain-off effect. It's well known and SOME engines are susceptible to it. High mileage motors, some race motors with loose clearances, etc. New modern OEM engines should not be susceptible ... Mostly it's about engines that sit for a week or more at a time.
Dino oils are made up a various molecules. Lots of synthetics are made of of a much more restricted regimen. Dino oils exhibit better capillary fill do to higher surface tension. The downside is the higher winter grade rating of say 15W. The phenomena that allows for thinner fills and drain-off, also generates 0W and 5W winter grade ratings (lower surface tension). Can't have it both ways.
If your motor is in good shape and it calls for 0W or 5W it was built tight enough that you should not be experiencing this issue. If the motor has over 100,000 or was originally spec'd for 10W or 20W oils, it MAY exhibit this issue. If it was/is one of my hot street motors that I call "droolers", it will exhibit this issue. I build them for thicker oil and I use HV pumps. But I know you do not have one, so that is not at hand
What caused this concern? Are you hearing cold start engine noise?
Originally Posted By: turnbowm
The industry consensus, however, is that synthetic oil provides better wear protection at startup.
Don't you love the ambiguity of language? Both statements can be true.
It's simple, solvent-refined GrI, certain GrV oils have more polar molecules in them which cling to parts. The clinging can be considered itself to disqualify a start as being 'dry'. GrII-IV oils are considered dry themselves because of the low content of polar constituents. With no molecular polarity to cling to parts, it could be said that after adequate time to drain off of the part, a start could be 'dry'. Nevertheless 'dry' oils have great VI, aiding pumpability in cold temperatures; the old 'cold flow' bit and in this way synthetics can be considered better for dry starts. So we have two completely different rationales that could each be technically true.
In reality, it's not necessarily so. The type of product (non-synth vs synth, whatever that means) has little bearing on startup wear protection from the cold flow perspective, because the rated viscosity determines that. Synthetic oils are also not just dry base oils, polar additives are added to the end product for exact reason of imparting polarity/solubility to the solution, so no proper 'synthetic' engine oil formulation is really dry, despite relying exclusively on the additive system to achieve it.
The industry consensus, however, is that synthetic oil provides better wear protection at startup.
Don't you love the ambiguity of language? Both statements can be true.
It's simple, solvent-refined GrI, certain GrV oils have more polar molecules in them which cling to parts. The clinging can be considered itself to disqualify a start as being 'dry'. GrII-IV oils are considered dry themselves because of the low content of polar constituents. With no molecular polarity to cling to parts, it could be said that after adequate time to drain off of the part, a start could be 'dry'. Nevertheless 'dry' oils have great VI, aiding pumpability in cold temperatures; the old 'cold flow' bit and in this way synthetics can be considered better for dry starts. So we have two completely different rationales that could each be technically true.
In reality, it's not necessarily so. The type of product (non-synth vs synth, whatever that means) has little bearing on startup wear protection from the cold flow perspective, because the rated viscosity determines that. Synthetic oils are also not just dry base oils, polar additives are added to the end product for exact reason of imparting polarity/solubility to the solution, so no proper 'synthetic' engine oil formulation is really dry, despite relying exclusively on the additive system to achieve it.
Originally Posted By: turnbowm
The industry consensus, however, is that synthetic oil provides better wear protection at startup.
Could someone provides clarity on how this works .....
other than contributions 'purely' from additives ?
Or synthetics here refers 'purely' to high polarity ester synthetic, and not other synthetics ?
The industry consensus, however, is that synthetic oil provides better wear protection at startup.
Could someone provides clarity on how this works .....
other than contributions 'purely' from additives ?
Or synthetics here refers 'purely' to high polarity ester synthetic, and not other synthetics ?
Yah, I have never found or read a peer reviewed professional paper that shows better wear protection... I've been looking and so has Shannow.
We do have older papers that show mono-grades exhibiting better wear protection in some areas (upper cylinder mostly) than multi's. But they were written before Group II+ was in wide use. They are comparing mono to multi's made up with VII's.
I suspect that there is not enough difference to publish ... But they can make a case for "cold flow" and then start banging that drum so folks think they are buying some protection ...
We do have older papers that show mono-grades exhibiting better wear protection in some areas (upper cylinder mostly) than multi's. But they were written before Group II+ was in wide use. They are comparing mono to multi's made up with VII's.
I suspect that there is not enough difference to publish ... But they can make a case for "cold flow" and then start banging that drum so folks think they are buying some protection ...
Is one of those older references the one regarding the Mercedes OM? I remember that one, haven't seen it in years.
Yup
If the oil film on parts like a cylinder wall drained off like some describe it would be really difficult to start the engine up again after being shut down for a few months. Friction would be a real problem. But that's not the case. There must certainly be differences between various types of oils but they all stick well enough. The real wear starts when the engine get running and continues at a bit higher rate until normal operating temperature is achieved.
Today all you really have to do is use some common sense and follow the factory recommendations. Reading a shop manual published in 1902 the recommendation was to change the oil every 100 miles and remove the head to scrape off carbon every 1,000 miles or every 6 months, whichever came first. People drive a bit more today and expect a bit more mileage before any required maintenance. Today a schedule like that would make that car very unpopular.
Today all you really have to do is use some common sense and follow the factory recommendations. Reading a shop manual published in 1902 the recommendation was to change the oil every 100 miles and remove the head to scrape off carbon every 1,000 miles or every 6 months, whichever came first. People drive a bit more today and expect a bit more mileage before any required maintenance. Today a schedule like that would make that car very unpopular.
Originally Posted By: BrocLuno
Yah, I have never found or read a peer reviewed professional paper that shows better wear protection... I've been looking and so has Shannow.
We do have older papers that show mono-grades exhibiting better wear protection in some areas (upper cylinder mostly) than multi's. But they were written before Group II+ was in wide use. They are comparing mono to multi's made up with VII's.
I suspect that there is not enough difference to publish ... But they can make a case for "cold flow" and then start banging that drum so folks think they are buying some protection ...
Yeh, I've been thinking this is strange for a while.
I doubt "not enough difference to publish ..." is really plausible as an explanation. While null differences can be harder to get published (I've managed one in an IEEE journal but it was a struggle) in this case it'd be of considerable general interest.
Either there isn't enough science in it to make it "academically respectable" (surely a stretch, and not really applicable anyway in an applied context) or........I'm trying to avoid typing "Big Oil Conspiracy" again.
Oops.
Yah, I have never found or read a peer reviewed professional paper that shows better wear protection... I've been looking and so has Shannow.
We do have older papers that show mono-grades exhibiting better wear protection in some areas (upper cylinder mostly) than multi's. But they were written before Group II+ was in wide use. They are comparing mono to multi's made up with VII's.
I suspect that there is not enough difference to publish ... But they can make a case for "cold flow" and then start banging that drum so folks think they are buying some protection ...
Yeh, I've been thinking this is strange for a while.
I doubt "not enough difference to publish ..." is really plausible as an explanation. While null differences can be harder to get published (I've managed one in an IEEE journal but it was a struggle) in this case it'd be of considerable general interest.
Either there isn't enough science in it to make it "academically respectable" (surely a stretch, and not really applicable anyway in an applied context) or........I'm trying to avoid typing "Big Oil Conspiracy" again.
Oops.
wemay
Site Donor 2023
BP is tapping into this with Castrol GTX Magnatec...(marketing "synthetic blends" and "synthetics"), not "conventionals".
http://www.castrol.com/en_us/united-stat...VYfAaArET8P8HAQ
THE INTELLEGENT MOLECULES:
•Cling to critical engine parts when the oil drains down
•Add a layer of protection during warm-up and beyond
•Dramatically reduce engine wear
•Leave critical engine parts 4X smoother
http://www.castrol.com/en_us/united-stat...VYfAaArET8P8HAQ
THE INTELLEGENT MOLECULES:
•Cling to critical engine parts when the oil drains down
•Add a layer of protection during warm-up and beyond
•Dramatically reduce engine wear
•Leave critical engine parts 4X smoother
- Status
Similar threads
- Sticky
