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Mobil One, Anyone?

TXFlyGuy

Well Known Member
With an auto conversion powered airplane, is there any reason not to use a good synthetic oil? Are synthetics compatible with 100 LL? If not, why not?
 
Don't

With an auto conversion powered airplane, is there any reason not to use a good synthetic oil? Are synthetics compatible with 100 LL? If not, why not?


My understanding, not personal knowledge, was that Mobil-1 aviation oil was taken off the market because it did not properly "scavenge the lead" in 100LL. It was used in the Voyager world flight, but later discontinued.

For car gas you have a different set of issues, of course.
 
Mobil One and "alternative" engines

From all I have read over the years the synthetics didn't work reall well in aircraft engines due to the greater amount of blow by associated with the looser clearance of rings on an aircooled engine, etc. Many of my rotary buddies (Mazda 13/20B engines) run Mobile one and 100LL or 87 octane car fuel without any issues and that is what I will use in my 13B when I get it flying...

Doug Lomheim
RV-9A; 13B / FWF (on hold for now)
RV-3 O-290 under restoration (former GPU...sorta of an "alernative engine" :)
 
With an auto conversion powered airplane, is there any reason not to use a good synthetic oil? Are synthetics compatible with 100 LL? If not, why not?

Anyone that has been around aviation a while would not use a 100% synthetic oil in an engine that uses 100LL if you gave them the oil free. Too many engines were destroyed by Mobil 1 aviation oil when it was on the market. The synthetic oil does not handle the lead well and the sludge that formed destroyed the engines.
 
Do NOT use synthetics

Bud Warren told me to never never use synthetics with 100LL. The lead will turn it to a gray sludge and destroy your engine. Use SAE 30W or 5w-30 and keep it clean. Period.
 
Leaded fuel + detergent additive package = Bad

Myron,
More important than the issue of Mobil 1 being synthetic is the fact that it is a DETERGENT automotive engine oil. [FYI, almost all automotive oils are detergent oils] Automotive detergent additive packages are NOT compatible with the use of leaded fuels.
Aircraft fuels are "ash-less dispersant". This means that they are designed to let the lead settle out of the oil and sink to the bottom of the sump. Use of Mobil 1 would be a great idea for your auto engine IF and ONLY IF you stick to unleaded fuels, which is what automotive engine oils are designed to use.
FYI, for those mentioning that Aviation Mobil 1 has been discontinued, the issues of that product would not be relevant here. The problem with the Aviation Mobil 1, was that it leached copper out of the engine. This seemed to be an issue with Continental Engines, more so than with Lycoming products. Since Myron is using an auto engine, not relevant here.
Charlie
 
Bud Warren told me to never never use synthetics with 100LL. The lead will turn it to a gray sludge and destroy your engine. Use SAE 30W or 5w-30 and keep it clean. Period.

So the primary fuel in use will be 93 octane mogas. And the engine most likely will be a Chevy. Considering that on occasion we might be limited to 100LL, what oil would be best suited for this application. And what about Aeroshell 15-50 synthetic blend?
 
Well let's just say the word never got to all of us

I use Aeroshell 15W-50 exclusively because of a consumer report years ago that said it was the only aviation oil with an anti-wear aditive that was verified to work by testing. When I changed to a Blended airfoil prop a few years ago I was surprised by the thick gray pudding consistency material covering everything in the end of my crankshaft. I assumed this was normal. I cleaned it out with a rag, installed the new prop and continued on.

The engine runs fine. I run it WOT all the time in cruise flight never less than 2450 rpm. I have a little over 800 hours on the engine and yesterday clocked a little over 215 mph in the MERFI 150.

My question to Gary Sobek, who I trust completely, is "Is this an example of what you were talking about and is there a demonstrated failure mode from this characteristic?"

Bob Axsom
 
You could run Mobil 1 if you take care of the ring and piston clearances. When was the last time you've seen a gasoline car engine oil turn black?
 
You could run Mobil 1 if you take care of the ring and piston clearances. When was the last time you've seen a gasoline car engine oil turn black?

Never seen black oil. And I change oil (Mobil One) every 7,500 miles on my wife's Explorer, 5.0 V8. Been using Mobil One for over 160,000 trouble free miles. And the oil consumption is minimal today. For the first 100,000 the engine did not burn a drop between changes. Now it will use a quart every 7,500 miles. I attribute this to the oil and the religious break in procedure we employed when the engine was factory new.
 
There may not be a good answer

As I now understand the question, it relates to the best oil for a Chevrolet engine used in an airplane. Let's admit that there is no oil on the market that was formulated for this application.

The obvious choices are:
1. Aero-Shell or Exxon-Mobil partly synthetic.
2. Mobil-1 or comparable synthetic for automotive
3. Whatever is the best oil for marine gas engines which often use automotive blocks.

Given that marine applications of car engines are meant to run long periods at high power settings and car engines are not, that would be worth a look.

I don't want to start a war over additives, but it's worth considering a non-synthetic car oil with a really good, patented oil additive which I will only name in a PM or email. I ran my 78 Toyota >230k miles on that and the cam lobes were still within specs when I sold it. That would solve part of the problem with lead. Of course, you still would have plug fouling and such.

Aviation oil, IMHO, is a poor choice simply because it is not designed for that kind of engine. When Mooney had a Porsche engine option, it used car oil, IIRC. AvOil does not contain, the last I heard, the comparable anti-wear package(s) because we don't want deposits in the combustion chambers which might encourage detonation at high, continuous power settings. Aviation oil is also higher in viscosity than what is normally used in an auto engine. The clearances are likely the reason, but the idea of running higher viscosity oil than that for which the engine was designed needs some careful thought, too.

A related question that bears careful decision making is the fuel to be used. If the fuel does not have lead, then the lead issue goes away. However, I don't mean to start a war over car gas vs. av gas. Everything about that has already been written. That said, car engines and even marine engines are no longer designed to run on leaded fuel. Of course, cars and boats don't have the same issues with altitude, seasonal blends and so on.

So there may not be a really good choice in this situation, but given that the decision was made to use an auto engine conversion, then the fuel and lube questions must be decided. It may come down to the least-bad choice.
 
Never seen black oil. And I change oil (Mobil One) every 7,500 miles on my wife's Explorer, 5.0 V8. Been using Mobil One for over 160,000 trouble free miles. And the oil consumption is minimal today. For the first 100,000 the engine did not burn a drop between changes. Now it will use a quart every 7,500 miles. I attribute this to the oil and the religious break in procedure we employed when the engine was factory new.

i ran my 2005 Honda Accord V6 33,000 (thirty-three thousand) miles one one Mobil 1 oil change and sent it in for oil analysis to Blackstone. Viscosity, metals, everything was within limits.
 
Mobil Aircraft Engine Oil

The following is a copy paste from:
http://www.lieffcabraser.com/defective-products/case/98/mobil-aircraft-engine-oil

Mobil Aircraft Engine Oil


  • Issue: Defective product
  • Result: $12.5 million settlement
  • 1995
Gross v. Mobil

Lieff Cabraser served as Plaintiffs' Class Counsel in this nationwide action involving an estimated 2,500 aircraft engine owners whose engines were affected by Mobil AV-1, an aircraft engine oil. Plaintiffs alleged claims for strict liability, negligence, misrepresentation, violation of consumer protection statutes, and for injunctive relief.
Plaintiffs obtained a preliminary injunction requiring Defendant Mobil Corporation to provide notice to all potential class members of the risks associated with past use of Defendants' aircraft engine oil. In addition, Plaintiffs negotiated a proposed Settlement, granted final approval by the Court in November 1995, valued at over $12.5 million, under which all Class Members were eligible to participate in an engine inspection and repair program, and receive compensation for past repairs and for the loss of use of their aircraft associated with damage caused by Mobil AV-1.




For some old but good reading on oil, try this link.


Added another link:
http://www.avweb.com/news/news/182891-1.html



For safety reasons, 100% synthetic oil should never be used in an aircraft engine that uses lead in its fuel. Semi-Synthetic oils have proven very effective in aviation engines that use lead. IF you want more info, I recommend using Google and spending a little time reading what you find.
 
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These class action suits make for interesting reading. The question is, will a synthetic oil operated in an auto-conversion engine burning 93 octane pump gas present a problem. And lets say that 30% of the time the only fuel available is 100LL. Are you still going to have the sludge problem? Is the problem related in the class action suit due to the fact that certified aircraft engines are rather loose (sloppy?) in the tolerance department and the result is much more contamination in the case? Auto engines are built to much closer tolerances and I would think this would abate the sludge issue to a certain degree.

Aeroshell 15-50 is a semi-synthetic blend. What is the ratio? Is it 10% synthetic, 20%, more, less? All the auto oil brands have syn-blends as well. I would be curious to know the ratio.
 
I have read somewhere it is 50% synthetic. Some people blame AS 15W50 for Lycoming's epidemic of cam failures.
 
These class action suits make for interesting reading. The question is, will a synthetic oil operated in an auto-conversion engine burning 93 octane pump gas present a problem. And lets say that 30% of the time the only fuel available is 100LL. Are you still going to have the sludge problem? Is the problem related in the class action suit due to the fact that certified aircraft engines are rather loose (sloppy?) in the tolerance department and the result is much more contamination in the case? Auto engines are built to much closer tolerances and I would think this would abate the sludge issue to a certain degree.

Aeroshell 15-50 is a semi-synthetic blend. What is the ratio? Is it 10% synthetic, 20%, more, less? All the auto oil brands have syn-blends as well. I would be curious to know the ratio.




I am not willing to risk my safety trying to find out.




Some people like to do dangerous things. I will not risk my life, money, or time going down that path.
 
These class action suits make for interesting reading. The question is, will a synthetic oil operated in an auto-conversion engine burning 93 octane pump gas present a problem. And lets say that 30% of the time the only fuel available is 100LL. Are you still going to have the sludge problem? Is the problem related in the class action suit due to the fact that certified aircraft engines are rather loose (sloppy?) in the tolerance department and the result is much more contamination in the case? Auto engines are built to much closer tolerances and I would think this would abate the sludge issue to a certain degree.

Aeroshell 15-50 is a semi-synthetic blend. What is the ratio? Is it 10% synthetic, 20%, more, less? All the auto oil brands have syn-blends as well. I would be curious to know the ratio.

Everyone seems to be getting off track with replies here. With an auto engine using mostly unleaded fuels, Mobil 1 is probably your best choice. Many people run it including me for the last 9 years and I've used it in very highly stressed turbocharged road racing engines for over 25 years. Never any wear on anything on teardowns. You can run a bit of Decalin Runup in your fuel to help mitigate any lead concerns when you have to fill up with 100LL.

BTW I hope after this time we have dispelled this myth that auto engines are not designed or capable of running WOT for long periods. They are validated like this for hundreds of hours by the OEMs before production release to the public- every single modern engine in the 20+ years.
 
Just got off the phone with a sales person for a major oil company. The claims by some oils to be synthetic are true in the legal sense, but the oil is not a true synthetic oil. Amsoil is one of the two or three brands available that is a true synthetic. The companies name that starts with an "M" is not truly synthetic, however they do make a market oils that are genuinely synthetic based oils.

His recommendation to me? Amsoil! And he does not sell it.
 
This might be of interest but not sure how impartial the information might be: http://www.synthetics.com/amsoil-and-mobil-1-comparison-tests.html

Just some random thoughts;

When given the choice, OEMs overwhelmingly choose Mobil 1 for factory fill- perhaps they are given a better deal by Exxon?

When given a choice, more NASCAR teams use Mobil 1 than any other brand- I doubt if cost is an issue for oil in NASCAR.

McLaren Mercedes uses Mobil 1 in their F1 engines- Perhaps a good sponsorship deal but they can't be using an inferior product at this level and cost of racing.

Amsoil could be superior but Mobil 1 has not become the popular oil choice for race engine builders worldwide or the most popular "synthetic" engine oil in the world because it is ****. Of course marketing could have a lot to do with this too.;)

Who knows, I just know I've used it since 1980 in all my race engines and have never seen a lubrication related failure in any engine so, I stick with it. Turbocharged road racing engines have FAR more stress on them, both thermally and mechanically than run of the mill aircraft engines.
 
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Yes, I too am a firm believer in M1. It was only after I spoke with my local oil company sales rep that I learned that Amsoil is purely synthetic, where M1 is not. And you are preaching to the choir in that we have run M1 in all of our vehicles for well over 100K miles with no issues at all.

As my friend pointed out, and you alluded to, there is a huge amount of marketing that does factor in to all of this.
 
Amsoil, baby!

Hey TXflyGuy:

I now run 25% Amsoil/75% 25W-60 X-CY. Why 25W-60? I have 2+ 55 gal barrels of the stuff, and I live in Texas (think warm WX flying). In addition, the dummy that designed the cooling system on my plane did things in a less than optimum manner. Guess who that was?:rolleyes: So, I have a 325HP engine that utilizes a 200HP cooling system. Following DanH thru his cooling design process, the light came on.
Think 'modifications'. MAJOR modifications. COMPOSITE major modifications. Ugh.
But, I digress.
The point is that my OT always runs warm, if not downright HOT (215-220F). So, 25W-60 is fine in my case. Well, until I actually manage to come up with a 325HP cooling system. I am trying an ADI approach, which seems to work quite well. 60/40 water/ethanol mix; keeps CHTs in the 360-370 range. Cruise temps are good.
In addition, I had occasion to change out my starter adapter, and have a peek inside @250SMOH. Looked like new in there, no sludge or deposits. I guess my chemistry is working.
FWIW, AMSOIL was designed as an aircraft engine oil. The M1 fiasco caused 'em to drop that marketing path, but the stuff still does what it was designed to do. It keeps lead in suspension (AD oil), so sludge is no worse that you would get with Av oil, or probably better.
Opinion: you could use M1 as I use Amsoil and get the same results. I would not run M1 straight - that has already been proven to be a less than optimal process.
Clear as mud?

Carry on!
Mark
 
Everyone posting here, remember what the question is- auto engine operating on mostly unleaded fuel. Experience with a traditional engine operating on 100LL is not really very useful in this discussion...

Sludge has never been an issue on my Subaru which burned 100LL exclusively for the first 270 hours and always used Mobil 1, even for breakin. I pulled the pan at about 250 to change the oil pan after moving the turbo drain fitting- engine was like brand new inside, no lead sludge. Oil change intervals were 40 hours initially for about 4 years and 30 after that.

Certainly I think you do not want to run Aeroshell in a Chevy engine running unleaded fuel. Why would you? Chevy factory fills the LS engines with Mobil 1, why not stick with their choice?
 
late to the party....

FWIW, every rotary engine flier that I know that uses mogas (not avgas) uses full synthetic oil. Some of them have hundreds (one has over a thousand) hours. The ones who have opened their engines (unrelated to oil issues) found the internals had virtually no nasty buildup like you typically see in a/c engines.

I'd need to check with the one guy I know who flies a rotary on nothing but avgas to see what oil he uses.


Charlie
 
Amsoil rep said...

I called Amsoil. The rep I spoke with stated that Amsoil with 100LL was absolutely not a problem. She did say that you might want to change oil more frequently, however.
 
This might be of interest but not sure how impartial the information might be: http://www.synthetics.com/amsoil-and-mobil-1-comparison-tests.html
Who knows, I just know I've used it since 1980 in all my race engines and have never seen a lubrication related failure in any engine so, I stick with it. Turbocharged road racing engines have FAR more stress on them, both thermally and mechanically than run of the mill aircraft engines.

According to my Shell rep and "motorhead" friend, almost never do you see a failure related to inferior oil. The failures are almost always related to a lack of oil, or some other peripheral issue, not to the oil itself.
 
Running a synthetic oil for the superior properties when you must change it more often to combat the lead suspension issues kind of defeats the purpose. But synthetic oil does seem to resist heat breakdown.

I've seen a oil related failure of a 14000 hp gearbox....it took less than a year of operation. After rebuild we started using Mobil SHC220(Mobilone synth)...it's been in operation since 1995...almost continuously.
 
Mobil SHC is THE ULTIMATE industrial gear oil. I concurr.

In a year or so I hope Mobil bring back the aviation version Mobil 1 as it is superior in every way, except lead. Along with running G100UL the Mobil synthetic would be a no brainer.

Until then........
 
lead issues??

Racing engines of many flavors run leaded race fuels. Some of these fuels contain more lead than 100ll does. These engines almost universally use synthetic oils (commonly Mobil 1) without any issues. Additionally in the US and Canada there were older cars running leaded fuel with standard and synthetic oils for many years through the late 1980's with out trouble. So if there are issues I dont think it is specificly lead related. Russ
 
I don't see too many racing fuels with TEL in them here. But if they were used the time in sump would not be long.

The typical V8 superacr engine (our most high profile form of racing) would be lucky to go 25-50 hours before rebuild and would have a minimum of 4-8 oil changes in that time and more like 8-16.

In aero engine terms you would be saying an oil change every 4-5 hours by comparison?

In a few years Mobil AV-1 should make a return I hope!
 
Approved Oils

HTML:
Racing engines of many flavors run leaded race fuels.

Case in point, Porsche has a list of approved oils, most if not all of them are synthetic or semi-synthetic. The list applies to all of their cars; newer water cooled designed to run on unleaded fuel as well as air cooled engines designed to run on leaded fuel.
If I recall, some of the oils are also used in diesel engines.
Mobile 1, Amsoil and Royal Purple are a few of the brands recomended.
 
Myron & H. Evan's:

Way, way back... When Mobile 1 first came out it was a 100% synthetic oil. Synthetic oil is GREAT for lubrication and working into tight spaces. BUT! 100% Synthetic oil suffers greatly in the main purpose of oil... And that is to CARRY HEAT AWAY. Now, with my statement there will be some that will say 'If you reduce friction you reduce heat'... TRUE! But this falls into the realm of: Which came first, the chicken or the egg?
Mobile 1 years ago only a few - I think it was 3 failure due to heat. AND, when they made a MIXTURE of 50% Synthetic and 50% Organic (Petroleum) the heat problem went away. The advertising has changed and one must REALIZE it is advertising that SELLS products - So the real term of 100% synthetic no longer exists. All good synthetic oils contain petroleum additives.
NOW! One big difference to consider is the LOAD capable charistics of oil. A car cruising down the road at 65 MPH is only using about 15 to 25 HP... While a plane in cruse is around 55 to 75% HP... Lets say you have a O-320 @ 150 HP that is 82.5 HP to 112.5 HP... Bigger engine BIGGER HP. So, I would consider AVIATION OILS before automotive oils. AND - Realize this is a subject that falls under OPINIONS... And you know what they say about OPINIONS!

Barry

"You enter yor next world through what you learn in this one; learn nothing and you have all the same lead weights and limitations to overcome" J.L. Seagull (IChing)
 
Myron & H. Evan's:

Way, way back... When Mobile 1 first came out it was a 100% synthetic oil. Synthetic oil is GREAT for lubrication and working into tight spaces. BUT! 100% Synthetic oil suffers greatly in the main purpose of oil... And that is to CARRY HEAT AWAY. Now, with my statement there will be some that will say 'If you reduce friction you reduce heat'... TRUE! But this falls into the realm of: Which came first, the chicken or the egg?
Mobile 1 years ago only a few - I think it was 3 failure due to heat. AND, when they made a MIXTURE of 50% Synthetic and 50% Organic (Petroleum) the heat problem went away. The advertising has changed and one must REALIZE it is advertising that SELLS products - So the real term of 100% synthetic no longer exists. All good synthetic oils contain petroleum additives.
NOW! One big difference to consider is the LOAD capable charistics of oil. A car cruising down the road at 65 MPH is only using about 15 to 25 HP... While a plane in cruse is around 55 to 75% HP... Lets say you have a O-320 @ 150 HP that is 82.5 HP to 112.5 HP... Bigger engine BIGGER HP. So, I would consider AVIATION OILS before automotive oils. AND - Realize this is a subject that falls under OPINIONS... And you know what they say about OPINIONS!

Barry

"You enter yor next world through what you learn in this one; learn nothing and you have all the same lead weights and limitations to overcome" J.L. Seagull (IChing)

Ok, why doesn't a small displacement 700hp F1 engine or a 500 hp Corvette engine blow up using Mobil 1? The load is many times greater here than any Lycoming engine. Automotive oils are engineered for automotive engines and Mobil 1 works just fine in my automotive powered RV6A and I'm running a lot more than 25 hp...

Mobil 1 does not contain 50% organic base stock, only the additive package has some non-synthetic ingredients.

BTW automotive engines are validated at WOT and hundreds of hours of full power using automotive oils. Seem to work just fine.

An opinion is one thing, reality quite another.
 
Myron & H. Evan's:

Way, way back... When Mobile 1 first came out it was a 100% synthetic oil. Synthetic oil is GREAT for lubrication and working into tight spaces. BUT! 100% Synthetic oil suffers greatly in the main purpose of oil... And that is to CARRY HEAT AWAY. Now, with my statement there will be some that will say 'If you reduce friction you reduce heat'... TRUE! But this falls into the realm of: Which came first, the chicken or the egg?
Mobile 1 years ago only a few - I think it was 3 failure due to heat. AND, when they made a MIXTURE of 50% Synthetic and 50% Organic (Petroleum) the heat problem went away. The advertising has changed and one must REALIZE it is advertising that SELLS products - So the real term of 100% synthetic no longer exists. All good synthetic oils contain petroleum additives.
NOW! One big difference to consider is the LOAD capable charistics of oil. A car cruising down the road at 65 MPH is only using about 15 to 25 HP... While a plane in cruse is around 55 to 75% HP... Lets say you have a O-320 @ 150 HP that is 82.5 HP to 112.5 HP... Bigger engine BIGGER HP. So, I would consider AVIATION OILS before automotive oils. AND - Realize this is a subject that falls under OPINIONS... And you know what they say about OPINIONS!

Barry

"You enter yor next world through what you learn in this one; learn nothing and you have all the same lead weights and limitations to overcome" J.L. Seagull (IChing)

Ok, why doesn't a small displacement 700hp F1 engine or a 500 hp "Vette" engine blow up using Mobil 1? The load is many times greater here than any Lycoming engine. Automotive oils are engineered for automotive engines and Mobil 1 works just fine in my automotive powered RV6A and I'm running a lot more than 25 hp...

Mobil 1 does not contain 50% organic base stock, only the additive package has some non-synthetic ingredients.

BTW automotive engines are validated at WOT and hundreds of hours of full power using automotive oils. Seem to work just fine. I don't think the engineers developing oils would agree with you assessment here.

An opinion is one thing, reality quite another.
 
As it turns out, we will be burning 100LL most, if not all of the time. The boys flying with the V8, V12, and V6's are running Shell Rotella Diesel engine oil, non synthetic. They are having very good results with this oil and running the leaded avgas.
Rotella is what they strongly recommend. And this oil was actually suggested by one of the techs from Shell Oil.
 
I have used both Mobil one synthetic and Now Amsoil synthetic with no adverse affects and I use 100LL all the time, no auto fuel.
No sludge build up. Oil stays clean for a long time after I change it. I change oil every 50 hours.
I use 10w-30 synthetic.
There is no way I would use anything other than synthetic with a turbo charged engine because synthetic oils can handle much higher temperatures.
 
I have used both Mobil one synthetic and Now Amsoil synthetic with no adverse affects and I use 100LL all the time, no auto fuel.
No sludge build up. Oil stays clean for a long time after I change it. I change oil every 50 hours.
I use 10w-30 synthetic.
There is no way I would use anything other than synthetic with a turbo charged engine because synthetic oils can handle much higher temperatures.

Thanks. That is good to know. Real world experience trumps theory every time.
 
I have used both Mobil one synthetic and Now Amsoil synthetic with no adverse affects and I use 100LL all the time, no auto fuel.
No sludge build up. Oil stays clean for a long time after I change it. I change oil every 50 hours.
I use 10w-30 synthetic.
There is no way I would use anything other than synthetic with a turbo charged engine because synthetic oils can handle much higher temperatures.

Robin: Aren't you running your RV-3B with a GM/Opel "ECO" Engine?

thx.

Doug Lomheim
RV-9A, Mazda 13B / FWF
 
It's a Corvair engine modified to run in the aircraft. A very smooth running 6 cylinder engine.
With a turbo I have about 125 hp.
 
We are planning to use Shell Rotella T, an ashless dispersant oil, just like Aeroshell. It is a full synthetic.
 
Here is what can be learned from this...do not use Mobil One in an aircraft engine, Lycoming, Continental, etc.

They are built with extremely loose tolerances, which results in far more "blow by" than you will ever have in a modern automobile engine.
 
While what you say about LYC/CON is true, that's not at all what I learned from this. My memory of the early problems with synthetic oil was that they couldn't/didn't hold the lead byproducts in suspension, so they accumulated in the engines as sludge.

Synthetic oil in a LYC/CON would be fine, as long as you're running lead free gas. (Temps shouldn't be an issue; synthetics have much higher heat tolerance than organic oils.)
 
While what you say about LYC/CON is true, that's not at all what I learned from this. My memory of the early problems with synthetic oil was that they couldn't/didn't hold the lead byproducts in suspension, so they accumulated in the engines as sludge.

Synthetic oil in a LYC/CON would be fine, as long as you're running lead free gas. (Temps shouldn't be an issue; synthetics have much higher heat tolerance than organic oils.)

That is why we have chosen an "ashless dispersant" oil, Rotella T, by Shell.
 
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