Ultimate Motor Oil Thread or Why we hate CJ4/SM oils

[movin]

No info. about GTX High Mileage?

[RWebb]

avoid Castrol

[cnavarro]

Castrol does make some good products, GTX is just an ok product, fine for very short drain intervals. Castrol has released a new Syntec 20w50, which I have not tested yet, but it is directly marketed to classic car owners with high Zn and P levels according to their marketing.

Still, I would go with the Brad Penn and Swepco 306, they are proven solutions.

[cnavarro]

Originally Posted by movin

I seem to recall Castrol GTX High Mileage 20W-50 was a synthetic blend too, just like Brad Penn. It's very available and superior to regular GTX. Is it worth a look?

The Castrol GTX HM is not a synthetic blend, Castrol makes a separate line of Syntec Blend oils.

If I had to use GTX, it would be an easy choice to say use the HM version, but I would still keep the short drain intervals.

Regardless, it doesn't necessarily boil down entirely to the group of base stock - it's the quality and the additive package used.

Brad Penn is only 10% syn (group II+ blended with group III) and Swepco has no synthetic, as it's a highly refined paraffinic base stock (II+) like the Brad Penn.

[GothingNC]

Here's the link on the Castrol 20-50 Syntec

http://www.castrol.com/castrol/genericarticle.do?categoryId=82915470&contentId=7032644


Today's engines face different demands than those of yesteryear. Now classic car owners who are particular about what they put in their vintage vehicles can receive modern wear protection from a high–zinc formula specially engineered for classic engines.


"SYNTEC 20W–50 does not meet the catalyst compatibility requirements of vehicles manufactured since 1993"

[rrnixonjr]

Since aircraft oils were suggested, how about 4 cycle outboard motor oils? Here is a quote from a magazine talking about the difference. May not be worth it depending on cost.



Until FC-W, engine manufacturers have specified the use of a high-grade automotive engine oil for four-stroke outboards. But in recent years automotive oil formulas have changed, as car and truck manufacturers put more emphasis on reducing internal friction to improve fuel mileage. This made auto-spec oil less desirable for use in marine engines, where operating conditions are significantly more challenging. For example, how often and for how long do you run your car or truck at full throttle? Maybe for a few seconds as you accelerate down an on-ramp. Your outboard, on the other hand, may spend a lot of time at WOT. Even when cruising, an outboard is under relatively heavy load and at least 75 percent throttle while it operates in an environment that includes high humidity and salt air. Compared to a car engine, an outboard leads a tortured life.

In designing the FC-W formula, the NMMA committee sought to address two key issues. The first is resistance to "shearing" during high-rpm and high-temperature operation that rarely occurs in an automotive application. Under shear stress, oil can become thinner and lose its ability to separate moving parts, leading to accelerated wear or even catastrophic failure in extreme cases. The FC-W spec imposes a higher minimum viscosity level, which means that FC-W oil will not thin out as much as automotive oil of the same viscosity under the same heat and rpm conditions.

[cnavarro]

Originally Posted by rrnixonjr

In designing the FC-W formula, the NMMA committee sought to address two key issues. The first is resistance to "shearing" during high-rpm and high-temperature operation that rarely occurs in an automotive application. Under shear stress, oil can become thinner and lose its ability to separate moving parts, leading to accelerated wear or even catastrophic failure in extreme cases.

That is the reason I like the Brad Penn 20w50 so much. It's not ultimately concerned with reducing internal friction to improve fuel mileage (or to give you more HP). That makes it very unique. It does however have the highest HTHS vis @ 150C of any oil we have tested. Mobil 1 V-Twin is 5.8 cSt and Amsoil Harley is 6.1 cSt - Brad Penn 20w50 is 6.8 cSt, all at 150C for the HTHS vis.

All of Brad Penn's formulations have some excellent film stregnths. Even their 0w30 has a higher HTHS vis @ 150C of 4.1 cSt compared to M1 0w40, which is ony 3.6 cSt.

Although Swepco doesn't test for HTHS, I would imagine considering their similar paraffinic base stock that the HTHS vis @ 150C would be in the low 5's or high 4's.

I know that at least here in town, the marine shop here uses at least 20w50 and in some cases even a straight 60 wt racing oil, but we're talking BIG HP, at least 2000HP marine drag boats.

[movin]

Originally Posted by cnavarro

The Castrol GTX HM is not a synthetic blend, Castrol makes a separate line of Syntec Blend oils.

If I had to use GTX, it would be an easy choice to say use the HM version, but I would still keep the short drain intervals.

Regardless, it doesn't necessarily boil down entirely to the group of base stock - it's the quality and the additive package used.

Brad Penn is only 10% syn (group II+ blended with group III) and Swepco has no synthetic, as it's a highly refined paraffinic base stock (II+) like the Brad Penn.

How about Valvoline 20W 50 High Mileage, it does state it is part synthetic? I thought GTX HM was also part synthetic to lower "burn-off".

[cnavarro]

All the other "high-mileage" oils I tested had low Zn and P levels, Castrol GTX HM the only one with good levels. The other brands also had stuff normally found in stop leak and stop smoke products (Restore/Bardhal) , not what I want to see in new oil for a 911. The HM starts off thicker than the non HM, that's how they get better noack volatility :-)

[JFairman]

Originally Posted by movin

How about Valvoline 20W 50 High Mileage, it does state it is part synthetic? I thought GTX HM was also part synthetic to lower "burn-off".

Keep in mind they can put just one drop of synthetic oil in a quart of petroleum based oil and call it a synthetic blend.

[RWebb]

This lengthy and informative thread now has nearly 10,000 views. It might be wise to define some terms in a simple, intuitive fashion for the less technically astute who are watching the thread...

JFairman's comment re marketing def'ns is also a wise consideration.

HTHS - ??

vis = viscosity; this is a liquid property similar to 'thickness' - honey has a high viscosity; water has a low one. There are 2 ways to measure this property. It is important b/c if too high, the oil will not flow thru small holes to get where it is needed; but if too low, the oil will "break apart" and not lubricate.

cSt - centi-Stokes; the units used for one of the ways to measure viscosity; named in honor of the mathematician who worked out a fluid flow theorem that is much-hated by engineering students

film strength - the ability of a liquid to not "tear apart" at its surface

Zn - an important lubricant in oils; apparently EPA is trying to reduce it's concentration to improve catalytic converrter performance and longevity

P- phosphorus; we are not talking about elemental phosphorus, but a molecule with phosphorus in it; people are using the elemental symbol as a shorthand; it is important for lubrication and works with the Zn (somehow? catalytic?)

NMMA committee -- ??

[cnavarro]

HTHS = High Temperature High Shear viscosity, tested at 150C. Basically the film strength under the worse kind of load and conditions, especially at high temperature. Not driving in bumper to bumper traffic :-) Sorry I can't give you a better definition, it's not something that is very well defined, just a spec that is provided.

FYI, Porsche has a min 3.5 cSt requirement for this test for "recommended" oils. M1 barely scoots by with the min, of 3.6 cSt for the 0w40. There are many 0 and 5w40s with much higher HTHS viscosities than M1.

[RWebb]

"Sorry I can't give you a better definition, it's not something that is very well defined"

- no, I think that is perfect for most readers.


"M1 barely scoots..."
- is that the V-twin version; or the SL?

[rickdm]

Well, you guys asked for it! Since you are now discussing oils used in marine applications I thought I would link to this thread on oil in the offshore racing forums. It was sent to me by a friend who does offshore racing. His boat has two cast iron, push rod, 8 liter engines producing over 800hp each (over 100hp/liter in a push rod engine). He uses Mobil 1 V Twin 20W-50 for the same reasons we do.

http://www.offshoreonly.com/forums/showthread.php?t=107808

rickdm

[cnavarro]

The M1 I was referring to with the low-ish HTHS was the 0w40.

I looked up the MX4T Mobil 1 10w40 and it is 4.15 cSt. for the HTHS vis @ 150C. The V-Twin 20w50 is 5.94 cSt. MX4T has a TBN of 9.0 and V-Twin has 9.81.

Just for comparison's sake, Porsche recommends a TBN of 10.0 and M1 0w40 is 10.0, as is Brad Penn 20w50. Swepco if memory serves me for the 15w40 is in the ~14 TBN range.

[mtbguy]

I bought some Brad Penn Racing 20/50 from Charles and put it in this week. car now runs 10 degrees cooler than it did with VR-1 (street legal) 20/50. I am happy about this, but can anyone explain why????????????????

It also seems to be a bit smoother/quieter, (but you know how those things are subjective.)

[GothingNC]

Less Friction = Less Heat

[hcoles]

we are going into winter... = colder outside temps. :-)

[mtbguy]

Originally Posted by hcoles

we are going into winter... = colder outside temps. :-)

No, its not that. Im in the south where we have temperatures (and drought) beyond anything in recorded history. It was 86 degress outside the day I noticed the temperature lower with the new oil, and the A/C was actually running at the highest setting that day. I'm leaning towards the friction theory I think. I thought the Vr1 I had been using was decent, but it WAS the newer SM formulation, so less good stuff in it.

[cnavarro]

I can't say why the Brad Penn ran cooler - when I had a customer do in car testing of oils (with a full 24-channel datalogger), he did notice the engine ran smooth and lower oil temps with the Brad Penn compared to Castrol GTX. In the 800 mi segments he ran with each oil, the UOA showed the Brad Penn to hold up as well as M1 V-Twin and Amsoil Harley, with the bonus of having equally low wear metals in the UOA with the Brad Penn. That's how we found out what others had confirmed, that GTX is not very good. It used up about 45% of the Zn and P where the other oils had used up about 15%. GTX has also become a 30wt, where the other oils were spot on with the VOA viscosities.

If anyone ever questions the high temperature stability of Brad Penn, I have a neat example of how damn good it is. One of my customers has a F-prod 914, running the Brad Penn. He had an oil cooling issue and was running 320-400F oil temps during a single day - I think he said he got in about 6 hours of track time running these temps. He had a big oil pump, so had good oil pressure, even at 400F (gauge pegged), dry sump, about 15 quart capacity (~180hp four cylinder type 4). It was a backup motor, made of used parts, so he really didn't care if it died. It did end up floating a valve - the valve springs were toast after being boiled for hours, but amazingly, everything in the engine looked perfect, bearings included (which were new, coated by Calico). The Brad Penn did not smell burn nor did it thin out or thicken up. We were amazed. They really have their base stock nailed.