The Cal-look Lounge

It's oil change time again and something weird happened.

I usually go to my local car parts shop and buy 10W-40 mineral oil and get on with it. In all honesty, I don't spend much time choosing: a few years back there were several brands but then last year there was only one, so I bought it (Valvoline Turbo) and in it went. Things got harder this year as they have no mineral oil at all  ???

So now I have to buy from the internet which means actually having to make a choice. So how do I choose..?

I have a street driven Bug, 1776cc with stock doghouse oil cooler, Berg 1.5qt deep sump, oil up to bottom mark on dipstick, Fumio heads (40 x 35.5), Engle 120, twin Dellorto DRLA40, CSP Python 42mm all the tinware fits nicely although I know I need to replace the rear engine bay seal as it's become ragged. VDO Cylinder Head temp gauge indicates 250-350F, 350 appearing when i've had my foot down on long steep hills. Berg dipstick sender light never comes on. I drive it all year and no racing.


I look for advice and find:

John Maher's Performance Guide: "Use a good quality SG multi-grade oil", "Don't use synthetic oil in your street car"
Gene Berg: "We run [] 10-30 weight in all street engines"

When built the motor came fitted it with 76 20W-50 and I used that for some years until it became much harder to find and the price kept creeping up.

So does the 'don't use synthetic' argument still apply with current synthetic oils? Is there any place for semi-synthetic oils in a street driven air cooled VW? Am I worrying too much - buy the mineral and get on with it?


A few hours of internet research and a little patriotism (I live in the UK) lead me to Morris Servol 15W-40 Performance Plus http://www.morrislubricantsonline.co.uk/servol-15w-40-performance-plus-motor-oil.html (http://www.morrislubricantsonline.co.uk/servol-15w-40-performance-plus-motor-oil.html). So choosing is almost coming down to what mineral oil I can find to buy rather than which one I want to use.

From other threads I can see that oil choice is pretty personal and there will be as many opinions as there are people on the lounge. I suppose i'm more interested in how you choose rather than what you use...

Jez

You want a oil that has plenty of zinc to protect the lifters. Many "modern" oil are very low on zinc.

You want to runt he thinnest oil you cam. For a new engine with a 26mm pump you should run 10W-30.

Thicker is not better. it will make your engine run hotter and cause excessive oil pressure... both not good.

This is what I use and it comes straight to your door.  It isn't cheap, but I guess that's the price you pay to keep your car going.  You may be able to find someone locally that stocks it.  Most shops only stock the 20-50.  That's why I order from LN Engineering.

http://www.lnengineering.com/store/catalog/bradpenn-penngrade-racing-10w30-motor-case-p-29.html

I use the same.. Brad Penn 10W-30.
(http://www.glenn-ring.com/temp/oil.jpg)

I run Liqui Moly 10W40 w/ MoS2

I only use synthetic oil, and have for almost 10 years in my 1776, 2017 and 2332 cc engines (all of these have the stock OEM German FI doghouse cooling system).

The two oils I use are Joe Gibbs 10W30 high zinc (for break-in) and then LubroMoly 5W40 thereafter:

http://store.concept1.ca/store/product/43854/Lubro-Moly-Oil-5w-40-%28505.00%29/

Look at the Millers range of oils, a UK company and they produce real good oils, 

cheers Richie

Ok, well the Brad Penn Grade 1 Racing oil and the Liquid Moly MoS2 are semi-synthetic. Neil68 has been using synthetic for a long time, so it doesn't seem like there is a need to avoid synthetic oils.

So what I need is something like a 10W-30 oil with decent amount of Zinc or some other lubricant like the MoS2.

Millers have a paper on ZDDP on their website and (http://www.millersoils.co.uk/automotive/useful-oil-facts.asp (http://www.millersoils.co.uk/automotive/useful-oil-facts.asp)) say: "All Millers Oils Motorsport and Classic formulations will continue to contain the optimum amount of ZDDP to give maximum possible protection against wear in highly loaded engine components.". So I'll take a look at their motorsport stuff.

Useful tips, thanks.

Jez

I live on the other side of the world, and so the oils I might readily suggest in my experience as being suitable mean jack when you can't get them over there, and really, who listens to a colonial anyway?  :D

I will though, perhaps remind you of the "good old days", when 1976 Beetles were new, and a really good quality oil was mineral and SF rated at best, and most oils had reasonable levels not just of zinc alone but a combination of additives designed to protect engines against "sliding surfaces" like flat tappets on cams, rockers on valve tips, and other old-fashioned crap that modern synthetics that cost an awful lot aren't usually designed to protect against (no matter how good their "shear index" is).

All is not lost however, because these good old fashioned mineral oils can usually still be found in the nearest motorbike shop, because the fine gentlemanly pursuit of motor-bicycling is still done with alarming regularity using air-cooled engines, and come in containers marked Castrol, or Mobil, or Silkolene (just the name excites me), or my favourite based purely on the picture on the box......., Motul. I do however understand that Motul is possibly French, and therefore I can understand your reluctance to purchase the product. Apparently there is a bit of history there I believe?  ;D

Oh yeah, you can also buy little economical bottles of stuff that has zinc as well as other stuff in it online very easily, which you add to a really cheap shitty oil from your local generic supermarket chain, to turn it into the sort of oil VW would have recommended for your ride when the dear old duck was brand new. Cool, huh? Now you don't have to walk into "The Auto Store" and get a blank and disbelieving look on the young blokes face when you try to explain what a VW Beetle is, let alone the fact the motor is up  it's bum.

As long as the honey stuff in the engine doesn't go black and gooey, you're all good really.  ;)

I use Brad Penn in my high performance aircooled engine , and yes it is semi-synthetic, but it has high levels of zinc and molybdenum. Standard synthetic oils meant for modern valvetrain engines have less anti-wear additives because they harm catalytic components. Stick with an oil designed for old engines. Avoid synthetic oil.

Motul 300V Smells good! Motul make a fine range of racing engine oils, they have a great viscosity range in the 300 v 0-20 to 60W
We use the 300V 15-50 in our To#¤ta 2zz Single seater race cars and have zero lubrication issues. I know there oil chemist, Kat's, Hes a japanese fellow, he works closely with TRD, Nismo and the superbike teams, Very interesting to talk about oils with him.
Another oil that I'm a great fan of is Lucas, I like there "tar" 20-50 racing oil, great in endurance engines where you need good pressure at elevated temps, also, heaps of Zinc.

On a side note, Motul does a classic oil with a high zinc content, aimed at cosworth bda's

I have been running amsoil z-rod oil made for flat tappet high performance engines. It has been a great product to date.

Z-ROD 10W-30 Synthetic Motor Oil
Modern Technology For Classic Cars
AMSOIL Z-ROD™ Synthetic Motor Oil is specially engineered for classic and high-performance vehicles. A high-zinc formulation to prevent wear on flat-tappet camshafts and other critical engine components, along with a proprietary blend of rust and corrosion inhibitors for added protection during long-term storage.

http://www.amsoil.com/shop/by-product/motor-oil/gasoline/z-rod-10w-30-synthetic-motor-oil/?code=ZRTQT-EA

I've used successfully only synthetic oils for years now. On hi-perf engines Gulf Racing 10W-60 or local Neste Oil 10W-50, on standard engines normal 10W-40 in different brands, or then the 10W-50 if it's mildly tuned or in harder use (eg. bus). Engine / cam break in - I've used zddp additive but after break-in oil change, just "raw" synthetics. My hardest used race engine (~150hp 2274cc for six hours endurance race) uses Gulf 10W-60 and it has lasted many years without noticeable wear - with Scat lifters and an Engle cam. The same goes with that engine's former Webcam / CB ultralight -combo. That engine also took us to SCC without problems - a fun but a bit tiresome 2000km trip on a -72 bus.

ValvolineVR1 racing oil has zinc in it....comes in 20/50 it's about 5 dollars US a quart

Do different countries have regulations on what ingredients can be used in oil? May be that oil in other parts of the world have different formulations? I know that certain products are not sold in California, but available in other states, because it violates law.

I use Kendall Racing Oil 20-50, I use to use the green stuff, seem pretty good to me.

Ted

Can someone please tell me why we are not supposed to use synthetic oil on our engines?

Thanks!

-BRBB-

It seems that synthetic oil doesn't have the same efficiency to cool our aircooled engine as mineral oil do. In our engine, oil not only lubricate but also cool our engine by traveling through oil cooler.  I asked to a oil reps from Total if he knew which oil to run in older engine. I ended up with Total Quartz 5000 in 15w40 or 20w50 grade.
The kind of grade will vary from an engine to another. Running an Hi po street engine or a bone stock 1600cc to daily commute will require a different kind of oil.

I choose the oil grade for my engines by checking the oil pressure at operating oil temp. I try to get it where VW want it.

Well that's almost exactly what John Maher said: "Using a synthetic oil will actually raise the cylinder head temperature". This was in the JMR performance guide" - my copy is (of course) falling apart and the price list within is dated March 1997. Synthetic oil sounded pretty exotic back then, but we are seventeen years further on now. I don't know anyone who works in the motor oil industry, but i'm guessing there has been lots of improvement in those years. Maybe the performance of these oils in an aircooled motor has changed?

For those who have switched what changes have you seen in cylinder head temps?

In a few weeks i'll be able to give you my experience because i've ordered a fully synthetic oil for my motor. I'll just have to remember not to change a single other thing :-)

I keep hearing good things about millers oil, but they do various ones. 
Millers Classic Performance 20W50 which is a mineral oil.  Suitable for higher mileage applications where oil consumption is a problem - High viscosity helps to reduce oil loss and leakage
Millers Classic sport 20W50 which is a Semi Synthetic,  Application: Use as received for lubrication of high performance engines manufactured from post war period to early 80s. Ideally suited to Aston Martin, Jaguar, Ferrari, Lotus and similar high specific output engines. Suitable for all discerning owners who want the best possible oil for their classic engine.
Millers Classic High Performance 15W50 Which is a fully synthetic.   Application: Use as received for engine lubrication of primarily pre1990 vehicles, both petrol and diesel, which were developed on the multigrade oils of their time.

All appear to have high levels of zinc.   But which to get.   I want to get one and then use that for life in the new engine.   And as you can buy it at halfords, it's something that if I run out, can be obtained in a hurry rather than relying on oil from online.    (Obviously I don't mean "run out" in the engine.   I'd have bigger issues there!.  :) )

Hi Jez,

If you speak to John Maher today he will give you a different opinion now to the use of fully synthetics. The last engine he built for me several year back he was strongly advising the use of Millers CFS 10-60. It may be something else now ?  Yes it was felt years ago that synthetic oils at the time did not absorb heat from the oil like minerals do therefore leading to higher head temps which are obviously bad news for us aircoolers. As others have mentioned already , today there seem to be several brands of synthetic oils that are suitable to use. But also you want to choose an oil with a ZDDP ( Zinc Additives Package ) again as others have already recommended.

Hope this helps ?

Shane.

It does, thanks. In fact it was Millers CFS I just ordered (though 10W-40)!

I've been reading about Harley Davidson engines too - the only air cooled engine I could immediately think of in production. I know these engines are different (for one thing, the H-D air cooled engines don't seem to have any forced cooling at all, I mean: no fan!) and I know precisely nothing about bikes in general so i'm sure there's many other differences which mean the comparison isn't perfect. H-D's official parts site carries both mineral and synthetic oils, both H-D branded: http://accessories.harley-davidson.eu/products/#!/oil-fluids (http://accessories.harley-davidson.eu/products/#!/oil-fluids)

The H-D owners seem to enjoy a discussion about oil just as we do: http://www.harley-performance.com/synthetic-oil.html (http://www.harley-performance.com/synthetic-oil.html). In this test, H-D mineral oil, H-D synthetic oil and then Amsoil synthetic oil were compared. The tester found the oil temperature was a couple of degrees cooler with H-D synthetic and then another 9 degrees cooler with Amsoil synthetic. Oil temperatures aren't everything either.

I'll see if I can construct a vaguely similar test - shouldn't be a problem with having to taxi my daughter to and from the local stables!

Jez

I went with Liqui Moly (Lubri Moly) 5W40 Synthetic because it's German and seems to have a good rep amongst the air cooled Porsche owners, etc. As soon as I get the chance I'm going to pick up some Liqui Moly Cera Tec. This is an additive that helps with metal on metal wear, which makes me think of the lifters and cam. My engine builder went straight for the Liqui Moly oil with a new engine rebuild recently (a 1776) after running some regular 10W30 for a few minutes. http://www.liqui-moly.de/liquimoly/produktdb.nsf/id/en_3721.html?Opendocument&land=GB&voilalang=e&voiladb=web.nsf

A bit theoretical here, but it's relative to the subject anlyway. Heat transfer to/from oil is twofoil - thermal conduction happens "inside engine" (external heat transfered to oil) and "outside" when heat is transfered from oil to air via oil cooler. You can increase heat transfer with oil via two methods (let's forget convection, pressure differences / pump losses, friction etc. this time to keep it simpler):

1. Changing the oil properties: decreasing thermal resistance of the oil eg. increasing thermal contact conductance of the oil

2. Increasing heat difference between oil and the engine:
 EITHER: Cooling the oil more, so it absorbs more heat as the heat difference is greater
 OR: Heating the oil more inside engine so that existing coolers operate more efficiently as the thermal diffecente between oil and air is greater

These parts "EITHER" and "OR" are quite simple here - install additional cooler, install piston oil squirters etc. But the part 1 is the one that's interesting here. As we know, the lubrication abilities of the synthetics are better than in minerals (thus generating a bit less heat), zddp and other pressure relative things are also discussed greatly, but is there somewhere data about thermal resistance of different oils, because it's about the only thing here that matters when transfering heat with oil.

Things that don't matter here (either "at all" or "not significantly"):

- Increasing oil flow (only if the engine has enough oil pressure to maintain oil film and not to generate greatly more heat from friction...)
- Temperature absorbing capability of the oil. It all goes down to heat _transfer_ capability of the oil: if the oil "can't absorb" the heat it allows to conduct, then it's temperature simply rises. It won't absorb as much heat from the engine, but in the same time, oil cools more in the radiator, thus there is equilibrium.

Quite old topic in different forum says for example: "...with additives, full synthetics are 10% more efficient in transfer of the heat by conduction and convection" but that's only one citation without references.

Very interesting reading.....

I have been using this Comma Classic 30SAE (straight 30 grade) in both the 65 & the 68 bus......

I did ALOT of freeway/motorway KM's this year in BOTH cars (approx 10,000!) in a wide range of weathers/temps and I found this a VERY VERY good oil, Low temps/good pressure etc etc....

This is actually the grade/type that the "Norwegian vw Handbooks" recommend.... Any thoughts/experience ??? :)

This might help some of you out, it's from a chap who is a oil chemist. Take from it what you will.

Background

There are four engine oil additive companies in the world; Afton, Infineum, Lubrizol and Oronite. They supply around 90 % of the additives used in engine oil in the entire world and 100 %of the additive packages used in oils with official claims. The other oils simply carry a manufacturing quality claim, in other words state that the oil is made to correct manufacturing specification, but does not have any tested performance in an engine.

The four additive companies not only supply individual additives, but design and test oils containing specific packages to meet engine oil claims. These additive packages and specific oil mixes are then sold to oil marketers where it is sold under commonly [and less commonly] known oil brands.

To state this more explicitly, the additive companies are responsible for taking an oil brief to a final oil that may be sold under a brand name, sometimes the larger oil marketers run their own programs internally, however the additive companies must still manufacture and supply the additives in order for this to happen.

I work for one of the four additive companies, and am writing this purely to provide factually accurate and unbiased information on engine oils; due to the number of oil marketers we supply, it is impossible to try to push or sell a single product through this article.

Oil technology

There are different grades of base stock that are used in an engine oil, they can be broken down as follows;

Group 1; oil sourced from crude oil with fairly low processing, high in sulfur and aromatic content. Viscosity changes greatly with temperature

Group 2; as group 1 with slightly more refining, resulting in less sulfur and less aromatic content.

Group 3. Highly processed crude oil, resulting in less temperature change in viscosity with temperature and low sulfur.

Group 4. Oil assembled synthetically, resulting in very controlled structure giving very low sulfur, very good viscosity control and low aromatic content

Group 5; everything else, typically very expensive and with specialist applications.



Small changes in viscosity with temperature means that the performance of the oil becomes very predictable at a range of temperatures, allowing it to maintain good lubrication and protection of engine parts.

Sulfur may form acidic species in the oil, which in turn reacts with and corrodes metal parts in the engine.

Aromatic content may be chemically attacked leading to viscosity growth of the oil and poor lubrication during the life of the oil, they could also lead to low temperature pumpability problems by forming gel structures, causing oil starvation.

There is disagreement as to whether group 3 oils are synthetic, they have a great degree of processing applied to them in comparison to group 1 and 2, in turn producing a much more controlled and higher performing base stock, however are sourced from crude oil and therefore not truly synthetic. Some countries allow the oil to be labeled as synthetic, others semi-synthetic, some not at all. As you will find out, it doesn’t make much of a difference.



Additive technology.

The base stock alone cannot adequately protect an engine, this can be seen in this report here: http://www.ilma.org/...qualityoils.pdf which compares an API SA oil [minimal performance claims, just base stock] with SL [a much later claims set requiring more in the oil than just base stock]

In order to add performance to the oil, the following chemicals are added:

Detergents

Added to remove varnish and deposits produced during the combustion process, most deposits and lacquer form in the cylinder and on the piston, at the hottest points as it’s typically formed from partially combusted fuel and engine oil.

Detergents also neutralise acids produced in the engine by the combustion process [fuels contain nitrogen and sulfur which form nitric and sulfuric acid in the engine], which prevents acidic corrosion of parts in the engine.

Anti-wear agents

Anti-wear agents decompose and form ‘sacrificial surfaces’ between rubbing contacts to protect the metal from wear. This is typically through the use of ZnDDP or ZDDP, the first commercial additive which demonstrated a clear benefit in the engine, and in use for around 80 years.

Dispersants

Incompletely combusted fuel, and insoluble particles will agglomerate and form highly structured networks in oil which causes viscosity to increase. Dispersants suspend these species in the oil and separate them, preventing viscosity increase.

Anti-oxidants

High temperature causes chemicals to split and turn into reactive species, metal in the engine acts as catalysts and increases the rate this happens. The reactive species attack anything available; oil, fuel and additives which causes degradation of the oil and viscosity increase. Anti-oxidants trap these attacking species to protect the oil

Viscosity modifiers

While high quality base stocks maintain some viscosity control with increasing temperature, it’s not sufficient to avoid very viscous oil at cold and very thin oil at high temperature. This leads to oil starvation and inadequate protection of the surfaces respectively. Viscosity modifiers collapse at low temperature but unfurl at high temperature, interacting with the base stock and creating an ordered structure in the oil, which increases viscosity. This allows an oil to be used all year around and provide engine protection over a wide range of temperatures

Pour point depressors

Poor quality base stocks or used oils form large gel structures at low temperature, when the engine is started the pump sucks up oil from the sump, if there are gel structures the oil will not flow and will cause oil starvation, pour point depressors break up the gel structures to ensure the oil flows.

Friction modifiers

Designed to reduce the energy losses created between rubbing metal surfaces, they are used more in America and Japan as the energy, and thus fuel saving is minor and therefore driven by legislation rather than a consumer saving.

Anti-foam

Prevents foaming in oil filters which can cause oil blockages.

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Why less is more

The problem with all these additives is they interact when they are combined, each group of additives have a wide range of chemicals that act at different temperatures, under different pressures or work on different part of chemical cycles. There are countless implications to consider when combining the additives, some examples:

More ZDDP should mean better anti-wear, however high ZDDP introduces more phosphorus, which can be burnt off and enter the catalytic converter, phosphorus poisons catalytic converters by blocking binding sites, resulting in a very expensive service by MOT time.

More dispersant means better viscosity control, but reacts with seals causing swelling, cracking and energy loss. Eventually this leads to an engine rebuild to replace all the failed parts.

More detergent means better deposit control, but the detergent is surface active and competes on metal surfaces with ZDDP, too much detergent and wear protection gets compromised.

What to look out for

All the attributes such as wear protection, viscosity control and deposit control are tested for, and indicated by the specification on the back of an oil. Oil sold in Europe will carry ACEA specification; the concept being with ACEA specification is a minimum standard for all oil, where any additional claims by engine manufacturers are added on top to boost performance. The ACEA claims are broken down as follows;

A/B mean suitable for petrol and diesel engines, C is suitable for engines with after treatment devices [such as diesel particulate filters and 3 way catalytic converters]. There is a number that follows the letter, where:

A1/B1 = good fuel economy with average engine performance

A3/B3 = normal fuel economy with average engine performance

A3/B4 = normal fuel economy with good engine performance

A5/B5 = good fuel economy with good engine performance

The date provided with the ACEA recommendations made for your car will be related to the date of manufacture, if you go for a newer year [eg. You are recommended ACEA ’04 and go for ACEA’10], you will have a better quality oil as the requirements improve each year.

A1/B1 and A5/B5 have reduced detergent inorder to allow for additional engine compatability, avoid them if your manual recommends A3/B3 or A3/B4. Always go for A3/B4 or A5/B5 compared to A3/B3 or A1/B1 respectively if given the choice, they offer tighter cam, tappet and piston wear limits than the former.

Proof

The oils with ACEA claims have undergone multiple engine tests designed to test the extreme point of operation of the engine, the current ACEA specification use the following tests:

TU5 high temperature deposit, ring sticking and oil thickening test [72 hour test]

Sequence VG low temperature sludge test[216 hour test]

TU3 Valve train wear test [100 hour test]

M271 sludge test

M111 fuel economy test

DV4 dispersancy test

OM646LA cam and tappet wear test [268hours]

VW TDI diesel piston cleanliness test [58hours]

Engine manufacturers have additional tests, some use bench tests to look at turbo charger deposits, others have much more stringent wear tests; the VW 504/507 specification requires a 650 hour weartest.

All these tests operate on the edge of what is considered normal operation, and typically much harsher than normal conditions. Any oil carrying the correct ACEA claims will be able to provide more than adequate protection for an engine, for additional protection I would recommend looking for an oil with a larger claim set, specifically one with VW claims as they typically have harsher limits.

There is no need to look for specialist engine oil; if it doesn’t have ACEA claims there’s no protection or proof that it is capable of protecting your engine. They are strict tests, and with a typical cost of around £70,000 a test, really do show confidence in the product.

ACEA Claims


Going back to the types of ACEA claims an oil carries, they can be broken down into two groups with two tiers;

Increased fuel economy
A1/B1 = average engine protection
A5/B5 = increased engine protection

Standard fuel economy
A3/B3 = average engine protection
A3/B4 = increased engine protection

Car fuel economy is dictated by legislation, there is only around a 1 % boost in fuel saving so the governing bodies have to legislate rather than sell the concept to the end user. Engine performance is almost always compromised to reach better fuel economy - not to the point that the engine oil is bad, simply that it won't perform as well as a cheaper, non-fuel saving oil.

As far specific applications go, there are a few key factors;

Rate of usage


Infrequent use leads to rust forming inside the engine; car manufacturers have the same problem between manufacturing and selling a car - they have specific corrosion tests that they include in the factory fill oil. Unfortunately it is very hard to source a factory fill oil, following the recommended service fill oil may provide you with the same oil type.

Type of usage


Track use compared to road use introduces very different stresses, engines used in track cars typically see hotter pistons and require greater oxidation control. Beware of 'true' race oils as the engines are expected to be rebuilt regularly so may not protect soft metal in bearings or may be too low in viscosity [lower viscosity = better energy transfer = more performance, however more stress]. Always ensure the oil has ACEA specifications too. I would suggest the best approach would be to run a normal oil and halve the change interval.
NA vs. Turbo vs. Supercharged


Honestly, there's not much difference here. Some oils are specified as turbo or supercharger compatible, this is usually for one of two reasons; marketing, or it's an oil sourced from America.

The key difference for the oil in forced induction engines is the charger bearings; they get to very high temperatures [particularly turbo chargers] and the flow of oil stops with the engine turning off, this leaves stationary oil to cook and form deposits on the bearings. With time these deposits cause the blade axis to wobble and eventually leads to the blades hitting the casing, causing catastrophic failure.

European engine oil has had to cope with turbocharged diesel engines for decades, American oil doesn't because diesel use is not widespread. This means that all ACEA oils assume the oil may have to cope with forced induction.

If you are using an uprated charger, the best oil you can get is one with VW 504/507 claims; this is one of the harshest tests for an oil and involves a 650 hour engine test, it also involves a series of four 'black box' engine tests where VW test out the next generation of engines, these inevitably include an iteration of their dual supercharged, turbocharged small capacity engine which is a severe test for charger deposit control.

Ok, the numbers are in....

I started with Valvoline Turbo 10W-40 mineral oil and swapped to Millers CFS 10W-40. The only other thing I did was to replace the filter (Fram HP-1 to K&N Gold 3001) and swapped the filter head so the oil lines were more neatly arranged. Would have very little effect on head temps, if any at all.

I have two test routes (to the same place)
a) 8 miles; 30/40 mph, climbing steadily, hottest at 40mph in 4th, foot flat on the floor.
b) 15 miles; 30/70mph, flat, steep climb, then flat; hottest at 60mph in 4th, foot 3/4 way down.

I'm using the VDO Cylinder head temp gauge, sender around plug at #3. I guess at 10 degrees margin of error as a combination of reading the gauge accurately whilst driving, traffic, reading at the exact same time on the trip. I noticed that cylinder head temps can change very fast so I tried to be accurate. Weather was pretty constant - by which I mean terrible - over the measurement period.

I measured the max temp on the way up the hills.
Arrival temp was measured once I parked up. I'm there for maybe 5 minutes before heading home.
Return temp was measured once I arrived back at home after coming down the hill.

Units are degrees Farenheit. If I say 300- I mean very slightly under. 300+ means very slightly over.

Mineral oil

Route / Max / Arrival / Return
a / 310 / 250- / 210
b / 350 / 260 / 220
a / 300+ / 250 / 230
b / 350- / 250+ / 220

So far so good - hotter on the faster, steeper hill. I see the peak temperatures for less than maybe twenty seconds.


Synthetic oil

Route / Max / Arrival / Return
a / 300+ / 250 / 200
b / 350- / 220 / 210
a / 300+ / 250- / 220
b / 340 / 250 / 220

Within the margin of error I estimated (10 degrees) there really isn't much difference. The last run (340) was slightly compromised as I had to momentarily back off as an Audi A6 driver failed to realise I was perfectly able to maintain the speed limit on the steep hill in my ancient VW and decided to pull out right in front of me. Bit surprised he didn't hear?!

So that's what I found out about my head temperatures between the two oils, in my car, at this time of year on these two hills with my head temp gauge.

just out of curiosity, what about oil temperature and pressure differences?

That is today definetly an old wives tale  :D

It would certainly have been more useful if I had oil temp and pressure gauges before doing the testing  ::)

So quoting me, and implying that my opinion has no merit, is your contribution to this thread? No facts or real world experiences?

Find more up to date info re fully synthetic oil in this article:
http://johnmaherracing.com/tech-talk/flat-cams-and-pitted-lifters-part-1/ (http://johnmaherracing.com/tech-talk/flat-cams-and-pitted-lifters-part-1/)

In the early days of synthetic oil, heat retention was an issue I.e. the oil wouldn't absorb heat to the same degree as mineral oil, allowing the heads to reach extremely high temperatures. There were also problems with oil leaks. All of those issues have been dealt with as oil technology has improved. Can't think of a single reason not to run the right fully synthetic oil in an aircooled VW engine today.

John is absolutely correct.

The heat retention of old Synthetic oils was a major problem especially with air/oil cooled engines not to mention degradability of base molecular structure and release of harmful particulates.

Bang for buck it's hard to beat Valvoline  VR1.

Great information!
thanks for that John!
When are you releasing part 2? :)

My builder hasn't had a cam go flat and says it's not the lifters or cam, it's the build that can cause problems. I'm hoping for the best for my engine that he built which has several thousand miles on it (webcam cam and lifters) running Liquimoly full synthetic. Another customer of his has had a couple cams go in his big engine, but he built the motor himself.