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MG MGB Technical - High ZDDP engine oils

A while ago I posted a note regarding engine oils and whether to use diesel oil given its generally higher ZDDP content. As it happens, the God's appeared to answer my prayer and I discovered Comma Sonic 20W50 which has a ZDDP level of 0.20% according to the datasheet compared to several so called 'classic' oils with ZDDP levels of only around 0.11%. I immediately noticed a smoother sounding engine and thought I had cracked it! It couldn't last of course, because I have now discovered that for some reason Comma have stopped producing Sonic oil and their so called 'classic oil' comes in at a measly 0.08%!! I have looked at several other 'classic' oils and some of them seem determined not even to give you ZDDP levels or keep it well hidden! Certainly none that I have found even approach that of the Sonic oil. Any thoughts on where I can get a suitable alternative? Thanks.
PJ Eades

No sooner had I posetd this link, than I looked back at my old post and there was a reference to Penrite Classic Light 20W-60. I have checked the data sheet on this and the ZDDP is 0.16% which is a lot healthier than most of the others, albeit more expensive. Any comments on this as an alternative anyone?
PJ Eades

I have used Valvoline VR1 racing oil for years. It has 0.14 percent zinc and 0.13 percent phosphorus. I buy 4 x 5 litres at a time from ebay.
Mike Howlett

Have used the Penrite 20w 60 in my V8, but usually in summer only.
In winter I have been using Morris' Golden Film 20w 50 but having checked their data they are not clear about the ZDDP content! Will maybe think again on the winter oil.
Allan Reeling

Penrite Classic light in my supercharged B and on a rebuild to upgrade to SC spec at 100,000 miles the crank and cam were still as new. Their web sight is very informitive as well. The classic oil of choice here in OZ. Denis
Denis4

It's the API rating you need to be looking at if you can't find out the zinc and potassium content, and the API rating should be on the can.

Funnily enough I've been using Comma Sonic - API SJ - in both mine for a couple of years, but being able to use the V8 quite often this winter I was not happy with what has been a very slow rise time, it's fine in the roadster. It also seems thicker when pouring than other 20W/50s I have used in the past.

Before that I used Halfords Enhanced Diesel 15W/40 also API SJ, but that has changed it's name to 'Mineral Petrol and Diesel Oil' and gone to API SL (although the Diesel rating is the same as before), which generally has lower zinc and potassium. It's produced by Comma, and they have advised me that the zinc is 0.11%, potassium 0.1%, and calcium 0.3% - not as good as before but better than some SLs, and in particular SM which should be avoided. Don't be concerned by the 'Diesel' in the name. Some are adamant that an oil is either for Petrol or Diesel, but as long as it specifies the API S grade for petrol as well as API C grade for Diesel it will be fine. I've got a couple of cans of Sonic left that I shall keep for the roadster, and use the Halfords for the V8.

I've not been able to find any 20W/50 to API SJ in the UK, only Russia and Iran!

I did try Valvoline VR1 but it came in the sort of plastic container that cheap reclaimed oils usually come in, only contained a gallon instead of the claimed 5L. I'm sure the engine got noisier during the year, and I just did not trust their website claims.

I wouldn't use a higher grade i.e. 60 when hot, that is going to be 'thicker' and so reduce the rate of flow through the bearings, not a good thing.

Paul Hunt

Incidentally Comma recommend Xflow SP to replace Sonic. This is also 20W/50, but API SL instead of SJ, with zinc, potassium and calcium the same as the Halfords 15W/40 Mineral and Petrol Oil.
Paul Hunt

Thanks Paul I spotted that also, the ZDDP on the XFlow is 0.11 instead of 0.20 for the Sonic! I did a quick search on Google and Millers do a Classic Sport 20w-50 Semi Synthetic Engine Oil which is an SJ. Haven't checked the prices yet though...and once again no ZDDP reading declared on the technical data sheet!
PJ Eades

Ha! That's coming up for me now. £40 for 5L from Halfords, £28 from various online sources. I've asked Millers.
Paul Hunt

Millers Classic 20W/50 API SJ and has 1250ppm of ZDDP, or 0.125% i.e. basically the same as the other SLs, less than the Comma Sonic SJ.

Incidentally I realised it was 15W/40 in SJ I couldn't find, not 20W/50.
Paul Hunt

The oil in mine doesn't hang around long enough to warrant anything too fancy. I'm using Wilko Everyday 20W50 but that is in no way a recommendation, as any form of description or specification is noticeably absent from the container. I'll probably go for Comma Motorway next time. Its liquid and looks fairly slippery, he says showing off his vast technical knowledge of multigrade motor oil.

Peter
P A Allen

I just use a good brand of oil and add a bottle of Rislone treatment with extra ZDDP. Don't know if it works on the cam, but it works in my head.


Cleve Crews

I use Castrol 4T 20W50 which is designed for HD use in off road ATVs and motorcycles. It has higher levels of ZDDP as it is designed for off road use and doesn't have to meet the requirements for vehicles driven everyday on public streets. My oil pressure runs about 5 to 10 psi higher and it contains a higher detergent package than regular oils. Most Diesel oils, produced today, have reduced ZDDP levels due to newer emission standards. RAY
rjm RAY

Ray,
Wonder if Harley brand oil would be good? It says to use it in the manual, but if not use Diesel HD oil.
Cleve Crews

This is a cyclical topic in classic car forums. I did a lot of research on it when it emerged and I know a number of contributors here did so as well.

One of the things I found was a warning offered regarding upper levels of zddp in oils for our cars. Knowledgeable people warned of risks from around 0.14/0.15 and upwards as potentially damaging, with a clear warning at the level of 0.2 concentration. It appears at that level the zddp breaks down prior to being able to form an effective protective film on wearing surfaces. It has something to do with the chemistry of the mix of elements in the zddp.

I also recall finding a tribology website research paper recording laboratory findings supportive of a problem at the 0.20 level and beyond. I have searched back on my saved files from then but unfortunately cannot locate that paper among the many files I dropped into computer memory.

Seeing PJ's opening post concentration reference of 0.2 made me think I should offer this info for what it is worth. Is there a risk of too much of a good thing I wonder, and should we be mindful when adding supplements to our oil?

Regards
Roger
R Taylor

Roger, Interesting point you make on too much of a good thing. It is becoming rather academic here in the UK though, as Comma Sonic cannot be had for love or money now and that is the only 20W-50 I have seen with ZDDP levels of 0.20%+. I will probably opt for the Penrite Classic Light, which has a 0.16% ZDDP rating.
Paul H - I wondered about Millers but haven't been able to find any reference to ZDDP in their data sheets. Where did you get 0.125% ZDDP from, I've obviously missed it?
Cheers
PJ
PJ Eades

I have just enquired with Millers and the best they
could come up with in an email was "our Classic 20w/50 has got over 1000ppm of ZDDP in." Hardly the accurate response I was looking for!
PJ Eades

I went back to Millers to query the figure, but they refused to give it as they say it is 'part of our formulation'. Can't see why it should be secret! Think I'll stick with Penrite, at least they give a figure and the API rating is SG!
PJ Eades

PJ, that's interesting. 1000ppm is 0.001. Certainly they said "more than", but I'm wondering whether the contact you had there really understood what you were asking?

Regards
Roger
R Taylor

I rather suspect they did... they were just avoiding the question....
PJ Eades

1000 is 0.1%. Don't forget that when you have finished dividing by 1,000,000 to convert from ppm you multiply by 100 to get percent.

I got that Millers ZDDP figure in response to an email to them asking about zinc and potassium, obviously a more informed respondent than you got :o)

The producers of ZDDPPlus quote a debunker of ZDDP as saying that concentrations of 0.2% "the ZDP started attacking the grain boundaries in the iron,
resulting in camshaft spalling." http://zddplus.labecon.com/TechBrief2%20-%20ZDDP%20and%20Cam%20Wear%20-%20Just%20Another%20Engine%20Oil%20Myth.pdf

ZDDPPlus go on to say "We have never been able to find the results of these tests on older engines." Their product "gives a 0.18% zinc and 0.13% phosphorus level when a single 4 oz bottle is added to a normal 5-quart oil change". That's American quarts i.e. 4.73 litres. I'm not being keen on putting something in my oil that hasn't been (AFAIK) independently tested so will stick to products that contain the higher concentrations to start with, albeit not quite as high as the above. Their product is primarily aimed at people who want to use API SM i.e. low zinc and potassium but have the added protection of the older SJ formulation.
Paul Hunt

MGA Guru has written on this http://mgaguru.com/mgtech/engine/of104a.htm
Geoff_MGB

Cleve, The Harley brand oil should have the same properties as the Castrol 4T, being designed for a 4 cycle air cooled engine. RAY
rjm RAY

Ray,
Everything I read about the Harley T3 says it keeps the bikes running cooler and protects the internal parts better than other oils, so they say. I always wondered if it works so well on an air cooled engine, how well would it protect my other engines requiring the same 20/50? At $10 usd per quart, it would have to do a noticeably better job. I use T3 in my Harley scooter just because they recomend it, not that there is anything better to my knowledge.

My little Harley scooter has almost the same displacement as my MGA!


Cleve Crews

For all engines with domed tappets, proper Molybdenum Disulphide (MoS2) Extreme Pressure assembly lubricants and a ZDDP (zinc dithiophosphate) oil additive (Moss Motors Part # 220-815) should be used during the break-in phase. The critical period for the camshaft and the tappets is during the initial break-in run, and perhaps through the first oil change. This is when it may benefit from elevated levels of ZDDP in the oil. ZDDP additive provides extra protection at the point of contact, preventing scuffing and thus helping the domed face of the tappet to properly mate with the lobe of the camshaft. Once the camshaft and the tappets have survived the initial break-in period, and perhaps the first 1,000 miles, it should do quite well with modern motor oil. Once the break-in phase is over, the use of this additive should be either carefully measured in relation to the ZDDP content of the oil with which it is combined, or discontinued. Be aware that this is not a case of “if a little is good, then more is better”. While the available data indicates that ZDDP in concentrations of 0.15% (1,500PPM) (PPM = Parts per Million) provides the needed additional protection against scuffing during the break-in period, these high concentrations will actually increase wear, due in part to chemical corrosion. At a concentration level of 0.20% (2,000 PPM), ZDDP has been found to attack the grain boundaries in iron. This is bad news for cylinder walls and iron piston rings. The better oils have a ZDDP content of 0.08% (800PPM), and this seems to be quite adequate for a BMC B Series engine once it has been properly broken in, although concentrations as high as 0.14% (1,400PPM) are acceptable. Check to see what the level of ZDDP is in your chosen oil and augment accordingly.

Of course, it makes good sense to start with a quality oil. Always check the API ratings of any oil that you are considering for purchase. If you look at the specifications on the containers, amongst the other markings you will then see an “API”, followed by a series of letter, S for gasoline (petrol) and C for diesel. Most gasoline (petrol) engine oils these days are rated either API SL or SM. Our B Series engines were originally designed when SB was the rating that was in force, and were produced through the SC, SD and SE ratings, with the SF, SG, SH. and SJ ratings for more recent engines (there are no SI or SK ratings). Up to and including the SJ rating they were all backwards-compatible, i.e., earlier engines get the benefits of the improved formulation from the later ratings as long as you continue to use the original viscosity, the modern very-low-viscosity oils being unsuitable for our B Series engines. After the SJ rated oils, the environmentalists managed to get the proportions of ZDDP (zinc dithiophosphate), phosphorus, and other additives reduced, partly for environmental reasons, and partly because they tend to poison catalytic converters over time, resulting in a reduction of their lifespan. Do not use an API “SL” or “SM” rated oil as they both have a very low ZDDP content and should be avoided, and as such they are known to cause problems. You should therefore stick to an API SJ rated oil or earlier, but the later the rating, the better. Castrol XL 20W-50 is an API SE rated oil, and thus is suitable, as is Halfords Classic 20W-50. Be aware that the lower viscosity oils also do not contain enough ZDDP to provide proper pressure protection for the tappets of the B Series engine. Castrol GTX High Mileage 15W-40 has an API SL rating, for example. A proper quantity of ZDDP additive should always be blended into these as well as with later oils, especially whenever such oils are used during the break-in period.
Stephen Strange

Thanks Stephen.

Charley
C R Huff

Stephen,
Always a pleasure to read one of your posts. I recently switched to Mobil one with an API of SL, SM - can you recommend an additive?
Thanks Again,

Bayard
Bayard DeNoie

The non-legislated, but administratively imposed, reduction in ZDDP in th3e US applies only to oils that are "energy saving" i.e. 0-5-maybe 10 weight at the lower end (I don't think 10 qualifies, though). And since API does not include the ILSAC ratings (where these limits are imposed), a 20W-50 oil can still meet SM API performance standards without meeting GF4/5 ILSAC standards. They are different "sanctioning bodies" if you will, and each imposes a fee for carrying the logo and for the testing necessary to qualify for that logo.

This is probably how VR1 and other oils provide "high" ZDDP content in an otherwise SM oil. 20W is not "energy" conserving thus does not qualify as a GF4/5 oil and thus need not conform to other parts of that spec.

I did not know the ZDDP matter was an issue in the UK. Has bureaucracy infected bureaucracy?<G>

WMT Townsend

Cats are cats everywhere, and SM and to some extent SL oils must have lower doses of these and other additives if they are not to be destroyed in short-order.

As for the rest, greenies get everywhere and cars of our age are low on the horizon for official 'protection' if not actively discouraged.
Paul Hunt

This thread was discussed between 30/03/2015 and 13/04/2015

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