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MG MGA - Zinc ZDDP. Can we Summarize?

I've been out of the info loop for several years while my MGA was in a very slow process of having the motor and transmission rebuilt. Now the MGA is back on the road acquiring break in miles. I discovered the BBS archives discussing the possible problems of breaking in a new motor with the SM category motor oils that lo longer contains zinc additives ZDDP. I'm using Castrol GTX 20-50wt with a category rating of SM from a case purchased about two years ago. Also I have an older case of GTX 20-50wt rated SL. Would it be best to change and refill with the SL rated oil? The oil in the motor now contains the original cam assembly pre-lube that I believe contains some essential zinc compounds so perhaps its best to stay on plan and change the oil at 500 miles, making certain I use the SL rated Castrol GTX 20-50wt. at the time of the oil change? Has there been any new information about the theoretical risk of no zinc SM rated oil? -M.S.
Martin Straka

Martin,

I think that the best oil to use would be the Castrol Syntec which has a zinc additive. This gives you all the advantages of a syntheic oil, but with the zinc for older cars. There are several variations of Castrol Syntec oil, you must use the one marked for classic cars.
See the image with this post and another image on the next post.
This oil seems to be for sale only in the USA. There may be some legal problems selling it in other countries as it damages catalytic converters and must not be used on modern cars.

Mick


Mick Anderson

Another image is attached of the Castrol Syntec oil. This shows the "classic cars" label which must be present to get the correct oil.

Mick


Mick Anderson

Sorry to show my lack of knowledge on this interesting subject but two questions. Does this synthetic oil get round the usually held opinions of "experts" who have always told me to use old style mineral oil and not synthetic for the clearances and other design issues present in older engines? And, if the answer to that is in the affirmative, is it also good for a Twin Cam engine? Grateful for advice.
Bruce Mayo

Martin:

You might check out "Collector's Choice Engine Oil with ZDDP" at www.Moss Motors.com. They also have an additive, ZDDPlus that can be added to your regular oil, for example, Castrol 20w/50. One 4oz. bottle to 4 to 5 qts of oil.

Bob
Bob Ravich

I didn't want to use a synthetic oil, so I looked at other options. Not being a refining expert, I'm also leery of just dumping a ZDDP additive into the oil, my logic being that oil manufacturers have a more specificly formulated and measured system to integrate the ZDDP into the oil. I settled on Valvolive VR-1 Racing oil.

http://www.valvoline.com/pages/products/product_detail.asp?product=50 Ths "product info" link on the sidebar gives you the specs on ZDDP content, specific gravity, etc.

They also have a Conventional Racing oil, which they say is not for use in street engines. I assume it's because it has low detergent levels, among other things. In any case, I plan on using it to break in my next engine since low detergents and increased zinc are important to that process.

Mark

Mark J Michalak

A little background...A few years ago the EPA mandated a lower ZDDP zinc/phosphorus spec oil to extend the life of catalytic converters to the min. 125,000 miles. This new SM spec reduced the sped by about half, causing flat tappet gasoline engine failures to begin to appear. Car clubs like Porshe and Corvette clubs started raising questions and funded research programs for answers.
The following links to an article requested by the Porsche Club of America and quoted by many clubs regarding why the new SM specification was ordered by the EPA and why flat tappet camshaft engines are failing. Gasoline engines were the subject because diesel engines did not have emission controls until recently. This is a great article with good background and links.

http://www.lnengineering.com/oil.html

I rebuilt my 1500 about 15 years ago, broke it in and drove it with Castrol 20-50 GTX. I put about 200 miles a year on the car, changing the oil & filter every spring, no problems. I bought a new case of oil a year ago, changed it, and immediately the engine was noisier and rougher. I ran a few months and changed the oil and found fine metal on the magnetic drain plug. (A must for our engines as an impending failure indicator if nothing else). It happened again. I raised a question regarding this on this BBS and was advised that the metal was probably coming from the cam/tappet interface due to the new oils. That is exactly the case with my engine. I researched and found that long range Diesel engine oils were available (CI-4 old spec, CJ-4 new lower Zddp spec).
I changed to the relatively new Royal Purple synthetic oil. When I first changed from Castrol 20-40 GTX SM with about 500 miles on it to it I actually had to set the idle down about 300 rpm! Cold idle through hot was 6 psi greater with no wobble of the guage at hot idle.
No more metal in the oil plug magnet.

I'm sure that the new Castrol and others are just as effective, I just go for the best. Anything worth doing is worth doing to excess!
GrandPaFuzz



http://www.royalpurple.com/rp-testing-summaries.html
GrandPaFuzz


Russ Carnes

So an older manufactured oil that still has the SL rating contains the zinc? I've always been told not to use a synthetic oil during the break-in period.

Mark - How does a non detergent oil help during the break-in period?

-M.S.
Martin Straka

Synthetic oil lubricates too well for break in. During breakin the metal rings and the freshly honed cylinder walls wear against each other so they will fit together. Non detergent oil allows the rings to seat to the cylinder walls. With out proper seating of rings the engine will always use oil.
R J Brown

This is from an article I found on a classic car web site:

"There are still a few oils on the market that have adequate levels of ZDDP. These include Shell Rotella T - a conventional (mineral-based) oil that was originally formulated for diesel engines. Rotella T still contains 1,200 parts per million ZDDP, according to Shell - which is as much as five times the amount found in other oils. Don't sweat it that Rotella was/is "for diesels." It's also an excellent choice for older, non-emissions controlled engines with flat tappet cams that need their ZDDP. Rotella's also modestly priced and readily available at most any auto parts store. Shell also markets a synthetic version of Rotella that offers even more protection - as well as longevity and a 5W-40 viscosity for those who operate their vehicles in colder climates. Standard Rotella comes in a heavier 15W-40 blend.

Another choice - in a full synthetic - is Amsoil (www.amsoil.com) which carries a line of oils with ZDDP in popular viscosities such as 10W-40 and heavier 20W-50. Redline oil (www.redlineoil.com) is also still fine for older engines with flat tappet cams. Unfortunately, both Amsoil and Redline can be hard to find at your local store; but if you plan ahead, you can order a case from any one of multiple suppliers online and just keep a stash on hand"

Cheers,
GTF
G T Foster

Does the SL rating, being the most current rating in an old case of motor oil, mean that this oil was manufactured before the Zinc was taken out?

Likewise, does the SM rating, being the most current rating (newer than SL,) mean that this recently refined oil now conforms to the required removal of zinc?
Martin Straka

Not aware of an update.

There is probably only 1 Zn free oil on market Fuchs Titan GT1.

Zn is more tied into operating temperature range as ZDDP is temperature/pressure activated.

SM oils tend to have 4x ZDDP than oil in 1960 but less than SL.

Diesel oil has more ZDDP but also more detergent and these interact as polar and attracted to metal surface. There is also probably an interaction with Sulphur in fuel.

Race and Bike oils tend to use even more ZDDP.

SM oils are tested on flat tappet engines and need to meet wear requirements, however my interpretation is that it is biased towards normal road going engines with gentle motoring.
P WILEY

Hello All,
In a non synthetic oil Kendall GT-1 High Performance motor oil has sufficient Zinc and Phosphate. I was able to find it in Canada at a local CarQuest auto store. It should be easy to find in the US. The higher ZDDP is only in the 20W-50 grade. Apparently at one time GT-1 was a very popular racing oil. Here is a link to the product data sheet. Its a mile long.
http://tds.econocophillips.com/catalogs/Kendall%20Motor%20Oil/Automotive%20Engine%20Oils/Ken%20GT-1%20High%20Performance%20MO%20TDS%20Web.pdf

Ralph
Ralph

A synopsis of web research combined from when I was researching what oils to use form my MGA: The Pennzoil Company bought the Wolf's Head Company sometime back in the 70's and Kendall and Amalie merged together by a company called Witco. Then The Pennzoil Company bought Quaker State Oil Company to form the Pennzoil/Quaker State Company and they still made Wolf's Head oil. Witco sold the Kendall name to Conoco/Phillips and Amalie moved their operations to Tampa, FL. Witco then sold the Bradford Refinery to American Refinery Corp where they now make Brad Penn and Gulf oils. After Shell Oil purchased the Pennzoil/Quaker State Company, they sold the Wolf's Head name to the company that owns Amalie in Tampa.

The current Kendall GT-1 is not green. The only green oil that I know of from all of this is the Brad Penn Racing Oils.The "green" Kendall that many old timers talk about is now Brad Penn oil made by American Refining Group in Pennsylvania still using Pennsylvania feed stocks.

http://www.bradpennracing.com/

The Kendall name was bought by Conoco Phillips a few years ago. The Kendall you see on the shelves today is basically the same as 76, TropArtic, Conoco, Motorcraft etc. They are all Conoco Phillips oils with similar specs and are very good oils.

If you are wanting to use Kendall, buy whatever one of the above brands you get for the best price ...you are basically buying the same oil. Look carefully as they are SM rated with less ZDDP than the previous SI or SL.

BTW, I am still impressed with the new Royal Purple synthetic oil. I made the mistake of driving my A into Grass Valley just as school let out and sat in 100F traffic for almost an hour. That would have been catastrophic with my previous oil. With the RP the water temp stabilized at 200, the oil pressure REMAINED as STEADY with no drop in pressure, the engine cooled down to 185F with normal (35 hot idle, 65 hot 3500 rpm) quickly when we started moving again. The tappets are adjusted correctly, have not changed since the RP oil and the engine sounds quieter and runs better than with the Castrol GTX.

Russ AKA GrandPaFuzz
Russ Carnes

This thread was discussed between 06/07/2008 and 14/07/2008

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