MGB & GT Forum

One of the readers states that Castrol is not friendly to cams without an addative. I am not sure what he is speaking of but I am concerned since I use Castrol and have used it for years. Does anyone know what the problem is here? How about synthetic oils...are they ok? Thanks

There is a LOT of debate on this.

Many of the modern fossil fuels no longer contain the same amount of the zinc additive that were were accustomed to having.

STP oil additive is a logical solution to this potential problem for our cars as it contains the additional zinc our engines appreciate.

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1952 MGTD - 1969 MGC - 1972 MGB - 1974&1/2 MGB/GT V8 conversion - 1978 MGB

mowog1@aol.com

Someone sent me an e-mail yesterday about this but I haven't had a chance to investigate it yet. Supposedly there is an additive ZDDT? that has been "requested" to be eliminated by the Feds. This additve is critical in cam/flat tappet break-in of new/rebuilt engines of our era. According to the e-mail, using a diesel oil like Shell's Rotella, get's around the problem and after initial break-in it's not an issue.

Keep in mind that this is all from one unsubstantiated e-mail.

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T. Keith Vezina
British Motoring Club New Orleans
1976 MGB, 1976 MGB Trailer & 1978 MGB V8

I use Castrol 20w50 in my 'B, and synthetic in my modern cars.

I don't know anything about Castrol trashing cams, but the oil pressure seems nice and steady when hot, and I don't see any evidence of cam problems - not that it would be easy to determine this without dismantling the engine. I can't imagine any quality oil of the correct grade and specification causing wear on the engine, as long as the oil and filter were changed regularly.

Synthetic is nice as the oil pressure comes up more quickly on a cold start - even after the car has been sitting for a while, as many of ours do from time to time. I have never seen it in 20w50, although there might be an appropriate weight of synthetic oil out there somewhere - perhaps aimed at diesel engines.

I haven't run it in the 'B though, as I am worried that I will end up with all kinds of oil leaks as it is so slippery. I figure it is best to avoid synthetic on any car where "water goes in the top, and oil comes out the bottom" for this reason.

Sounds like hype to me.

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Lord, please give me patience because if you give me strength I will have to ask for bail money, too

I would stay away from the diesel oils such as Rotella.

Valvoline 20w50 Racing oil still contains zinc additives (as it's marketed for off-road use). This is also what remains in STP in the blue bottle.

Apparently the green-folks feel that zinc is fouling the catalytic converters (similar to lead of years ago, and want it abolished. Probably the same folks who work for the big industrialists that receive credits allowing them to polute the air even more.

Even the medical profession is being hit....many asthma inhalers will no longer be available next year in their old formulation because of the fluorocarbon propellant (minimal) that they use.....

< sigh >

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1952 MGTD - 1969 MGC - 1972 MGB - 1974&1/2 MGB/GT V8 conversion - 1978 MGB

mowog1@aol.com

mowog1 Wrote:
Why? I would have thought that diesel service would be more demanding than your typical gasoline engine.

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T. Keith Vezina
British Motoring Club New Orleans
1976 MGB, 1976 MGB Trailer & 1978 MGB V8

All of the articles that I've recently read (there has been a gaggle of them on this board as well as the MG Enthusiast BBS) advise that the diesel oils lack many of the detergents (or the level of detergent) that our cars need as well.

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1952 MGTD - 1969 MGC - 1972 MGB - 1974&1/2 MGB/GT V8 conversion - 1978 MGB

mowog1@aol.com

So, adding STP will make up the zinc difference?

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Carl W. French
Alfred, Maine
Southern Maine LBC welfare shelter
67B will be in our will
73BGT Daily driver
72 Triumph Bonneville
Many more that change often

http://s5.photobucket.com/albums/y183/leylandauto/

<<ven the medical profession is being hit....many asthma inhalers will no longer be available next year in their old formulation because of the fluorocarbon propellant (minimal) that they use.....>>

sTEVEN bARNES WROTE A (sorry) SciFi novel awhile back called Darwin's Radio. (recommended)

COncept was that evolution happens not slowly with time but suddenly at the appearance of a threshold. Neandrathal (sp?) to Cro-Magum (sp?) in 1 generation not hundreds. And that current man is due for another change. RSN.

Maybe we'll have nose filters like gills, radiation shields like bony plates, and will be genetically disposed to vote Democratic<BG, D&RVVF>.

There is an article on this in th elast edition of the British Marque newspaper. It seems to be real. (Heard that at car club meet this morning - unfortunately Brit Marque has screwed up my subscription and hasn't sent me an issue in over 2 years!)

Carl, I don't know if the amount in one bottle of STP is equivalent to the level of zinc contained in *about* 4 quarts of *old* Castrol or not...I need a "round tuit" in order to take the time to go online and find that answer!



But...for "peace of mind", I'm using in in all of my cars (and the tractor) at present.

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1952 MGTD - 1969 MGC - 1972 MGB - 1974&1/2 MGB/GT V8 conversion - 1978 MGB

mowog1@aol.com

Oh, I didn't know that about diesel oils.

Here is the e-mail I recieved. I don't know this guy nor have I vetted anything in this e-mail so take it with a grain of salt.

Keith Ansell, President
Foreign Parts Positively, Inc.
www.ForeignPartsPositively.com
360-882-3596
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More:
At this time, late October 2006, it appears that our old staple, Castrol, has reduced the ZDDP in GTX to about half what it used to be. The safest bet right now seems to be either the use of Redline (synthetic) or Valvoline VR1. Today I purchased 7 quarts of Valvoline VR1 20W-50 at AutoZone for $2.79/quart.
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More from Keith Ansell:

Oil is Killing our cars Part II

Last month's report on this subject is turning out to be just the tip of the iceberg! Many publications have had this subject of zinc-dialkyl-dithiophosphate (ZDDP) covered in varying depths over the last few months. Some publications have even had conflicting stories when you compare one month's article with their next month's article! They are all ending up supporting our report.

I have had the good fortune to have the ear of quite a few leaders in the industry including some wonderful input from Castrol. We have been very reluctant to "dump" Castrol, as it has been such a great supporter of our cars and industry over the years. Castrol hasn't really abandoned our cars, just shifted to a more mass marketing mode. Many Castrol products are not appropriate for our cars today, some still are.

Now for the latest report:
#1 Castrol GTX 20W-50 is still good for our cars after break-in! 10W-40, 10W-30 and other grades are NOT good. Absolute NOT GOOD for any oil (Any Brand) that is marked "Energy Conserving" in the API "Donut" on the bottle, these oils are so low with ZDDP or other additives that they will destroy our cams. Virtually all "Diesel" rated oils are acceptable.

#2 Castrol HD 30 is a very good oil for break-in of new motors. This oil has one of the largest concentrations of ZDDP and Moly to conserve our cams and tappets.

#3 Only an unusual Castrol Syntec 20W-50 approaches the levels of protection we need when we look to the better synthetic lubricants. We are attempting to get this oil but will be using Redline 10W-40 or 10W-30 as these are lighter weights for better performance, flow volume, less drag and has the additive package we need.

#4 The trend today is to lighter weight oils to decrease drag, which increases mileage. Most of these seem to be the "Energy Conservation" oils that we cannot use.

#5 Redline oil and others are suggesting a 3,000-mile break-in for new engines! Proper seating of rings, with today's lubricants is taking that long to properly seal. Shifting to synthetics before that time will just burn a lot of oil and not run as well as hoped.

#6 The "Energy Conservation" trend was first lead by automakers to increase mileage numbers and secondly because the ZDDP and other chemicals degrade the catalytic converter after extended miles, increasing pollution. We don't have catalytic converters and the mileage gains are not that significant for most of us.

For you science buffs: ZDDP is a single polar molecule that is attracted to Iron based metals. The one polar end tends to "Stand" the molecule up on the metal surface that it is bonded to by heat and friction. This forms a sacrificial layer to protect the base metal of the cam and tappet from contacting each other. Only at very high pressures on a flat tappet cam is this necessary because the oil is squeezed/wiped from the surface. This high pressure is also present on the gudgeon pin (wrist pin) in diesel engines, therefore the need for ZDDP in diesel engines.

Second part of the equation is Molybdenum disulfide (Moly). The moly bonds to the zinc adding an additional, very slippery, sacrificial layer to the metal. I found out that too much of the moly will create problems; lack of this material reduces the effectiveness of the ZDDP. The percentage, by weight is from .01 to .02%, not much, but necessary.

Latest conclusions: Running our older, broken in engines on Castrol 20W-50 GTX is ok.
Break in a new engine for 3,000 miles on HD 30 Castrol.
New engines (after break-in) and fairly low mileage engines will do best with the Redline 10W-40 or 10W-30 synthetic.

We'll keep you apprised of any new findings! Happy motoring for now!

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T. Keith Vezina
British Motoring Club New Orleans
1976 MGB, 1976 MGB Trailer & 1978 MGB V8

Intersting read that parallels those I mentioned in the previous post. Thank you.

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1952 MGTD - 1969 MGC - 1972 MGB - 1974&1/2 MGB/GT V8 conversion - 1978 MGB

mowog1@aol.com

This is real. There have been several post about this and I joined in. I read all the articles and called many of the oil companies. Shell and Castrol admitted as much. Shell recommended Rotella although I decided to go to their VR-1 racing oil because its easier to find and actually has more ZDDP. I spoke to Redline, and although they are pretty pleased with themselves and their product, they said they've been watching this for a long time and been waiting for it to hit the critical level which it has now.

Read this as a start. http://www.hotrod.com/techarticles/engine/flat_tappet_cam_tech/index.html