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MG MGB Technical - Synthetic oil in an MGB?


Hey all,

Perhaps this topic has been beaten to death but I don't watch this board enough to know so I'll ask anyways...

In the interest of being able to use my '67 BGT in our cold Midwest winter months (only on salt-less days of course) I can't start it with the thick 20W-50 in the sump. I keep 10W-40 in bulk in my shop but I think it still may be too heavy for an MG in the winter. I figure that perhaps a good synthetic would allow for faster starts in the winter. We use Agip lubricants at my shop and stock a fully synthetic 5W-40 because all '98 and newer Mercedes are required to use synthetic oil. It would seem that a 5W-40 would be ideal for an MG with its broad temperature ability. The big thing though is that at $7.50 a quart (my cost!) it would be mighty expensive to add a quart every thousand miles! But for the rather limited use the car would see, I suppose it couldn't hurt the pocketbook that badly. Take this evening for instance; it's below zero here in Ohio and if the B were sitting outside there isn't a chance it would start but I think that with some synthetic and maybe a gear reduction starter (by the way, those of you who have those, how do you like them?) the car would reliably start in temps like this. Any ponderings or feedback would be greatly appreciated.


Rgds,
Aaron Greenberg
owner- MB Classic, LLC
Service and Restoration for Vintage Mercedes-Benz Automobiles
'65 TR4
'67 MGB-GT
'76 TR6
Aaron

What type of batteries do you have? Our roadster with two 6 volt types never wants to go in the cold, but my '67 GT with a single (not particularly large) modern 12V always went first bang even when well below freezing.

Just a thought.
--
Olly
Oliver Stephenson

Aaron-
I've been using Mobil 1 synthetic oil for 26 years. It doesn't thicken up at winter temperatures and doesn't thin out at high operating temperatures either. Engines crank over easily even when the thermometer dips to zero. Most engine wear takes place while the engine is warming up, so the effect on engine lifespan is considerable. My old 1978 Caprice Classic had no ring ridges in the cylinder bores at 138,000 miles and compression was still within factory specs when I sold it 1n 1995 with almost 200,000 miles on it! That made me a believer. However, 5W-40 is too thin. Use 15W/50 Mobil 1 instead. Less expensive than your Agip lubricant, too.
Steve S.

I'm using 10:30 synthetic right now thru the winter, Amsoil). Honestly I think it's too thin for an MG engine andwill be going to 10:40 or even 20:50 if I can find in synthetic. My Saab Turbo has 274K on it original with Mobil 1 all it's 19 years. Original Turbocharger too. Last year I did a Head Gasket and timing chain on this engine....the hone marks were STILL there, no ridges and it still doesn't use oil...case closed!
P J KELLY

There's synthetic and synthetic. Modern very low viscosities would be bad for the MGB as they have much larger bearing clearances then modern cars, but there are higher viscosities which are suitable. In non-synthetic 10W/40 was originally recommended for MGBs along with 10W/50 and 20W/50 for temps above -10C (15F), 10W/30, 10W/40 and 10W/50 for 10C to -20C (50F to -5F) and 5W/20 and 5W/30 for temps below -10C (15F).

Castrol in the UK do 15W/40 in GTX Magnatec, but there is little visible difference (other than a huge increase in price) over the same grade in non-synthetic, and a noticeable difference (lower pressures) than the old 15W/50 we used to get, so I have changed to a brand that still does 15W/50.
Paul Hunt

Castrol partial synthetic for diesel engines has more zinc for cam and lifter protection and is certified for gas engine use also. partial synthetic 15-40. Works great about $2.50 per quart (us).
Barry
Barry Parkinson

Forgot to tell my war story

I bought a 78 mgb with 132,000 miles on it (non overdrive) The car was very rough and barely ran because of bad valves. It had been a one owner car until the last 25,000 miles when it had been neglected.

the maintenance record showed Mobil 1 oil up to 105,000 miles. I pulled the head and there was virtually no cylinder taper and no perciptible ridge. The pistons slid right out just like a new engine. The head was something else, 1 exhaust valve had recessed almost 3/8". The cam was bad as well. The rod & main bearings and the crank were all in excellent condition - The main & rod journals were all within new factory specs.

Good lubrication helps.

Barry
Barry Parkinson

Always find this interesting for this type of thread:
I remember reading a few years back that Consumer Report did a year long test of various oils and change intervals with about 50 New York Checker Taxis. They used cheap oils, brand name oil to synthetics They used short intervals to extended intervals etc. etc.
Being they were NY taxis, the driving conditions were reasonable similar.At the end of the test they tore the engines down and came to the following conculsion.

It didn't matter much about the quality of oil, synthetic or conventional, cheap or exspensive. What matter most for wear was
the shorter intervals....interesting!

Kevin Wournell
K.D. WOURNELL

Aaron,

Excellant info provided by Martin altough Classics are near end

http://www.xpowerforums.com/Motor_Oil_FA_Questions.htm

Kevin,

I have a link somewhere to NY Cab test, but this is not stop start or performance vehicles.

Paul
Paul Wiley

K.D.

I recall that article - re-read Steve's contribution to this thread "Most engine wear takes place while the engine is warming up"

As you may know, Taxis are generally always warm or running. Each taxi is generaly is used 24/7 by up five drivers in a day.

I use Mobil 15w-50 year round. The difference between cold and hot oil pressure is smaller than with mineral oil. That is, cold oil pressure is lower and hot oil pressure is higher with synthetic.

I've used Mobil 1 in my 1994 Volvo 960 for over 160000 miles, my 1989 Volvo 245 with 216000 miles and my 2001 Honda Van with 67000 miles - all these cars do not burn oil and have the original engine.

Earlier this year I tried Royal Purple - because it's difficult to purchase, i switched back to Mobil.

rn
RN Lipow

We just had two of our Police Cars fail due to timing chains breaking due to no oil circulation MAYBE due to AMZOIL. When the valve covers were pulled off, the shop called me and ask if I would come look at the engine and that I might want to bring a camera. Boy, what I saw, you could hardly see the valve springs due to the 1" -1.5" of sludge that had stopped up everything in it. Two different mechanics say that it is due to the NON-DETERGENT Castrol that contains no cleaning agents. I am sending off a sample to an independent lab to see if we can determine the cause. The oil is changed at recommended intervals and are taken very good care of. Mileage--First Car 44000 Second Car 62000. I will post the labs findings when we get them back. I haven't seen an engine this bad since the Quaker State days.
Steve C.
LPD
Steve C.

The last thread should have said NON-DETERGENT AMZOIL
Steve C.

Taxi use isn't particularly relevant to general ownership becuse of the type of use, police cars even less so when used by 3 shifts in 24 hours. The worst conditions are granny getting the car out on an occasional sunny Sunday afternoon and pottering a couple of miles down the road for 30 years.
Paul Hunt

The Granny is the real test.

Real life Mobil test
http://neptune.spacebears.com/cars/stories/oil-life.html

New York Taxi Cabs updated by Amsoil, obviously not Police cars

http://www.authorized-amsoil-dealer-for-synthetic-motor-oil.com/amsoil_testimonies/satisfied_customers_cars/oil-comparison-using-new-york-taxi-cabs-with-amsoil-10w40-oil.html

"Most engine wear takes place while the engine is warming up"

Magnatec in UK is sold on this basis?

Paul
Paul

I think the most wear when you start up line is grossly exagerated. It was a sales pitch to sell teflon additives. To this day there is no proof they do anything other than empty your wallet.
In the good ole days cars had chokes that grossly richened the mixture while the car was cold. Over use could wash the oil off the cylinder walls and cause ring wear. The resulting contamination of the oil would reduce it's film strength. A half hour of running at temperature was needed to 1/ get the low output generators to charge the battery and 2/ to get the moisture and gasoline remnants boiled out of the lubricating oil.
Modernly the injectors only richen the mixture for starting for a very short period and only a moderate amount. Result, far less contamination of oil and little or no washing of cylinders.
The synthetic oils are much less affected by top end cylinder heat and are much less volatile, resulting in dramatically better upper cylinder lubrication and increased ring life. The greater lubricity (slipperiness) also reduces ring and bearing wear. Modern petroleum oils are near to Synthetics when poured from the can and far better than only a few years ago. Synthetics probably last longer. The EP (extreme pressure) characteristics between the two types of oil does not appear to be that great. Witness failed lifters on synthetic oil. The plain bearings in an engine are never dry and there is never evidence of seizing at start up, even when started with an empty oil filter after sitting for weeks. By the time a load is placed on the engine the pressure lube is there. The taxi test showed no teflon or synthetic advantage. The test was critiqued by Teflon people for not involving start up situations. The Teflon people have never produced such a study. I'm sure they have been conducted -- but for some reason never published. With modern detergent oils it is rare to see any meaningful deposits of gunk or carbon in the pan or rocker cover. I see Quaker State offers a guarantee for 250,000 miles against exess wear or failure by a lubricated part if you use their product and can prove you have regularly changed the oil and filter every 3,000 miles. They don't exclude engines that have lot's of cold starts.
Barry
Barry Parkinson

I worked for a company that made motor oil additives for almost every lube oil company in the world. The consensus was that synthetic was better especially in cold climates. However, that difference has shrunk considerably since the new "mineral" oils are quite enhanced by things such as hydrotreating and better refining. Synthetics are also better when you have concern about oxidation due to long term running hot. Typically this could be a differential not an engine as engine oils have antioxidants and get changed more often.

Also, synthetics take less viscosity index improvers to get the multiple viscosity ranges. These improvers are actually oil soluble rubber. These improvers can break down into deposits especially in the upper part of the piston under severe conditions.

So, synthetics are superior. But are they worth the cost? For most automotive engine applications probably not. They do last longer but how long is still open for debate. Sludge builds up in all oils and antiwear additives etc. do get depleted.

But, I don't think an MG is going to be happy with 5W30 oil. You'll need to go to 10W-40 or 20W-50.
Robert McCoy

Robert
Interesting comment on VI improver additives, this was always a big concern with the Mini and other BMC cars where the gearbox is in the sump and the shearing action of the gears could turn a 20w50 into a 10W30 in short order!

There is also the issue that modern cars have to meet the challenges of emissions and fuel economy, hence there is a compromise between lower viscosities and sacrificing some wear. Lower viscosity, lower drag, more efficient power transmission.

The real challenge in the UK is that cars are sold with service intervals of 12-15k miles or 12 months, and budget motorists and dealers with an eye to profit margins are using low cost oils. With the crowded roads, the engines idle quite a bit in traffic, or never properly warm up on local trips. And now some councils want us to switch our engines off when we're stood in traffic. So the poor old bearings and crank runs without hydrodynamic lubrication and into the boundary lubrication zone as the engine stops and starts more frequently. With a good quality oil and additive package, with regular changes, this damage will be minimised, but, hey, who cares - cheap credit deals mean that the average motorist probably will use the car upto 60-80k miles at the most, so why pay extra to look after the car for the second owner?

Martin
Martin ZT

Modern cars still need an enrichened mixture, it just doesn't involve a manual choke knob that was convenient for wimmin to pull out all the time and hang their handbags on. The increased wear during warm-up is not so much a matter of circulation as so many think and wonder about fitting pre-oilers, more the chemical changes like acidic corrosion that go on at the lower temperatures.

As well as switching off at traffic lights (which I believe has been compulsory in Switzerland (?) for many years) the powers that B are suggesting we all drive round in 3rd gear as an aid to not exceeding the speed limits. Maybe one will counteract the other ... or maybe we will all die that much sooner from global warming and lack of oil.
Paul Hunt


A pre oiler like accusump surely only improves circulation and not the low temp issue?

Interesting comment I read is that at the "coal face" the oil temp is a lot higher than sump - so is a low oil temp much of a concern?

Is it a general assumption that a older style engine esp Rover V8 produces more sludge than newer engines so the regular oil change is more important, but a regular change with Synthetic, subject to some provisos, is the best care of engine if not to wallet.

Also US users prob cover a lot higher average journey conditions than those in the UK, which may allow for extending the drain interval.

Paul
Paul Wiley

I have always thought a pre-oiler is simply to ensure oil is in the lines so that when it starts, although not up to pressure, it is immediately being pumped in as the crank turns. Obviously long periods of standing allows the oil to drain down despite the tackiness agents beloved of Magnatec, so a start-up will not have oil reaching the working parts for a few seconds, especially on B V engines with an inverted filter and possibly a poor, or non-existent anti-drain back valve?

There are a number of additives that work by clinging to the surfaces, such as the anti-wear, rust & corrosion inhibitors, and tackiness agents. The quality all-round oils take a compromise on allowing sufficient surface space to each of these. Other oils, (no names!) improve the one aspect at the expense of the others. I usually hear the arguement that that doesn't matter because with their additive the oil simply then needs to dissipate small amounts of heat as no wear takes place, and hence other addtive functions become redundant - Oh please! An engine is a complex mix of lubrication regimes with additional challenges from the combustion and fuel. Lubricant companies spend fortunes on research and often abandon ideas because of negative aspects, so stick with a quality product that meets the ACEA or API test criteria.

Aftermarket additives compete with existing additives for surface occupancy, and chemically can unbalance the equilibrium. Chlorinated Hydroccarbons are not new, but is being touted as an aftermarket additive and are an exceptional AW/EP additive but..... these are also potentially harmful when mixed with water from condensation and pose a greater handling problem when exhausted. In fact the gear oil s formulated in the 70s were phased out because they fell foul of the environmental laws.
Teflon is a great dry lubricant but can potentially block filters and oilways as can any other solid additive such as Borate, Moly or graphite. These are better Extreme Pressure additives in gears in high load, low speed applications. And in some instances, such as synchro rings and rolling element bearings require some friction to work, otherwise the ball slides, instead of rolling (think of walking on ice) with resultant flat spots.

Martin
Martin ZT

Martin

So tackiness = UMA from the moment you turn the key (good marketing!)

Circulation is prob not correct description but works when low oil pressure including oil surges.

Paul
Paul

This thread was discussed between 31/01/2004 and 04/02/2004

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