[Mgs] Update of MGA Lubrication Chart

Barney Gaylord barneymg at mgaguru.com
Wed Sep 2 11:14:01 MDT 2009


At 03:47 PM 9/1/2009 -0500, Robert J. Guinness wrote:
>Has anyone seen a modern conversion/substitution table for the old 
>NLA products listed in the MGA lubrication charts, as found on page 
>P2 of the Workshop manual.  A copy can be seen at: *http://tinyurl.com/orgbtg.
>....

There is nothing special about the lubricants by brand name, and most 
of the specifications are right there in the original chart.

Engine oil and air cleaners: 30W, 20W, 10W, depending on ambient temperature.
Back in the day these were mostly straight weight non-detergent oils, 
because that's what was widely available.  Today we have nice 
multi-weight detergent oils.  You can use any multi-weight grade the 
spans the straight weight spec.  For instance, 10W-30 can be used in 
place of 10W or 20W or 30W, so you no longer have to do seasonal oil 
changes.  If you're not terribly picky about a minor difference in 
fuel economy you can use 10W40 or 20W50 oil for a little better 
engine protection.  I wouldn't recommend 20W50 for sub-freezing 
temperatures, because it may be harder to crank and it makes for low 
oil pressure on startup until it warms up some.  I've been running 
20W50 for warm weather and 10W40 for cold weather in my MGA  for the 
last 230,000 miles.

I'm surprised the chart doesn't mention gearbox oil, but use engine 
oil in the gearbox, same stuff as in the engine and for all the same 
reasons.  The gearbox is not so sensitive to cold weather, so I use 
20W50 oil in the gearbox all year round.

Rear axle (hypoid) and steering gear: EP90 or EP80.
The key here is the "EP" spec, meaning Extreme Pressure".  This is to 
protect the high pressure point contact interface in the ring and 
pinion hypoid gears.  This is usually accomplished with Sulfur 
additives, which can give the oil that rotten egg smell.  Do not put 
EP oil in the gearbox, as it tends to ear brass synchro rings.  These 
days we have nice multi-weight EP oil in the form of EP85-90, EP80W90, EP75W90.

Water pump and lubrication nipples:  General purpose Lithium grease.
Nothing special here, just the common stuff you get in the cardboard 
cartridges for your modern grease gun.

Utility lubricant, S.U. Carburetor dampers, Oil can points, etc:
Again nothing special, just 20 weight engine oil to put in your hand 
held oil can.  Good also for distributor mechanical advance parts, 
generator rear bearing, and some water pumps that may have an oiler 
cap instead of a grease nipple, any place you see an oil can in the 
shop manual.

Upper cylinder lubricant:
This is the fun one.  Aside from all the fancy brand names, "Upper 
cylinder lubricant" is a generic description of a specific type of 
oil.  You can think of it as 100% dino oil with no fancy additives 
(at least the original version), 20 weight for most uses, 10 weight 
for cold weather.  The most common brand name from 1923 to present is 
"Marvel Mystery Oil".  http://www.marvelmysteryoil.com
More modern formulations may include a touch of solvent (kerosene for 
instance) to clean fuel injectors and remove carbon from combustion chambers.

In case you didn't know, you put this stuff in the gasoline (or apply 
with intake oil injector for running engine).  Modern engines do okay 
with 1000/1 mixing ratio for daily use, older engines or fuel systems 
of engines in need of a one time cleansing may like 500/1 mixing 
ratio for teh first tank of fuel.  That translates to 1-1/4 to 2-1/2 
ounces per 10 gallons of fuel.  If your car gets 25 mpg, it's 1 to 2 
ounces for every 200 miles.  That makes it hard to meter at such a 
low flow rate (see special oil metering devices).

This stuff was more important back in the day when fuel formulas 
might vary all over the map, as it may increase octane rating as well 
as help lubricate and clean parts in the combustion chamber, and it 
may decrease problems of wax or water in the fuel tank in cold and 
humid weather.  Some modern products are claimed to be formulated 
different for diesel engines vs. gasoline engines.  Modern engines 
might run 1/4 million miles without using this stuff, but it seems to 
be gaining popularity again since removal of lead from motor 
fuel.  It may still hold some benefit for use in older engines to 
prolong life of valves, valve seats, and valve guides.  Any claims 
that the engine might run smoother or have more power may be entirely 
subjective, or might have something to do with a worn out 
engine.  Any claims for increased fuel mileage probably cannot be 
proven.  It may very well make the engine last longer before it wears 
out, but any financial benefit would only be realized many years 
later when the engine might continue running beyond it's normal life 
expectancy.  I would not even venture to guess how much it might ad 
to the life of an engine (if any).  Like any fuel additive, if you 
abuse it (incorrect quantity for instance) it may cause more harm than good.


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