By Staff
1 / 2
2 / 2
An ad for Balso oils from the March 1919 issue of Tractor and Gas Engine Review.

The following was a recent topic on SmokStak, which can be found
on the Internet at: As ever,
various individuals started, commented on and concluded the
following bulletin board thread.

What’s the best bearing grease?

I’d just like to know what you guys use for grease on your
main bearings. The grease I’m currently using is too thin and
the bearings heat up. I believe the grease is just being flung out
of the bearings. And no, the bearings are not too tight, they have
three to four thousandths clearance. Thanks in advance for any
advice. – Andy

Andy, I use the same grease I use for my big truck. It’s
Retinax by Shell; a good, heavy red grease. I’ve never had the
problem you’re having, but if you’re running them for long
periods of time and they are getting slightly warm, that’s
normal. – Mark

The lithium grease they use on front wheel bearings for cars
with disc brakes will take the heat, and keep the bearings lubed.
You can get it at any parts store. -Chuck

You might want to try Lucas grease. It is sticky and won’t
fling itself all over your engine. It also stands up well to heat.
It is used in a lot of big trucks and in race cars. – Mike

I may be wrong, but Kendall blue grease is about the only one
left that is entirely petroleum based, not soap based. – Bob

I have found that if I have a question about lubricants I call
our local commercial lubricant dealer. Most of them will sell a
case of grease to anyone. They will also be happy to give technical
information as to temperature range, rotational or longitudinal
speed, clearances, etc., and what would be the best grease for an
application. They normally get a big thrill out of helping us
figure out what will work best in these old engines and

I sent down Rumely lubricant data sheets on suggested lubricants
for their engines and transmissions. After a few days our local
Mobil lubricants dealer reported back to me that they had found
comparable lubricants for all of Rumely’s recommended oils.
They cross-referenced a 60 weight engine oil that is made for use
in kerosene burning engines. This oil is the same as Rumely’s
original oil of 80 years ago. There is one jet engine that still
requires the same oil. They were even able to find thermal transfer
oil for the radiator of the same viscosity and additives as
originally required by Rumely. If they ask what company you are
with, tell them it is ‘your name restorations,’ or
something like that, and pay in cash.

One thing to remember: As the last poster said, most of
today’s greases are soap based, and Rule #1 is never mix soap
types. This means don’t mix red grease with white grease, black
grease, blue, green or whatever. Clean your application thoroughly
before using a different type of grease. – Mark

Seems like one of the owner’s manuals for Hercules engines
said ‘Do Not Use Axle grease.’ It also seems that’s
what we’re all using now, as that’s all that’s readily
available. I would like to find some of the old yellow
paraffin-based low melting point grease that was used way back
when. – Bob

Just a few thoughts on grease. Today’s wheel bearing greases
are optimum for ball bearings. They work best in very thin films
and in that application are very effective. If you are lubricating
a wagon axle, any grease will work fine. Moly greases are very good
in slow speed applications where the clearances are 0.002-inch to

As you know, the moly works into the metal surfaces and provides
enhanced lubrication when there is the potential for metal-to-metal
contact. The reason moly is not recommended for ball bearings is
because the moly can build up on bearing race surfaces and reduce
bearing clearances enough to cause bearing failure. Some years back
the Model A Ford club recommended a moly grease for rear axle ball
bearings. A rash of axle bearing failures followed, which were
traced to moly build-up on the races. It is in fact an irregular
build-up of the moly and forms patches on the races, and it had the
same effect as dirt in the bearing. So don’t use moly or any
moly additive on any ball or roller bearing application. This
includes transmissions, too.

On the other hand, there are real benefits to using moly grease
on our engines, since most bearings are operating with 0.003-inch
to 0.005-inch clearances and the moly will protect the bearing and
shaft with a molecular coating of moly.

Lubriplate makes a moly grease used for construction machines
and other types of exposed gears and bearings. It is tacky and will
not spray out of bearings or off of open gears. It is called No.
3000 Heavy Duty Tacky Moly Grease (part # 10108-098). A large tube
costs about $3.50 and can be found at any bearing supply house or
construction machine supplier. This grease is black, soft and very
sticky. – Sherm

Andy, I use this grease, I bought a five-pound can at a surplus
shop. It works very well for me. It’s a ‘short’ grease
and it stays in place. When you use long-threaded grease it works
itself out the bearings. The following text goes with the grease.
‘Aero Shell Grease 14 is the leading multipurpose helicopter
grease used for most helicopter main and tail rotor bearings (where
specified). It is made with mineral base oil and a calcium soap
thickener, which provides outstanding protection against moisture,
corrosion and fretting. It has a useful temperature range of -65 F
(-54 C) to +200 F (+93 C). Aero Shell Grease 14 is qualified under
MIL-G-25537C specification.’ – Sixm John

Thanks for all the advice, guys. Would have thanked you sooner,
but the computer caught a bug. – Andy

All the engines I’ve restored have had various hunks of bad
stuff in the bottom of the grease cups. This stuff is old, hardened
grease mixed with dirt, sawdust or whatever was in the environment
the old engine worked in. Keep in mind that many of these engines
worked through the Depression, when food on the table might have
been more important than oil or grease for the engine. Many of them
ran without the daily or hourly lube job you see happening at our
engine shows. Clean the grease cups, right down to the bottom, and
run a cleaning stick through the bottom hole. Your engine
restoration will last longer without the dirt in the bearings, no
matter what your choice of grease. – Harry

‘Seems like one of the owner’s manuals for Hercules
engines said ‘Do Not Use Axle Grease.”

SmokStak is an engine conversation bulletin board and is part of
the Old Engine series of Web sites that started in 1995 as
‘Harry’s Old Engine.’ Harry Matthews is a retired
electronic engineer and gas engine collector from Oswego, N.Y., now
residing in Sarasota, Fla.

Gas Engine Magazine
Gas Engine Magazine
Preserving the History of Internal Combustion Engines