1928 Seagrave oil spec??

[Retro]

I received the email below from a relative helping to restore an antique fire truck.

Our fire department is restoring a 1923 Seagrave pumping engine.
It is powered by a 6-cylinder, "T" head gas engine displacing 1720 c.i.
We have found a copy of the lubrication manual from that era.
It was prepared by the Vacuum Oil Co. of New York in collaboration with
Seagrave.
They recommend "Gargoyle Mobiloil" grades A, B & C for the various driveline
components.
Could you provide the current equivalents to these lubricants?
Any direction or information will be greatly appreciated.
Thank you,
Monessen VFD #1

In my research Type C is the currently available 600W, however an equivalent to Type A and B eludes me. I know Type A is recommended for winter use and B for summer. The engine has been completely rebuilt so sludge will not be an issue. The flat tappet design may be an issue with new oils with reduced ZDDP. I contacted TechSupport at ExxonMobil with no results. I was thinking of Rotella 15w-40 with a break-in additive. Opinions and data would be appreciated. Thanks

 

[Chris142]

I dont think they had much for antiwear addatives back then. Mostly just mineral oils in SAE10,20,and 30 for engine oils.

I'd guess any oil even todays SM oil would have more antiwear addatives than oil did 90 years ago.

 

[Garak]

Originally Posted By: Retro
I was thinking of Rotella 15w-40 with a break-in additive. Opinions and data would be appreciated.


Even SM rated Rotella 15w-40 should have more than sufficient ZDDP.

 

[Retro]

I'm no so worried about lifter wear as the springs are not as heavy as on later engines and additives can correct any shortcomings. What I am really looking for is an equivalent SAE viscosity for Type A and Type B motor oils. Thanks.

 

[Jim Allen]

I think I can be of help.

Engine Lubricants:
I have the manuals for M1917 FWD Model B, and a M1918 Nash Quad, plus some other vintage truck resources. In them, they equate is the engine oils as "light," "medium" and "Heavy" with an equivalent SUS rating @ 100F. If I use my BITOG viscosity chart, they convert to approximately these viscosities as listed below. The manual says the Light oil is to be used only in very cold weather. The Medium is the general use in winter or for break in of new engines. The Heavy oil is for use in summer or for old, worn engines:

Light= 170-230 SUS @ 100F= 10W into the low grade 20 range
Medium= 270-330 SUS @ 100F= 20 grade
Heavy= 470-530 SUS @ 100F= high grade 30 into low 40 grade

I think the A, B and C specs you mention may equate to Light Medium and Heavy. I know many antigque truck owners that use 30 and 40 grade mono viscosity oils. If you have to hand crank, you want the grade 30. I have been told, but cannot verify, that those old engines are shear monsters and will rapidly shear down multigrades. On the other hand, a multigrade would make hand starting much easier, plus be easier on the fragile and weak electric start systems of the era.If the truck is a "baby" (a dang big one!) then the oil might never be worked hard or be in there long enough enough to shear (assuming the stories are true). You can still find CI rated engine oil, and I think that's plenty of ZDDP. Frankly, considering what the period oils were like (no ZDDP at all!), even CJ-4 likely has more than enough ZDDP. Didn't Seagraves use a Wisconsin T-head six?


Axle Lubricants:
In the old manuals, the axles (generally non-hypoid bevel gears) are spec'ed for something called "Non-FLuid Transmission Lubricant" equivalent to "#00" grease, which is equivalent to 38 cSt @ 100 or 140 grade gear oil. You can buy 00 grease (ISO 460) from many sources. I know several old truck guys that use 140 grade gear oil. BTW, the old manuals tell you how to mix up your own gear oil starting with a 20 grade mineral oil, adding 10 percent Saponifiable fat (tallow oil, neatsfoot oil, lard oil or horse oil - calcium soaps, they call it all of that). Bet it smells just wunnerful.

Transmission:
For Transmission oil, they list 195-220 SUS @ 100, which equates to approximately a 75W grade gear oil. I'll bet a 75W80 GL4 oil would be great there.

Hope this helps.

 

[Retro]

Jim--Thanks alot. The folks down at the station will appreciate the information. Best to you

 

[Jim Allen]

Retro: Forgot to add something to the post above. If the rear axle has a lot of bronze in it (which some did in those days), it may be better off with #00 grease than 140 grade gear oil. A typical sulphur phosphorus gear oil can attack the brass/bronze parts.

 

[addyguy]

Wow - that's an old truck!

Honestly, I'd be more concerned with having the right gear/drivleine lubricant in it.

Engine oils back then had next to no additives, so any oil you can get will be light years ahead. All sludge and debris has been cleaned out by the re-build, so any 15W-40 should keep the engine clean and rust-free, and be 'close' to what was originally used.