Is Mobil DTE Oil Heay Medium the correct oil for the Sundstrand pump?

The metal tag on the Sundstrand pump says to use Mobil DTE Oil Heavy Medium, but that tag is 80 years old. Is the current Mobil DTE Oil Heavy Medium the correct lubricant? The pail also says Bearing and Circulating oil, ISO 68, and is the same oil I use in the 10EE gearbox.

It's still around and the right viscosity, I can't see any problems. Here's a copy and paste of the lowdown on it. Sounds good for a lot of things.

Mobil DTE Oil Heavy Medium is a premium performance ISO Viscosity Grade (VG) 68 circulating oil. DTE Oil Heavy Medium is designed for use in steam and hydro turbine sets, bearings, pumps and other systems where long service life is required. It is formulated from highly refined base stocks and an additive system that provide extremely high levels of thermal and chemical stability, rapid separation from water and excellent rust and corrosion protection. Additionally its air release properties help to make Mobil DTE Oil Heavy Medium an excellent choice where ISO VG 68 double inhibited R & O oils are recommended.

I underlined a relevant term.

rimcanyon said:

The metal tag on the Sundstrand pump says to use Mobil DTE Oil Heavy Medium, but that tag is 80 years old. Is the current Mobil DTE Oil Heavy Medium the correct lubricant? The pail also says Bearing and Circulating oil, ISO 68, and is the same oil I use in the 10EE gearbox.

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Since this is an hydraulic drive, I think I would go with Mobil DTE 26, ISO 68 hydraulic oil. McMaster carries it: McMaster part #2158K13

Cal

Cal Haines said:

Since this is an hydraulic drive, I think I would go with Mobil DTE 26, ISO 68 hydraulic oil. McMaster carries it: McMaster part #2158K13

Cal

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I don't know if iso68 is the correct viscosity for the Sundstrand pump. All I know is that the pump tag specifies 80 year old DTE heavy medium. I was hoping one of the people who rebuilt their Sundstrand pumps would comment.

To further muddy the waters, here are a couple of photos of Sundstrand pump tags. The first tag is from EE 8321, a late 1940 machine. It is the same tag I have on my machine, EE 7552 (7/1940). The second tag is from EE 7196 (2/1940), and calls for Gargoyle DTE Oil Light!





I called Exxon Mobil technical support, and could not get them to tell me the ISO viscosity of 1940 Gargoyle DTE Oil (Light or Heavy Medium). All their product information has been digitized, they don't have access to 1940 lubricant specs, so all they could tell me was that the current DTE Oil (Light or Heavy Medium) is equivalent. I would have preferred to make my own decision based on the additives and viscosities. I'll keep looking.

Mobil makes a couple of varieties of DTE ISO 68 hydraulic oil in addition to DTE Heavy Medium: Zinc-Based (DTE 26) which is general purpose wear-resistant, and non-zinc-based (DTE XL 68), which is manufactured with oil purification methods that are capable of preventing sludge even in long-time use at high temperature (according to product blurbs...). Sludge is probably a concern with the Sundstrand drive, I would guess that is the reason there is a manual filter wiper that is supposed to be turned daily, so XL may be the way to go.

Mobile has gone through a progression of names. It started out as The Vacuum Oil Company in 1866, became Socony-Vacuum Oil, then Mobile, now Exxon-Mobile. Over the years the products have also gone through a series of names: Gargoyle oil, became Vactra, became DTE (and there may have been other names in between).

I'm pretty sure that the viscosities of the "Heavy Medium" and "Light" versions of the product were never the same. Gargoyle Heavy Medium would have morphed into DTE Heavy Medium and Gargoyle Light into DTE Light. It's a real head scratcher why two fairly different viscosities would have been called for in this application. That's a question for an old-time hydraulic pump expert--way beyond my pay grade.

Cal

Cal, I think you meant Mobil. Their tech support said virtually the same thing about the company history. However, modernization, digitization, and a younger generation who think they know everything, and aren't about to get out of their chair to go into the printed library and do some basic research in old product specs, combine to mediocrity.

rimcanyon said:

Cal, I think you meant Mobil. Their tech support said virtually the same thing about the company history. However, modernization, digitization, and a younger generation who think they know everything, and aren't about to get out of their chair to go into the printed library and do some basic research in old product specs, combine to mediocrity.

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Correct, Mobil. No, their tech support won't be able to help you here.

Sundstrand is still around (link). Have you tried them?

Cal

When I bought this machine and did the initial clean-up and maintenance, 25 years ago, I called Sundstrand. They were even then unfamiliar with the drive unit used on the 10EE, and said that division of the company had been sold off years before. I think others have tracked down the successor company, but I am not sure what it is.

I called Exxon Mobil technical support, and could not get them to tell me the ISO viscosity of 1940 Gargoyle DTE Oil (Light or Heavy Medium).

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From 1984 Brief Product Descriptions

Light is ISO 32
Medium is ISO 46
Heavy Medium is ISO 68
Heavy is ISO 100
Extra Heavy is ISO 150
BB is ISO 220
AA is ISO 320
HH is ISO 460 (man, that must be real Glop!)

I have no doubt that older names have the same general "weights", even if ISO has not come along yet

My '56 K&T 2CH seems to like the modern equivalent to Gargoyle Heavy Medium emblazoned on its tag near the knee fill

The original spec was for "Gargoyle DTE (Socony-Vacuum Oil Co) Heavy Medium Oil or equivalent (Viscosity 325 S.S.U. at 100 degF)). Crossing that to hydraulic circulating oils nowadays that's a Mobil DTE 26 off my shelf. From Industrial Lubricants Cross-reference Charts – Glazeen Industrial Lubricants

rke[pler said:

The original spec was for "Gargoyle DTE (Socony-Vacuum Oil Co) Heavy Medium Oil or equivalent (Viscosity 325 S.S.U. at 100 degF)). Crossing that to hydraulic circulating oils nowadays that's a Mobil DTE 26 off my shelf. From Industrial Lubricants Cross-reference Charts – Glazeen Industrial Lubricants

Anti-Wear Hydraulic Oil

68

284-346

Perlube AW-68

Tribol 943 AW 68

Renolin AW 68

DTE 26; Hyd 68

Tellus Plus 68

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Thank you Russ! You did better than Mobil technical support. However, the numbers are hard to compare. The DTE 26 viscosity is at 10 degF, and the Gargoyle is at 100 degF. At least they are both Sayboldt viscosities (SUS). I also looked at DTE XL 68, which has a Kinematic viscosity of 68.4 at 40 degC (104 degF). According to one online calculator that corresponds to a viscosity of 317 SUS at 100 degF. So I think it is a good match.

I am also planning on disassembling the unit for a cleaning and to see what is worn. After 80 years, it needs a basic service.

rimcanyon said:

Thank you Russ! You did better than Mobil technical support. However, the numbers are hard to compare. The DTE 26 viscosity is at 10 degF, and the Gargoyle is at 100 degF. At least they are both Sayboldt viscosities (SUS). I also looked at DTE XL 68, which has a Kinematic viscosity of 68.4 at 40 degC (104 degF). According to one online calculator that corresponds to a viscosity of 317 SUS at 100 degF. So I think it is a good match.

I am also planning on disassembling the unit for a cleaning and to see what is worn. After 80 years, it needs a basic service.

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I think you have the Sunstrand data that's available?

rke[pler said:

I think you have the Sunstrand data that's available?

View attachment 281120

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Yes, thanks to you. I got a copy of that a decade or more ago from you.

Dave