Gear Oil For Corrosion Inhibitor Pump Mechanism. 4

[Kaadm]

Hello,

I would be gratfeul if someone could advive me if the SAE 75W 90 oil can be replaced by SAE 10W 40.

I've asked this question as there are some pumps at site where I work that need the periodic change of the gear oil (75w 90)

and this later is not available. We do only have 10W 40 at the moment.

Many thanks,

Adem

 

[geesamand]

10w-40 is a motor oil. It will typically have anti-wear additives.

75w-90 is a gear oil. It will typically have extreme pressure additives. It is available at any auto parts store.

Although the viscosities are similar, the formulations probably are not. I would not consider them a substitute.

 

[tbuelna]

I would be gratfeul if someone could advive me if the SAE 75W 90 oil can be replaced by SAE 10W 40.

You could use the 10W-40 oil in your gearbox in an emergency situation. But even then you would need to be very careful about the speed and loads you operate the gearbox at if you wish to avoid damage. Your oil lubed gearbox is designed to operate with a certain minimum dynamic oil film thickness at each of the bearing and gear contacts. Oil properties like dynamic viscosity are an important factor with regards to operating oil film thickness. If the operating oil film thickness is substantially reduced below what the gear/bearing contact was designed for, a scoring/scuffing failure can quickly occur. As geesamand noted, gear oils have specific EP additives to provide added protection from scoring/scuffing damage during periods when it is more likely to occur, such as start-up or low-speed, high-load operation.

 

[Kaadm]

geesamand & Tbuelna,

Thank you for your reply.

I understand now that we can have a similar oils characteristics but each is designed

for an appropriate application as they have different additives.

I mean the oil usage is based on the additives (EP,AW..etc) not on the characteristics.

Please correct me if I am wrong.

Many thanks.

 

[Tmoose]

Is gear oil not available, or gear oil with that viscosity rating/

In the unlikely event there are hypoid gears in your device they need hypoid oil, not motor oil.

I'd think the owner's manual or certainly the manuacturer has a list of equivalents and acceptable substitutes.

 

[Kaadm]

Hello,

Yes, the gear oil is not vailable within the storeroom.

The equivalents oil recommended by the manufacture are:

ARAL HYP SYNTH, DEA Deager SX 75W-90, ESSO GX 75W-90, SHELL HD 75W-90.

All of these are not available at the momment.

My understanding is that the AW additives within the 10W40 create a film against

metals which prevent metal to metal contact. as well as for the EP additives in

75W90,they create a film against metals to prevent high pressure oil affecting metal

surface.My question is,is it because the film created by 75W90 strongest than the film

created by 10W40 we can not replace 75W90 by 10W40? or it has a relation with the

cleaning factor..etc?

Many thanks to everyone.

Regards

 

[Tmoose]

Hi Adamia,

Gear oil is Not available in YOUR storeroom, or the storeroom of any industrial supply place local enough to consider?

Viscosity is very important.

http://www.synlube.com/images/viscosity_table_2.jpg

But gear oil has some claimed "special" properties that you equipment //might// actually need.

 

[Kaadm]

Hi Tmoose,

Thank you for the link.

The oil is not available in our site storeroom at the moment.

Regards

 

[MikeHalloran]

Substituting motor oil for gear oil is not a good idea, as has been pointed out repeatedly. ... and perhaps too politely, as you do not seem to be getting the point.

Somebody needs to go buy the right gear oil.
That would normally be the job of the storekeeper, or his/her supervisor, or a related buyer.

If they're not aware of the need for gear oil, it would be appropriate for you to call it to their attention.

If they are aware of the need and are not taking steps to meet it, you should be escalating the problem so that the appropriate person takes action.




Mike Halloran
Pembroke Pines, FL, USA

 

[tbuelna]

....My understanding is that the AW additives within the 10W40 create a film against metals which prevent metal to metal contact. as well as for the EP additives in 75W90,they create a film against metals to prevent high pressure oil affecting metal surface.My question is,is it because the film created by 75W90 strongest than the film created by 10W40 we can not replace 75W90 by 10W40? or it has a relation with the cleaning factor..etc?

As I previously described, while you could use the 10W-40 in your gearbox in an emergency situation, you would also need to be very careful in how you operate the gearbox when doing so. You would need to significantly reduce the load put thru it, and you would need to be very careful in how you start-up/shut-down the gearbox. While 10W-40 and 75W-90 have similar kinematic viscosity, what matters with regards to dynamic oil film capability is dynamic viscosity. If oil film thickness in the unit's gear/bearing contacts degrades to boundary conditions, then a scoring/scuffing failure will occur very rapidly. Scoring/scuffing type failures are usually quite nasty. The EP additives that gear oils commonly have don't prevent scoring/scuffing failures, but they do provide some additional operating margin against them.

To be safe I'd suggest following the advice given by others and forget about using any oil in your gearbox except what the OEM specifies.

Good luck to you.
Terry

 

[Kaadm]

I appreciate your help Terry.

We can not reduce the load for this pump as there is a flow ratio we need to respect

between the gas comming from the well and the corrosion inhibitor flow rate pumped by

the pump. I mean we will have more risk of corrosion in the pipelines if we reduce the

pump parameters.

I believe we need to keep the pump mechanism runing with SAE 75W 90 despite the overdue

of the preventive maintenance(change out the oil within 6 months).

The time of changing the oil will be scheduled once receiving the oil.

Regards

 

[Tmoose]

"The time of changing the oil will be scheduled once receiving the oil."

that's good news.

 

[tbuelna]

Adamia- continuing to use the existing 75W-90 oil in the gearbox until you can obtain a replacement supply of the same is probably the most prudent action. In reality, the oil itself never "wears out". And the reason for replacing it is that it can become contaminated and the additives can become depleted.

Good luck to you.
Terry

 

[Kaadm]

Many thanks for your cooperation Terry.

I also contacted the manufacturer and he disagreed the oil substitution.

Our planners team had already established a purchase request for the suitable oil and hope everything will be okay with our pumps .

Thanks to everyone.