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1926 Transmission oil, which grade??


bifda

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I have a 1926 standard 6 with the accessory 4 wheel braking system. When I purchased the car the pump in the gearbox had been bypassed, I have since returned it to operational condition, however it is slow to act.

In the workshop manual it states use a "medium engine oil in the transmission of cars with hydraulic brake equipment in warm weather and a light, cold-test oil in cold weather" I am not sure what is meant by a Cold test oil.

I have used SAE 30 engine oil, and when the brake pedal is applied it takes about 2 seconds for the brake piston to extend, and apply the brakes. Once applied the brakes pull up well. 

What grade oil would anyone suggest I try to make the hydraulics more responsive?

Any suggestions greatly received.

Regards

Wayne

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Ken, 

 I am in the UK where currently it is about 7C or or 43F however it acted the same in the summer when it was warmer.

I have spoken with a specialist oil company here in the UK and they were meant to get back to me, with a recommendation, but I have rang a couple of times and they don't return the call, hence why posting on here.

The company do a SAE10, they also do a ISO46 the guy I spoke with said he would do some research and let me know the best option. A fellow Studebaker friend suggested trying an Automatic Transmission Fluid, Im not sure if that is a good idea or not, someone else mentioned using a thin hydraulic oil.

 

The link you mention above is from when I initially started playing with the brakes. I suppose I would have been better continuing with that thread rather than starting a new post, but I wanted to put the title with my new question. 

 

I will update the previous thread with where I am at with the braves.

 

Regards Wayne

 

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4 hours ago, Spinneyhill said:

I think in the mid-20s they had SAE 30 and SAE 20 for winter and maybe a SAE 10. SAE viscosity ratings started in the mid-20s.

 

These days the "cold test" part is the number before the W, e.g. 5W-30.

 

So are you suggesting a multi grade such as 5w - 30 would probably be suitable?

 

thanks wayne

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Is that SAE 30 a "detergent" oil? Non-detergent oil thickens with use (i.e. turns to sludge). That wouldn't help your situation.

 

Because it is asking for engine oil, I think the 5W-30 would meet the criteria specified. I would expect the performance before it reaches operating temperature would also make brake response quicker during that time - it behaves like a 5W oil, not a SAE 30 oil.

 

It is easy to find oil company "demonstrations" on you-tube showing the superiority of their synthetic oil. e.g. Amsoil in a cold pour test.

 

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OK, lets have a little comparison to try to get from 1926 to 2016.

 

As an oil is cooled it reaches a point at which it becomes semi-opaque or cloudy. The temperature is known as the cloud point. After further cooling, it will reach a temperature at which it is no longer fluid. This temperature is known as the setting point or cold test.

 

So when the manual refers to a cold test oil, they are probably referring to an oil that has a low cold test point without saying what it might be. However, the use of the arbitrary terms "light" and "medium" indicate to me that Studebaker had not yet adopted the SAE viscosity number system.

 

For reference, Dyke's Encyclopedia 1937 says (Instruction No.16) "to give an idea", the viscosity of oils at 100°F (40°C) would be approximately as follows, with correlations from Bob's chart referenced above.
Light oil 200 to 260 sec. Saybolt SUV = SAE viscosity number about 20, low end;

Medium 260 to 400 sec. = medium SAE 20 high end;
Heavy oil 400 to 800 sec. = SAE 30 and 40 for engine and 80W-85W-90 for gear oil;
Extra heavy 800 to 1,300 sec. = SAE 90 gear oil.

 

At 212°F (100°C), the corresponding values are:
Light 34-47 sec. = 10W engine and 75W gear oil;
Medium 47-55 sec. = SAE 20 engine and 75W-80W gear oil;
Heavy 55-70 sec. = SAE 20 to 30 engine and 80W-85W gear oil;
Extra heavy 70 to 100 sec. = SAE 40 to 50 engine and SAE 90 for gear oil.

 

As one would expect, they give similar results!

 

So a "light cold test" oil might be something with viscosity number 10W or maybe 5W and a low pour point. So I think the 5W-30 would be good. It would be even better if it were synthetic. Here is a web site with a chart showing some pour points: https://www.micapeak.com/info/oiled.html. Amsoil's web site is repleat with such comparisons too.

 

 

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20 hours ago, Spinneyhill said:

OK, lets have a little comparison to try to get from 1926 to 2016.

 

As an oil is cooled it reaches a point at which it becomes semi-opaque or cloudy. The temperature is known as the cloud point. After further cooling, it will reach a temperature at which it is no longer fluid. This temperature is known as the setting point or cold test.

 

So when the manual refers to a cold test oil, they are probably referring to an oil that has a low cold test point without saying what it might be. However, the use of the arbitrary terms "light" and "medium" indicate to me that Studebaker had not yet adopted the SAE viscosity number system.

 

For reference, Dyke's Encyclopedia 1937 says (Instruction No.16) "to give an idea", the viscosity of oils at 100°F (40°C) would be approximately as follows, with correlations from Bob's chart referenced above.
Light oil 200 to 260 sec. Saybolt SUV = SAE viscosity number about 20, low end;

Medium 260 to 400 sec. = medium SAE 20 high end;
Heavy oil 400 to 800 sec. = SAE 30 and 40 for engine and 80W-85W-90 for gear oil;
Extra heavy 800 to 1,300 sec. = SAE 90 gear oil.

 

At 212°F (100°C), the corresponding values are:
Light 34-47 sec. = 10W engine and 75W gear oil;
Medium 47-55 sec. = SAE 20 engine and 75W-80W gear oil;
Heavy 55-70 sec. = SAE 20 to 30 engine and 80W-85W gear oil;
Extra heavy 70 to 100 sec. = SAE 40 to 50 engine and SAE 90 for gear oil.

 

As one would expect, they give similar results!

 

So a "light cold test" oil might be something with viscosity number 10W or maybe 5W and a low pour point. So I think the 5W-30 would be good. It would be even better if it were synthetic. Here is a web site with a chart showing some pour points: https://www.micapeak.com/info/oiled.html. Amsoil's web site is repleat with such comparisons too.

 

 

 

Well.... today I went out and bought a gallon of 5W 30 engine oil, drained the transmission and filled it back up with this oil. I only took it on a short test drive, as here it is just below freezing and being a roadster it was a bit fresh to drive, however in the mile or so I drove what a difference, the brakes are now a whole heap better, they respond to the pedal being pushed and stop the car. 

I think I need to alter the length of the pivot very slightly as the brakes are a bit on or off, but they work instantly, instead of the 1 - 2 second delay I have been experiencing.

Hopefully if it warms up in the next couple of days I can take it for a longer drive and actually enjoy driving it, instead of being constantly on edge in case anyone pulls out.

 

A big thank you to the responses above, great advice which has actually worked!!!

 

Regards Wayne

 

 

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