STP and Transmission: any negative experience ?

[Joe K]

More likely the "time" involved was the time necessary to "heat" the oil to operating temperature.

I know even with my STP - the first 400 yards of driving is a miserable gear change. Then it sort of "loosens up" and becomes more normal. Not a lot of gear clash - and yes, as I drive and re-attune myself to the car I clash less.

Joe K

[SAJ]

I agree with Joe K. I use a mix of Mobil 680, STP and Moly disulphide. First thing when it is really thick the gears slow down so fast when you de clutch that I can just whisk it through like a synchro box -Straight through as fast as you can. After a few minutes the lube warms and thins and gears slow down less rapidly and then normal double de-clutching becomes necessary.
This cold oil experience proves that thicker oils change easier than SAE 140 or 190 in my opinion.
I tested and set my brew to an SAE 280 viscosity spec, with higher viscosity index (less reduction in viscosity with increasing temperature) than the raw Mobil 680, due to the added STP
SAJ in NZ

[M2M]

Originally Posted by Forddan

I drove the A ~3 miles. As I am new, I am not sure if what happened was normal or not after a transmission oil change.

Started and warmed the car for a few minutes. Until the idle sounded good. Left the barn and when I tried to do 2nd gear it was too difficult. I tried double clutching or directly when the car just started to move. Very difficult. I live in a quiet street and drove along it, several times, stopping and starting again. Trying to understand if I screwed it. Then shifting started to go better and better with no grinding at all or very soft.

Question to the experts: I drained the transmission overnight and filled next morning with the Meropa 1500.

Could be It took time to this gear oil to oil all the gears ? (As if they were too dry)

Could be it was a combination of temperature (~21 C/70F) with the fact the oil was new and not yet well distributed?

Well, after I feel all was going back to normal I took it for a ride to the gas station under a soft midday local traffic. I tried not to think too much if the gears will grind or not. I focused my attention on the motor sound and time to shift. It went very well. Shift changed much better.

Let's see tomorrow during the long trip.

Cheers
Daniel

Good that you opened your mind and didn't join the STP bandwagon but you chose a ISO 1500 oil, the thickest possible gear oil, while you don't live in a hot climate area; see:

https://cglapps.chevron.com/msdspds/...&docFormat=PDF

Meropa 1000 or 680 would have been better for you but it's not sold in quart bottles as far as I know

Do you plan to use your A in cold weather? If yes, you could perhaps mix in some of the supplier's "600W" or better yet Lubriplate SPO-299 or SPO-288, or Amsoil SAE190 or SAE250.

[M2M]

Originally Posted by SAJ

I agree with Joe K. I use a mix of Mobil 680, STP and Moly disulphide. First thing when it is really thick the gears slow down so fast when you de clutch that I can just whisk it through like a synchro box -Straight through as fast as you can. After a few minutes the lube warms and thins and gears slow down less rapidly and then normal double de-clutching becomes necessary.
This cold oil experience proves that thicker oils change easier than SAE 140 or 190 in my opinion.
I tested and set my brew to an SAE 280 viscosity spec, with higher viscosity index (less reduction in viscosity with increasing temperature) than the raw Mobil 680, due to the added STP
SAJ in NZ

How did you come up with the SAE 280 figure for your brew? Does adding STP increase or decrease the viscosity index (a measure of the quality of the oil)?

[Forddan]

Originally Posted by M2M

Good that you opened your mind and didn't join the STP bandwagon but you chose a ISO 1500 oil, the thickest possible gear oil, while you don't live in a hot climate area; see:

https://cglapps.chevron.com/msdspds/...&docFormat=PDF

Meropa 1000 or 680 would have been better for you but it's not sold in quart bottles as far as I know

Do you plan to use your A in cold weather? If yes, you could perhaps mix in some of the supplier's "600W" or better yet Lubriplate SPO-299 or SPO-288, or Amsoil SAE190 or SAE250.

I got the car on the first week of January this year. I was very lucky that we didn't have snow yet. Normally we have a white Christmas. The seller drove it home. Next day I drove it a few miles (-11 Celcius/12F that day in January) (seller used 600W) and went to the barn. 3 days later we had a nice snow storm. The Tudor spent the rest of the winter comfortable in the barn. I do not plan to drive it this next winter either. Only until the town start to salt the streets.

Nevertheless temperatures in October/November could be around 8 Celcius/46 F or lower. If I start to see that the Meropa 1500 affects the shifting then I will mix it with the 600W, as suggested, like 50/50.

In my club there is only 1 member using STP mixed with 600W (50/50). If that ratio is working for him with MA temperatures, I suspect that the mix of Meropa 1500 and 600W will work too. I also read a posting of 2 members using STP, one living in CT and the other in NH. They have too my temperatures. If STP density is working for them, could be the Meropa 1500 will work for me. I will see.

Today will be a normal June day with good temperatures and no rain (finally :-) ).

Temperature will be between 18C/64F and 23C/73F . In a couple of hours I will drove the A ~30 miles to the Model A club picnic. All backroads and i will get the true feeling if I am happy with my decision (at least for the summer).

Thank you for proving your experts comments. I learn from every posting.

Will let you all know what happened.

Best
Daniel

[Corley]

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I've had a ton of these trans apart over the years, and found them filed with everything from light weight motor oil to almost axle grease. I can't honestly say that any failure I've seen was due to the WRONG lub. Failures due to NO lub, yes, but not due to the wrong lub. It is not that fussy guys... But, use something that won't leak out too easily, meaning a thicker pub, not motor oil.

To those with grinding gears: Shift slowly, you don't have synchronizers, and remember, get into second right away. First is only needed to get her rolling, then move up to second. Second to third, just slow down your shifting and you won't be grinding. (And as previously mentioned, a nice low idle speed to allow the gears to align helps a lot.)

The biggest problem with using STP is cleaning up after getting near the stuff. A trans full of it is a sticky messy proposition, when you have to work on it. Plus, it is a bit thicker than needed.

Just my opinion...

[SAJ]

M2M. If you are asking how I got SAE 280 viscosity I used a Brookfield viscometer to return the Mobil 680 to its original viscosity after adding a percentage (I think 10% from memory) of MoS2 oil and then adding STP oil treatment to thicken back up. STP polymers increase the viscosity with temperature index.
I am in Canada at present so don't have access to my laboratory books.
I made 20 litres up years ago and other club members have been using it up too.
I had a full oil lab then since I manufactured oils and greases under the Rocol brand. I still have viscometers but no longer other lubricant testing gear.
If you are asking why I chose SAE280 viscosity spec. it was simple because that is what the original 600W oil viscosity was as far as I recall without access to my notes from many years ago.
I did not spend any time on researching and testing, just made the mix and found it worked better than that from one of the parts suppliers.
Plus I studied tribology when it was a new science in the early 60s and have experience of gear lubes from my manufacturing days.
SAJ in NZ

[Forddan]

Drove 60 miles today with the Meropa 1500 and haven't seen/feel any difference with the 600W, from one of my local model A parts sellers, when shifting.

It is a learning curve.

Best to all, this is the end, for me, of this threads. You guys can continue posting. Interesting comments on the last postings.

Daniel

[M2M]

Originally Posted by SAJ

M2M. If you are asking how I got SAE 280 viscosity I used a Brookfield viscometer to return the Mobil 680 to its original viscosity after adding a percentage (I think 10% from memory) of MoS2 oil and then adding STP oil treatment to thicken back up. STP polymers increase the viscosity with temperature index.
I am in Canada at present so don't have access to my laboratory books.
I made 20 litres up years ago and other club members have been using it up too.
I had a full oil lab then since I manufactured oils and greases under the Rocol brand. I still have viscometers but no longer other lubricant testing gear.
If you are asking why I chose SAE280 viscosity spec. it was simple because that is what the original 600W oil viscosity was as far as I recall without access to my notes from many years ago.
I did not spend any time on researching and testing, just made the mix and found it worked better than that from one of the parts suppliers.
Plus I studied tribology when it was a new science in the early 60s and have experience of gear lubes from my manufacturing days.
SAJ in NZ

SAJ, if you can find the info that says original 600W is SAE 280 I'd be very interested in that...that's always been a mystery in 600w discussions.

Does anyone know how hot the gear oil usually gets inside a transmission and inside a differential?

[Terry, NJ]

Originally Posted by M2M

SAJ, if you can find the info that says original 600W is SAE 280 I'd be very interested in that...that's always been a mystery in 600w discussions.

Does anyone know how hot the gear oil usually gets inside a transmission and inside a differential?

I have measured mine after runs for comparison with other components. The exterior has been a consistent 110 -120 deg. F depending on the ambient temperature and whether or not I came home by way of a long, steep hill and how much heat it absorbs from the engine. These are external temperatures, and not the internal, which may be slightly higher.
Terry

[Tom Wesenberg]

After a 17 mile drive at 85* my rear axle temp was still below 100*.
I didn't shoot the tranny temp.


BTW, I like MMO, STP, and Sea Foam. They've all done good things, just as they are supposed to.

[M2M]

Originally Posted by Terry, NJ

I have measured mine after runs for comparison with other components. The exterior has been a consistent 110 -120 deg. F depending on the ambient temperature and whether or not I came home by way of a long, steep hill and how much heat it absorbs from the engine. These are external temperatures, and not the internal, which may be slightly higher.
Terry

Thanks Terry for the info but wouldn't the temperature of the oil inside the tranny be significantly higher rather than slightly higher?

[Terry, NJ]

Originally Posted by M2M

Thanks Terry for the info but wouldn't the temperature of the oil inside the tranny be significantly higher rather than slightly higher?

Good Question! Possibly in the winter. Not appreciably in the summer. These temperatures were taken immediately after shutting the car down from a run. One part of which is on a highway, which is long and steep. Ambient summer temperatures locally, run about 75 to 90 F, so the transmission and rear end are not getting a good chill as they would in the winter.
Terry