The Ford Barn

mrtexas · 06-24-2010, 03:37 PM

Don't confuse weight with viscosity. Mobil 600W is 375 cSt(centistokes the SI units for viscosity) @ 40C(centigrade temperature) viscosity. Mobil also makes steam cylinder oils at 460, 680, and 1000.

I bought 5 gallons each of Texaco 460 and 680 at a local industrial oil supplier for about 1/3 the cost of getting it from a Model A supplier. Here in Texas in the summer the 680 IMHO is a much better product for the Model A transmission. It is thick enough where I can shift without double shifting, I just hesitate about a second with the clutch and the transmission shifts without grinding. The 460 didn't do as well. In the winter, shifting can take a little muscle to get into gear. But I don't drive my 28 RPU in cold weather anyway.

My experience is consistent with what Marco Tahtaras has said in the past that today's 600W is not what it was in the day and that the 680 is more like what 600w was.

I looked up 140wt gear oil and one brand was 568 cSt @ 40C, somewhere between the 460 and 680.

This chart is handy:

06-24-2010, 03:37 PM	#9
mrtexas Senior Member Join Date: May 2010 Location: Sugar Land, TX Posts: 4,420	Re: What was the approximate viscosity of 600W? Don't confuse weight with viscosity. Mobil 600W is 375 cSt(centistokes the SI units for viscosity) @ 40C(centigrade temperature) viscosity. Mobil also makes steam cylinder oils at 460, 680, and 1000. I bought 5 gallons each of Texaco 460 and 680 at a local industrial oil supplier for about 1/3 the cost of getting it from a Model A supplier. Here in Texas in the summer the 680 IMHO is a much better product for the Model A transmission. It is thick enough where I can shift without double shifting, I just hesitate about a second with the clutch and the transmission shifts without grinding. The 460 didn't do as well. In the winter, shifting can take a little muscle to get into gear. But I don't drive my 28 RPU in cold weather anyway. My experience is consistent with what Marco Tahtaras has said in the past that today's 600W is not what it was in the day and that the 680 is more like what 600w was. I looked up 140wt gear oil and one brand was 568 cSt @ 40C, somewhere between the 460 and 680. This chart is handy: Last edited by mrtexas; 06-24-2010 at 06:26 PM.