Motorguard as an ATF Filter

[mjo]

There are a couple setups that you could build depending on the fittings you buy. Frantz sells an adapter to tee inline with the transmission oil cooler hoses. This adapter, similar in functionality to the Amsoil dual remote housing discussed a few threads back, causes a pressure drop across the hose by using a flow restrictor. The adapter itself serves as a flow restrictor. This pressure difference is then used to "feed" the Frantz or Motorguard with a pressure source and drain. No separate flow restrictor orifice is connected to the filter inlet. The only drawback of this is that it restricts flow to the tranny cooler somewhat.

If you have an transaxle temperature sensor (TTS) bolted to the side of the transmission you might be able to get an adapter to tee off of it - but you'll need to calculate the approximate flow restrictor that you'll need. The advantages of such a setup would be no reduction in oil cooler flow (safer) and perhaps easier to control the pressure inside the filter. The car that I have has a TTS that has a 1/8" NPT thread. You may have to borrow a TTS that corresponds to your car's make and model then take it to a hardware store to find it's thread size. Thus you could tee off of this port, add a flow restrictor to one end and run that (through a hose) to the bypass filter. As the drain, perhaps tapping the top of the throttlebody plate would do. From an engineering student's point of view, the 1/16" restrictor orifice allows too much flow to the bypass filter because there would then be more ATF flow compared to engine oil flow. This would cause too much of a pressure drop across the Filter and the canister would then pop or leak excessively. How much MORE ATF flow would there be compared to 5W30 flow using the same orifice? I use Mobil1 ATF. After reading the datasheet on Mobil's website it says that the viscosity of its ATF is approximately 1/3 that of Mobil 1 5w30. Also, the maximum pressure that is found at the TTS is 160 PSI. Because flow is inversely proportional to viscosity and directly proportional to the square root of the pressure, I found that the required flow restrictor must be approximately four times as restrictive as the 1/16" restrictor orifice. Thus I would need a 1/32" restrictor orifice because flow is proportional to the square of the orifice diameter.

Flow Equation
-------------

flow at fixed temperature = (some constant) x(square root of max. pressure) x [(diameter of orifice) ^ 2] / (viscosity)


This is an example of my car (Saturn '95 SL2)
----------------------------------------------

The maximum pressure found at the oil pressure sender of the engine is 60 PSI. The maximum pressure found at the transaxle temperature sensor is 160 PSI.

Through a 1/16" orifice, the Flow of Mobil1 5W30 versus the flow of Mobil1 ATF at 100 degrees C is:

Flow of motor oil = K x (square root of 60 PSI) x [( 1/16" ) ^ 2] / (motor oil viscosity)

compared to ATF:

Flow of ATF = K x (square root of 160 PSI) x [( 1/16" ) ^ 2] / ( viscosity 1/3 that of motor oil)
= 4.89 times that of motor oil flow

Because the flow of ATF is 4.89 times the flow of 5w30 for a 1/16" flow restrictor, the flow restrictor would have to be smaller in diameter. Take the square root of 4.89 = 2.2. Thus in order for the flow of ATF to be the same as the flow of motor oil, the diameter of the flow restrictor orifice for ATF would have to be 0.0282" (about 1/32") or 2.2 times smaller than the flow restrictor used for motor oil.

[ June 09, 2005, 05:22 PM: Message edited by: mjo ]

 

[97Astro]

I have a 97 Chevy Astro Van. I am using the pressure line returning from the radiator cooler now routes to my Motor Guard ATF then continues on to the external cooler then back to the transmission. I have used it for around 6k miles. I've changed the filter once just to see what it looked like. Ralph has it setup so there is no need for adding an orifice. I'm very happy with the results I've seen so far. The van has 145k miles on it.

 

[johnd]

When using the Motorguard as an ATF filter is it acutally being used in-line without the restrictor or it filtering a portion of the ATF flow which is directed out of the pressure line?

 

[RalphPWood]

I have had very good service with the 1/8" orifice as an element bypass orifice for almost 40 years. The design of the Motor Guard allows the element bypass to be drilled in the filter instead of using an external fitting. The 1/8" element bypass orifice is for 3/8" lines and smaller.
My first ATF installation was a 61 Buick Dynaflow. I looked in a Motors Repair Manual and found a test plug. It was the high drive accumulator and only sent fluid to the Motor Guard when the transmission was in drive which was enough. I returned the fluid to the pan with a self tapping hollow bolt. My concern now days is the large lines like the Duramax Allison with 5/8" lines.
A safe way would be to use a Perma-Cool ATF filter in a line to the cooler. The Perma-Cool ATF filter is nothing more than a remote full flow filter mount that takes a filter such as a Fram PH 8 A. Then if you want to go submicronic you could use a Perma-Cool 181 sandwich adapter and install a Frantz or Motor Guard. It would be an excellent dual remote system. You would want to make sure that the flow is going thru the full flow filter in the right direction. You break the line and hook up hoses. Turn the engine and the one that flows oil hooks up to the in port of the remote adapter.
I think I will go back to the external orifice because I am concerned about having too many filters out there that have the internal orifice. At some point someone will be hooking up one and trying to filter fuel or motor oil in the conventional way. The Motor Guard MG-30 ATF will only work with a sandwich adapter or ATF. The Motor Guard is the strongest of the TP filters. In the 60s they were rated at 300 PSI working pressure.

Ralph

 

[RalphPWood]

I need to STRESS that if you hook up a Motor Guard to an automatic transmission the same as you do an engine you need to use a filter with a restrictor orifice such as the Motor Guard MG-30. I will be going back to the external ATF adapter. All of the Motor Guards will be the same except the 1/16" orifice can be removed for fuel, two port sandwich adapter use or use with the external ATF adapter.

All Motor Guards will be brass copper and aluminum. The MG-30 can filter a huge amount of ATF with no element bypass orifice. I have always used an element bypass orifice of 1/8". It doesn't matter where the bypass orifice is but it is less confusing to put the orifice in the external ATF adapter. Right now I have two Frantz oil cleaners in use with the Frantz type external adapters and two Motor Guard MG-30 ATF filters with the element bypass orifice in the filter. They work equally well.

Ralph

 

[johnd]

I was wondering how much pressure differential there would be at the entry vs. exit of the atf cooler. Perhaps a tap on the input side and return on the exit side would have sufficient pressure differential to give flow to the filter. With or without a restrictor-I guess it would be determined by the pressure differential.

 

[tig]

Ralph,
Is it necessary to have a restrictor orifice if using a sandwich adaptor and motor guard on the transmission?

 

[Gary Allan]

johnd

I agree. I'm sure that there's at least 2psid (probably a good bit more) across the cooling circuit. Merely bridging acorss the output and return line would probably work without any other modifications. No one has done this AFAIK.

 

[RalphPWood]

You can do the ATF fluid in two steps. Install a remote mount such as a Perma-Cool 771-1211 3/4"
-16 thread. Make sure the fluid is flowing thru it in the right direction. Install any full flow filter you wish, such as a Fram PH-8a. Then if you want to filter submicronic add a 771 181 sandwich adapter and hook it up to any submicronic filter. The restrictor orifice isn't necessary. I did this with a new Dodge Cummins with the 1/2" fluid lines. Actually I installed a remote oil filter kit 771_10695. The spring in the relief valve of the 181 sandwich adapter keeps fluid going to the Motor Guard or any bypass filter. That is why the fluid must go thru the mount in the right direction. The 181 sandwich adapter will only work in one direction.
The difference between the remote filter kit and the Perma-Cool ATF filter is the size of the hose. For smaller fluid lines you could do the same by using the auxiliary transmission filterkit 771-10678. The Perma-Cool ATF filter is a big improvement over the stock filter without the submicronic part of it. Most inline ATF filters leave a lot to be desired. I still have the Frantz system on the old Ford diesel. The internal filter on the C-6 looks like a window screen. I'm exaggerating, it's a little better than a window screen

These numbers are from www.jegs.com. For small lines you can make your own ATF adapter similar to what we used on Frantz and Motor Guards in the 60s. It takes two tees with a 1/8" orifice in between. It gets more complicated with the large cooler lines such as the 1/2" and 5/8". The dual remote systems takes care of it.

Ralph