MotorGuard flow rate

[Quickbeam]

I recently changed the plumbing on my Motorguard from a sandwich adapter to the "classic" method because the sandwich setup was taking too long to heat up.

I left the sandwich adapter on as the pressure source but took the supply from the filter side of the sandwich, the side after the 2 psi valve. This is normally the return side. I plugged the engine side outlet. I drained the MG to the valve cover. Both source and drain are AN 4 size lines.

Because of this I installed an .064" orifice in the drain fitting by machining a drilled brass plug for an interference fit within the ID of the fitting. To my surprise when I checked flow with hot oil I was getting less than 1/8 quart/min. I increased the orifice several times until finally reaching .125" which still only got me 1/4 quart/min. In the end I removed the drilled plug completely which resulted in a tad over 1/2 quart/min. So I'm running this thing with no "external" orifice.

Anyone care to comment on why this is? Ralph? Gary? Is the the valve in the sandwich limiting flow to the filter because I picked off from the "wrong" side? The oil is GC if that matters.

 

[Gary Allan]

Can I assume you also measured at other speeds then idle? That is, max normalized pressure at typical normalized oil temp (and hence visc)??

If so ...good show...ready to roll

 

[Quickbeam]

Gary, all these flows are at 2000 rpm and 45 psi of pressure on hot oil. The flows at idle are much less. It has to be the sandwich. I noticed I'd plumbed it "wrong" before reinstallation (neighbor came into the garage to "supervise" and distracted me. You know how that goes) but figured it wouldn't make such a difference. Now I'm gonna have to take it off and plumb it the "right" way just to see what happens. As you say, Izgotstonose

 

[Gary Allan]

Well, I don't know if you'll see anymore flow ..but there has to be some differential across the sandwich ..even with hole that you drilled.

You'll find out soon enough, I guess.

 

[RalphPWood]

Using a sandwich adapter is similar to using a smaller orifice. It allows the oil to go thru the filter slower and filter better. I drive about 20 miles to work. Sometimes I check the filter on a cold day and it is just starting to warm up when I get to work. A cold depth filter with a cold oil is very restrictive. if you are filtering 1/8 quart a minute in cold weather you are doing OK. I just sent a MG-30 and sandwich adapter to Norway. It might have been a good idea to drill it internally so that the element bypass orifice would heat up the filter. Some heavy duty filters have a thermostat controlled element bypass orifice. It is very difficult to tear down the MG-30 to drill the orifice. Using the MG-60 with a sandwich adapter in cold weather you could reach into the out port and drill a 1/8" hole in the wall thru to the center bolt. I don't like to drill the filter because it is confusing to a lot of people. I end up with people deciding to use the filter for fuel. A drilled filter only works for ATF inline filtration or with a sandwich adapter with two ports. When converting a two port sandwich adapter to a one port drill extra holes in the adapter. That eliminates the resistance thru the adapter. Sometimes on GM engines with the relief valve in the filter mount the oil will simply bypass both filters. The path of least resistance might be directly to the engine without being filtered. It is always best with the engines that have the relief valve in the filter. That way the oil the Motor Guard can't filter goes directly to the full flow filter. All the oil gets filtered. As a rule of thumb if the oil is thin enough to flow thru the precision parts of an engine in cold weather it will be thin enough to flow thru the filter enough in cold weather. I have no idea what GC oil is. I know what thick and thin is. I got burned out on abbreviations in the military.

Ralph

 

[Quickbeam]

The only think that confuses me Ralph is the way you write but thanx for the reply

. I'm using a sandwich adapter but not both ports. If I'd drilled a filter bypass orifice (why is that hard on the MG-30 btw? Looks very easy to me) I'd have even less flow.

Gary, I'd forgotten about that hole. It's still in there. If I'd plugged it the flow would've been even less. If I move the source to the engine side of the adapter or take Ralph's advice and drilled more holes thru it I'd be stuck using an external restrictor like I started out with. Seems the current setup is better so maybe I'll ljust leave it alone.

 

[Cujet]

I use a unmodified motorguard on a Lister CS twin. I use no restrictor on the filter, have very low oil pressure and get fairly good flow. Enough to keep the oil clean. Your situation seems odd.

But I started to think that maybe you do not need 1/2 quart per minute flow rate. In fact, my best guess is that the flow rate can be much lower than that.

Chris