Bypass oil filter- should canister be full?

[jsd245]

It’s me again… 

 

so I opened up the oil filter on the truck- it has the metal encased cartridge that’s about 3.5 x 4”. Should this can have oil in it? Almost looks like it should drain empty when the truck is off. When I pull the filter out it remains about 1/2 full of oil. 

[TodFitch]

The drain on that goes to a spool valve on the side of the block that has two actions: First, it is the oil pressure relief valve. Second, it shuts off flow through the bypass filter if the oil pressure drops too low. So when the engine stops, the oil pressure drops to zero and that valve controlling the return from the oil filter closes. Since the valve is closed the oil filter canister cannot drain and will have oil in it.

[jsd245]

Thanks! Makes sense. 

[Merle Coggins]

Also, it depends on the design of your filter. Some filters return oil from the upper fitting, and the feed port in the bottom actually comes out about half way up inside the filter. It's very normal for the filter to be full of oil when you service it. Many filter housings have a drain plug near the bottom so that you can drain it down before removing the cover and pulling out the filter element. 

[pflaming]

Years back Greybeard, since passed on, helped me repair and start my first engine, the 218 flathead. I asked about the oil filter. He said to leave if off, it didn't ‘do enough to bother with it’. He taught high school mechanics so was quite knowledgeable and a VERY nice guy.  So now I have three of those on my parts shelf. 

Edited January 10, 2022 by pflaming

[PT81PlymouthPickup]

1 hour ago, pflaming said:

Years back Greybeard, since passed on, helped me repair and start my first engine, the 218 flathead. I asked about the oil filter. He said to leave if off, it didn't ‘do enough to bother with it’. He taught high school mechanics so was quite knowledgeable and a VERY nice guy.  So now I have three of those on my parts shelf. 

I have spoken to a few vintage vehicle owners over the years that do not have any oil filtration on their engines and claim it not necessary?  I know one fella that has over 150k on a ford flathead 8 without any issue. He does change the oil religiously. Seems like some filtration would be better than none? On the other hand, it would certainly be simpler having less connections to leak and not having to deal with messy filter changes?

[jsd245]

Given that it will certainly be time and not mileage that dictates oils changes, yes maybe these bypass filters don't do much, but its there, so I may as well change it. 

[Merle Coggins]

If a bypass oil filter "does nothing", then diesel engine manufacturers wouldn't still be using them. They do filter your oil, just not in the same way that a full flow filter would. 

[pflaming]

Modern engine filters clean all the oil all the time, maybe the diesel one is different. I may be in error, but just don’t like the clutter by the engine.. JMPO

[jsd245]

Generally the bypass filter on a diesel is a much higher filtration, and it is in addition to the normal full flow filter. On these- they look like essentially a normal oil filter, and I guess 30% of the oil flow is diverted through them? So they don't do nothing, but the oil is exposed to 70% less filtration  than a normal full flow filter. I think better than nothing, so I will leave it in place and pay the 15 bucks or so every  year when I change the oil. 

[desoto1939]

18 minutes ago, jsd245 said:

Generally the bypass filter on a diesel is a much higher filtration, and it is in addition to the normal full flow filter. On these- they look like essentially a normal oil filter, and I guess 30% of the oil flow is diverted through them? So they don't do nothing, but the oil is exposed to 70% less filtration  than a normal full flow filter. I think better than nothing, so I will leave it in place and pay the 15 bucks or so every  year when I change the oil. 

The old PB1/2 oil can filter which was a throwawy filter was good for 8K milage.  So you can change out the drop in oil filter every other year.. I use a NAPA Gold 1010 filter and after removing the filter I use a turkey baster fromt he $1 store to remove the remaining oil in the canister then wipe it clean.  This not a messayjob just take your time. I have owner my 39 Desoto for 35 years.

 

Rich Hartung

desoto199@aol.com 

[kencombs]

The diesel bypass is much different than the older ones.  The one on my old Mitsubishi was a true bypass in that it filtered all the oil that was bypassed by the pressure limiting valve.  All the oil through the bearings was filtered by the normal full flow filter.  Oil excess to the bearing needs to maintain pressure was filtered before returning to the oil pan.  

 

I have my 230 drilled, tapped  and plugged for a full flow system and have mounted a filter base on a fabbed mount but still need to get the lines made up. I've considered adding a bypass too, just because I think that cleaner oil is better oil. 

 

Good filtration is one of the reasons newer engines can get away with 5 and 10 thousand mile oil changes.  Of course, very frequent changes can help too, but that can get expensive.

[lostviking]

On 1/10/2022 at 12:15 PM, kencombs said:

The diesel bypass is much different than the older ones.  The one on my old Mitsubishi was a true bypass in that it filtered all the oil that was bypassed by the pressure limiting valve.  All the oil through the bearings was filtered by the normal full flow filter.  Oil excess to the bearing needs to maintain pressure was filtered before returning to the oil pan.  

 

I have my 230 drilled, tapped  and plugged for a full flow system and have mounted a filter base on a fabbed mount but still need to get the lines made up. I've considered adding a bypass too, just because I think that cleaner oil is better oil. 

 

Good filtration is one of the reasons newer engines can get away with 5 and 10 thousand mile oil changes.  Of course, very frequent changes can help too, but that can get expensive.

I'd be interested in seeing the oils path, the way you have it modified. I too like the idea of having all the oil go through a modern filter. I haven't worked on it yet, but I purchased a remote PH8A (I think) adapter that fill fit inside the canister. Externally it will seem stock. I'll probably reverse the way the lines connect to the canister, but that won't be so noticeable. I'd like to see how the oil lines connect to the block in your mod, so I can incorporate that.

[kencombs]

I didn't originate the idea.  There is a good example on this site, done during a complete rebuild.  I'll see if I can locate it.   Basically there are two holes drilled into the block on the boss where the oil pump mounts.  There is a passage for both to the pump and from the pump in that area.  Holes are drilled and tapped in the passage for the pump output.  They are threaded  for 1/4" pipe thread adapters.   p

 

Then a small welch plug is driven into the passage centered between the holes.  This forces the oil out to your remote filter and then back to the passage to the oil gallery.

 

Mine is not yet plumbed, just drilled, tapped and the remote fiter (PH8 base) mounted.  I'm really delaying selecting the lines as I want hard lines and haven't successfully bent a pair as yet.

[lostviking]

Thanks. Pictures? Are you using steel lines, or NiCop?