HELP!!! with my oil lines

[John Burke]

I am mounting an outboard oil filter on my Desoto engine. There are 2 outlets low on the block on the drivers side for the lines to hook up to. I can't remember which is the line to the filter and which one is the return line. There are plugs in the outlets now. They are lined up vertically, one above the other. anyone have an answere for me? thanxz, John

[Merle Coggins]

The one higher up on the block is the pressure. The lower one is return.

Merle

[John Burke]

Many tankz Merle....John

[Don Coatney]

Was your Desoto setup for a full flow oil filter? Is the filter you are installing full flow or by-pass? You can go either way on youy engine but if you are setup for full flow and install a by-pass filter assembly you will most likely starve your engine for oil as the small lines on the by-pass filter will restrict the flow. You will notice in the picture below an arrow showing where a pipe plug can be installed internally in the block. This pipe plug is required for a full flow setup and not required for a by-pass setup. The factory full flow filter housing has a by-pass valve built in so if the filter media plugs up the by-pass valve opens allowing the engine to get oil. If you install an aftermarket full flow filter make sure it has this by-pass valve incorporated. This information is for long block Desoto and Crashler engines only. Does not apply to short block Plymouth and Dodge engines. Any questions let me know.

[John Burke]

OK Don, as I understand it, using the wrong filter flow system would possibly deep 6 the engine......Last year I did not run a filter. The block fittings were plugged off....The unit I was going to use is a vintage aftermarket that I took off of a 50 Desoto but as I understand you, I still won't know if I have a bypass system or the other unless I drop the pan and see if the plug is there...Right? or do I missunderstand what yer saying....The pan is NOT coming off...jb

[Merle Coggins]

Looking at the drawings that Don posted, the lower connection is slightly different. On the by-pass setup it appears to angle down into the relief valve similar to how mine is. On the full flow setup it appears to come out of the block horizontally just above the pressure regulator. Also, Don's full flow filter housing bolts directly to the block and doesn't have any external lines.

Also, if you've been running the engine with the lines plugged, and it is a full flow system, you'd have a junk engine. That would have stopped any and all oil flow into the vital pieces of the engine. I'd have to guess that you have the by-pass arrangement.

Merle

Edit... I just reread the part about the full flow setup. I suppose you could still get oil to the bearings with the ports plugged, but only if the regulator was stuck closed. Once the pressure rises, it is supposed to move the regulator and block the flow of oil into the engine through the filter bypass channel. But if the regulator was stuck closed I would think your oil pressure would be pretty high since it wouldn't be able to relieve the excess pressure if stuck closed.

[Don Coatney]

John;

If you ran your engine last year with no filter and the filter connections plugged most likely you are not setup for a full fllow system (ie no internal plug). What oil pressure did your engine carry last year? Did you ever figgure out why your camshaft broke?

Does your engine have a diamond shaped area just to the right of the distributor? Is this the holes that were plugged as pictured. I have pluges screwed into these holes so I would not drop anything into the holes when I was assembling my engine on the workbench.

[John Burke]

The engine was plugged when I got it from George..(it's an S-18)...1953...

Never did run a filter.....Oil pressure runs about 60-70 psi when cold,.....drops to to around 45-50 when hot...according to your drawing, when the plug is installed, the return goes into the top hole...Does it go into the bottom hole on a bypass system?? The only things we could come up with on the cam is to much spring pressure causing the cam to flex and crystalize or just about any other cockamamie thing you could think of....You could see on the broken edges where it had been running cracked for some time.....Now back to the filter...what do you think I should do...If my engine blows, I need somone to send the bill to....John

[Don Coatney]

The engine was plugged when I got it from George..(it's an S-18)...1953...

Never did run a filter.....Oil pressure runs about 60-70 psi when cold,.....drops to to around 45-50 when hot...according to your drawing, when the plug is installed, the return goes into the top hole...Does it go into the bottom hole on a bypass system?? The only things we could come up with on the cam is to much spring pressure causing the cam to flex and crystalize or just about any other cockamamie thing you could think of....You could see on the broken edges where it had been running cracked for some time.....Now back to the filter...what do you think I should do...If my engine blows, I need somone to send the bill to....John

John;

Give George a call and see if he recalls installing or removing the internal pipe plug. As much as you do not want to remove the oil pan it might be worth doing just for the piece of mind. Can you remove the pan without pulling the engine?

[John Burke]

If i were to have the plugs open and cranked the engine over, could i tell by which hole the oil came out of whether it is a bypass system or what ever????

[Don Coatney]

If i were to have the plugs open and cranked the engine over, could i tell by which hole the oil came out of whether it is a bypass system or what ever????

John;

If the internal pipe plug is in place all of the oil should come out the bottom hole. If the plug is not in place both holes should be equal so the path of least resistance would come into play. How about screwing a gauge into both holes for a pressure check. Less mess that way.

[John Burke]

I'll try that...ain't worried about the mess...gonna change oil anyway...here is a couple of pics of the vintage filter mounted....Manufactured in the 50's in Lincoln NE. my home town...Insert requires one large roll of UNUSED bun wipe. you have to remove the doot-de-doot (cardboard roll) before you put it in....John...Don, I tink yer stuff is goin' out 2 morrow....john

[Merle Coggins]

If it's the by-pass system the bottom port should be a drain to sump, so there shouldn't be any pressure there. The pressure should be at the upper port. From Don's drawings of the full flow system, the lower port would have full pressure and the upper port would only have pressure if the pressure regulator was fully closed opening up the "idle pressure gallery".

That's how I read that info anyway.

Merle

[Merle Coggins]

I just thought of something else. If you look at the two documents that Mr. Coatney posted, the pressure regulator spools are different. That would be easy to pull out without droping the pan. Compare your regulator spool to the two photos. The one in the full flow system has an orifice through the center of it. The by-pass one is solid.

Merle

[Reg Evans]

John,

From your engine photo it appears that you have that diamond shaped flat spot on the block for a full flow oil filter like on Don's engine.

[Don Coatney]

I just thought of something else. If you look at the two documents that Mr. Coatney posted, the pressure regulator spools are different. That would be easy to pull out without droping the pan. Compare your regulator spool to the two photos. The one in the full flow system has an orifice through the center of it. The by-pass one is solid.

Merle

Merle;

Not sure if the spools are different. I think they may be the same. On my engine there was originally a by-pass filter assembly. I installed the internal pipe plug and the full flow filter. I did not change the spool. Just cleaned it and replaced a broken spring.

[Merle Coggins]

I don't know for sure. I was only going by what those documents showed. If your regulator spool doesn't have an internal orifice as shown in the second document you probably wouldn't notice anything. As I understand how it's written, this provided a bypass around the filter at lower pressure situations to ensure oil to the bearings. Without that orifice your oil will have to pass through the filter to get to the bearings. I don't see that being a problem unless your filter becomes clogged.

[Don Coatney]

I don't know for sure. I was only going by what those documents showed. If your regulator spool doesn't have an internal orifice as shown in the second document you probably wouldn't notice anything. As I understand how it's written, this provided a bypass around the filter at lower pressure situations to ensure oil to the bearings. Without that orifice your oil will have to pass through the filter to get to the bearings. I don't see that being a problem unless your filter becomes clogged.

If the oil filter element becomes clogged there is an internal spring controlled valve in the filter housing that will open and by-pass the filter element insuring oil still goes to the engine. I made a point of testing this internal valve before I installed the full flow system. I also pre fill the filter housing at every oil change so I build oil pressure faster. I have thought about converting this system to an OBERG filter and adding an oil cooler. Might do that some day as I have an OBERG filter.

[John Burke]

Well I took both plugs out of the oil ports and cranked the engine over...oil came out of the bottom hole only...ie: must mean I have a full flow system...I don't know how to tell if the filter cannister is that style or a by- pass type...This one came off of a 1950 Desoto AND I had a 1954 Chrashler NYKR (331 hemi) that also had the identical aftermarket filter on it...so I am still looking for comments...John