1956 Cadillac 365 oil pressure issue

Need some knowledge on Caddy 365s. Recently bought this coupe de Ville project. Here's the back story.
Paperwork trail ended in 1997 with a second lien sale in California. Car was bought and shipped to Texas and has been stored by a couple different owners since then. I bought it a couple weeks ago and have been piecing it back together. It appears one of the past owners pulled the motor and had it rebuilt and had a lot of stuff chromed and reinstalled it and that's as far as it went. I had to hook up a bunch of stuff that was disconnected when the motor was pulled. I got it to run without to much trouble but it's making noise. I had to put new pipes and mufflers on it so I could hear what was going on. It just had straight manifolds. Now that I can hear it, sounds like there is no oil pressure. Valve train is really making noise. Im planning to pull the valve covers tonight and also hook up a gauge to verify. I've never opened up a 365. Is there some common issue associated with oil pressure on these motors I should look into first? From the outside it appears the oil pump is setup like a SBC....driven by the distributor shaft. I was wondering why there was a used oil pump in the trunk.'

 

TX-- See my reply on the CLC message board.

Curly

 

The 331 and 365 have the less desirable oiling systems n the cad ohv motors. I think it has to do with oil touting and small passages that get clogged easily. They're bad to spin bearings.


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I saw that.....but my issue is before the heads. I'm losing pressure before the oil gets to the top end.

 

I need some input from someone with experience with the Cadillac 365. This motor was removed and rebuilt sometime back in the late 90s. I don't think it has been run much since it was put back in. I got it started but it has very little oil pressure. I've only run it a few times for short periods. It wasn't getting oil to the top end so I started troubleshooting. I pulled the distributor last night so I could spin the oil pump shaft to verify it was pumping. I connected a gauge where the plug is at the back of the block. This is the end of the vertical oil passage coming up from the pump that connects to the two horizontal oil passages.
I put my cordless drill on it and spun it at full speed waiting to see oil fill the line going to the gauge. It took 2-3 minutes for the line to fill and then the gauge only showed a couple psi. I also noticed the distributor hole was full of swirling oil. It was almost high enough to spill out the hole. So the pump is working but I'm losing all my pressure somewhere around the end of the cam. Is there a plug or something in that area that could have been left out? If I keep spinning the pump for several minutes I will start seeing small amounts of oil coming from the rocker shafts but it's very little.

 

Do these engines require that at least the distributor housing be installed for priming to get a true oil pressure reading?

 

I don't know....I asked that question on another forum and never got an answer. It sure seems like there is a big hole in that area with the amount of oil I see. I was planning to put the distributor back in tonight and see what happens.

 

I used my Boroscope to look down into the distributor hole. There is a drilled/machined hole in the block just above the cam. It's about 3/8" or so. When I spin the oil pump the oil flows out of that hole under pressure toward the back of the block. I put the distributor back in and started it and still no pressure in the gauge or on the top end. Is this hole suppose to be plugged or is something suppose to attach there?

 

Sorry.....best pic I could get. Top is the oil pump shaft, left side is the cam gear, right side is the hole all of the oil comes out of and the hole in the middle is a drain back hole I think.

 

There has to be at least one caddy motor expert on here.

 

I can give you the number of the guy who is in the middle of building my caddy motor, which is identical to yours. He has mine all the way apart and has cleaned up every single oil pasage. Maybe he might have some ideas?

 

Maybe so....

 

You were spinning counter clockwise yes?

 

Yes

 

Sounds like a plug was left out somewhere.

Tommy

 

It should build pressure pretty good that way. My motor did about 20lbs on the drill and then more while running.


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It would if it all wasn't coming out that hole and draining right back into the pan. I just don't know if a piece is missing or if there is a plug that goes in that hole. But it doesn't look threaded.

 

Let me know if you need it.

 

Oh shit, I just reread your second post. If you're looking at the block from the rear there is a steel plug on the drivers side of the cam plug. Behind that is where the small oil plug sits behind the distributor gear. Without it you have pressure but not much.


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you can use 50 weight oil ,what will help the oil pressure ,cad motor`s have about 5 lbs at Idol the 50 weight will help

 

My Caddy has 20 at idle. I run 40 weight. I realize 20 is high for a Caddy but it is reassuring.

 

the hole I'm talking about is directly in line with the distributor shaft.if you are standing at the back of the motor and facing toward the front the hole would be on the front side of the distributor shaft. The distributor shaft also has a hole in about the same location on the front side but I don't see how it would seal in the pressure. Check out the picture I attached. The hole has no threads for a threaded plug and I don't think a hole that big is necessary to lube the distributor shaft.

 

This hole shows up on the lubrication diagram in the service manual but you have to really look close to see it. I'm sure it is the hole to lube the distributor shaft as was suggested, but I don't think it's suppose to be a 1/2" hole.

 

Looking in my MOTORS auto repair manual from 62,,the oil diagram for a 55-59 Cad engine ,,,that hole the oil is coming out of looks like the end of the oil galley on that side,,,,that looks like the end of the oil chain.
Could a plug have been left out ?,,,,I have heard of this happening before with other engines.
You might be looking at the same manual as me,,either way,,I can't imagine that that much oil should come out of there just to oil a dist. shaft.

Tommy

 

its in the middle of the block. Its not one of the ones that runs horizontally from the rear to the front. This one looks to be in the horizontal passage that runs from the right side to the left that feeds oil to the forward running passage on the left side of the block. If the hole was threaded I would feel pretty confident in putting a plug in the hole with a small hole drilled in it to squirt oil to the distributor.....but its not threaded. If I get time tomorrow I'll stick a plug in that hole and see if I get pressure on the gauge when I spin the pump.

 

Not real familiar with Cadillac engines, but my guess, from what was pointed out is that there was some sort of pressed in plug with a tiny oil hole for lubing the disty. If the plug was soft metal, then it could have melted from hot tank chemicals when the engine was rebuilt.

 

Sure would like a confirmation on that though. I don't even know where to find a plug that small. I've never rebuilt a motor with a plug that small. I guess a machine shop would be the first place to look.

 

You know......I wonder if this is the oil pressure relief passage. If the regulator on the pump is stuck it could be bypassing all the oil tru this hole.

 

I primed my 59 390 engine with a cut off screwdriver shaft and my drill. I had oil psi come up almost right away and oil to the rocker shafts in under 30 seconds. I didn't measure the actual psi, but it was enough to load my 1/2 drill motor and I ran the drill for a minute or so to make sure the filter housing filled. I never had any oil surge up in the valley as you describe.

Curly

 

Worked on it some more today. It appears the plug was left out of the right longitudinal oil header. I shoved a rubber plug in the hole today and spun the oil pump real slow and I got pressure on the gauge briefly before the plug blew out. Tomorrow I'm going to measure the hole and go get a plug for it.