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By peeeot - 13 Years Ago
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My 312 came with the external oil lines to the rocker shafts already installed. The oil pressure switch is on the end of a tube that extends a few inches out from the block. Threaded into this tube at 90* is a valve with the oil line heading up to the rockers, so that the flow to the rockers could be shut off or reduced with the valve.
The oil pressure light is on at idle speed, and while there are plenty of potential reasons why oil pressure might actually be low, it seems to me that having the switch located on a line that leads to two relatively large openings (the oil overflow tubes at the ends of the shafts, not to mention all the rocker oil holes) might give a false low reading. Currently the valve to the rockers is wide open and there is a good stream of oil that flows out of the overflows.
I'm thinking the flow to the rockers could be reduced which should elevate the pressure reading at the switch. But how much flow is enough?
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By PF Arcand - 13 Years Ago
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How much is enough? I don't know, but first you need to find out if there is an overall low pressure problem. So, with the valve covers off, does there appear to be reasonable oil flow at the rockers? If they are generally wet with oil, & it's flowing, close that valve completely for a minute or two & see if the oil light goes off at idle. Then report back...
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By peeeot - 13 Years Ago
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Ok, I'll check that in the next day or two and report back!
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By MoonShadow - 13 Years Ago
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I think the best place to test oil pressure is on the driver side of the block towards the front where the original oil pressure sender screwed in. Its just behind the block breather. Chuck
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By lyonroad - 13 Years Ago
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Moonshadow, my 55 292 came (to me) with the oil pressure sender located just rear of the oil filter, right above the oil pump. Is this the wrong location? If it doesn't matter a whole lot I will leave it there because i have already cut the sender wires to fit that location.
Mark
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By peeeot - 13 Years Ago
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So: I removed the valve covers and was surprised to find that there was not a steady flow out of the overflows as I had previously observed. I installed a new oil pressure switch just a few days ago and had noticed that around the same time there seemed to be more valvetrain noise than usual. Anyway, I closed the external oiler valve and observed no change: the oil light would come on, flicker off, flicker, come on steady, etc. Then I reopened the valve and lo and behold, there is oil coming out the overflows again and the oil pressure light is off for good. Also the valvetrain was a bit quieter.
I believe there was some sort of debris in the passage restricting flow to the rockers and the pressure switch alike. Whether that debris was petroleum-based and dissolved or has simply moved on to the rocker shaft, my plan is to remove and thoroughly clean the rocker shafts to ensure the oil is going to every hole it should up there.
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By MoonShadow - 13 Years Ago
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I'm definately not an expert on the Y but I don't recall seeing any oil senders in the back. All I've seen were in the front. I'm sure someone will prove me wrong. It probably makes little difference. Chuck
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By BudMan - 13 Years Ago
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Looking through the "Mercury Repair and Adjustment Manual - 1954" and the "Ford Y-Block" book, all photos and diagrams that I found show the oil sending unit to the rear (right) of the oil filter. That's where it is on my '57 312. However I do have a question. On the left side of the engine there are three other small plugs. One is between the fuel pump and the breather pipe, one is just below the block drain petcock, one is about 3" left of the oil filter, and the fourth is to the right of the oil filter (sending unit goes here). My question is - are all of these oil channels and can any one of them be used for an oil sending unit? The oil gauge on my '54 Merc works OK, but I may want to put a second oil pressure gauge just for safety's sake and I am wondering if I could use one of the other ports.
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By MoonShadow - 13 Years Ago
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The oil galley runs in a straight line from rear to front. So any screw in plugs on that line are into the oil passage. I think the front is as far away from the pump as you can get so you would be reading the oil pressure at that point. I really don't know if it makes any difference. My 57 (back in 59) had the sending unit towards the front. Chuck
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By charliemccraney - 13 Years Ago
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I've had my sender at the very front since I can remember and the indicated pressure has always been lower than I expected but still reasonable. I've wondered if placing it closer to the filter will make a difference but haven't tried it.
The hole at the very front corresponds with the front main so it makes sense that some pressure will have been lost by then because of the passages to the other 4 mains.
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By peeeot - 13 Years Ago
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UPDATES!
I removed both of the rocker shafts and thoroughly cleaned them, making sure every hole was clear and ready to move oil. I installed them and adjusted the valves, started the engine, and...no oil to the rockers! Once again, the oil pressure light was on at idle and off above idle.
I removed the external oil line leading up to the rocker shafts, made sure it was clear, and ran the engine with the valve open to observe the flow of oil that SHOULD be going up to the rockers. There was a flow of oil, though not as much as I would've guessed, and it would frequently spit air. Reassembled, still no oil to the rockers.
Then I removed the pressure switch and ran the engine. Liberal flow of oil, but once again, it frequently spit air with the oil. The oil level in the pan was sufficient in both instances according to the dipstick. There was no leakage of oil at the pickup tube to oil pump either. Puzzled by the presence of air but not sure what to do about it, I reassembled everything, and suddenly there was oil to the rockers as it should be. The oil pressure light went off, even at very low idle speed. At this point I was assuming air got trapped in the oil circuit somehow and had worked its way out.
Today I went in to re-check the valve adjustment and verify proper oil flow to the rocker shafts. Started the engine up and once again there was no oil to the shafts and the oil pressure light was on at idle. This time I disassembled the rocker oil valve, removed the block adapter and pressure switch so that I was left with just the threaded hole in the oil galley where the pressure switch would go on a stock engine. All of the components I removed were clean with no trash or debris in them. I probed around in the block with a small screwdriver and found a few light sludge deposits, but nothing substantial enough to block flow to the pressure switch or the rocker shafts, even cumulatively. I reassembled everything and once again I had full oil flow to the rockers and the oil light off at idle.
I'm stumped. If it was air in the lines, disassembling everything would hurt not help. If it was debris, I should have found it plugging the holes when I took pieces apart. I don't know why the oil flow wasn't smooth and steady when I removed the pressure switch or opened the rocker oil valve with the line removed; where was the air coming from?
The only other pertinent information I can think of to add is that 1. the oil pump is the original rotor-style, though I had it apart and everything looked and felt great and 2. I noticed that the oil filter adapter "TOP" marking was not perfectly at the top, but rotated about maybe 10-20* clockwise. Part of the opening was still at 12 o'clock; it just wasn't centered over 12 o'clock.
Any ideas about what's going on here? I'm going to keep verifying flow to the rockers every time I start the engine until I get it consistently. Hoping I don't have to disassemble things every time I want to drive.
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By MoonShadow - 13 Years Ago
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Check the rubber O-ring that goes on the oil pickup tube at the pump. I've been told they can suck air and cause oil pressure problems. Chuck
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By Ted - 13 Years Ago
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Peeeot. I’m thinking the oil viscosity when cold is keeping the oil from moving through your lines. Once the engine has heated up some, then the oil thins just enough for it to move. What oil are you using and what is the ambient (outside) temperature?
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By peeeot - 13 Years Ago
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Moonshadow: I was thinking about that too, but if it wasn't sealing right, wouldn't oil seep out of it when the engine's off?
Ted: I'm using Rotella T 15W-40 and the ambient temperature has been around 50*F.
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By MoonShadow - 13 Years Ago
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If its sucking air at the top its possible no oil would drip out. If the seal looks good try a light coating of sealent around the tube and see if it makes a difference. Have you put a mechanical gauge in the sender hole? Just to double check the cars gauge. Does the passenger side oil ok when its flowing? Its really strange how you have good flow after opening up the system and then bad again after sitting. It's possible there is a bit of gunk in the oil pressure relief spring area that is not letting the valve seat. Its behind that flat bolt head on the side of the oil pump. Could be a piece of gasket or something is holding relief valve open. Chuck
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By peeeot - 13 Years Ago
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Moonshadow, I think you have won the prize!
I started the car again today with the same scenario as I've been describing. This time, before the engine had a chance to warm up enough to speak of, I shut it off and got under the car and tightened up the pickup tube nut a bit. When I restarted the engine, I had oil coming out of the overflow tubes in a few seconds.
I'm going to check it again next time I start it up, but I think that's got it taken care of. I still think it's strange that the symptoms would go away without addressing the real source of the problem in the previous instances, assuming that I have indeed found it.
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By peeeot - 13 Years Ago
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Just another follow-up: I haven't removed the valve covers again because ever since I snugged up the pickup tube nut, the oil light has never even flashed as long as the engine is running and the valvetrain has been nice and quiet. Problem solved! Thanks again for all the input!
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By green-beret - 12 Years Ago
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Hello, My older brother, and that makes him really old, has just completed spending his savings rehabing an old 57 T-bBird. Looks like a million dollars. Unfortunatly he thought the antique engine would just start and run foreve, He is in Hawaii and I'm stuck trying to get the right rockers arms oiled. I can't find an exteranl oiler anywhere but know a lot of guys that would help me make one if I just had a couple of photos. Can anyone help with some pictures? I know that some of you think this is a poor substitute to having it run correctly but I just want to get him running so he can drive it another 200 miles to LA and get it on a bardge. Then it is out of my hair. Help Please!!
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