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Re: Oil pump valve spring pressure
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20 psi at idle with the engine warm?? If yes I would say that's okay, low oil pressure light doesn't come on until around 5 psi.
Have you checked clearances on your pump? Maybe it needs rebuilding. What is the condition of your engine? If it's a bit tired it will be hard to get higher oil pressure. At start up my Cavalier has about 35 pai at idle, which drops to about 12-15 when warm at idle. Not a fresh engine and haven't checked my pump, but it's on my list.
Posted on: Yesterday 20:22
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Re: Oil pump valve spring pressure
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Quote:
I took the spring out and actually measured the spring pressure, only about 8 pounds at about 3/8” and only 20 fully compressed. I Im definitely dealing with a low pressure problem; cold engine and thick oil the needle hardly moves off zero on my gauge. I haven’t gotten an actual number yet. My engine is newly rebuilt and I rebuilt the oil pump as well I dont suspect the sending unit/ gauge to be faulty either. (Ive been trying to get a mechanical gauge on the sending unit port to verify this but it has been fighting me maybe I will get to that by tomorrow.)
Posted on: Yesterday 20:49
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Re: Oil pump valve spring pressure
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How did you rebuild the pump, exactly? What new parts, if any?
V8 pump clearances, typical of your pump: - gear to body 2.5 to 4.5 diametral - gear endplay 2 to 6 (engine manual recommends no more than 3) - driven gear to shaft 1.5 to 3 - driveshaft to body 1.5 to 3 Why not measure the area (diameter) of the plunger, and necessary compressed length for the spring, and the spring rate, to calculate the necessary pressure to open the relief port?
Posted on: Yesterday 21:06
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1955 400 | Registry | Project Blog
1955 Clipper Deluxe | Registry | Project Blog 1955 Clipper Super Panama | Registry Email (Parts/service inquiries only, please. Post all questions on the forum.) service@ultramatic.info |
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Re: Oil pump valve spring pressure
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I added a gauge right where the sending unit goes.
 Verify oil pressure and go from there. You'll want good oil pressure/flow to break in your rebuilt engine. Did the car have okay oil pressure before the engine rebuild? Maybe the tee for the oil filter is installed incorrectly? I believe some have a smaller opening going to the filter so that the majority of flow goes to the engine.
Posted on: Yesterday 21:06
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Re: Oil pump valve spring pressure
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Update
Was finally able to fit a mechanical gauge onto the sending unit port. Oil pressure is about 37 at idle and 40 under normal driving speeds; perfectly within specifications. Time to shell out the money for a new sending unit, Max Merritt quoted me about $300!  This at least gives me peace of mind to start actually driving my car. Unfortunately I am still dealing with an issue. I can tell my engine has a significant amount of wear already. (I probably only have a total of 2-3 hours run time over the past year since the rebuild and that is a generous estimate.) The oil has quite a bit of metal in it telling me that something is trying to self clearance. I had thought it was just this oil pressure issue but now I have to look further into it. I know the break in should dirty the oil rather quickly but surely this has to be excessive, yes?
Posted on: Yesterday 22:32
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Re: Oil pump valve spring pressure
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New shaft, gears, spring, the gear that touches the cam, the plate and retainer for the distributor drive, and gaskets. Pretty much everything new except for the piston and body. Quote:
This is where my thinking was flawed; I was thinking the spring needed to have the same pushback as the set oil pressure; which would only be the case if the face of the piston had an area of 1 inch which it does not. 
Posted on: Yesterday 22:38
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Re: Oil pump valve spring pressure
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That's good news that you have good oil pressure! Not good news about the price a new sending unit, ouch! Someone must know of a better source!
Here's a note about engine break in from the service manual.  I'm not an engine builder so can't speak to what the oil should/could look like when breaking in one of these engines. I believe it's perfectly normal to see some small particles. Do you have pictures of what you're seeing in the oil? Have you changed the oil to see if the oil stays clear after your initial few hours of running?
Posted on: Yesterday 22:53
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Re: Oil pump valve spring pressure
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Is the oil just a bit glittery? There should be no pieces in particular that are visible but the oil can look a bit sparkly from the cylinder wall break-in.
Posted on: Today 0:32
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1955 400 | Registry | Project Blog
1955 Clipper Deluxe | Registry | Project Blog 1955 Clipper Super Panama | Registry Email (Parts/service inquiries only, please. Post all questions on the forum.) service@ultramatic.info |
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Re: Oil pump valve spring pressure
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You can collect an oil sample and have it analyzed. Since you know what went into the rebuild, you can compare the measured metals in the oil with the metals of the rebuild components and identify what is wearing.
Posted on: Today 0:43
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