Need help 427 low oil pressure ?

[priobe]

Vettestr:

I am not sure if I understand you correctly. The filter that I am running is a Motorcraft FL1A not a 8A. Am I running the wrong filter?


OldDog:

Do you know what the distance should be from rod to rod. I will check that tonight.

Originally Posted by olddog

You should be able to watch the oil pressure climb with rpms until the pressure reachs the point where the bypass valve opens. From that point on the oil pressure should stay pretty much the same.

What is the oil pressure at 1000 rpm, 2000 rpm, 3000 rpm, 4000 rpm - hot and 1000 rpm & 2000 rpm cold?

Oil Pressure is
1000 RPM 20 psi
2000 RPM 25 psi
3000 RPM 28 psi
4000 rpm 28 psi


Iceberg:

I am not sure what a Pond block is. This is a block from 1965 (I guess cast iron) sideoiler. ( Sorry I am affraid to use the word original around here I dont want this thread to get side tracked by using the wrong word.
Or not an aftermarket Block.
Is this what is referred to a Pond block?


Again thank you all of you for your advice.

[patrickt]

That filter is tried and true; it is not the source of the problem. You do not have a Pond block from 1965, so ignore that as well. Those pressure numbers are below what they should be, so you have a real problem. I looked back on this thread and didn't see whether the builder broke the engine in on his dyno. If so did he note the pressures at that time? Or did the engine have good pressure on the dyno and only recently start experiencing low pressure issues?

[olddog]

Originally Posted by priobe

OldDog:

Do you know what the distance should be from rod to rod. I will check that tonight.

Oil Pressure is
1000 RPM 20 psi
2000 RPM 25 psi
3000 RPM 28 psi
4000 rpm 28 psi

Sorry to have been away for a while. I do not know the rod clearance off the top of my head, and my wife put my books (that I left in the living room) in a mountainous pile in front of my dresser. I hated to try to find anything in the pile for fear of an avalanch. I'll get back to you on that one.

I think Patrickt is onto something. Follow his advice first.

Just looking at your rpm verses pressure numbers I'll tell you what I suspect. I suspect there is a flow restriction between the oil pump and the pressure gauge. There is a big pressure drop at this restriction (say 40 psi). The pressure at the pump is still up in the 50 - 70 range. Somewhere between 2000 and 3000 rpm the pressure at the pump is high enough to open the pressure relief valve built into the pump, which is why the pressure you are measuring levels out at 28 psi. The most likely place for this restriction is in the external plumbing that Patrickt wants you to remove.

The adapter that is bolted to the block may not have the holes lined up correctly. A line may have a bad spot where a chunk folds over and forms a blockage under flow (rubber brake lines do this a lot). I really suspect there is some problem here.

[priobe]

UPDATE:

Ok after cursing for about 2 hours and battling the removal of the toploader tranny, I think I figured out the low oil pressure problem. Apparently my Engine builder installed the pressure relief valve incorrectly in the back of the block.

This is what I found after removing the allen plug that is located above the camshaft was the spring then plunger in the block.

I know it should be spring 1st the plunger with the stem facing toward the allen plug.

Now since I have the oil pump in hand which I verified is a HV pump shoul I replace it with Precision oil pump and high pressure spring?


The oil old pump looks perfect.

I just figured since it is off should replace it.


What are your thoughts?

[patrickt]

Originally Posted by priobe

Apparently my Engine builder installed the pressure relief valve incorrectly in the back of the block...

What are your thoughts?

But weren't you, and the builder, both getting good pressure numbers before you put the engine in your car? I guess it couldn't hurt to put it back together and fire it up and see what the new numbers are now though. If they're still down low, then that wasn't it.