oil pressure

[BUNK]

Boy, I sure got a lot of bathroom reading from that post. Thanks to all.
I live in Southern Colorado and those of you who do, or have been here, know that directions to anywhere start with, "You take xxxxxx Pass..." My base elevation is 9000' and I go up from there. Most of my driving is in the '64 convt. or the '62 van with the pressure problem. Neither has been above 3500 rpm, but there is often some good pulling. The '64 has never had a problem. I built that engine. +/- 60 psi at cold start, +/- 45 driving speed and +/- 20 at idle with a stock pump.
The low pressure I described on the van was another of my builds on fresh guts and a stock oil pump. Those low idle pressures were why I got the HV pump, same problem, I use Valvoline 20-50 in both cars because of the high zinc and what I perceived to be heavy loads from mountain driving.
I like the idea of some kind of obstruction in the pressure valve area and will go there first before swapping to a known solid engine.
Thanks to all for your input. Another set of eyes, ears and experiences is most appreciated.

[Gasman63]

I cant help ya Bunk. Sorry.
But Im wondering where you are. How about a hint? Im in the Springs. Not many cities in CO at 9000ft that are south. Maybe hoosier, kenosha or Wolf creek? BTW, Im a Truckdriver and have been on them all. Lol.

Good luck sorting out the oil pressure.

[66vairguy]

Boy, I sure got a lot of bathroom reading from that post. Thanks to all.
I live in Southern Colorado and those of you who do, or have been here, know that directions to anywhere start with, "You take xxxxxx Pass..." My base elevation is 9000' and I go up from there. Most of my driving is in the '64 convt. or the '62 van with the pressure problem. Neither has been above 3500 rpm, but there is often some good pulling. The '64 has never had a problem. I built that engine. +/- 60 psi at cold start, +/- 45 driving speed and +/- 20 at idle with a stock pump.
The low pressure I described on the van was another of my builds on fresh guts and a stock oil pump. Those low idle pressures were why I got the HV pump, same problem, I use Valvoline 20-50 in both cars because of the high zinc and what I perceived to be heavy loads from mountain driving.
I like the idea of some kind of obstruction in the pressure valve area and will go there first before swapping to a known solid engine.
Thanks to all for your input. Another set of eyes, ears and experiences is most appreciated.

Based on your latest statement the low hot idle oil pressure existed with a stock pump and the high volume pump has not solved the problem. I did not see if you checked the crankcase for pressurization after the engine is hot that I suggested. It will lower idle oil pressure. I have seen it twice with plugged up crankcase vents (one PCV the other road draft tube). If that is not the issue then a problem pressure regulator seems likely.

I had one oil pressure issue and I could solve after check the pump and pressure valve. I replaced the entire end cover. Problem solved. Oh! I always plastigauge the oil pump cover across BOTH gears. Sometimes I find one gear clearance is greater than the other and there are wear marks only on one side of the cover. I rotate the cover and then select a gasket so BOTH gears have the same clearance to the cover. Good luck and let us know what you find.

[BUNK]

Well, over 6 months of trying to figure it out and I finally had two solutions. I don't know which solved it.
I watched a Larry Claypool video on the oil pump idler shaft leaking. He mentioned that stock pump clearance was .002 - .004. Then stated, "Any more than that and you won't have oil pressure at idle." Since I had installed the hi flow while in the car and was skeptical of an accurate clearance reading, when I had the engine out, I removed the rear housing to do this right. While inspecting the housing, behind the idler gear, I found a pit that extended into the housing body. Apparently, oil was leaking past the gear at this point. After replacing the housing, and following Larry's advice on clearance, the problem was solved. Thanks for all your comments and thoughts.

[66vairguy]

Well, over 6 months of trying to figure it out and I finally had two solutions. I don't know which solved it.
I watched a Larry Claypool video on the oil pump idler shaft leaking. He mentioned that stock pump clearance was .002 - .004. Then stated, "Any more than that and you won't have oil pressure at idle." Since I had installed the hi flow while in the car and was skeptical of an accurate clearance reading, when I had the engine out, I removed the rear housing to do this right. While inspecting the housing, behind the idler gear, I found a pit that extended into the housing body. Apparently, oil was leaking past the gear at this point. After replacing the housing, and following Larry's advice on clearance, the problem was solved. Thanks for all your comments and thoughts.

Thank You Bunk for letting us know what was the problem. Glad you solved it.

As I mentioned, more than once I've pulled a plate and noticed only wear on one side. I've been told the end of the oil pump housing was EXACTLY 90 degrees to the pump gears axis due to machining tolerances. Seeing the end plates with wear at an angle only confirms this. Problem is if the plate (it is symmetrical) is not orientated back to the original position one gear clearance will be more than the other --- this is why I plastigauge under BOTH gears when selecting a gasket thickness to make sure the clearance under BOTH gears is acceptable.

Enjoy you car.

[jimbrandberg]

With the engine on a stand with the oil pump level I do the Plastigage thing but I also like to play around with the feel of the oil pump while turning it with a screwdriver. I'll sneak up on it with ever thinner gaskets until I can feel the drag of the gears against the plate then go to the next thicker gasket. Then turn the engine upright and feel it with the screwdriver again.

I didn't read through all the text and perhaps I'm overly simplistic but I have to believe a high volume pump can't do much if there's no where for more volume to go.
The oil filter seal is probably the first thing that will only bear so much pressure. One time I missed a shift between 3 and 5 at Road America and blew out the C483A alternator mount gasket.
My oil filters were in the trunk by the oil cooler and right or wrong I was using a high volume pump there. Accusump too but I digress.
One time I blew a front mounted non-Corvair oil filter seal when the pressure relief valve piston thingy in the rear housing stuck.

Just my opinions and I could be wrong.