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Low oil pressure ... do i have a big problem?
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Author:  ScampNYC [ Thu Aug 22, 2024 7:45 pm ]
Post subject:  Low oil pressure ... do i have a big problem?
Hello, I posted this in another forum but figured I ask you guys since this is a slant six specialty forum! I have a 1971 Scamp that I recently found in a "barn" (small garage) as part of an estate sale in Brooklyn, NY. The last time it was on the road, according to documents, was 23 years ago.

The oil light is coming on and I'm trying to figure out if I have a big problem.

I brought it back to life and she runs great for the most part. Part of "bringing it back to life" was of course changing the 23+ year old oil and oil filter. The filter was seized to the oil pump so badly that I had to get a strap wrench and apply lots of torque to get it off. The filter was completely wrecked before I was able to get it unstuck—it looked like it had been chewed on by a dog with steel teeth.

I have been tooling around a bit in it, and noticed that on start-up, the oil light was coming on and going away after about 15-30 seconds.

Then I decided to take it for a longer drive, and after about 30 minutes of driving, the oil light was coming on at every stop sign. I live in the outer boroughs of NYC, so there are a lot of stop signs. Once I picked up revs, the oil light would turn off. This freaked me out so I drove back home. As I was driving home, the oil light came on more and more, and higher and higher rpms were needed to keep the red light off.

So today, I decided to try and hook up a mechanical gauge to get an actual read on my PSI. The idiot light sending unit was frozen on there pretty bad. It also looks to be a lot larger than the 1/8" NPT I was expecting. The sending unit doesn't want to come off and is right now soaking with PB Blaster. Curious, is there anywhere else to hook up the mechanical oil gauge?

But I noticed something really weird. In the nipple that the oil filter screws, there appeared to be a piece of debris sitting on top of a spring. I thought maybe this was the source of my problem. I picked up the piece of debris, and it looked like a mechanical part. What is this thing? Do I need to put in a new oil pump? Can I do so with the engine in the car? Can I remove that spring? See photos...

Thanks!

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Author:  ScampNYC [ Thu Aug 22, 2024 7:45 pm ]
Post subject:  Re: Low oil pressure ... do i have a big problem?
Heres the mystery object

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Author:  ScampNYC [ Thu Aug 22, 2024 7:45 pm ]
Post subject:  Re: Low oil pressure ... do i have a big problem?
Another view of the object

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Author:  ScampNYC [ Thu Aug 22, 2024 7:47 pm ]
Post subject:  Re: Low oil pressure ... do i have a big problem?
The car as I found it. I replaced the fuel tank and all fuel lines before getting it running.

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Author:  mcnoople [ Fri Aug 23, 2024 5:59 am ]
Post subject:  Re: Low oil pressure ... do i have a big problem?
Your object is likely part of the old oil filter. I don't recognize it personally. I will say put an actual oil pressure gauge on the car to see what it is at, your frozen fitting is I believe 3/8 npt. Get a normal TEE from the plumbing section of your local hardware store and use thread tape on the fittings.

But be advised that in the owners manual from when they built these car that chrysler believes it is perfectly fine and normal for the oil pressure light to flicker when fully warmed up in gear in hot weather.

The engines can idle so low stationary in gear that they only build 4 or so psi, hence the need of an actual gauge to see what pressure is when driving. You don't need the gauge to be permanent just a diag tool to determine the engines health.
Author:  SlantSixDan [ Fri Aug 23, 2024 1:42 pm ]
Post subject:  Re: Low oil pressure ... do i have a big problem?
That's not part of the oil filter, no; it's the valve plate from the check valve in the oil filter adapter screwed into the middle of the oil filter mount pad part of the oil pump. That check valve's nominal job is to prevent oil leaking down out of the filter after engine shutdown. The spring you see in the adapter used to hold the plate against the rim at the "ceiling" of the adapter, but it has come apart. There used to be a steel standpipe about 3 inches long pressed into that adapter; it appears to have gone missing sometime in the last 53 years, and with that gone, the valve components had enough more wiggle room to escape.

Replacement standpipe/valve assemblies are no longer available; new oil pumps come with just a plain, hollow adapter.

Remove the spring and discard it and that escaped plate, leaving you with a hollow adapter. The valve and standpipe's function can be duplicated by using a filter with an inbuilt standpipe, that is Fleetgard LF701 (best available filter of this type), or Wix 51806.

As to the problem you're experiencing: don't panic just yet. Service the oil pressure relief valve to make sure it's doing its job and isn't stuck partway open, as described in these two threads: thread 1, thread 2.

Oil pressure sending unit is 3/8" Dryseal thread. The sender is another likely cause of this oil light behaviour; it might go away just by replacing the sender (but you should still service the relief valve).

Alternate location to put in a mechanical pressure gauge: the 3/8" dryseal-threaded pipe plug on the passenger side of the block, near the rearmost extent of the oil galley.
Author:  ScampNYC [ Sun Aug 25, 2024 10:06 am ]
Post subject:  Re: Low oil pressure ... do i have a big problem?
Thanks, Dan! Very encouraging.
Interesting about the standpipe. I wonder if its possible that it came off with the extreme amount of torque I had to apply to get the seized oil filter off.
Author:  SlantSixDan [ Sun Aug 25, 2024 10:42 am ]
Post subject:  Re: Low oil pressure ... do i have a big problem?
No. It doesn't touch the filter. It just loosened up and came off sometime in the past.
Author:  Jase [ Tue Aug 27, 2024 7:39 am ]
Post subject:  Re: Low oil pressure ... do i have a big problem?
I had lower oil pressure upon startup last year. Rather than 45 PSI, I had 38 or 40 PSI on a cold start. I impulsively changed the oil, and filter, and found that the stand pipe was slightly loose..

Not sure if the loose stand pipe was causing lower oil pressure, of if the filter was going into bypass.. It was low mileage oil, and a new filter, and the oil pan has been removed and cleaned to address an oil leak at the front of the engine.. so I don't think the filter was going into bypass due to being plugged..

Seeings that I run the 51806 filter, I may remove the oil pump stand pipe on the next oil change..
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