Ok guys, I need your advice. After driving my Slant 6 Scamp and it gets up to operating temp, the oil light begins to flicker when I am idling in gear. When I put it in Neutral or Park it goes out. And of course when I am driving it is not on. My past experience with this on another car led me to change the oil pump on the Slant 6 in my 70 Satellite. Don’t get me started about the 5 bolt hole vs. 6 bolt hole pumps. (Why the hell would they have switched to a 5 hole version that just begs to leak where the 6th bolt would be is beyond me)
BTW, this motor has only 48k on it, so I don't think the actual pump is worn out - but I suppose it could be.

Should I just remove the spring on the pump and replace with a high pressure MP spring I have?

Should I go through the hassle of changing the pump?

Isn’t there a procedure to remove the current spring and lifter- looking part and clean them up and reinstall?

HELP!

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Harry
1975 Plymouth Scamp 225/904/8.75
1968 Plymouth Road Runner 383/727/8.75

When it comes to matters such as this, its usually best to get another gauge to verify it is indeed the engine that is the problem and not a faulty gauge or sending unit if its an electric gauge. Try putting a mechanical gauge on it and see if it gives you the same results.

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There's no such thing as too much cam....only not enough engine!

I just ordered an oil pressure gauge from Summit.
When I install the gauge, would I just remove the oil pressure sending unit and run a new fitting with the line for the gauge in it's place?
I know a 12volt power with ignition wire will be needs along with power for a light.

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Harry
1975 Plymouth Scamp 225/904/8.75
1968 Plymouth Road Runner 383/727/8.75

It will also be a good idea to service the oil pressure relief valve to make sure it's doing its job, as described in these two threads: thread 1, thread 2.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Is the sender leaking? Replace it.

BTW you can "T" this and keep the idiot light and have a gauge.

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'72 Duster 198 stock cam, 3:23's Hookers on jack stands for 8 years in the driveway
'79 Maxivan 360 Offy Qjet Comp RV cam/rusting in the driveway.
93 D350 160HP Cummins Auto Dually Clubcab needs a injector pump
2005 Golden Couch Buick

No leak at the sending unit. I will connect the OP gauge that's on the way.

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Harry
1975 Plymouth Scamp 225/904/8.75
1968 Plymouth Road Runner 383/727/8.75

... and service the oil pressure relief valve... to be sure it is not sticking open and bleeding-off your low rpm oil pressure.
DD

I know Dan mentioned it was a scheduled maintenance item, but in both my 75 and 68 FSM I could not find this procedure anywhere.

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Harry
1975 Plymouth Scamp 225/904/8.75
1968 Plymouth Road Runner 383/727/8.75

It's not a scheduled maintenance item. It's a you-drive-an-old-car; you-wear-out-strange-things maintenance item.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

OK, both gauges installed, no leaks, both work. My Oil pressure at idle was between 35 - 40 on my '75 Slant 6. I didn't drive it cause I ran out of time.

For the Oil Pressure gauge, I removed the factory oil pressure sending unit and ran the end of the mechanical oil pressure gauge there.

For the Temp gauge, I used the Coolant Control Idle Enrichment Valve (CCIE) port on the head near the stat so my dash gauge still works too.

I routed these the best I could with the amount of line supplied with these gauges, each should have been about 6" to 1' longer.

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Harry
1975 Plymouth Scamp 225/904/8.75
1968 Plymouth Road Runner 383/727/8.75

Ok, here's the data. First let me add some info I found in my 1975 factory service manual. According to the manual Minimum oil pressure for the slant six at idle is 8 lbs of pressure. Operating pressure should be between 30-70 lbs @ 2,000 rpm.

I went out for a nice long cruise tonight. At between 180 and 190 degrees driving at 60 -70 mph my oil pressure was around 35 lbs and as high as 38/40.

At idle at a stop light it was 10 lbs on the nose.

What do you guys think? FSM says it's kosher, but....... 10 lbs at idle and 180 degrees?

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Harry
1975 Plymouth Scamp 225/904/8.75
1968 Plymouth Road Runner 383/727/8.75

Still waiting to learn the results of your pressure relief valve service.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Not trying to rob this thread - after 3 years of low oil pressure (I don't drive it much) my 79 Aspen now is a daily driver for work (20miles round trip) I said- ENOUGH- stumbled on the "fix your relief valve" threads and figured I got nuthin to lose and dont want to drop $70 plus on a new pump- 95000 miles on the clock, at idle barely registering any PSI - 20 PSI at 2000 RPM-

AFTER the cleaning- solid 25 PSI idling in park, and 45 -50 PSI on the highway - BTW I added 2 rivet washers (perfect fit) on top of the spring in fear that perhaps just a cleaning wouldnt be enough. So far so good- Oh yeah - FINALLY replaced the oil filter from previous owners "professional" tune-up (A$$ clown put a PH16 on it) with a PH8A-

Excellent info - much appreciated - darn thing runs and drives better than ever- SWEET !

Curious if any one has used the Hemi mopar perf spring and what the results where ? Thanks again

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37 Plymouth pickup -project-
69 D-200 -LA 318 , driver
79 Aspen /6 daily driver
01 Ram

Now go replace that Fram ticking-time-bomb of a pathetic excuse for an oil filter with one that stands less chance of fragging your engine. Wix 51515, NAPA Gold 1515, Purolator L30001, etc.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Been running Fram all my life- I did however read the review of different filters today- This was my last Fram filter on the shelf- I'll be switching when I restock my supply - I'll guess that Quacker State is crap oil also ?

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37 Plymouth pickup -project-
69 D-200 -LA 318 , driver
79 Aspen /6 daily driver
01 Ram