I want to find out what the correct oil pressure i should be looking for on the six cyl engine. The shop manual says 35-60 psi at 2000 rpm, but for engine with themactor. It does not list a number for without.

Thanks for the help. I have done several searches.

 

Why would it make a difference with or with out?
Is that reading motor hot or not?
What dose your motor have now hot at idle & at that RPM?
I would say if you have that reading hot not to worry.
As a rule 10 to 15 at hot idle and 10 PSI for each 1000 in RPM is good.
Dave ----

 

At cold idle, i have 32 psi. Not sure about when i get it hot. But with that number and your advice, i guess i am good.

Thanks

 

I just came back from a 1/2 hour ride. The pressure started out at 30, but as it warmed up and i drove it more, it began to drop to between -, then it dropped and stayed at about 10 until i got home.

I opened the hood to see if any of the fittings i used to set up the new gauge were leaking. None were, but i noticed air in the new line going to the gauge. Might this have something to do with it?

 

I don't think the air will affect the readings much. I put one in my '64 with a 390 and it works fine and has air in the line.
When you say it dropped and stayed at about 10 psi, Are you saying your pressure at idle is 10 psi? Or is the pressure constant at about 10 psi?

 

I bled out the air in the line and took the same 45 min drive. In the end i had 10 psi.

I have read about the orange oil filters being bad, I am going to change this and see if things change.

I grounded out my wire to the sending unit and the light on the dash lit up, so i guess the light works.

 

I just put in another oil pressure switch i had and started the engine, the oil light came on, so that confirms i have low pressure and the mechanical gauge is correct showing low pressure.

Should i try changing the filter and adding the stp treatment or am i wasting money?

 

Ben, is this a fresh rebuild on the engine and it's just been fired up or is this a engine with some miles on it? If it has some miles what you are seeing sounds normal. The 240 and 300 can go for years like this. Some people swear you can run them without oil for a brief period of time. Kidding, of course, but the engines can take a licking and keep on ticking (valve train noise most likely, lol).

Chad

 

Chad,

I know nothing about this engine. This truck was in a field for 20 years when i bought it.

I checked the oil pressure when i first started working on it and it was about 30. The light did not go on. So i assumed it was good. Me being a novice, did not know i needed to check it after the engine was hot.

The truck is 100% done, and now i need to take it apart.

Anyhow. I got some advice from my uncle who is a mechanic (500 miles away) who said to check the pick up screen and see if it is clogged.

So i am starting to take things apart now to remove the oil pan. Its a bit of work compared to your 4 wheel drive. I read another thread in which you described how easy it is for 4 wheel drive.

Should i replace the pump while i am down there?

Thanks

 

It wouldn't typically hurt to replace the pump but I wouldn't go with a super high-flow pump on an older engine, assuming it's getting some larger than stock tolerances, or you might float a bearing. But, yes, a new oil pump might help some. The old pump could certainly have some internal wear. And, as long as you are in there....

I went with a Sealed Power on my 4x4. Their model 224-41124. Napa had it local but Summit and others sure carry it, too.

https://www.summitracing.com/parts/slp-224-41124




Chad

 

Thanks Chad. I will start looking.

 

For what it's worth...I had the exact same worry about low to no oil pressure on my 65's 240 eng. I drove it 3 days a week for errands and after warm-up it went down to zero psi. I confirmed this with a direct reading gage plugged straight into the block. Im the second owner and I called the old guy who owned it since 1965. He said he drove it like that for 15 years. So I stopped fretting about it for the most part. The low OP is eventually what triggered me to disassemble the truck and start the total resto Ive been doing for 2 years. But I bet that 240 would still be running fine with no OP.

 

Thanks. Should i go with the 4 piece gasket or the new one piece? anyone have thoughts?

 

An easy way to see if you are getting enough oil flow to keep the engine alive is to warm it up and remove the valve cover and observe how much oil is getting to the top of the engine. If you are getting a decent amount through all the pushrods then it should be getting enough to the bearings. I don't know if you ever had a 6 cyl. chevy from the 40's or 50's but a good one was lucky to have 15 lbs of oil pressure the one in the picture wouldn't hold 5 psi hot but I've been told it's still on the road. That picture is from 1978.

 

Ok 2 things
First GET RID OF THAT ORANGE CAN OF DEATH! I have had it show lower oil psi all the time in less than a100 miles after an oil change. Just to prove this next change used a different filter, then 3rd change went back to the orange can. This was because of who I used and where I was when I needed the oil changed. After seeing the low psi I never went back to that place, would drive on dirty oil before using the orange can of death.
BTW the death can also acts like a plugged oil screen pickup and why the low PSI all the time.

2nd you say 10 pis hot is that at idle, at speed (rpm?) or both?
10 PSI at idle is ok as long as it goes up at speed / rpm.
If all the time well not good but as said they have run for ever like that also.
Dave ----