Oil pressure light question

[Steve Garner]

If its a stuck valve a leak down or compression test will find it but doesn't explain the loss of oil pressure.

I think he's talking about a relief valve in the pump.
It's a visual thing. I don't recall what a small block pump looks like but you will have to identify the valve and try to examine the business end.

 

[Sonny]

I think he's talking about a relief valve in the pump.
It's a visual thing. I don't recall what a small block pump looks like but you will have to identify the valve and try to examine the business end.

Yes. Oil pump Relief valve. Thanks for clarifying.

 

[Steve Garner]

You're looking for a broken spring or debris lodged between the spool and the seat. If you don't see either of those you will remove the spring and make sure the spool moves freely in the bore. That part is unlikely. You fix it as required. If the spool is sticking polish it and the bore with ultra fine crocus cloth. If it's scored, replace the pump.
A stuck spool where you still have better than 10 psi at minimum is not going to be responsible for engine noise.

 

[Wietse]

If its a stuck valve a leak down or compression test will find it but doesn't explain the loss of oil pressure.

I think he means te pressure relief valve on the pump.

I never opened a pump of these cars yet but you can inspect it for damage or wear.
Normally it's like a small piston that is kept in place against its seat by a spring.
Broken spring, damage on piston/seat that allows oil to pass, thats were it will be losing oil.

 

[Sonny]

I’ve been going a lot of thinking and researching my oil pressure issue. Here’s what I think I’ll find Monday when I get home from vacation and pull the pan:

I swapped my 318 for this 360 4 months ago. The 360 is a crate engine with approx 20k miles and was in a ‘78 Karry van. I replaced the timing chain, water pump, intake and carb, and also had to buy a car pan because the 360 had the rear sump truck pan (see photos). I also took off the pump and added the correct pickup tube.

From the minute I made the swap, I’ve heard this hard rattle. It only happens when I get on it hard from a dead stop or at a couple mile an hour. Never at idle, cruise, nothing. Not a sound. Only hear it hard off the line. Basically a High torque situation like something is loose and knocking. Right before the pressure loss, I got on it at about 5 miles per hour and heard that same knock but louder. 1/4 mile later I see the oil pressure reduction. I have a feeling that noise was the pickup tube hitting the side of the pan, and now it’s either cracked the pump housing or the bolts have come lose. Ill let you guys know what I find.
Sonny

 

[Sonny]

Question. This is a ‘70 Belvedere. Nothing seems to be in the way of removing the pan but the steering linkage. Will the pan come off without removing the linkage? Looks like the rear pan notch “could” pass over the oil pump and remove the pan forward? I know I’m reaching but figured I’d ask anyway.

 

[miller]

Drop the center link...makes life a whole lot easier.

I've never been into a small block, but parts is parts. Pan needs to clear the crank counter-weights, besides the pick-up tube.
I'd suggest taking a good look at the crank itself, while your in there, for any place it got hot. Even if it is the pick-up tube, could have spun a bearing, or some scoring.

Good luck on it!

 

[HT413]

View attachment 554227 Question. This is a ‘70 Belvedere. Nothing seems to be in the way of removing the pan but the steering linkage. Will the pan come off without removing the linkage? Looks like the rear pan notch “could” pass over the oil pump and remove the pan forward? I know I’m reaching but figured I’d ask anyway.

Agreed with miller, the center link has to come out tand make your life easier. Besides, it has to clear the pickup.

 

[Sonny]

Completely forgot about the crank weights. I’ll pull it.
Thanks.

 

[Don Frelier]

Completely forgot about the crank weights. I’ll pull it.
Thanks.

You should be able to remove the motor mount bolts and jack up the motor a couple inches from the front.
It's easier than pulling the whole motor. I did it on my 383 this fall and it really wasn't very difficult.

 

[Steve Garner]

Can't imagine why high torque would cause the pickup to hit the pan. The torque makes the engine twist on its mounts, not it's internals to twist relative to themselves.

 

[Sonny]

Update. I finally got time to pull the oil pump shaft and distributor. I inserted a mopar small block oil pump priming shaft into the oil pump and I can barely spin it with 2 fingers. Is that correct? Is that a sign the oil pump is bad? The new pump I bought spins super loose and easy. I put a drill on the primer shaft and it came up to 40 lbs but at that point my drill stopped and couldn’t over come the pressure I guess. Thoughts?

 

[khryslerkid]

Update. I finally got time to pull the oil pump shaft and distributor. I inserted a mopar small block oil pump priming shaft into the oil pump and I can barely spin it with 2 fingers. Is that correct? Is that a sign the oil pump is bad? The new pump I bought spins super loose and easy. I put a drill on the primer shaft and it came up to 40 lbs but at that point my drill stopped and couldn’t over come the pressure I guess. Thoughts?

I never tried spinning the priming shaft by hand with oil in the pump. It might have more resistance then when dry.

I know on the 440 priming, you need a good drill. A 1/2" electric is best. I've used a good battery powered drill and it was a bit much for it.

Did you get any oil up to your rockers? I'm thinking without the oil ports in the cam being lined up, there might be more resistance, being the oil pressure hasn't anywhere to go like if there was an outlet to the rockers. Just thinking out loud.

 

[miller]

I've used both a speed wrench, or drill motor, to turn the primer shaft. Yes, it will, and should drag down some, once the pump is filled with oil. But, that's past the point...is the oil getting pumped through the engine?
If your getting a pressure read on your gauge, assume so.

Ever drop the pan, to see what's going on in there? Still wondering about the noise you were talking about.

 

[Sonny]

I've used both a speed wrench, or drill motor, to turn the primer shaft. Yes, it will, and should drag down some, once the pump is filled with oil. But, that's past the point...is the oil getting pumped through the engine?
If your getting a pressure read on your gauge, assume so.

Ever drop the pan, to see what's going on in there? Still wondering about the noise you were talking about.

Not yet. Been too cold!

 

[Don Frelier]

A drill motor will stall hard when you develop oil pressure. Sounds correct to me.
Believe me you think Florida is cold, it's awful here in New York today...

 

[Sonny]

Finally pulled the pan. Oil pump not loose, not cracked. I can’t get the plug out that caps the relief valve, but I can move the piston freely with a pick. Does it look to be in the proper position in the picture? There was about a dime size pile of debris in the center of the pickup tube screen. Mostly rubber particles. I’m replacing the pump regardless. What is my next move? Install new pump and try it?

 

[miller]

There was about a dime size pile of debris in the center of the pickup tube screen. Mostly rubber particles.

That rubber debris could have easily been the problem. Again, I don't have experience with SBs, so don't know rubber locations. O-ring installed wrong? Anyway, yeah, a different pump, or...rebuild the one you have, with new seals, if the clearances are good. With the trash in there, easy to have some in the relief valve seat...knocking the oil pressure down. I'd get the valve out, for a look.

At least your not looking at loose metal!

 

[Steve Garner]

The bits of rubber are most likely pieces of old valve stem seals. There are no o-rings or seals in a pump. I don't see anything there that would leave me to believe you have found your problem. I wouldn't be putting the pan back without looking at the mains and rod brgs.

 

[Sonny]

The bits of rubber are most likely pieces of old valve stem seals. There are no o-rings or seals in a pump. I don't see anything there that would leave me to believe you have found your problem. I wouldn't be putting the pan back without looking at the mains and rod brgs.

Thanks Steve. Can someone point me to the rod and main torque specs for a ‘78 360?