383 low oil pressure

[ZDECKICH]

Electric gauge? Wrong ohm sending unit? What's a mechanical gauge read?

As stated above the mechanical autometer gauge. "Mechanical gauge I hooked up shows hot idle its around 5 (on mechanical gauge) shows 0 on the dash gauge. driving shows 15-16 on mechanical gauge and 12-13ish on the dash gauge."

 

[rickseeman]

This is a tough one. I still don't know what to do next except to prime it with an electric drill. It has a new oil pump. It's full of oil. The psi should go to 70 real fast. If it doesn't, how does it "feel"? Does it feel like it's really pulling hard and pumping a lot of oil and a galley plug is missing or a lifter popped out? Or does it "feel" like it's freewheeling and sucking air? Pay attention to the "feel". You are the doctor on this. Is it pulling really hard or is it kinda freewheeling? That is what we need to know. I had a 68 Charger once. Beautiful lines.

 

[4speed68rt]

This is a tough one. I still don't know what to do next except to prime it with an electric drill. It has a new oil pump. It's full of oil. The psi should go to 70 real fast. If it doesn't, how does it "feel"? Does it feel like it's really pulling hard and pumping a lot of oil and a galley plug is missing or a lifter popped out? Or does it "feel" like it's freewheeling and sucking air? Pay attention to the "feel". You are the doctor on this. Is it pulling really hard or is it kinda freewheeling? That is what we need to know. I had a 68 Charger once. Beautiful lines.

Great idea rickseeman. Just to add to that. with a HV oil pump, it should try to twist the drill out of your hand, and make the drill strain.

 

[lewtot184]

As stated above the mechanical autometer gauge. "Mechanical gauge I hooked up shows hot idle its around 5 (on mechanical gauge) shows 0 on the dash gauge. driving shows 15-16 on mechanical gauge and 12-13ish on the dash gauge."

Start taking things apart starting on top. Definitely not right. Could be something as simple as bleeding through rocker shaft not installed properly. Bearing clearances, camshaft or rods/ mains, would have to be very bad for that kind of pressure loss.

 

[BSB67]

1) show us a picture or two of the mechanical and electric gauge hook- up to the block.

2) Remove all fittings attached to the block for both oil pressure gauges.

3) make sure the block passages are clear for both fittings.

4) make sure the fittings/reducers/pipe nipples and tubing are all clear.

 

[lewtot184]

I've been thinking of something that may seem radical but possible. Could a standard rod or main bearing have been used with a .010" crank? Engine would run but roughly, and oil pressure would be very poor.

 

[PRHeads]

I ran into that situation on a 350 SBC ages ago.
10/10 crank, std bearings.
Ran perfect, no noise at all.
Normal-ish oil pressure on cold start, very very low pressure when warm.

 

[Bird 426]

My money is on the front cam plug wasn't installed. Yes, it will still have some oil pressure. I left the back one out on the left rear of a small block, the one that's easy to miss because you don't see it. The engine ran, and didn't hurt anything, was very slow getting oil.to the top end. He's got take it apart and find out what's wrong. I know it, and so does the OP. Can only do so much arm chair quarterbacking.

 

[lewtot184]

And, what if the crank was ground and somebody really missed the number? Pipe plugs can be an issue, cracked pick-tube, etc, etc. Best thing is to take the engine out and do a thorough check.

 

[ZDECKICH]

Engine will come out for sure at the point. Im going to drive it for the next month, if it lets go it lets go. After the month it will just get rebuilt the correct way. Thank you all for the help. Ill let you know what we find once the motor comes out.

 

[ZDECKICH]

Just a update on this thread if anyone was following or curious.

Motor is out, and found out it had been rebuilt, but by someone who has no business rebuilding motors. car is .040 over and 2 of the 8 piston rings where stock size. Sent for a Blackstone oil Analyze. tons of copper and bearing material in the oil. The oil sling shield that goes over the crank nose behind the timing cover, was installed wrong and was chewed up by a grinder for clearance and installed. So just a bunch of half assed problems.

So car is now going to be a 4bbl with a Edelbrock dual plane (2186) and Holley 750 carb, Comp Cam (275/287 525/525 110) TTI headers and X pipe with Corsa mufflers, B&M Torque Master stall (2600 I think) MSD Pro Billet distributor (get rid of the points) and little head work on the 906 heads and pistons to help up the compression. Hoping for low to mid 400hp. Hope to get the car back on the road soon.

 

[ZDECKICH]

Few pics so far.

 

[BSB67]

Measure how far down the pistons are below the deck.

 

[Dusty Dude]

Few pics so far.

View attachment 1764456View attachment 1764457View attachment 1764458View attachment 1764459View attachment 1764460View attachment 1764461View attachment 1764463View attachment 1764464

You might want to re-think the distributor and get one with adjustable vacuum advance. Your idle, throttle response and mileage will all benefit greatly.

 

[69conv]

You did the right thing pulling the motor. All those problems you would have never found. You're about to get a rompin motor you can have confidence in.

 

[ZDECKICH]

Measure how far down the pistons are below the deck.

Yea, the machine shop advised in new pistons to bring it up to raise the compression. That’s in the cards.

 

[Fran Blacker]

Yea, the machine shop advised in new pistons to bring it up to raise the compression. That’s in the cards.

What was the reason for low oil pressure ? There are 2 plugs in cam gear area, motor needs to be almost upside down to see second one.

 

[diesel_lv]

The oil slinger was installed correctly. That is what happens to a lot of them w certain double row timing chains, not from a grinder. Leaves lots of metal in oil obviously. I removed my slinger as it doesn't make any difference.

 

[ZDECKICH]

You might want to re-think the distributor and get one with adjustable vacuum advance. Your idle, throttle response and mileage will all benefit greatly.

This is the one my engine builder recommends. What exactly is the issue with the one I got?

 

[Dusty Dude]

This is the one my engine builder recommends. What exactly is the issue with the one I got?

The lack of vacuum advance. Take a few minutes and watch this video as this guy has it figured out. You will be glad you did.


Give Rick a call at Firecore and put some benjamins back in your pocket.