Oil pump priming question
- Thread starter Dusten
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nm9stheham
Well-Known Member
Most (?) will spin at 400-500 RPM loaded down in low speed mode (equal to 800-1000 engine RPM), and with cold oil, that ought to get many 10's of PSI of pressure. I use a Milwaukee corded 1/2" right angle drill (Milwaukee electrician's 'hole-shooter' LOL) running at 500-600 RPM, and with cold 10W30 oil it will hit the 72 psi relief valve limit.
One thing we have not mentioned IIRC, is that the oil pump could be shot.
One thing we have not mentioned IIRC, is that the oil pump could be shot.
Dusten
Active Member
So I checked all of the oil galley plugs they are all in. I also took the oil filter off and replaced it and while it was off I turned the engine over and oil is gushing out of that hole. The oil pump is new and appears to be working as oil is gushing out of 2 places (the hole to the oil filter and to the oil gauge). There is also no oil getting up to the rocker arms. Could it be a spun cam bearing? would that cause no oil pressure and no oil to the rockers?
nm9stheham
Well-Known Member
You can have flow but the inability to build pressure with a stuck pressure relief valve in the pump, or a significant leak at the pump or beyond. So having flow is NOT a complete test. You need to now put the filter back on, and the pressure sensor, and see if you are building pressure too. From the original symptoms, it sounds like not... which would indicate a leak somewhere from the pump onward. So unless you can build pressure, then the pump and it's mounting to the rear main cap are not yet fully checked out, as well as possible leaks elsewhere.
Again, the pump's relief valve could be stuck open and you would still have some flow out of it, but could not build pressure Just being new is not a guarantee that it is 100%. Or it could be mounted improperly as discussed in earlier posts. The only way to see this is to take the pan off and remove the pump and check it's mounting for any gaps. Sorry....
Oil is sent to the rockers only occurs once per every 2 revolutions of the engine (IIRC it is every 2 revolutions, not each revolution), and then does not flow the rest of the revolution of the crankshaft. The rocker supply oil has to flow through some holes that line up in the #2 and #4 cam bearings and the cam journals, to get to the rockers supply hole. Refer back to post #5 for the crank angles at which this occurs for each side. You have to rotate the engine to these angles, and then maybe rotate the crank a bit each way to get the holes in the cam to line up for oil flow to the rockers.
It will take a while to oil oil at the rockers after you have reasonable PRESSURE to the pressure sensor location and the crank is at the right angle. So you need to have pressure at the oil pressure sensor before you can check out the rocker oiling. Focus on that first. A spun/mis-aligned cam bearing could cause no oil to one set of rockers or the other, but would not be the overall cause of low oil pressure, unless the cam bearing was just mostly or completely gone!
Again, the pump's relief valve could be stuck open and you would still have some flow out of it, but could not build pressure Just being new is not a guarantee that it is 100%. Or it could be mounted improperly as discussed in earlier posts. The only way to see this is to take the pan off and remove the pump and check it's mounting for any gaps. Sorry....
Oil is sent to the rockers only occurs once per every 2 revolutions of the engine (IIRC it is every 2 revolutions, not each revolution), and then does not flow the rest of the revolution of the crankshaft. The rocker supply oil has to flow through some holes that line up in the #2 and #4 cam bearings and the cam journals, to get to the rockers supply hole. Refer back to post #5 for the crank angles at which this occurs for each side. You have to rotate the engine to these angles, and then maybe rotate the crank a bit each way to get the holes in the cam to line up for oil flow to the rockers.
It will take a while to oil oil at the rockers after you have reasonable PRESSURE to the pressure sensor location and the crank is at the right angle. So you need to have pressure at the oil pressure sensor before you can check out the rocker oiling. Focus on that first. A spun/mis-aligned cam bearing could cause no oil to one set of rockers or the other, but would not be the overall cause of low oil pressure, unless the cam bearing was just mostly or completely gone!
CMcAllister
Well-Known Member
Screw a gauge directly into the back of the block. Use adapters as needed. Eliminate the gauge and line you've been using until you get it figured out. Did it fill the oil filter?
Dusten
Active Member
I finally found out why there was no oil pressure. It was a broken pushrod. The pressure from the oil was pushing the lifter up and spewing out every where at the lifter, since there was no rod to hold it down.
Cal Tonsley
Well-Known Member
So, I guess the next question to pose and investigate, is why did the pushrod break? More than likely that there’s been mechanical interference at some point.
Wackers Rodshop
Member
I have rebuilt a dozen LA engines over the last 50 years but I am having a hard time figuring out what this cup plug under the main cap looks like ya'll are discussing . Getting old!
Locomotion
Well-Known Member
It's gotta be just the right size, but it's a regular "cup", like a baby freeze plug, that is installed from the rear main end of the block and it bottoms out about 1/2 way to the oil pressure sending unit next to the distributor.
It should come out for proper cleaning and needs to be installed so oil pressure won't be bled off to where it shouldn't be going to. There is a Direct Connection/Mopar Performance diagram out there showing the details.
It should come out for proper cleaning and needs to be installed so oil pressure won't be bled off to where it shouldn't be going to. There is a Direct Connection/Mopar Performance diagram out there showing the details.
67Dart273
Well-Known Member
The oil pressure tapping goes all the way down through the engine and out the bottom, with another branch gallery meeting it. There's a small cup plug has to be up in there to separate the two.
Discussion of that area
SB Oil Galley Plug Depth?
The machine shop that done my 318 knocked out that heavy plug that goes under the rear main cap and I don't know how far down it's supposed to go to put it back. The plug looks like a 3/4"L x1/2" slug/round bar. Anyone know how far down it's supposed to go??
www.forabodiesonly.com
Mopar Engine Performance Guide: Oiling System - Mopar DiY
The oiling system isn’t as high profile or glamorous as heads, cams, and other parts. But as we all know, it plays a vital role in the performance and longevity of an engine. The oiling system touches all of those parts. Clearance is an issue for street cars and street/strip vehicles, so you...
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