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oil pressure issues #1428239 04/30/13 07:30 PM 04/30/13 07:30 PM
Joined: Jun 2010 Posts: 591 Champion City The Sphinx OP mopar
The Sphinx OP mopar Joined: Jun 2010 Posts: 591 Champion City	I've rebuilt a few small blocks in the past and never had an issue like this. I primed the oil system and fired up the engine and it maintained (cold 75PSI) (hot 40PSI) at 2000 RPM. Now my issue is at idle my pressure drops down to 15PSI regardless of it being hot or cold. I use a snap-on 1200 RPM drill on an old distributor that has been lengthened to reach the oil pump as a priming tool. What I noticed that is strange is: 1) When priming it, it takes about 3 seconds to feel any resistance in the drill. If you stop and start the drill again a few seconds later it still takes about 3 seconds to feel any back pressure on the drill. Like the pump is loosing its prime. 2) When I prime it and get the oil pressure up to any pressure and then stop, you can hear the sound of oil pouring into the pan. It sounds more like pressurized oil dumping. I've checked the gallery plugs, they are all in. The oil pump pick up is just shy of 1/4 off the bottom of the pan. What else should I check? I'm down to thinking it's either a bad pump (Melling M72), gasket between pump and main cap poo pooed on my, or a leak between the pick up and the pump. Any other guesses? For the heck of it I primed the system on an old 360 I rebuilt several years ago and noticed once It's primed and I reprime I get instant pressure and resistance on my drill. Once I stop priming you can hear a slight trickle of the oil back to the pan.

Re: oil pressure issues [Re: The Sphinx] #1428240 04/30/13 07:41 PM 04/30/13 07:41 PM
Joined: Oct 2012 Posts: 1,106 Northeast V VincentVega super stock
VincentVega super stock V Joined: Oct 2012 Posts: 1,106 Northeast	oil pump pressure relief valve? spring - as in none? broken? too short? what do you know about the oil pump? Looking for 1975 through 1978 B body 4 door sedan sheet metal or parts cars - monaco, fury, coronet. Please let me know

Re: oil pressure issues [Re: The Sphinx] #1428241 04/30/13 07:44 PM 04/30/13 07:44 PM
Joined: Sep 2007 Posts: 14,889 up yours Supercuda About to go away
Supercuda About to go away Joined: Sep 2007 Posts: 14,889 up yours	Quote: I've rebuilt a few small blocks in the past and never had an issue like this. I primed the oil system and fired up the engine and it maintained (cold 75PSI) (hot 40PSI) at 2000 RPM. Now my issue is at idle my pressure drops down to 15PSI regardless of it being hot or cold. I use a snap-on 1200 RPM drill on an old distributor that has been lengthened to reach the oil pump as a priming tool. Not a Mopar engine is it? My guess is it's a Fram filter with a bad anti drain back valve. They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.

Re: oil pressure issues [Re: VincentVega] #1428242 04/30/13 09:14 PM 04/30/13 09:14 PM
Joined: Jun 2010 Posts: 591 Champion City The Sphinx OP mopar
The Sphinx OP mopar Joined: Jun 2010 Posts: 591 Champion City	Quote: oil pump pressure relief valve? spring - as in none? broken? too short? what do you know about the oil pump? Brand new Melling M72

Re: oil pressure issues [Re: Supercuda] #1428243 04/30/13 09:16 PM 04/30/13 09:16 PM
Joined: Jun 2010 Posts: 591 Champion City The Sphinx OP mopar
The Sphinx OP mopar Joined: Jun 2010 Posts: 591 Champion City	Quote: Quote: I've rebuilt a few small blocks in the past and never had an issue like this. I primed the oil system and fired up the engine and it maintained (cold 75PSI) (hot 40PSI) at 2000 RPM. Now my issue is at idle my pressure drops down to 15PSI regardless of it being hot or cold. I use a snap-on 1200 RPM drill on an old distributor that has been lengthened to reach the oil pump as a priming tool. Not a Mopar engine is it? My guess is it's a Fram filter with a bad anti drain back valve. Mopar small block, I only use WIX oil filters.

Re: oil pressure issues [Re: The Sphinx] #1428244 04/30/13 09:34 PM 04/30/13 09:34 PM
Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska	Quote: I've checked the gallery plugs, they are all in. What else should I check? Did that include the gallery plug that goes in the rear of the DR horizontle oil gallery inside the valley? live every 24 hour block of time like it's your last day on earth

Re: oil pressure issues [Re: RapidRobert] #1428245 05/01/13 09:09 AM 05/01/13 09:09 AM
Joined: Jun 2010 Posts: 591 Champion City The Sphinx OP mopar
The Sphinx OP mopar Joined: Jun 2010 Posts: 591 Champion City	Quote: Quote: I've checked the gallery plugs, they are all in. What else should I check? Did that include the gallery plug that goes in the rear of the DR horizontle oil gallery inside the valley? checked

Re: oil pressure issues [Re: The Sphinx] #1428246 05/01/13 09:26 AM 05/01/13 09:26 AM
Joined: Mar 2008 Posts: 5,746 Ontario, Canada Dodgem master
Dodgem master Joined: Mar 2008 Posts: 5,746 Ontario, Canada	The oil galley plug on the back driver side that is right inside the engine?? you have to remove plug in back of engine to get to it or have intake off and feel down in there! machine shops are good at taking it out not so good putting it back sometimes! rocker shafts have holes down? Last edited by Dodgem; 05/01/13 09:27 AM.

Re: oil pressure issues [Re: The Sphinx] #1428247 05/01/13 10:16 AM 05/01/13 10:16 AM
Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska	I think 15 at idle is acceptable (barely) as long as it jumps up immediately when you gun it. You might double check with another mechanical gauge. There might be excessive clearances somewhere on the pressure side that's letting it bleed off quicker than most (lifter bore clearance). Juat me I'd let it go if above idle it's acceptable & I'm anal/very picky about things live every 24 hour block of time like it's your last day on earth

Re: oil pressure issues [Re: RapidRobert] #1428248 05/01/13 12:52 PM 05/01/13 12:52 PM
Joined: Feb 2003 Posts: 12,675 Columbia, CT M moper I Live Here
moper I Live Here M Joined: Feb 2003 Posts: 12,675 Columbia, CT	Like Robert said - 15psi hot at idle is fine, and 40psi at 2K is fine. What is it's peak pressure hot? Does it go up any more over 2K? What are the clearances on the lower end? My "first impresion" is it's the lifter bores and nothing to really worry about so long as it can maintain a pressure of 10psi for each 1000 rpm. Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.

Re: oil pressure issues [Re: moper] #1428249 05/02/13 10:48 AM 05/02/13 10:48 AM
Joined: Jan 2010 Posts: 509 Middle River, MD M Mapandjlp mopar
Mapandjlp mopar M Joined: Jan 2010 Posts: 509 Middle River, MD	How about this plug behind the oil filter plate (missing in this pic)? 7691252-DSC04239.JPG (63 downloads)

Re: oil pressure issues [Re: Mapandjlp] #1428250 05/02/13 06:47 PM 05/02/13 06:47 PM
Joined: Jun 2010 Posts: 591 Champion City The Sphinx OP mopar
The Sphinx OP mopar Joined: Jun 2010 Posts: 591 Champion City	Ok, Think I got it figured out. I am missing one gallery plug. It's the one in the #5 main saddle. Does anyone know the part number to it? My Goggle search came up empty. Last edited by The Sphinx; 05/02/13 06:48 PM.

Re: oil pressure issues [Re: The Sphinx] #1428251 05/02/13 08:35 PM 05/02/13 08:35 PM
Joined: Jan 2003 Posts: 32,930 Grand Prairie,Texas stumpy I Win
stumpy I Win Joined: Jan 2003 Posts: 32,930 Grand Prairie,Texas	Hardware store part.

Re: oil pressure issues [Re: The Sphinx] #1428252 05/02/13 09:03 PM 05/02/13 09:03 PM
Joined: Mar 2006 Posts: 1,402 State of Corruption camdog440 pro stock
camdog440 pro stock Joined: Mar 2006 Posts: 1,402 State of Corruption	Quote: Ok, Think I got it figured out. I am missing one gallery plug. It's the one in the #5 main saddle. Hopefully you've caught your problem. I had a similar issue rebuilding a 340 years ago with about the same symptoms you are talking about. It turned out that the factory had enlarged the lifter bores over the stock bore size. There were actually factory Mopar oversized lifters available to solve the problem.

Re: oil pressure issues [Re: stumpy] #1428253 05/02/13 09:51 PM 05/02/13 09:51 PM
Joined: Jun 2010 Posts: 591 Champion City The Sphinx OP mopar
The Sphinx OP mopar Joined: Jun 2010 Posts: 591 Champion City	Quote: Hardware store part. What does it look like? Any pics or dimensions? It sounds like it's a press in plug

Re: oil pressure issues [Re: The Sphinx] #1428254 05/02/13 09:57 PM 05/02/13 09:57 PM
Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska	Quote: I am missing one gallery plug. It's the one in the #5 main saddle. If you mean the mini plug that's driven in the oil passage that's next to the #5 main cap pass side bolt up into the vertical passage so the 2 in/out horizontle oil galleries to/from the oil filter are blocked off/seperated from each other I would not think it would cause a psi loss. It only (but critically) forces the oil to make a right turn from the vertical passage & flow out horizontally to the filter then horizontally from the filter back to the vertical passage then up a bit to the main pass horizontle oil gallery. It's a common size mini plug & MP carries it as would your parts house. EDIT maybe the restriction of the filter DOES keep the oil from draining back as I've never been without the plug. Since it's a must have I'd install it at the right depth & we just might get lucky & that be it Last edited by RapidRobert; 05/02/13 11:29 PM. live every 24 hour block of time like it's your last day on earth

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