Prime Oil Pump
Thread Starter
Advanced
Joined: Jan 2011
Posts: 69
Likes: 1
Prime Oil Pump
I just replaced the rear main seal with a new oil pump screen and oil pan on my 1970 LT-1.
Should I prime the oil pump by removing the distributor or remove the spark plugs and spin the engine until I get oil pressure?
Should I prime the oil pump by removing the distributor or remove the spark plugs and spin the engine until I get oil pressure?
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
If the engine was running recently, I would just spin the engine with the coil wire off and maybe pull a few spark plugs for free spinning. You should have pressure within 10 seconds. If the engine has been sitting for weeks, pull the dizzy and prime it.
Last edited by hugie82; Mar 16, 2016 at 09:08 AM.
Burning Brakes
Joined: Jul 2015
Posts: 823
Likes: 57
From: Austin TX
If you're going to spin the motor, you might as well just start her up. That's not how I would do it though. The priming tool is cheap, and it's not difficult to do. It's good insurance against running too long without pressure.
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
The pump got primed when you filled the pan with oil. Just start it.
Le Mans Master
Joined: Oct 2007
Posts: 9,700
Likes: 3,469
From: Akron Ohio
2025 Corvette of the Year Finalist - Modified
2024 C5 of the Year Winner - Modified
2023 C5 of the Year Finalist - Modified
2022 C5 of the Year Finalist - Modified
St. Jude Donor '09-'10-'11
I always prefer pulling the distributor and priming the engine without turning it over after doing anything with the oil system. Like mentioned, good insurance and easy to do.
Drifting
Joined: Jan 2012
Posts: 1,908
Likes: 129
From: Fredericksburg Virginia
Agree. The oil pump itself does not need to be primed.
What you are doing when you 'prime' the engine is circulate oil throughout the engine, through all the gallies, to the bearings, through the pushrods, to the top end, and removing the huge air bubbles that could be there.
Air bubbles could only be there (or the bearings could be dry as a bone) if the engine was sitting for a VERY long time or it was recently assembled.
As far as spinning versus starting, I'm mixed.
If my engine has set for more than a month, I generally spin the engine without touching the gas for the 5 seconds it takes to get oil pressure. Yes, I'm putting wear on the starter and such, but my rationale is that this is better than having all the huge explosions happen in the engine that could potentially drive a bearing into a metal-to-metal condition because it is even a little drier than it should be. Probably overkill, but that's how I roll. Overkill.
If I'm driving my car normally...every week or two...I don't do anything special. Pump until she lights off.
The only time I'd consider priming the oil system is if the oil pan has been off for a really long time and everything has dripped out of every galley (not an oil pan project...I mean OFF for, like, weeks) or the engine hadn't started for more than 6 months.
What you are doing when you 'prime' the engine is circulate oil throughout the engine, through all the gallies, to the bearings, through the pushrods, to the top end, and removing the huge air bubbles that could be there.
Air bubbles could only be there (or the bearings could be dry as a bone) if the engine was sitting for a VERY long time or it was recently assembled.
As far as spinning versus starting, I'm mixed.
If my engine has set for more than a month, I generally spin the engine without touching the gas for the 5 seconds it takes to get oil pressure. Yes, I'm putting wear on the starter and such, but my rationale is that this is better than having all the huge explosions happen in the engine that could potentially drive a bearing into a metal-to-metal condition because it is even a little drier than it should be. Probably overkill, but that's how I roll. Overkill.
If I'm driving my car normally...every week or two...I don't do anything special. Pump until she lights off.
The only time I'd consider priming the oil system is if the oil pan has been off for a really long time and everything has dripped out of every galley (not an oil pan project...I mean OFF for, like, weeks) or the engine hadn't started for more than 6 months.
Last edited by keithinspace; Mar 16, 2016 at 10:26 AM.
Le Mans Master
Joined: Oct 2007
Posts: 7,454
Likes: 977
From: RI, Now Franklin/Nashville TN
Agree. The oil pump itself does not need to be primed.
What you are doing when you 'prime' the engine is circulate oil throughout the engine, through all the gallies, to the bearings, through the pushrods, to the top end, and removing the huge air bubbles that could be there.
Air bubbles could only be there (or the bearings could be dry as a bone) if the engine was sitting for a VERY long time or it was recently assembled.
As far as spinning versus starting, I'm mixed.
If my engine has set for more than a month, I generally spin the engine without touching the gas for the 5 seconds it takes to get oil pressure. Yes, I'm putting wear on the starter and such, but my rationale is that this is better than having all the huge explosions happen in the engine that could potentially drive a bearing into a metal-to-metal condition because it is even a little drier than it should be. Probably overkill, but that's how I roll. Overkill.
If I'm driving my car normally...every week or two...I don't do anything special. Pump until she lights off.
The only time I'd consider priming the oil system is if the oil pan has been off for a really long time and everything has dripped out of every galley (not an oil pan project...I mean OFF for, like, weeks) or the engine hadn't started for more than 6 months.
What you are doing when you 'prime' the engine is circulate oil throughout the engine, through all the gallies, to the bearings, through the pushrods, to the top end, and removing the huge air bubbles that could be there.
Air bubbles could only be there (or the bearings could be dry as a bone) if the engine was sitting for a VERY long time or it was recently assembled.
As far as spinning versus starting, I'm mixed.
If my engine has set for more than a month, I generally spin the engine without touching the gas for the 5 seconds it takes to get oil pressure. Yes, I'm putting wear on the starter and such, but my rationale is that this is better than having all the huge explosions happen in the engine that could potentially drive a bearing into a metal-to-metal condition because it is even a little drier than it should be. Probably overkill, but that's how I roll. Overkill.
If I'm driving my car normally...every week or two...I don't do anything special. Pump until she lights off.
The only time I'd consider priming the oil system is if the oil pan has been off for a really long time and everything has dripped out of every galley (not an oil pan project...I mean OFF for, like, weeks) or the engine hadn't started for more than 6 months.
I would only prime the engine if it has sat for a VERY long time or recently assembled. On my 78, I do the exact same thing when I start it....spin the engine without setting the choke until I have oil pressure on the gauge.Once I have good pressure, I let the engine fire.
I also use this same technique on my 10 C6Z06 which sits most of the time. All modern cars with FI have a clear flood condition by putting the gas to the floor before you hit the start button. The engine will just spin without firing...works like a charm to prime the 427 LS7!! Just release the gas when you want the engine to fire and presto, it lights. If the Z06 has been sitting for more than 2 weeks, I always spin the engine without firing to get good oil pressure.
Last edited by jb78L-82; Mar 16, 2016 at 10:47 AM.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
It is not LT-1 specific....any small block primer will work.
Make sure you purchase this type that simulates a distributor...with the cam galley plug.....
The shaft by itself type is worthless as it does not get the oil upstairs.
Jebby
Race Director
Joined: May 2006
Posts: 18,737
Likes: 2,583
Le Mans Master
Joined: Jan 2006
Posts: 6,506
Likes: 139
From: Butler Pa
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
on AMC engines, (never done this to chevys i build, but have no reason why i do not) we always fill the pump with Vaseline... This starts pulling oil almost instantly... learned this trick from 2 different engine builders..
Le Mans Master
Joined: Jan 2006
Posts: 6,506
Likes: 139
From: Butler Pa
The oil pump in a chevy is submerged in oil. It fills up as the oil is added to the engine.
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
You really don't have to but it's not a bad idea to run the pump to ensure the pump is still working and it will make oil pressure before you start it and find there isn't any pressure. Having it not work is unlikely, but not impossible.
Le Mans Master
Joined: Jan 2006
Posts: 6,506
Likes: 139
From: Butler Pa
You can do the same thing by cranking it with the starter, and you don't need to buy the tool to do it.
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
Priming Chevrolet Oil Pumps
As oil will remain on the bearings for at least 1000 years and the bearings only require a single drop to lubricate them for about 5 minutes of running there is no sense in priming a Chevrolet V8 as long as the anti-drainback oil filter is full. Have you ever seen You Tube videos of guys draining all of the oil out then starting the engine to see how long it'll run before it seizes? The engine will often run 5 minutes or more. Are we learning anything yet?
Last edited by toobroketoretire; Mar 18, 2016 at 11:52 AM.
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
dry pump in a timing cover....
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
I would just start it up. But, if the weather is cold enough that the choke could be on the 'fast idle' step, I would manually reset the choke down to the 1st or 2nd notch. Crank it for 10 seconds, if it doesn't light off quickly; that will force oil throughout the engine. Then, you can quick-pump the gas pedal to reset the choke to higher idle and start 'er up.
Last edited by 7T1vette; Mar 18, 2016 at 04:57 PM.