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#1
10-17-2023, 07:43 PM
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Low oil pressure!
Brand new rebuilt motor on the stand. I went to prime the oil pump using an electic drill wide open and I am only getting 13 lbs of oil pressure. When the motor is at top dead center, only #7 exhaust rocker has oil flow. If the crank is rotated in a differnet position, I still get 17 lbs of pressure but no flow to any rocker. I only get flow to rocker #7 exhaust.
Now I have built several motors with out any problem till now! The motor is a .030 over 1967 block, crank turned .010 rods .010. Line honed because of main stud installation. The only thing that I have done this time around is use rhoads lifters. The cam is a crower 60243. I know that has nothing to do with my problem but i figured the rhoads might be affecting the oil pressure! The oil pump is a brand new melling 60lb and taken apart to make it was clean inside, then reassembled and installed. The old oil filter housand was reused from a previous build and worked find. So I have no reason to believe the by pass is open inside of it. I do remember that the rear cam bearing gave me a fit, i ended up carring the block back the machine shop because the cam would no install into the final bearing. Turns out the new cam bearing, when installed was to tight for the cam. After a couple of cam bearing install attemps, new one each time, it was determined that the outside of the cam bearing needed cut down so it could be installed without being to tight for the camshaft after install. So does anyone have an idea where I need to start looking? Sent from my SM-G996U using Tapatalk
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87 GP le 455 200r4 3.42 rear |
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#2
10-17-2023, 08:19 PM
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Are you running the drill in reverse ?
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#3
10-17-2023, 08:27 PM
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Is the "hidden" 3/8 pipe plug in the passenger side oil passage installed? Easy enough to look through the dizzy hole. If so, have you verified pressure with another gauge?
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Will Rivera '69 Firebird 400/461, 290+ E D-Ports, HR 230/236, 4l80E, 8.5 Rear, 3.55 gears '64 LeMans 400/461, #16 Heads, HR 230/236, TKO600, 9inch Rear, 3.89 gears '69 LeMans Vert, 350, #47 heads: Non-running project |
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#4
10-17-2023, 08:34 PM
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Another possibility to check is freeze plugs, ( they look like freeze plugs) in front of block that go to oil galleries. It’s always a good idea to tap them and put plugs in them.
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#5
10-17-2023, 09:22 PM
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1. Lack of oil to rockers isn't surprising. Make sure they get oil AFTER the engine is running, and the lifters are jiggling up 'n' down with the cam lobes.
2. Potential oil pump pressure relief valve stuck open. 3. Everything else already mentioned. |
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#6
10-17-2023, 10:12 PM
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Quote:
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1979 Firebird Trans Am 301/4spd (Now 428) 1977 Firebird Formula 400/Auto 2007 Grand Prix GXP 5.3L |
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#7
10-18-2023, 06:42 AM
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When you have a drill spinning the oil pump driveshaft in the needed counter clockwise direction the pump should load the drill pretty hard .
If this does not take place then as posted the check ball is unseated or you have a front or rear galley plug out, or you have a issue with a bad filter.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
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#8
10-18-2023, 12:36 PM
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Can you get the valley pan off? You can see if you have oil coming from around the lifters during the prelube. With 30wt oil, it should be pretty easy to get 45+ PSI when turning the pump with a cordless drill. I would not run it until I found the source of the low oil pressure.
I've taken a piece of aluminum and made a plate that bolts in place of the filter housing. I threaded it for a pressure gauge so I could measure the dead-head pump pressure at which the relief ball lifts when running pump with a drill. If you've got good pressure, the oil pump relief is working, the issue is downstream in the engine. If you don't get 55+ PSI pressure, the pump or pickup is the issue.
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I could explain all this to the girl at the parts store, but she'd probably call the asylum. White '67 LeMans 407/TH350/Ford 3.89... RIP Red '67 LeMans. 407/TH400/Ford 3.25 |
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#9
10-18-2023, 12:41 PM
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Thanks for the input guys, found the culprit and I am a little embarrassed about it. I have working on building this motor for a while and just plain forgot what I was going to do next.
I had taken the front plugs out inorder to tap them for pipe plug installation. Needless to say all is good now after I reinstalled both plugs! Happy camper now! And yes plenty of oil pressue!  Sent from my SM-G996U using Tapatalk
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87 GP le 455 200r4 3.42 rear |
| The Following 3 Users Say Thank You to Fullhouse For This Useful Post: | ||
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#10
10-18-2023, 01:05 PM
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Nice to find an easy solution! Long projects are prone to this sort of thing.
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| The Following User Says Thank You to JSchmitz For This Useful Post: | ||
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#11
10-18-2023, 01:43 PM
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Good deal!! Glad it's addressed and done while on engine stand!
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Will Rivera '69 Firebird 400/461, 290+ E D-Ports, HR 230/236, 4l80E, 8.5 Rear, 3.55 gears '64 LeMans 400/461, #16 Heads, HR 230/236, TKO600, 9inch Rear, 3.89 gears '69 LeMans Vert, 350, #47 heads: Non-running project |
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#12
10-18-2023, 03:52 PM
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Use note that the left side plug can not go in as deep as the right otherwise there is a oil feed passage there it will partially block off to the front cam bearing.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
| The Following User Says Thank You to steve25 For This Useful Post: | ||
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#13
10-18-2023, 06:52 PM
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Things I've done I never forget!! Never. Sometime you'll be drinking and remember this tine.
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#14
10-18-2023, 07:31 PM
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not sure if you tapped earlier for the screw in plugs or put in the freeze plug type plugs, but if you used the freeze plug type dont forget to stake them well or they might pop out
also if you forgot the fronts check and see if you did the ones in back
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A man who falls for everything stands for nothing. |
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