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Old 07-26-2021, 11:33 AM   #1
rwdmayhem
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Exclamation Lost oil pressure during cam break in.

I have a 95 k1500 that I'm sticking a fresh cam in. Just finished buttoning up the motor the other day and ran the oil pump primer. According to the gauge on my dash I was getting 40psi with my 3/8 drill. But went to fire it up and about 3 minutes into the break in and 0psi on the dash. Now I'm getting no oil at the rockers. I am using royal purple break in oil. Now since I had to shut it off so early into the break in do I need to take the motor apart and relube the cam/lifters?
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Old 07-26-2021, 02:36 PM   #2
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Re: Lost oil pressure during cam break in.

Oil pump go bad?
And no, you just need to re-prime the oil system before starting again.
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Old 07-26-2021, 02:54 PM   #3
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Re: Lost oil pressure during cam break in.

Oil filter or pickup clogged? The pump goes to the filter then to gauge, so if you used a lot of assembly lube then you might have clogged up the filter. I'd start there.
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Old 07-26-2021, 03:32 PM   #4
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Re: Lost oil pressure during cam break in.

Did you have oil pressure the first 3 minutes?
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Old 07-26-2021, 04:12 PM   #5
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Re: Lost oil pressure during cam break in.

Did the distributor get fully engaged when you put it back in after priming it? I have seen that fairly often in the past.
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Old 07-26-2021, 05:45 PM   #6
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Re: Lost oil pressure during cam break in.

First I would change the oil filter...(fill new filter with oil before screwing it on) and inspect adapter while your there. Then put a different gauge on... at the engine! Fire it up and check the secondary gauge at engine. You should be fine to run it at 2200 rpm or so for 22 min. if your oil pressure not around 50 lbs give or take turn it off!!! check oil pump and pick up ... Did you install new cam bearings?
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Old 07-26-2021, 05:52 PM   #7
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Re: Lost oil pressure during cam break in.

i would hope its just a coincidence and either the sending unit or the gauge went bad. Trying a new sending unit is much easier than dropping the oil pan!
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Old 07-27-2021, 10:58 AM   #8
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Re: Lost oil pressure during cam break in.

Alright so first, truck showed 60psi in the 3 minutes.

second I'll try replacing the filter and see what happens

third I'm fairly certain the distributor was fully engaged as the only way I could get it to fully sit down on the intake was moving the rotor a tooth at a time till it sat flush.

fourth I didn't change the cam bearings.
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Old 07-27-2021, 12:59 PM   #9
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Re: Lost oil pressure during cam break in.

UPDATE!

Changed the oil filter and I have pressure again. Buuuuut its only showing 40psi and the gauge is all over the place.
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Old 07-27-2021, 01:12 PM   #10
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Re: Lost oil pressure during cam break in.

Quote:
Originally Posted by rwdmayhem View Post
UPDATE!

Changed the oil filter and I have pressure again. Buuuuut its only showing 40psi and the gauge is all over the place.
there's probably some leftover assembly lube in the oil pressure sending unit. There's not a big hole on it so I would pull the unit and spray it with injector cleaner quickly to get the crap out of it. Also a manual gauge wouldn't hurt in its place for the time being.
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Old 07-27-2021, 01:38 PM   #11
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Re: Lost oil pressure during cam break in.

Well I cleaned up the sensor and no change. So I'll try a mechanical unit next.
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Old 07-28-2021, 01:01 PM   #12
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Re: Lost oil pressure during cam break in.

So mechanical gauge is reading zero.
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Old 07-28-2021, 01:38 PM   #13
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Re: Lost oil pressure during cam break in.

test the mechanical gauge, then change the oil filter again. They can clog up pretty quickly on break-in
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Old 07-28-2021, 01:40 PM   #14
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Re: Lost oil pressure during cam break in.

What he said. Also, I would try and run it with the priming tool until you get pressure again, that way you lessen the chance of damaging the cam.
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Old 07-28-2021, 02:24 PM   #15
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Re: Lost oil pressure during cam break in.

That was with the priming tool. And how do i test the gauge?
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Old 07-28-2021, 03:35 PM   #16
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Re: Lost oil pressure during cam break in.

Myself, I would loosen the gauge sending unit and put a wrag over that area and try and see if it spits out any oil. Only other thing I can think of is to pull a valve cover and see if oil is getting to the top of the engine.
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Old 07-29-2021, 11:48 AM   #17
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Re: Lost oil pressure during cam break in.

Well I changed the oil and cleaned out the old oil from the gauge and now I'm not even getting oil to go into the pressure line for the gauge. So either the line that my gauge screws into on the block is plugged or I guess its time to go after the oil pump.
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Old 07-29-2021, 12:14 PM   #18
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Re: Lost oil pressure during cam break in.

This may have been covered before but...

Possibly the oil pump pick up is set to high or fallen off?

You could try overfilling the crankcase a couple quarts and see if it picks up from there.

Either way looks like the you'll have to dig into it.

Sorry for your troubles but sure do appreciate your sharing.
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Old 07-29-2021, 12:27 PM   #19
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Re: Lost oil pressure during cam break in.

well the short block was never messed with and I didn't get any noise when lightly tapping the bottom of the oil pan. But I am getting oil off the tool so its definitely pushing oil. Just not getting any pressure.
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Old 07-29-2021, 01:11 PM   #20
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Re: Lost oil pressure during cam break in.

try pulling the oil filter off and blowing a little air into the gauge fitting
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Old 07-29-2021, 01:54 PM   #21
rwdmayhem
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Re: Lost oil pressure during cam break in.

well I unscrewed the line from the block and its only dribbling out oil with the tool running.
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Old 07-29-2021, 02:01 PM   #22
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Re: Lost oil pressure during cam break in.

change the oil filter again unless you did that with the oil change. You may need to drain the pan and remove it to check the oil pickup screen
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Old 08-06-2021, 07:29 AM   #23
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Re: Lost oil pressure during cam break in.

Update: Decided to give it one last chance on testing for pressure and the gears in the pump have started making noise despite the priming tool coming out covered in oil. So just waiting on the new pump and parts to show up for it.
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Old 08-06-2021, 08:52 AM   #24
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Re: Lost oil pressure during cam break in.

When you install a new pump always use a new Melling brand heavy duty intermediate shaft it's all steel .

https://www.youtube.com/watch?v=nmR--EYH4TQ
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