The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1988 - 1998 GMT400 Chevy & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 07-26-2021, 11:33 AM   #1
rwdmayhem
Registered User
 
Join Date: Apr 2017
Location: CO
Posts: 58
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?
rwdmayhem is offline   Reply With Quote
Old 07-26-2021, 02:36 PM   #2
Tom
driving is in my blood
 
Tom's Avatar
 
Join Date: Dec 1999
Location: Mesa AZ
Posts: 5,359
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.
__________________
-78 c10 short/step: 388cid, M20, 5/5 drop, lots more. Playtoy and first vehicle.
-98 c1500 x-cab: 5.7L, 17" rims, 5/6 drop, flowmaster, helper bags,NBS rear disk brakes.
-02 Suburban 4x4: leveled front
-CBR600F4i, CBR600RR, CBR1000RR, and standup skis
DISCLAIMER: I cant spell for the life of me.
Tom is offline   Reply With Quote
Old 07-26-2021, 02:54 PM   #3
sntrym95
Senior Member
 
sntrym95's Avatar
 
Join Date: Jan 2006
Location: Cleveland, Oh
Posts: 695
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.
__________________
Mike

Toy list:
1995 GMC Yukon 4dr 2wd 5.7 Vortec conversion, AAM TracRite
1979 Mako 23 CC
sntrym95 is offline   Reply With Quote
Old 07-26-2021, 03:32 PM   #4
MySons68C20
Senior Member
 
MySons68C20's Avatar
 
Join Date: Sep 2014
Location: Wenatchee, Wa
Posts: 488
Re: Lost oil pressure during cam break in.

Did you have oil pressure the first 3 minutes?
MySons68C20 is offline   Reply With Quote
Old 07-26-2021, 04:12 PM   #5
Palf70Step
State of Confusion!

 
Palf70Step's Avatar
 
Join Date: Jul 2002
Location: Gulfport, MS USA
Posts: 42,979
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.
__________________
Bill
1970 Chevy Custom/10 LWB Fleetside
1981 GMC High Sierra SWB Stepside

Member of Louisiana Classic Truck Club (LCTC)
Board Vendors
Bill's Gallery
Life isn't tied with a bow, but it's still a gift.
Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God!
It's scary when you start making the same noises as your coffee maker.
Palf70Step is online now   Reply With Quote
Old 07-26-2021, 05:45 PM   #6
Spike 72
Registered User
 
Spike 72's Avatar
 
Join Date: Sep 2012
Location: Lees Summit Mo
Posts: 12
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?
__________________
Spike 72 is offline   Reply With Quote
Old 07-26-2021, 05:52 PM   #7
Spike 72
Registered User
 
Spike 72's Avatar
 
Join Date: Sep 2012
Location: Lees Summit Mo
Posts: 12
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!
__________________
Spike 72 is offline   Reply With Quote
Old 07-27-2021, 10:58 AM   #8
rwdmayhem
Registered User
 
Join Date: Apr 2017
Location: CO
Posts: 58
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.
rwdmayhem is offline   Reply With Quote
Old 07-27-2021, 12:59 PM   #9
rwdmayhem
Registered User
 
Join Date: Apr 2017
Location: CO
Posts: 58
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.
rwdmayhem is offline   Reply With Quote
Old 07-27-2021, 01:12 PM   #10
sntrym95
Senior Member
 
sntrym95's Avatar
 
Join Date: Jan 2006
Location: Cleveland, Oh
Posts: 695
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.
__________________
Mike

Toy list:
1995 GMC Yukon 4dr 2wd 5.7 Vortec conversion, AAM TracRite
1979 Mako 23 CC
sntrym95 is offline   Reply With Quote
Old 07-27-2021, 01:38 PM   #11
rwdmayhem
Registered User
 
Join Date: Apr 2017
Location: CO
Posts: 58
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.
rwdmayhem is offline   Reply With Quote
Old 07-28-2021, 01:01 PM   #12
rwdmayhem
Registered User
 
Join Date: Apr 2017
Location: CO
Posts: 58
Re: Lost oil pressure during cam break in.

So mechanical gauge is reading zero.
rwdmayhem is offline   Reply With Quote
Old 07-28-2021, 01:38 PM   #13
sntrym95
Senior Member
 
sntrym95's Avatar
 
Join Date: Jan 2006
Location: Cleveland, Oh
Posts: 695
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
__________________
Mike

Toy list:
1995 GMC Yukon 4dr 2wd 5.7 Vortec conversion, AAM TracRite
1979 Mako 23 CC
sntrym95 is offline   Reply With Quote
Old 07-28-2021, 01:40 PM   #14
Palf70Step
State of Confusion!

 
Palf70Step's Avatar
 
Join Date: Jul 2002
Location: Gulfport, MS USA
Posts: 42,979
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.
__________________
Bill
1970 Chevy Custom/10 LWB Fleetside
1981 GMC High Sierra SWB Stepside

Member of Louisiana Classic Truck Club (LCTC)
Board Vendors
Bill's Gallery
Life isn't tied with a bow, but it's still a gift.
Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God!
It's scary when you start making the same noises as your coffee maker.
Palf70Step is online now   Reply With Quote
Old 07-28-2021, 02:24 PM   #15
rwdmayhem
Registered User
 
Join Date: Apr 2017
Location: CO
Posts: 58
Re: Lost oil pressure during cam break in.

That was with the priming tool. And how do i test the gauge?
rwdmayhem is offline   Reply With Quote
Old 07-28-2021, 03:35 PM   #16
Palf70Step
State of Confusion!

 
Palf70Step's Avatar
 
Join Date: Jul 2002
Location: Gulfport, MS USA
Posts: 42,979
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.
__________________
Bill
1970 Chevy Custom/10 LWB Fleetside
1981 GMC High Sierra SWB Stepside

Member of Louisiana Classic Truck Club (LCTC)
Board Vendors
Bill's Gallery
Life isn't tied with a bow, but it's still a gift.
Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God!
It's scary when you start making the same noises as your coffee maker.
Palf70Step is online now   Reply With Quote
Old 07-29-2021, 11:48 AM   #17
rwdmayhem
Registered User
 
Join Date: Apr 2017
Location: CO
Posts: 58
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.
rwdmayhem is offline   Reply With Quote
Old 07-29-2021, 12:14 PM   #18
MySons68C20
Senior Member
 
MySons68C20's Avatar
 
Join Date: Sep 2014
Location: Wenatchee, Wa
Posts: 488
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.
MySons68C20 is offline   Reply With Quote
Old 07-29-2021, 12:27 PM   #19
rwdmayhem
Registered User
 
Join Date: Apr 2017
Location: CO
Posts: 58
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.
rwdmayhem is offline   Reply With Quote
Old 07-29-2021, 01:11 PM   #20
sntrym95
Senior Member
 
sntrym95's Avatar
 
Join Date: Jan 2006
Location: Cleveland, Oh
Posts: 695
Re: Lost oil pressure during cam break in.

try pulling the oil filter off and blowing a little air into the gauge fitting
__________________
Mike

Toy list:
1995 GMC Yukon 4dr 2wd 5.7 Vortec conversion, AAM TracRite
1979 Mako 23 CC
sntrym95 is offline   Reply With Quote
Old 07-29-2021, 01:54 PM   #21
rwdmayhem
Registered User
 
Join Date: Apr 2017
Location: CO
Posts: 58
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.
rwdmayhem is offline   Reply With Quote
Old 07-29-2021, 02:01 PM   #22
sntrym95
Senior Member
 
sntrym95's Avatar
 
Join Date: Jan 2006
Location: Cleveland, Oh
Posts: 695
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
__________________
Mike

Toy list:
1995 GMC Yukon 4dr 2wd 5.7 Vortec conversion, AAM TracRite
1979 Mako 23 CC
sntrym95 is offline   Reply With Quote
Old 08-06-2021, 07:29 AM   #23
rwdmayhem
Registered User
 
Join Date: Apr 2017
Location: CO
Posts: 58
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.
rwdmayhem is offline   Reply With Quote
Old 08-06-2021, 08:52 AM   #24
Grumpy old man
Senior Member
 
Grumpy old man's Avatar
 
Join Date: Dec 2013
Location: Gods country East,Tn
Posts: 7,449
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
__________________
Grumpy old man is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 11:39 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Copyright 1997-2020 67-72chevytrucks.com