TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > AMC V8 Engine Repair and Modifications
  New Posts New Posts RSS Feed - 360 V8 Oil Pressure
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Click for TheAMCForum Rules / Click for PDF version of Forum Rules
Your donations help keep this valuable resource free and growing. Thank you.

360 V8 Oil Pressure
 Post Reply Post Reply Page  123>
Author
Message
  Topic Search Topic Search  Topic Options Topic Options
Dan1500 View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: May/26/2019
Location: Auburn, IN
Status: Offline
Points: 70 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Dan1500 Quote  Post ReplyReply Direct Link To This Post Topic: 360 V8 Oil Pressure
    Posted: Sep/24/2022 at 3:02pm
I had a 360 built by a well known AMC engine builder in 2020.  Been working on the rest of the car and just got it to where it was street drivable this August.  I've put maybe around 200 miles on it.  The oil pressure is low, cold its around 20 psi at idle and when it gets hot it's very close to 0 on the gauge at idle.  Around 20 psi hot when driving at 2000 rpm.  When I first got it in the car it seemed on the low side.  I want to say around 10 psi hot at idle, but it's also possible I wasn't getting all the way warmed up since I was just driving up and down the driveway, etc.   Either way it isn't getting better and may be getting worse.

The engine doesn't make any odd noises and runs pretty good.  I originally had a mechanical gauge on it, then my dashboard electrical gauge,  then checked it again with a diagnostic style mechanical gauge today.  The all match.  They were all using the port on the right front of the block where the original gauge senders were.  I checked the 90 fitting that is there and it isn't plugged up or anything.   I pulled out the pressure relief valve today and it looks fine but kind of hard to tell if for some reason it isn't getting all the way closed and bleeding pressure?

It has 10W40 oil in it and a Baldwin B39 Filter.  It does have the extra oil line in the valley.

I'm looking for help on a game-plan on what I should check from here.  The thought of pulling the engine makes me sick, but what all can I check first? 


Edited by Dan1500 - Sep/24/2022 at 3:16pm
Back to Top
Dan1500 View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: May/26/2019
Location: Auburn, IN
Status: Offline
Points: 70 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Dan1500 Quote  Post ReplyReply Direct Link To This Post Posted: Sep/24/2022 at 8:48pm
I don't think this looks too bad? I can't feel the marks?
Back to Top
Rebel Machine View Drop Down
AMC Addicted
AMC Addicted


Joined: Jul/03/2007
Location: Western Il
Status: Offline
Points: 5122 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Rebel Machine Quote  Post ReplyReply Direct Link To This Post Posted: Sep/25/2022 at 8:48am
Originally posted by Dan1500 Dan1500 wrote:

I had a 360 built by a well known AMC engine builder in 2020.  Been working on the rest of the car and just got it to where it was street drivable this August.  I've put maybe around 200 miles on it.  The oil pressure is low, cold its around 20 psi at idle and when it gets hot it's very close to 0 on the gauge at idle.  Around 20 psi hot when driving at 2000 rpm.  When I first got it in the car it seemed on the low side.  I want to say around 10 psi hot at idle, but it's also possible I wasn't getting all the way warmed up since I was just driving up and down the driveway, etc.   Either way it isn't getting better and may be getting worse.

The engine doesn't make any odd noises and runs pretty good.  I originally had a mechanical gauge on it, then my dashboard electrical gauge,  then checked it again with a diagnostic style mechanical gauge today.  The all match.  They were all using the port on the right front of the block where the original gauge senders were.  I checked the 90 fitting that is there and it isn't plugged up or anything.   I pulled out the pressure relief valve today and it looks fine but kind of hard to tell if for some reason it isn't getting all the way closed and bleeding pressure?

It has 10W40 oil in it and a Baldwin B39 Filter.  It does have the extra oil line in the valley.

I'm looking for help on a game-plan on what I should check from here.  The thought of pulling the engine makes me sick, but what all can I check first? 



That's really low for cold pressure. Something is seriously wrong.

To start with I'd verify the overpressure valve and spring are installed. Next I'd put the oil pump back together and use a drill to run the pump and see how much resistance the drill gets from the pump. The drill should struggle to turn the pump. If you can watch the pressure gauge at the same time that's a plus. If the drill doesn't encounter much resistance there's a leak somewhere. Could be bearing clearances or even pan to pickup clearance.

I'd also remove the valve covers and check the flow to the rockers while running the oil pump.

Do you have any details on the build? Flat tappet or roller cam? The wheel cutout in some roller lifters expose the oil gallery and bleed oil through.

-Steve-
Back to Top
Dan1500 View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: May/26/2019
Location: Auburn, IN
Status: Offline
Points: 70 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Dan1500 Quote  Post ReplyReply Direct Link To This Post Posted: Sep/25/2022 at 9:01am
Thanks Steve, the overpressure spring was in there and the pointy end of the valve was pointing in away from the spring.  There was tension on the spring, the plug popped back when loosened and I had to squeeze it to get the plug threaded back in.

It's just a regular flat tappet cam.
Back to Top
BU1 View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Aug/11/2016
Location: MN
Status: Offline
Points: 2012 		Post Options Post Options   Thanks (0) Thanks(0)   Quote BU1 Quote  Post ReplyReply Direct Link To This Post Posted: Sep/25/2022 at 9:05am
Valley line issue??
AMO #2726
#1 1968 AMX Rally Green 343 Z code 4spd since 1975 #02642
#2 1968 AMX Rally Green 290 N code 4spd since 2019 #02959
Back to Top
Dan1500 View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: May/26/2019
Location: Auburn, IN
Status: Offline
Points: 70 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Dan1500 Quote  Post ReplyReply Direct Link To This Post Posted: Sep/25/2022 at 9:06am
There does seem to be some scoring on the sides of the pump cavity.
Back to Top
Dan1500 View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: May/26/2019
Location: Auburn, IN
Status: Offline
Points: 70 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Dan1500 Quote  Post ReplyReply Direct Link To This Post Posted: Sep/25/2022 at 9:07am
Originally posted by BU1 BU1 wrote:

Valley line issue??

I suppose if I take the intake off and run the pump with a drill I could check that too.
Back to Top
BassBoat View Drop Down
AMC Addicted
AMC Addicted


Joined: Aug/29/2008
Status: Offline
Points: 1719 		Post Options Post Options   Thanks (0) Thanks(0)   Quote BassBoat Quote  Post ReplyReply Direct Link To This Post Posted: Sep/25/2022 at 9:49am
In my experience the oil pump needs to have 0.002 max end clearance.  Some oil pump gaskets are as much as 0.015 thick.  My opinion on the normal range is 0.0095 to 0.0115 based on mic'ing FelPro and Melling gaskets.  Bulltear made some very thin ones that allow you to reduce the end clearance with a thin gasket without actually removing the timing cover and machining the oil pump housing.  Try and take as much end play out as you can.  yes you need to check for a leaking valley line.  You should switch to 20W50 immediately.  You should try a Napa Gold oil filter or better yet an AC PF24 if you can find one.  Relief plunger sticking open is consistent with your symptoms.  Might want to try a different oil pressure gauge to verify your data.  Sorry to hear about your problems.  Good luck.
Back to Top
Rebel Machine View Drop Down
AMC Addicted
AMC Addicted


Joined: Jul/03/2007
Location: Western Il
Status: Offline
Points: 5122 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Rebel Machine Quote  Post ReplyReply Direct Link To This Post Posted: Sep/25/2022 at 9:58am
Originally posted by Dan1500 Dan1500 wrote:








What's the groove ground in at the top of the cavity where the pump gears mesh? I've got a groove in mine too but it's on the other side. Is yours bleeding pressure back to the inlet side?

-Steve-
Back to Top
scott View Drop Down
AMC Addicted
AMC Addicted


Joined: Jul/10/2007
Location: Wildwood Pa.
Status: Offline
Points: 3501 		Post Options Post Options   Thanks (0) Thanks(0)   Quote scott Quote  Post ReplyReply Direct Link To This Post Posted: Sep/25/2022 at 10:52am
I'd check with the "well known AMC engine builder" that built the engine & see what they say.

Best to start with the person that knows the engine build better than anyone on the forum.
"Prolly" is not a word.
Back to Top
 Post Reply Post Reply Page  123>
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.03
Copyright ©2001-2019 Web Wiz Ltd.

This page was generated in 0.142 seconds.
All content of this site Copyright © 2018 TheAMCForum unless otherwise noted, all rights reserved.
PROBLEMS LOGGING IN or REGISTERING:
If you have problems logging in or registering, then please contact a Moderator or