Forum Home Forum Home > The CJ2A Parts Project > Parts List > Engine Group
  New Posts New Posts RSS Feed - Oil Pressure/Oil Pump
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Oil Pressure/Oil Pump

 Post Reply Post Reply
Author
Message
HistoryTeacher5 View Drop Down
Member
Member
Avatar

Joined: 26 July 2015
Location: Conshohocken
Status: Offline
Points: 24
Post Options Post Options   Thanks (0) Thanks(0)   Quote HistoryTeacher5 Quote  Post ReplyReply Direct Link To This Post Topic: Oil Pressure/Oil Pump
    Posted: 30 July 2015 at 2:47pm
Hello. First post here.  I have a 1948 CJ2a that has oil pressure of 35-40 on startup but then drops to about 5 or 6 at idle. Sometimes lower with time... When she runs though it gets up to 20-25 depending on speed. I feel like the bearings or what not are worn, but I don't have the money right now to rebuild the motor. Thinking of getting a new oil pump. Would this possibly buy me some more time? Or is it not even worth it. I was going with the pump by KaiserWillys. ALSO how difficult is this to install. I just put a new head on, radiator, water pump, and wired up gauges, but that is as far advanced I am with the Jeep stuff... Any help would work, I feel like I need to be walked through it literally step by step... Thanks!
Back to Top
Hud View Drop Down
Member
Member


Joined: 21 Aug. 2013
Location: Atwater, CA
Status: Offline
Points: 73
Post Options Post Options   Thanks (1) Thanks(1)   Quote Hud Quote  Post ReplyReply Direct Link To This Post Posted: 30 July 2015 at 11:42pm
Welcome Teacher,
According to the Universal Service Manual which can be downloaded here http://48cj2a.com/images/manuals/UniversalServiceManualForJeepVehicles.pdf 
your '48 should have the later type gear rotor pump.
 
The manual states  that safe minimum press. at idle is 6 lb. and 20 lb. at 2000 RPM.
I have a '48 as well and the press. like yours is higher at initial start up but decreases as the oil warms up.  The press. relief can be adjusted by adding or removing shims from behind the relief valve spring.
If all else is good with your engine, I don't think that you have a problem.
 
Download the manual; all the detailed information is in there.
 
Regards, Hud
"Go For Broke"
Back to Top
HistoryTeacher5 View Drop Down
Member
Member
Avatar

Joined: 26 July 2015
Location: Conshohocken
Status: Offline
Points: 24
Post Options Post Options   Thanks (0) Thanks(0)   Quote HistoryTeacher5 Quote  Post ReplyReply Direct Link To This Post Posted: 31 July 2015 at 1:20am
Thanks Hud

I took it out for a spin today and noticed that at 2,000 rpm (32 mph) it actually only had I'd say 15 max. Should be at 20 minimum. Still just at 5/6 at idle. Think I am doing damage? Haven't had any knocking noises though...still concerns me. Have you tried adding shims? I read that stainless steel number 8 fit in there but I don't wanna touch the pump if it's not worth it. Thanks for the link to the manual!
1948 Cj2a
Back to Top
WeeWilly View Drop Down
Member
Member
Avatar
Sponsor Member

Joined: 07 May 2009
Location: Clayton IN
Status: Offline
Points: 2407
Post Options Post Options   Thanks (0) Thanks(0)   Quote WeeWilly Quote  Post ReplyReply Direct Link To This Post Posted: 31 July 2015 at 11:31am
Teacher, I feel for you.  I am in the same boat with the low oil pressure after the oil is warm, but my engine only has a couple thousand mile on it.  After checking the oil pic-up tube and rebuilding another oil pump to minimum clearance it still has the low pressure when oil is warm.  I don't think you need to worry about it to much unless you hear a engine knock and or the engine temp. starts running high.  It really bothered me at first but after everything else is normal  I don't pay to much attention to mine anymore.  I am going to use thicker oil and Lucas oil additive on the next oil change and until I feel like taking it apart again and check the bearings.

   Jim 
47 CJ2A (Ranch Hand) 48 CJ2A, 48 Willys truck, T3C 3782, M274 (Military Mule)
Back to Top
HistoryTeacher5 View Drop Down
Member
Member
Avatar

Joined: 26 July 2015
Location: Conshohocken
Status: Offline
Points: 24
Post Options Post Options   Thanks (0) Thanks(0)   Quote HistoryTeacher5 Quote  Post ReplyReply Direct Link To This Post Posted: 31 July 2015 at 11:57am
Thanks for the advice. I just added thicker oil and Lucas last week. It didn't make a difference it seems. I put a new water pump and radiator in with a 160 thermo and she runs at 180-190 (it's been 90 plus with high humidity in Philly area). The PO had a heater hooked up and the bypass is still there bc the drain cock on the head is busted and I don't wanna mess with it. Don't know if that seems like she is running hot or maybe just bc of high heat/humidity and heater bypass being on.. So far no knocking noises at all..
1948 Cj2a
Back to Top
WeeWilly View Drop Down
Member
Member
Avatar
Sponsor Member

Joined: 07 May 2009
Location: Clayton IN
Status: Offline
Points: 2407
Post Options Post Options   Thanks (0) Thanks(0)   Quote WeeWilly Quote  Post ReplyReply Direct Link To This Post Posted: 31 July 2015 at 4:37pm
   On hot days mine runs those temps. My heater isn't hooked up and the holes on the engine are plugged.  I have taken mine on  50 - 100 mile road trips with no problem other than at first worrying about that low pressure and this is the second summer I have been running it that way.

    Jim 
47 CJ2A (Ranch Hand) 48 CJ2A, 48 Willys truck, T3C 3782, M274 (Military Mule)
Back to Top
HistoryTeacher5 View Drop Down
Member
Member
Avatar

Joined: 26 July 2015
Location: Conshohocken
Status: Offline
Points: 24
Post Options Post Options   Thanks (0) Thanks(0)   Quote HistoryTeacher5 Quote  Post ReplyReply Direct Link To This Post Posted: 31 July 2015 at 4:57pm
Ok cool. Thanks for the help
1948 Cj2a
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.00
Copyright ©2001-2018 Web Wiz Ltd.