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Oil Pressure Question

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larry12574@sbcglobal View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote larry12574@sbcglobal Quote  Post ReplyReply Direct Link To This Post Posted: 23 Jan. 2018 at 11:57pm
I haven't put a test gauge on it, but the indicator is brand new and registers 30 to 35 psi when the engine is cold drops when the engine warms up. I think maybe the oil pump weakens when it warms up, weak regulator spring maybe. We'll see.
88mike "Shot Out"
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Post Options Post Options   Thanks (0) Thanks(0)   Quote TERRY Quote  Post ReplyReply Direct Link To This Post Posted: 24 Jan. 2018 at 2:26pm
Verify the pressure readings before replacing parts.Smile
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Post Options Post Options   Thanks (0) Thanks(0)   Quote cdn2a Quote  Post ReplyReply Direct Link To This Post Posted: 24 Jan. 2018 at 4:21pm
The hidden oil pressure killer on these engines, is the cam bearings, or lack there of.

Only the front one is factory replaceable.
I hear you can have them bored and have ford 302 bearings installed....
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Post Options Post Options   Thanks (0) Thanks(0)   Quote cal.bar Quote  Post ReplyReply Direct Link To This Post Posted: 24 Jan. 2018 at 10:57pm
OK - now I have to wonder.  L134 running 10w30 oil.  My resting pressure is 20psi.  Holds firm at 60psi when running at full speed.  How are you guys running near 5 psi??  I START at 20.
 
Is mine going to "blow a gasket" as they say?  I have 1000K on mine so far with no problems.  But wonder if the high oil pressure is an issue?
 
Thanks
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Post Options Post Options   Thanks (0) Thanks(0)   Quote elawson Quote  Post ReplyReply Direct Link To This Post Posted: 25 Jan. 2018 at 3:35am
When my Jeep's 4L134 engine warms up, the idle oil pressure is around 10psi and at 45mph, the oil pressure comes up to about 35psi.  When the engine is cold (well, cold for Phoenix, AZ), the oil pressure is around 60psi.

The bearings in the engine are quite large and it doesn't take much oil pressure to keep the oil film between the bearing surface and the crankshaft surface. 

I run 10W30 oil in the winter and 30W oil in the summer..and add some zinc additive just in case.

I've always felt that a lot of engine bearings were ruined by using a very heavy oil on a cold day.  The pressure reading measured in the relatively large oil gallery looks great, but the oil has a difficult time flowing into the small space between the bearing and the crankshaft...and the bearing is starved for oil until the oil warms up....my opinion and I'm sticking to it.... :-)

If I recall, 60psi is where the oil pump pressure relief valve opens up, so 60psi maximum oil pressure you should see on the gauge.  Your engine won't "pop" due to high oil pressure.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote cal.bar Quote  Post ReplyReply Direct Link To This Post Posted: 25 Jan. 2018 at 11:22pm
OK - so should I endeavor to lower the oil pressure?  Running lighter oil perhaps?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1947-cj2a Quote  Post ReplyReply Direct Link To This Post Posted: 26 Jan. 2018 at 3:14am
5W-30W? DOESN'T THIS ENGINE USE JUST 30W? COULD HE JUST BE RUNNING TO THIN OF A OIL WEIGHT?
RICH

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Post Options Post Options   Thanks (0) Thanks(0)   Quote cal.bar Quote  Post ReplyReply Direct Link To This Post Posted: 26 Jan. 2018 at 5:13am
Originally posted by 1947-cj2a 1947-cj2a wrote:

5W-30W? DOESN'T THIS ENGINE USE JUST 30W? COULD HE JUST BE RUNNING TO THIN OF A OIL WEIGHT?
 
 
Not sure if you are referring to me (Cal.Bar), but I'm running 10w30. (thought that what was what the manual called for)
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote cpt logger Quote  Post ReplyReply Direct Link To This Post Posted: 26 Jan. 2018 at 7:53am
Cal.bar, just drive that Jeep. Your oil pressure is just fine. As has been said, it is regulated at 80 PSI maximum, so that is good. Five PSI is the MINIMUM warm idle PSI. So again, your Jeep is just fine. Your re-builder did a good job. They probably machined your block to take the 302 cam bearings. Use the oil they recommend. Warranty.

Larry, Just because the gauge is new does not mean it is accurate. We have seen many new parts that were bad new from the box. Test your Jeep with a known good gauge.

If I am understanding you correctly, you get 30 PSI at cold Idle, you get 40 PSI at cold cruise, & you get 5 PSI at warm idle. What are you getting for oil pressure at warm cruise speeds?

My concern is that you should have a bit more pressure with a freshly rebuilt engine. Five PSI is minimum for a worn engine.

Check the gauge first. Lets make sure that your numbers are correct. I see no sense in chasing a problem that may not exist. That would be a waste of time & money.

IHTH, Cpt Logger.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote cal.bar Quote  Post ReplyReply Direct Link To This Post Posted: 26 Jan. 2018 at 5:42pm
Thanks Cpt.!
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