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  #1  
Old 09-19-2020, 10:08 PM
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Full Size Jeeper Full Size Jeeper is offline
304 AMC
 
Join Date: Jul 20, 2014
Location: Mandeville Louisiana
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Oil pressure problems

Need someone to get me pointed in the right direction. I have only driven the Wagon in my neighborhood 1 to 3 miles at a time. it would come up to temperature, and the oil pressure was always the same. once warmed up,(185f.) I would have 12 to 13 psi @ idle, and 45 psi under acceleration. These numbers are with an electric Auto Meter oil pressure gauge, the sender screwed into the block near the oil filter.

Today I took it out on the road, and drove it for 30 miles. Stop and go, cruising speed(45mph), and out on the interstate at (75mph). Oil pressure was good the whole time.

Later in the day I drove it ten miles to a friends house, all was fine on the way to his house. On my way home I noticed the pressure not rising under acceleration, it was staying around 25psi. and when I would come to a complete stop, it would drop down to near zero. (never made any noise like it had low oil pressure. Total trip was 20 miles.
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1978 Wagoneer

401/turbo 400 trans. Quadra-Trac BW1339 (with Low) 4" Rusty's lift with 31" Summit Mud Dawgs

Mods:
Fuel Tank, Red Holley Fuel Pump, Razor Grill (profile pic out dated), Rebuilt steering box
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  #2  
Old 09-19-2020, 10:16 PM
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Full Size Jeeper Full Size Jeeper is offline
304 AMC
 
Join Date: Jul 20, 2014
Location: Mandeville Louisiana
Posts: 2,362
Just went out and started it, coolant temp sensor was at 123f. and oil pressure was a steady 55psi at idle. These are some pics of what I did to my timing cover. If someone sees something wrong with what I did please let me know.
Before clean up on glass.
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1978 Wagoneer

401/turbo 400 trans. Quadra-Trac BW1339 (with Low) 4" Rusty's lift with 31" Summit Mud Dawgs

Mods:
Fuel Tank, Red Holley Fuel Pump, Razor Grill (profile pic out dated), Rebuilt steering box
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  #3  
Old 09-19-2020, 10:17 PM
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Full Size Jeeper Full Size Jeeper is offline
304 AMC
 
Join Date: Jul 20, 2014
Location: Mandeville Louisiana
Posts: 2,362
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1978 Wagoneer

401/turbo 400 trans. Quadra-Trac BW1339 (with Low) 4" Rusty's lift with 31" Summit Mud Dawgs

Mods:
Fuel Tank, Red Holley Fuel Pump, Razor Grill (profile pic out dated), Rebuilt steering box

Last edited by Full Size Jeeper : 09-20-2020 at 11:21 AM.
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  #4  
Old 09-19-2020, 10:19 PM
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Full Size Jeeper Full Size Jeeper is offline
304 AMC
 
Join Date: Jul 20, 2014
Location: Mandeville Louisiana
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1978 Wagoneer

401/turbo 400 trans. Quadra-Trac BW1339 (with Low) 4" Rusty's lift with 31" Summit Mud Dawgs

Mods:
Fuel Tank, Red Holley Fuel Pump, Razor Grill (profile pic out dated), Rebuilt steering box
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  #5  
Old 09-19-2020, 10:25 PM
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Full Size Jeeper Full Size Jeeper is offline
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Join Date: Jul 20, 2014
Location: Mandeville Louisiana
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It was between .004 and .006, is that to much clearance and did it get wider as I drove it?
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1978 Wagoneer

401/turbo 400 trans. Quadra-Trac BW1339 (with Low) 4" Rusty's lift with 31" Summit Mud Dawgs

Mods:
Fuel Tank, Red Holley Fuel Pump, Razor Grill (profile pic out dated), Rebuilt steering box
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  #6  
Old 09-19-2020, 10:27 PM
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Full Size Jeeper Full Size Jeeper is offline
304 AMC
 
Join Date: Jul 20, 2014
Location: Mandeville Louisiana
Posts: 2,362
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1978 Wagoneer

401/turbo 400 trans. Quadra-Trac BW1339 (with Low) 4" Rusty's lift with 31" Summit Mud Dawgs

Mods:
Fuel Tank, Red Holley Fuel Pump, Razor Grill (profile pic out dated), Rebuilt steering box

Last edited by Full Size Jeeper : 09-20-2020 at 11:27 AM.
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  #7  
Old 09-19-2020, 10:31 PM
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Full Size Jeeper Full Size Jeeper is offline
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Location: Mandeville Louisiana
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I did the face of the timing cover too, but I don't have a pic. I did nothing to the inside of the cover where the gears touch the top and sides of cover. Here is a pic of that.
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1978 Wagoneer

401/turbo 400 trans. Quadra-Trac BW1339 (with Low) 4" Rusty's lift with 31" Summit Mud Dawgs

Mods:
Fuel Tank, Red Holley Fuel Pump, Razor Grill (profile pic out dated), Rebuilt steering box
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  #8  
Old 09-19-2020, 10:33 PM
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Full Size Jeeper Full Size Jeeper is offline
304 AMC
 
Join Date: Jul 20, 2014
Location: Mandeville Louisiana
Posts: 2,362
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1978 Wagoneer

401/turbo 400 trans. Quadra-Trac BW1339 (with Low) 4" Rusty's lift with 31" Summit Mud Dawgs

Mods:
Fuel Tank, Red Holley Fuel Pump, Razor Grill (profile pic out dated), Rebuilt steering box

Last edited by Full Size Jeeper : 09-20-2020 at 11:30 AM.
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  #9  
Old 09-19-2020, 10:36 PM
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Full Size Jeeper Full Size Jeeper is offline
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Join Date: Jul 20, 2014
Location: Mandeville Louisiana
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If I remember correctly, the side clearance checked out okay. I used a flat feeler gauge, but don't remember the number.
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1978 Wagoneer

401/turbo 400 trans. Quadra-Trac BW1339 (with Low) 4" Rusty's lift with 31" Summit Mud Dawgs

Mods:
Fuel Tank, Red Holley Fuel Pump, Razor Grill (profile pic out dated), Rebuilt steering box
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  #10  
Old 09-19-2020, 10:42 PM
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Full Size Jeeper Full Size Jeeper is offline
304 AMC
 
Join Date: Jul 20, 2014
Location: Mandeville Louisiana
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Also, I'am not running the pressure relief spring and plunger, should I ? thanks in advance. Running VR-1 20/50 with a NAPA oil filter.
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1978 Wagoneer

401/turbo 400 trans. Quadra-Trac BW1339 (with Low) 4" Rusty's lift with 31" Summit Mud Dawgs

Mods:
Fuel Tank, Red Holley Fuel Pump, Razor Grill (profile pic out dated), Rebuilt steering box
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  #11  
Old 09-20-2020, 08:52 AM
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tgreese tgreese is offline
 
Join Date: May 29, 2003
Location: Medford MA USA
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The oil pump cover could be perfect, and you could still have low oil pressure. Note that the oil gets thinner as the engine warms up. It also loses its multivis character as it gets old. Both of these factors will affect the reading.

How did you measure? The TSM has a section on what and how to measure. The gear-to-body clearance is not important compared to the end clearance.

How can you leave out the pressure relief piston and spring? I'd expect the overpressure bypass would be wide open all the time and you'd have zero pressure.

Indeed, engine-cold readings are meaningless, since you never drive the car when the engine is cold. Your engine-cold readings will be much higher than at operating temperature.

If you refurb'd the oil pump and the pressure did not change, you could have
1) bad gauge or sender - just because it's a new gauge does not mean it's proven
2) worn out bearings
3) cam bearings delaminated (known to happen)
4) something else?

Your posts are confusing to follow. Many empty posts. Perhaps you have trouble with your phone or computer?
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Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination ATs, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
ECO Green: '15 FCA Jeep Cherokee KL Trailhawk
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  #12  
Old 09-20-2020, 11:59 AM
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Full Size Jeeper Full Size Jeeper is offline
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Location: Mandeville Louisiana
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Sorry about the pics. I tried to fix, but they won't load. Anyway, this morning I put a mechanical gauge on the engine. At cold start up I had 60 psi at idle. Drove it about 20 miles and at idle with an engine temp of 180f. I had about 19 psi. At 75 mph, around 2700 rpm, I had 58 psi. Stop and go pressure starts at 20 psi and jumps up to 40/45 psi. depending on rpm. So I believe the electric auto meter sending unit is not functioning as it should. Also, I did a search online and auto meter does not want the sender screwed into the engine block, like I had it. They claim the vibration from the engine could damage it. They want you to run an oil line and sender to a spot somewhere under the hood, like a fender well. Then run the wire to the sender and then don't forget to ground the sender.
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1978 Wagoneer

401/turbo 400 trans. Quadra-Trac BW1339 (with Low) 4" Rusty's lift with 31" Summit Mud Dawgs

Mods:
Fuel Tank, Red Holley Fuel Pump, Razor Grill (profile pic out dated), Rebuilt steering box
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  #13  
Old 09-20-2020, 02:47 PM
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Cliff Cliff is offline
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Join Date: Mar 30, 2002
Location: Upper East Tennessee
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I have owned three FSJ's and half a dozen AMC cars with V-8's. A warm engine at idle has consistently been below 10 PSI, whether a mechanical gauge or a sending unit. I ran a high pressure setup in a drag car and even that had low PSI at idle (10-12). My current 401 Cherokee will go as low as 3 PSI at idle on a hot day, warmed up engine. That's a digital gauge through a sending unit. Of course the slightest increase in RPM and PSI jumps to 20 then increases with RPM.

And I have always threaded the sending unit into the block, never had one fail or read inaccurately. Sending units have been so reliable that I will never go with a mechanical gauge again. My only failure was a copper line, as odd as that may be. Never had a nylon line break or melt.
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1977 Cherokee S

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  #14  
Old 09-20-2020, 11:10 PM
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letank letank is offline
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Join Date: Jun 03, 2002
Location: San Francisco
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for these early years the way the gauges work is tantamount to medieval technology... it works but with time the voltage regulator built inside the temp gauge fails and the readings can be unreliable.


You can do a little surgery and get some more reliable readings, key words

Instrument cluster voltage regulator upgrade




https://www.fsjnetwork.com/forum/vie...hp?f=10&t=8334
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Michel
74 wag, 349Kmiles on original ticker/trany, except for the rust. Will it make it to the next get together without a rebuilt? Status: needs a new body.
85 Gwag, 226 Kmiles. $250 FSJ test lab since 02, that refuses to give up but still leaks.

See Ouray 2013, Engine bits and Fuel and brake lines, and Body work
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  #15  
Old 09-21-2020, 09:02 AM
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tgreese tgreese is offline
 
Join Date: May 29, 2003
Location: Medford MA USA
Posts: 11,280
I would shelve the Autometer gauge (unless the seller will take it back) and run a mechanical gauge. You hear occasional horror stories about the lines breaking, but they have consistently worked well for me. Autometer sells an installation kit with copper line, if that feels more safer than nylon - this is what I currently am running in my CJ-6. The Stewart-Warner installation kit with nylon line has also worked well for me, as has the Summit plastic line kit for their gauge. If you use copper, I suggest adding a big stress-relief loop between the engine and the dash, since copper does fatigue with continued bending. If running nylon, suggest you sheath the entire length in rubber vacuum hose before installing the ends. Keep the line away from the hot exhaust.
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Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination ATs, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
ECO Green: '15 FCA Jeep Cherokee KL Trailhawk
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  #16  
Old 09-22-2020, 05:10 AM
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Full Size Jeeper Full Size Jeeper is offline
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Join Date: Jul 20, 2014
Location: Mandeville Louisiana
Posts: 2,362
Thanks all, I'am going to try the electric gauge one more time.
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1978 Wagoneer

401/turbo 400 trans. Quadra-Trac BW1339 (with Low) 4" Rusty's lift with 31" Summit Mud Dawgs

Mods:
Fuel Tank, Red Holley Fuel Pump, Razor Grill (profile pic out dated), Rebuilt steering box
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