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Re: Oil Pressure by pass sticking
[Re: BSB67]
#1958352
11/26/15 02:22 PM
11/26/15 02:22 PM
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Joined: Mar 2006
Posts: 9,865
MI, usa
dvw
master
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master
Joined: Mar 2006
Posts: 9,865
MI, usa
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If it's idling at 40 psi and has 45 psi at rpm that's as much as the system will produce with the oil and temp it's at. If the bypass was stuck the idle/rpm swing would be huge. The faster the pump spins the more volume it flows until it's maxed out. If the bypass was open the low rpm idle pressure would be way low. It is possible that the spring tension on the bypass is low and allows the bypass to open at 45 psi.
Doug
Last edited by dvw; 11/26/15 02:27 PM.
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Re: Oil Pressure by pass sticking
[Re: NANKET]
#1958462
11/26/15 06:48 PM
11/26/15 06:48 PM
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Joined: Feb 2003
Posts: 16,160
Mesa, Arizona
dart4forte
OP
I Live Here
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OP
I Live Here
Joined: Feb 2003
Posts: 16,160
Mesa, Arizona
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Little history on the project. The motor was assembled last fall (2014). It was primed at that time showing 60 pounds of pressure. It sat in a clean room until this past spring when we put the engine in the car. The car wasn't fired until mid August. We again primed the motor and again it showed 60 Pounds. Once fired the motor idled at 60 pounds. We drove the car to seat the rings and when warmed it was just below 60 pound at cruise speed. It idled at around 50 pounds when warm.
When I brought the car down to Mesa it idled warm just below 40 pounds and wouldn't pull more than 45 pounds at cruise speed.
I've changed the gauge to hard line where it now idles at 40 pounds. Haven't driven it yet. I plan on changing the oil on Sunday and taking it for a drive.
“So if it’s on the internet it must be true”
Abe Lincoln
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Re: Oil Pressure by pass sticking
[Re: dart4forte]
#1958561
11/26/15 11:14 PM
11/26/15 11:14 PM
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Joined: Aug 2003
Posts: 43,269
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,269
Bend,OR USA
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The oil temps. have a big affect on the oil pressure, I've seen a 15 lb difference on motors on the dyno with 40 F degrees oil temp. increase at the same RPMs  I have lived in the Mojave Desert in SO CA as well as up here in central OR for the last ten years, my old pump gas Duster would see a lot more oil temps in SO CA when the outiside air temp where 95F + than up here with the air temps at or below 85 F I had a oil temp. gauge in it, how far I drove it and how hard had a lot to do with the oil temps, tranny temps and engine coolant temps It would take 20 minutes plus driving time in the summers up here to bring the oil temps up to or above 160 F locally, not so in the desert when the air temps where 115 F It's right at 25F outside air temps. here now, how warm is it there  
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Oil Pressure by pass sticking
[Re: Supercuda]
#1958688
11/27/15 08:25 AM
11/27/15 08:25 AM
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Joined: Feb 2003
Posts: 10,225
Someplace you aren't
SomeCarGuy
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 10,225
Someplace you aren't
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Quit buying melling pumps, they have a sticky bypass issue and have had it for years across makes.
X2
I want my fair share
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Re: Oil Pressure by pass sticking
[Re: Cab_Burge]
#1958727
11/27/15 12:33 PM
11/27/15 12:33 PM
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Joined: Feb 2003
Posts: 16,160
Mesa, Arizona
dart4forte
OP
I Live Here
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OP
I Live Here
Joined: Feb 2003
Posts: 16,160
Mesa, Arizona
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The oil temps. have a big affect on the oil pressure, I've seen a 15 lb difference on motors on the dyno with 40 F degrees oil temp. increase at the same RPMs I have lived in the Mojave Desert in SO CA as well as up here in central OR for the last ten years, my old pump gas Duster would see a lot more oil temps in SO CA when the outiside air temp where 95F + than up here with the air temps at or below 85 F I had a oil temp. gauge in it, how far I drove it and how hard had a lot to do with the oil temps, tranny temps and engine coolant temps It would take 20 minutes plus driving time in the summers up here to bring the oil temps up to or above 160 F locally, not so in the desert when the air temps where 115 F It's right at 25F outside air temps. here now, how warm is it there It's 37 this morning. The days have been averaging mid 60s. Evening have been low 60s
“So if it’s on the internet it must be true”
Abe Lincoln
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Re: Oil Pressure by pass sticking
[Re: perfmachst]
#1958729
11/27/15 12:34 PM
11/27/15 12:34 PM
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Joined: Feb 2003
Posts: 16,160
Mesa, Arizona
dart4forte
OP
I Live Here
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OP
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Joined: Feb 2003
Posts: 16,160
Mesa, Arizona
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ok, when a motor is new, cam lube gets washed into filter, causes flow restriction, any motor ,I have been around, after changing filter, pressure comes back up. same as what it was new.
change oil and filter first!! That's the plan
“So if it’s on the internet it must be true”
Abe Lincoln
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Re: Oil Pressure by pass sticking
[Re: perfmachst]
#1958951
11/27/15 08:58 PM
11/27/15 08:58 PM
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Joined: Feb 2003
Posts: 16,160
Mesa, Arizona
dart4forte
OP
I Live Here
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OP
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Joined: Feb 2003
Posts: 16,160
Mesa, Arizona
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Done on the hard Line setup
“So if it’s on the internet it must be true”
Abe Lincoln
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Re: Oil Pressure by pass sticking
[Re: perfmachst]
#1959155
11/28/15 11:45 AM
11/28/15 11:45 AM
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Joined: Feb 2003
Posts: 16,160
Mesa, Arizona
dart4forte
OP
I Live Here
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OP
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Joined: Feb 2003
Posts: 16,160
Mesa, Arizona
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also, did you use Teflon tape on threads?? a small piece can get cut off and partial plug line. shows lower pressure. I seen that before. he ended up blowing out the line. then re purged it on start up. Checked that. I used thread sealant from the tube
“So if it’s on the internet it must be true”
Abe Lincoln
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Re: Oil Pressure by pass sticking
[Re: perfmachst]
#1959302
11/28/15 04:31 PM
11/28/15 04:31 PM
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Joined: Feb 2003
Posts: 16,160
Mesa, Arizona
dart4forte
OP
I Live Here
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OP
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Joined: Feb 2003
Posts: 16,160
Mesa, Arizona
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[quote=perfmachst]If it was me, I'd blow the line out just to be sure!! might as well cover all bases. also purge the system when running. I assume the opening in tubing is not closed down or pinched. that happens when using a tubing cutter. [/quot
I'm using a -4 braided hose. Stopped using that copper and plastic line years ago.
“So if it’s on the internet it must be true”
Abe Lincoln
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Re: Oil Pressure by pass sticking. Update
[Re: dart4forte]
#1961457
12/02/15 01:48 AM
12/02/15 01:48 AM
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Joined: Feb 2003
Posts: 16,160
Mesa, Arizona
dart4forte
OP
I Live Here
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OP
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Joined: Feb 2003
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Mesa, Arizona
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Spent yesterday and today working the problem. Drained the oil into a clean clear plastic container. Ran a magnet through the oil, no metal. I then removed the filter. Cut the filter and found it to be clean. Went ahead and changed the oil.
Today I installed a mechanical gauge and a hardline. I always use a braided -4 line. Once I completed the install I again checked the oil which was at the correct level. Fired the motor.
Motors runs a little over 50 pds cold at idle. Ran the RPMs up to 2500. Motor pull just over 60 pds cold. I'll take it out tomorrow for a drive.
“So if it’s on the internet it must be true”
Abe Lincoln
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