Oil Pressure issue?

Lubrication System (oil feed pump and scavenger pump, reservoir, filter, and lines)
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BastardBoy
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Oil Pressure issue?

#1

Post by BastardBoy »

:?:
I rebuilt my Panhead motor and just got it running. I acquired the bike a couple of years ago and last year was the first time I rode it, putting maybe 2000 miles on it. I didn't have a oil pressure gage or light last year so I was just crossing my fingers that the oil system was OK and had no problems, but I had no way of knowing what the oil pressure was running at.
I did add both a oil light and gage this year. And now when I cold start the bike, there seems to be about 15-20PSI and spikes to about 30-40 when reved. But as it warms the oil pressures starts falling to the point the oil light is on continually.
I read somewhere the light comes on below 4PSI? I have also read that pressure is not as important as flow in a Panhead? But how do I know if I have flow.
I had the oil pump completely apart and everything looked good.
I did send my heads to flo Headworks and had them machined for overhead oiling, so my oil pressure switch port has the two head oil lines and a pressure gage hanging off it.
Does anyone have any thoughts? Is there a pressure relieve valve in the oil pump? Maybe it needs a new spring?
Any advice would be greatly appreciated. I am itching to ride!
TIA
Rick
old52pan
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Re: Oil Pressure issue?

#2

Post by old52pan »

Rick, glad to see you have doing your home work. A quick way to check is to simply open the dipstick cap on the oil tank while it is running, You should see oil burping back into the tank from the return line. Old pans do not have a tremendous amount of pressure, worse when they warm up. As long as oil is circulating through the entire system your good, get rid of that gauge also. No use on these old bikes and will just give you something to worry about :wink: . tim
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Re: Oil Pressure issue?

#3

Post by panhead_kicker »

Rick,
I just replaced a Drag specialties oil pressure sending unit with an old stock one. I see alot less red light now.
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Re: Oil Pressure issue?

#4

Post by Panshovevo »

If I understand you correctly, you are now sending oil to the heads from the same port as the oil pressure sending unit. You will never read normal pressure under those conditions unless the flow is identical to original condition. That does not mean that there is anything wrong with your oil pump, just that there is more flow than normal from that port, and as a result, the pressure reads lower.
Pressure is caused by resistance to flow. If you lower the resistance, the pressure will drop.

What weight oil are you running?

John
BastardBoy
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Re: Oil Pressure issue?

#5

Post by BastardBoy »

I was running 60wt but changed oil to 70wt (temp is running in the high 80ies low 90ies here daily) and moved the overhead oilier lines to the tappet screen port (I have solid lifters). It now takes longer for the pressure to drop but it still does. Checked the oil temp after the engine reached full temp, its about 180 deg F. Does this seem about right?

The pump and cam covers coming apart next. I just can't take a chance with "ditching the gauge and light" until all else fails. I understand Panheads use a flow oil system. But you need some pressure to create flow and I'm not getting any.

I will report back with outcome!
Panshovevo
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Re: Oil Pressure issue?

#6

Post by Panshovevo »

180 is a reasonable temperature. Personally, I would stay with the 60 wt.

You can have flow without measurable pressure. Get the oil hot,disconnect your return line (if you can't see it inside your tank), put the line in a container, and start the motor for a few seconds, if you doubt that you are getting flow.

I'm not sufficiently familiar with the two systems to know for sure if the outside oiler setup flows significantly more oil than the original system, but I assume that is the reason for the conversion. If your pump is okay, it is possible that you may need to find a higher volume pump.
FlatHeadSix
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Re: Oil Pressure issue?

#7

Post by FlatHeadSix »

BastardBoy wrote:I understand Panheads use a flow oil system. But you need some pressure to create flow and I'm not getting any.
Yes and Yes, but flow is inversely proportional to pressure, as flow increases the pressure decreases. That's a good thing for a pan engine. So, you can safely ditch the guage, they're worthless on a pan engine, all you need to do is check for steady return flow to the oil tank.

The idiot light was never intended as a pressure indicator, all the factory literature of the day refers to it as a circulation (flow) indicator:
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Re: Oil Pressure issue?

#8

Post by awander »

The idiot light was never intended as a pressure indicator, all the factory literature of the day refers to it as a circulation (flow) indicator:
That may be true, but you can;t argue with the fact that the sensor DOES indocate pressure....
pan57
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Re: Oil Pressure issue?

#9

Post by pan57 »

I have a oil light that just started to come on and as soon as it came on I pulled over to check the flow. the flow was fine but the light never goes off. I checked with some of the guys locally and they say to just take it off. The average temp here is about 95-99. I have put about 300 miles on the bike since then and the light has never gone off. I am thinking about switching to a pressure gauge but I was told that when it is cold it will run about 60 and when it is hot especially around here it may get as low as 10 lbs. So other than looking in my tank and seeing the oil flowing is there another way to check the to make sure I'm getting enough oil?
kitabel
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Re: Oil Pressure issue?

#10

Post by kitabel »

The lamp is a pressure switch, not a "flow indicator", since it cannot detect flow at all, unless there is pressure.
The pressure is about 5-8 psi, which is fine if it only flickers at hot idle.
If the lamp is on at all times, there is either something wrong with the lamp (wrong spring, short circuit), or something wrong with the engine. There is no third choice.
Try another switch.
FlatHeadSix
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Re: Oil Pressure issue?

#11

Post by FlatHeadSix »

kitabel wrote:The lamp is a pressure switch, If the lamp is on at all times, there is either something wrong with the lamp (wrong spring, short circuit), or something wrong with the engine. There is no third choice.
Third choice: wrong switch (indicator). The switches work on pressure, but they are NOT pressure indicators. The OEM switches, when they worked as intended, had a very low tripping point, somewhere around 4 psi. The after market replacements have a much higher psi thresh-hold and will NOT perform like an original.

A guage is not the answer, an oil sensor switch that perform like the original is. The bottom line is checking for flow, if you have a steady return of oil to the tank you have what you need, don't worry about it!

mike
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Re: Oil Pressure issue?

#12

Post by duoglide58 »

If you have no flow, your lifters and valves will let you know soon enough, but I don't want to bring up that bad memory. :oops:
Doug
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Re: Oil Pressure issue?

#13

Post by Panshovevo »

BTW, are the original oil passages to the heads blocked, or is oil passing through both routes???
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Re: Oil Pressure issue?

#14

Post by Sir_Rat »

I did send my heads to flo Headworks and had them machined for overhead oiling, so my oil pressure switch port has the two head oil lines and a pressure gage hanging off it.
Rick....Running outside oilers is great. But did you remember to block the original inside oil feed?

Good luck...Mike

oops!! I just read the above reply...after i posted this one..sorry :oops:
Don P
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Re: Oil Pressure issue?

#15

Post by Don P »

BastardBoy wrote:I was running 60wt but changed oil to 70wt (temp is running in the high 80ies low 90ies here daily) and moved the overhead oilier lines to the tappet screen port (I have solid lifters). It now takes longer for the pressure to drop but it still does. Checked the oil temp after the engine reached full temp, its about 180 deg F. Does this seem about right?

The pump and cam covers coming apart next. I just can't take a chance with "ditching the gauge and light" until all else fails. I understand Panheads use a flow oil system. But you need some pressure to create flow and I'm not getting any.

I will report back with outcome!
The system is basicly a circulation system and for those who may think their motor is pumping 45 psi no way. There isn't a pan made that can pump that kind of pressure. I also do not believe in 20-50wt. In summer 70wt and in winter 60wt
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