TESTING OIL PRESSURE SWITCH

[FLHMAN880]

I HAVE A 50 FL THAT NEEDS AN OIL PRESSURE SWITCH, I BOUGHT AN ORIGINAL ONE ON EBAY AND I WANT TO BENCH TEST IT BEFORE I SCREW IT INTO PUMP, CAN SOMEONE TELL ME HOW TO TEST IT?

[LittleAl]

well since none of the smart guys answered yet, I'll give it a shot. This is just from general knowledge and not specific to your Panhead switch:

Typically oil pressure/sending units give ground to the gauge or idiot light. I'd try hooking up a battery (or 6 volt charger, the idea here is to supply positive voltage to the meter) positive terminal to the positive terminal of a 6 volt meter. the negative side of the battery or charger to the body of the switch. Best is probably clipped to the threads as there may be insulators separating parts of the body you may not notice. Last clip the negative side of your meter to the terminal post of the switch.

Apply some air pressure to the small hole in the end of the threads (the part that would normally thread into the motor) and if the switch works you should have no volts showing on the meter. Without any air pressure applied your meter should show 6 volts
It probably only takes a few pounds of pressure so you can probably just put the threaded end in your mouth and blow. If you use an air hose I would keep the pressure under maybe 10-15 pounds as you don't wanna blow the switch. It might take lots of pressure to blow, maybe 100 pounds or more but why take the chance? besides to turn off the idiot light you only need minimal pressure, likely 2-3 pounds.

Hope this works as a test for you

[Cotten]

Good idea Al!

I only found one dead pre-'54 sending unit in my OEM stash, but I had six brand new Dixie repops in inventory to test;
They opened at the following psi readings:
5.0; 6.0; 6.5; 7.0; 7.6; and 10.5

I had one used OEM bakelight '54 & up off of my '65, and it opened at 3 psi.

An Accell repop was dead right out of the box. Very typical for Accell.

....Cotten

[Ohio-Rider]

I'd say thats the proof that these oil light switches are not to be trusted.

[mbskeam]

this sender saved my engine once... if I did not have the IDOT light come on, and did not see it....
I bet the engine would have gone kabOOM.....
its when the light comes on and stays on that you have to worry....LOL

[FLHMAN880]

THANKS FOR ALL YOUR HELP, WILL PUT 6 VOLT CHARGER AND METER TO IT TOMORROW. FLHMAN880

Good idea Al!

I only found one dead pre-'54 sending unit in my OEM stash, but I had six brand new Dixie repops in inventory to test;
They opened at the following psi readings:
5.0; 6.0; 6.5; 7.0; 7.6; and 10.5

I had one used OEM bakelight '54 & up off of my '65, and it opened at 3 psi.

An Accell repop was dead right out of the box. Very typical for Accell.

....Cotten

[Panacea]

I'm sure the topend would start clattering to the point where you would shut 'er down if you lost to much pressure...

[FLHMAN880]

YEA, YOUR RIGHT, I WOULD RATHER TRY TO GET THE SWITCH TO WORK RIGHT IF I CAN, POSSIBLY GET A HEADS UP TO HAVING LOW PRESSURE, BUT I DONT WANT TO GET TO THE POINT OF A REAL NOISY TOP END, I DONT WANT TO HURT HER.

[59Panman]

I am not meaning to change this thread but I want to mention that my oil return line came off my oil bag due to the oil filter bracket broke. I was lucky enough to catch it in time. I am thinking to install a LED in the vicinity of my handle bars wired into the oil light and this way I will see a problem right away. As you all know, you don't see your lights on your dash until you look down and that can be too late. Has anyone else had this idea and done this?

[john HD]

mark,

i don't think that would be to hard to do. however i wonder if it is worth the effort. your lifters should collapse giving a very audible alarm.

if you are running loud pipes or solids it may be worth the effort.

i have gotten my bike very hot out west a couple of times, so hot the light stayed on most of the time below 25 mph. my lifters stayed pumped up so i figured i was ok.

it is still running fine years later.

john