Yet Another Oil Pressure Question

[RKS.PA]

The 59 AB in my '39 usually registers close to 50 psi at speed and perhaps 25 or so at idle after warm up. Recently, my original gauge started giving me erratic readings, both at idle and at speed, all lower than normal. I think the sending unit is original, so I replaced it with a new 80 psi sending unit, hoping that would be the source of the funny readings. Now, I'm getting a steady 15 psi, both at idle and at speed after warm up. I believe the oil pump is a 50#.

I have done nothing to the engine to influence oil pressure, so I'm at a total loss as to what may be going on and I'm hoping it's not an internal engine issue, but I will deal with it if it is. And, I could plumb in a mechanical gauge to isolate the new sender and my original gauge, but have not done that yet.

As always, the resources here are awesome and I appreciate all the help you all provide us.

Regards....Dick.

[41LjH]

I would suggest "T"ing a mechanical gauge to verify the new sender. If the old sender is 50 and the new one is 80 that could be your problem. The mechanical gauge will give you an accurate reading to compare to the new sender. Simply remove the sender insert the "T" into the block, attach the sender and the mechanical line to the "T" and start it up.

[JSeery]

I would second the backup mechanical gauge suggestion. Need to verify the what the problem is before you attempt to fix it.

[Merc Cruzer]

Is the dimple on the back of the sending unit at the top of the unit? If not adjust accordingly and try it again.

[RKS.PA]

Working on the mechanical gauge plumbing and will report back. Perhaps should have ordered a 48-9278 60# unit vs. the 80# one I got. Also, no dimple on the new sender, but a round dimple on the old one, but I can't see how any adjustment can be made.

Dick.

[51 MERC-CT]

Sponsored Links (Register now to hide all advertisements)

Originally Posted by RKS.PA

Working on the mechanical gauge plumbing and will report back. Perhaps should have ordered a 48-9278 60# unit vs. the 80# one I got. Also, no dimple on the new sender, but a round dimple on the old one, but I can't see how any adjustment can be made.

Dick.

The dimple on the back of the sending unit is only a concern if the sending unit is mounted horizontally.

[Old Henry]

I have found that, no matter what I've done to get my stock oil pressure gauge to read accurately, nothing has worked. So, I added a backup mechanical gauge in my glove box to look at if I really want to know what the pressure is. It always shows just what one would expect for speed and temperature.

[RKS.PA]

Bingo....found the problem to be the 80# gauge on a 50# pump....learn something new every day working on these old Fords. Mechanical gauge registers 50#. Will order the proper sending unit.

Hope this might help somebody avoid this in the future. As always thanks to all who answered my post for help.

Dick.

[Ol' Ron]

I have an oil gauge and temp gauge in the back of the glove compartment. It just gives me comfort when looking at he instrument panel and seeing those weird things

[Drbrown]

Speaking as a grandpa who acquired a modernized '47, my children and grandchildren love ride at night with all those up-front gauges lighted-up. They never saw a dash board like that, with all those pointers, and say its like flying in the cockpit of an air liner (don't know when they ever did that ! ).

For me it brings back teenage memories of my lovely '51 Merc Coupe. I wrapped all its dash light bulbs with theatrical grade violet cellulose. The girls called it the "sex palace" and their parents wouldn't let them ride with me.

[corvette8n]

"The girls called it the "sex palace" and their parents wouldn't let them ride with me."
My shoebox Ford had blue clearance lights installed under the dash, we called them sex lights back in the day.

[RKS.PA]

Originally Posted by corvette8n

"The girls called it the "sex palace" and their parents wouldn't let them ride with me."
My shoebox Ford had blue clearance lights installed under the dash, we called them sex lights back in the day.

Seems like my original post got a little highjacked!!! Some reference to "Johnson Lifters" can't be far away!!!

[Old Henry]

I've had several new passengers in my car ask what that huge gauge on the right of the radio is. I tell them to study the pattern of the numbers and see if they can figure it out. Eventually, they realize it's a clock.

[RKS.PA]

Craig, a five year old grandson of one of my friends rode in our '39. "This is the funnest car I've ever been in !!!".....Roll up windows!!!!