I cant take this pressure any longer.

Capt Kirk

Capt Kirk

Well-known member
OK, I've been told by knowledgeable flathead people and have done some reading that low oil pressure is normal. My engine was professionally rebuilt years ago and probably doesn't have 200 miles on it. The gauge is original and the sending unit was new when I restored the car. I took it to the Dream Cruise today...it was about 90 out. When cold started, the pressure is 3/4 up the gauge. As it warms up...the pressure drops. Today, just tooling down the road the pressure indicated about 7psi and at idle, it was reading 0. Tap the throttle a bit and the needle moves in relation to the RPM. I'm having a really hard time ignoring these pressures. I did about 30 miles today and the coolant temp never reached the upper line and the engine sounded good. Should I just put some tape over the gauge or is there something I can do to improve these numbers? Different type of oil? Different pressure relief spring (if they have one)?
 
Heavier weight oil will improve your readings, what are you running now ?
Pressure relief spring aint the main issue if it has high readings cold and nothing warmed up.
Either the pump has to low flow, your bearings are a bit loose or you have a bypass leak somewhere.
 
I would install another mechanical gauge in addition to the original and see
if it shows the same results.

Bob
 
I agree with Bob. Install a mechanical gauge. I installed a Stewart Warner oil pressure gauge and water temperature gauge at the bottom of my dash centered. I don't have a Concours trophy car. I think 'Ol Ron set his up in the glove box. I like to monitor mine continuously. I use 20-50 weight. On start up my pressure reads 90 psi. As the engine warms I have between 30 and 40 psi. My original gauge never shows over 20 psi and zero at idle the same as yours.
If you don't want to do this,find a mechanical gauge and hook it up under the hood and monitor the pressure. Look at start up then let the engine idle to operating temperature and read that. Then you will know what your original gauge really means.
 
I installed mech oil and temp gauges in my 56 a few weeks ago because I didn't trust the readings on the original gauges. New gauges now show the originals were way off. I thought of doing the same thing with the 35 and I'm struggling with the thought. The glove box crossed my mind as well as mounting under dash on a short piano hinge that could be flipped up behind the dash when in "show mode". The car's put to bed for the night...I'll check out options tomorrow. I know I could look this up but remind me of the oil quantity on a 59 AB...it's been awhile since the last change.
 
One thing....The oil pressure sender unit in your 35 must be a fifty pound unit. Fitting an 80 lb sender will give lower readings.
 
My dash OP gauge is off by 20 psi at midrange, but I know it is, so I don't worry about it.

BTW I checked it with a "vintage" S-W mechanical gauge, which showed higher readings. Then I got some 4" certified/calibrated industrial gauges. They showed the S-W gauge to be off quite a bit too. A good industrial pressure gauge costs about $150 these days.
 
Brian, I'm not sure what sender it is. When I was restoring the car, I would go through the catalog and pick the part that was applicable to my car. Great point but I have no way of knowing if that's the right sender
 
The "put some tape over the gauge" comment made me chuckle. About 20 years back I got real good at cutting just the right size and shape of electrical tape to put over the "Check Engine" light on my "beaters" (made the little lady not worry so much).
 
Is there another tap on the block where I could screw in a mechanical gauge. I don't have a filter. 59AB.
 
Tubman...LOL. I flew DHC-2 Beaver for 4 years. It had aux tip tanks and the gauges for those were right in front of the copilot seat...we never used those tanks. Passengers would always ride in that seat and have a look of horror on their face, tap me on the shoulder and point out that "we are all going to die!!!". After having my fun with that for awhile, I taped them over.
 
Brian said:
One thing....The oil pressure sender unit in your 35 must be a fifty pound unit. Fitting an 80 lb sender will give lower readings.
Click to expand...

You are correct. I ran into this on my Zephyr. New engine had 20 psi . Installed mechanical gauge and got 50 psi. Changed the sending unit and now it corresponds with the mechanical gauge. Sending unit must match the dash unit.
 
Capt Kirk said:
Brian, I'm not sure what sender it is. When I was restoring the car, I would go through the catalog and pick the part that was applicable to my car. Great point but I have no way of knowing if that's the right sender
Click to expand...

If your restoration was within the last 25 years or so, your only catalogue option would be a 80 lb sender.

Just a bit of info on the sender... The original senders were never identified as 50 or 80 lb senders, because there was only the 50 lb sender. When the 80 lb sender began (I don't know the year?), then all senders manufactured had either the number 50 or 80 on the unit at the bottom. Should by odd chance that a sender turned up today with no I.D., you'd know it to be a 50 lb sender.
 
Ford38V8, The restoration was probably 12 years ago and I bought a lot of stuff through MAC's so this sender is probably one of theirs. It's starting to sound like this might be a sending unit problem. Is there a reliable source to get the correct sender? LOL...didn't know there was supposed to be a "ue" at the end of "catalog"...is that a European thing? :)
 
Capt,

Then you must know the Fretless Bar Girls and their famous ditty about Beavers. It was a classic in the northwest where I lived for awhile. Had several nice rides courtesy of Kenmore Air, both in Beavers and their Turbo Otters.

https://www.youtube.com/watch?v=3w_v0k57KhE

I have an original gauge in my 36 and it showed 40-50 warmed up and rolling, and about 10 at hot idle, with 15-40 oil. The new '39 engine (brand new) shows about the same and so did the mechanical gauge I had.

Model Ts have no oil pressure at all, just splash and trickle (good name for a comedy team). Main thing about having oil pressure is that it means good flow for cooling the bearings, which is why splash lubrication didn't last past the Model As.

John
 
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.didn't know there was supposed to be a "ue" at the end of "catalog"...is that a European thing? :)

I spell it as its spelled [spelt?] on my copy of 'Fast Moving Parts CATALOGUE 1928-1949' for all Ford of Canada products.
Is Canada European?
 
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