Oil Pump?

[Firechickenzz]

I have a 36 3 Window. While out this weekend I noticed as soon as the oil warmed up pressure dropped to near zero (mechanical gauge) Started off around 15psi. Its never been high since I've had it, maybe 15-20 psi when on throttle.

Does this sound like the pump or should I be looking at something else?

Any recommendations on best Oil pumps to go with or sources?

Thanks,
Andy

[69a]

I doubt that it is your oil pump. Plenty of previous posts on this subject. Probably wear in the bearings is the most common cause. And the general recommendation is to just keep driving it.

[petehoovie]

This, from Ron Bishop's book "Rebuilding The Famous Ford Flathead" - Page 51 - "Ford used 40 non-detergent oil (Summer) in all of the flathead motors. The flathead oil system ran between 10-15 pounds of pressure, but is not considered a pressurized system by today's standards."- This, for factory stock engines back in the day....

[tubman]

Originally Posted by petehoovie

This, from Ron Bishop's book "Rebuilding The Famous Ford Flathead" - Page 51 - [B]"Ford used 40 non-detergent oil (Summer) in all of the flathead motors. The flathead oil system ran between 10-15 pounds of pressure, but is not considered a pressurized system by today's standards."- This, for factory stock engines back in the day....

I don't believe any of that for a minute. Did you know that the factory specification for oil pressure for an 8BA was 57psi at speed. Even the early engines ran a lot more than 10-15 psi unless they were all worn out. Also, non-pressurized engines have "dippers" on the rods; never seen any on any flathead Ford V8's. Model "A"s and stovebolt Chevy's yeah, but not Ford V8's.

Burn all copies of Bishop's book if that kind of crap is in it.

[marko39]

Originally Posted by Firechickenzz

I have a 36 3 Window. While out this weekend I noticed as soon as the oil warmed up pressure dropped to near zero (mechanical gauge) Started off around 15psi. Its never been high since I've had it, maybe 15-20 psi when on throttle.

Does this sound like the pump or should I be looking at something else?

Any recommendations on best Oil pumps to go with or sources?

Thanks,
Andy

what weight oil are you running?

[Bored&Stroked]

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While a new/better oil pump could certainly help, you might also have worn bearings.

Personally, I would not want to run an engine with no or that low oil-pressure . . . that is just asking for bad things to happen.

At the very least, pull the oil-pan, clean it out and consider putting a new oil-pump in it. I'd probably use a 49-53 oil-pump in it. You'll need to buy/fabricate the right pickup . . . starting with one that Speedway has for the later pump. The later pump has higher volume and pressure than what you have - so it might be a sort of "band aid" for a bit.

The only caution is that the later pump may cause some oil-leaks out of the back of the rear-main . . . depending on how worn the bearing is. Currently you have almost no pressure - so it would be worth a try.

[Firechickenzz]

Thanks for all the feed back.

I'm running 15W40 Rotella. After talking to my bother last night it sounds like there was a lot of sludge in the pan when he was working on it to get it running again a few years back.

I think I'm going to start with dropping the pan and cleaning the screen. The Oil pressure gauge could also be obstructed so will check/replace that as well.

[Adam/Mill Valley CA]

I ran into this with my '36 pickup, which has a poured-bearing stock 221 cu in motor. I posted about this in September 2022, ultimately came to replacing the oil pump with a high volume Melling M-15 pump; this was my conclusion at that time:

"I thought I would give an update on this issue. To recap, it is a 221 cu in stock 85 hp Babbitt bearing motor; with extended highway driving in hot weather oil pressure at 55 MPH (3.78 rear end, Valvoline VR-1 20/50) was down to about 18 psi, dropping to zero at idle. The motor continued to perform fine, as it always has, but I was concerned about the 0 psi at idle. It had a no-name/offshore 8BA #50 pump about 15000 miles ago, with an 8 RT pickup. The old pump actually spec'd out fine when I removed it.
After a lot of thought I decided to put in a new high volume Mellings M-15 pump(from Speedway, marked made in USA), which is reputed to increase the volume by 25%. The main bearings showed .0035-.004 thou clearance with Plastigauge (vs previous .002 thou 15000 miles ago-total miles on the motor unknown)-still within specs, I believe. As Mart has said, it is "worn, but not worn out"
With the new pump after a long highway run, including uphill at 55 mph on a warm day, the pressure at speed is 45 PSI( retained the original #50 pressure relief spring in the valley with a 1/4" shim), dropping to 18 psi at hot idle. I was concerned the increased volume might cause excessive leakage out the back of the crank since there is no proper seal there, just the labyrinth, but that has not been evident at all.
Time will tell if this will let the motor live a bit longer, and I understand I may be just treating my psyche here. I'll update again in the future.


Adam"

In the 1/1/2 years since then I've put several thousand miles on the truck, it runs great, oil pressure remains 40-45 hot on the freeway, 10-15 at idle (hot). No increased leakage at the back of the oil pan. By all means you should drop the pan, check your bearings with Plastigauge, consider a high volume pump. BTW when I first got my truck many years ago and dropped the pan, the amount of sludge was absolutely astounding.

Adam

[Bored&Stroked]

Nothing like some real-world examples . . . as I remember the conversation with Adam. Nice to see that the "big pump band-aid" trick has worked for him. Worth a try at the very least . . .

[Firechickenzz]

I finally was able to get all the tools necessary to pull the engine (hoist, load leveler, stand, Stumpy's stand adapter) I did find a considerable amount of sludge in the pan. Screen was clear. My theory is that I had pressure while the engine was cold, once the sludge warmed up enough it would clog the screen of the pump and restrict oil flow.

I would like to check the pump before I put the engine back into the car. Is there a procedure for checking clearances?

[Lawrie]

Check the bearings while you are in there
In my mind you are mad not to .
Plus you can close up the main clearance
Lawrie

[tubman]

I have found that Ford specified the clearance between rotors on the pump and the bottom plate. I don't have it here, but if no one else can come up with it, I can get it when I go to my shop tomorrow. I remember that I checked mine with plasti-gage several years ago. Also, the bottom plate should be perfectly flat and not scored. You may want to see if you can find a new relief spring.

[Firechickenzz]

I will pickup some plastigauge tonight. I did pull the cover on the oil pump. there is some ghosting but it is perfectly smooth.

How do you close up the clearance on the mains?

[petehoovie]

Originally Posted by Firechickenzz

I will pickup some plastigauge tonight. I did pull the cover on the oil pump. there is some ghosting but it is perfectly smooth.

How do you close up the clearance on the mains?

[tubman]

Originally Posted by Firechickenzz

I will pickup some plastigauge tonight. I did pull the cover on the oil pump. there is some ghosting but it is perfectly smooth.

How do you close up the clearance on the mains?

That's what they make "shim stock" for. Also, they used to make .002" undersize bearings for this. Before I put the used Merc engine in my '51 I checked the bearing clearances. I did this because I had just grabbed a set of .002 undersize 8BA rod bearings from Rock Auto real cheap. They brought the rod clearances back towards the tight side of the specification. The engine has excellent oil pressure.

I didn't make it to the shop today (Drs. Appt.). I'll get that clearance tomorrow.

[Ol' Ron]

15/40 Keep driving it.
Gramps

[Mart]

You can't close up the clearances on the mains. They either need to be used as is or fit new bearings.

[Ron_r1959]

I am surprised you can still get .002 undersized bearings, i would have thought that technology was long since gone! Lol

[tubman]

Originally Posted by Ron_r1959

I am surprised you can still get .002 undersized bearings, i would have thought that technology was long since gone! Lol

As said, they were on closeout at Rock Auto and incredibly cheap. I bought all they had (weren't many).

[19Fordy]

To add to Tubman's post:

On page 69 of Bishop's book the firing order for 1946-48 and 1949-53 V-8 Ford engines is incorrectly listed as : 1 5 8 4 6 3 7 2 . I wonder how many folks have been misled by this misprint?

It should be 1 5 4 8 6 3 7 2