oil pressure gauge

[wingski]

Hi guys, I have an oil pressure gauge on my “29 cabriolet. It is connected to the engine where the oil pump hold down fitting used to be, so it is directly connected to the oil pump shaft below the distributor. What kind of oil pressure should I expect?

The gauge itself goes from 0 to 10. I used to expect between 20 and 30 psi on my other old cars, but I realize that is not possible on my A.

Thanks again,

Mike

[glenn in camino]

I'd guess about 2-4# depending on the temperature of your engine, probably 0 at idle.

[WHN]

To a degree pressure depends on the weight of the oil your using and air temperature.

We run 20-50 oil in summer, water in radiator, engine running temperature around 160 degrees.

Pressure starts out over 10 lbs. After car warms up, pressure drips to about 3 lbs.

Remember this is not a pressure oil system. You are just seeing pressure of oil going to valve chamber. At least with gauge you know Oil is moving up into chamber. Enjoy.

[burner31]

I find a oil pressure gauge to be of little to no use on a stock engine Model A
Your opinion my differ

[Marshall V. Daut]

The only thing an oil pressure gauge in a stock Model A will reliably tell you is the oil pump is still working. But the pressure will be so low (1 or 2 pounds) after the engine warms up that unless you are almost constantly monitoring the gauge as you drive, the pump could fail and the engine will be ruined even before you become aware of the gauge dropping from 2lbs. to zero. You will see maybe 5-7 pounds of pressure upon start up, but that will drop quickly. Don't be concerned about that. It's normal. A Model B engine will run about 5 pounds of pressure while driving, which is easy on the gauge to see any sudden needle drop. Not so easy when only 1 or 2 pounds of pressure is present. An oil pressure gauge didn't save my B engine in 2003, however, when the pump failed on the highway and the engine seized up. 'Can't drive 60mph on the highway with your eye constantly glued to the pressure gauge!
By the way, that slot-plug does not retain the oil pump! It is merely a block-off plug. If someone has screwed in a long bolt in its place, the pump casting is mostly likely now cracked. The large spring on the bottom of the pump was designed to accommodate the pump's movement up and down. If a bolt is locking the pump in place, that stress and rigidity will break the casting, as I and others have discovered. If there is a bolt in that hole, order the correct plug and remove the bolt. Hopefully the pipe threads were not damaged by someone using a bolt. The threads are incompatible. The pump will not drop down into the oil pan when you remove the bolt unless someone has removed the large spring on the bottom of the pump or it is broken.
Marshall

[Marshall V. Daut]

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'Sorry. I now see that you already have an oil pressure gauge installed, not just considering the installation of one. 'Doesn't matter. The warnings and advice in my posting are still valid for other Model A owners.
Marshall

[wingski]

If I understand you guys crorectly, the only thing holding the oil pump up in the block is the spring on the bottom of the pump against the pan. So, I shouldn’t have been concerned when the oil pump dropped down into the pan when I pulled it. It was somewhat of a hassle to put that pan back on and align the pump as well. I tried using a string pulling sideways on the shaft to hold the pump up in position, but that didn’t work worth squat. I finally got it, but that pan sure is heavy especially with the weight of the pump in it, and those wishbones fought me constantly.

Isn't there a little bottom end noise coming from that pump when the engine is running since the pump is not held in place?

Sore shouldered,

Mike

[Purdy Swoft]

There is a special pump holder tool offered by most vendors for this purpose . Brattons has one on page 46 of their catalog part # 9895 price $5.25

[Purdy Swoft]

If you ever decide to sell the car it would probably be best to remove the gauge before the potential buyer looks at the car . If the potential buyer doesn't know model A's he will think that something is wrong because of the low pressure that is registered .

[Marshall V. Daut]

Yes, the pump should drop down with the pan. That's gravity at work there. Remember: only that bottom spring keeps the pump in place inside the block, nothing else. When the pan is lowered, the tension is off the spring and the pump will drop out. Most 1928 Model A pans had a removable round piece just below the pump. It unbolted and then the pump could be withdrawn for cleaning the screen of debris, and if your hands were small enough, wiping out any gunk that had settled at the bottom of the pan. That made dropping and re-installing the pan a breeze because you didn't have to find a way to keep the oil pump in place. Once the pan was bolted to the engine block, the pump could be inserted up through the cleaning port and the bottom piece bolted back in place. That's what the large round gasket with holes in it is for that is included in complete engine gasket sets - and which hardly anybody has a need for, unless the original 1928 oil pan had been retained. Often these 1928 oil pans were changed out for later pans that no longer had this outstanding feature, especially if an engine-for-1929-1931-engine-swap took place. I'm guessing Ford eliminated this clean out port as a cost-cutting measure. That most certainly made it cheaper to make millions of oil pans.
Yes, there is an inexpensive little tool sold by most vendors that is threaded properly to go into the oil pump port hole in the side of the block. Then the bolt inside the nut is screwed inwards to apply pressure against the oil pump body shank. The pan can then be put back in place. Unscrew the tool and the pump will remain seated, as long as the big spring on the bottom of the pump is functional. Applying lateral pressure against the cast iron oil pump shank for this kind of static work will not hurt it. You don't need to crank the set-bolt down much, just enough of an interference fit to hold the pump in place for a few seconds while the pan is raised.
Marshall

[James Rogers]

Two alternate ways to hold the pump besides the special tool are to 1 have a helper to hold the pump with a phillips screwdriver in the hole where your gauge is connected till you have the pan up or just use the distributor hold down bolt and screw it into the hole to hold the pump. Mind you this last method should only be used in an emergency situation when the other methods are not available. The distributor screw is a standard thread and the hole in the block is a pipe thread. I do, however, remove LOTS of standard thread bolts from blocks and just go back to the pipe thread plug.

[Marshall V. Daut]

One more point to address for "Wingski": I never noticed any extra noise coming from the oil pump as it operates. The spring tension will keep the pump pretty much flush up against the engine block rail. It doesn't bounce up and down, as one might envision with a spring tension. A bouncy pump WOULD cause noise. No, that spring is one stiff little guy that makes pushing the pan up against the engine block's side rail a bit of a chore. I sometimes use a floor jack to help. If a pump is making knocking noises while the engine is running, I would suspect a weak or broken spring. A pretty much simplistic Ford design that actually works.
Marshall

[burner31]

OIL PUMP HOLDER TOOL

PART #: 9895

$5.25 /ea