Re installing oil pump

Jim,

Years ago, I did as George suggested above.

It makes a HUGE difference in properly placing the oil pump on my Series 80.

I have great oil pressure and do not leak a drop of engine oil.

I don’t recall exactly, but I believe that I made my own gasket from a standard gasket material package that I bought at NAPA.

Peter

Jim: DON’T do it ! It is not necessary, and can lead to additional problems in the future. I’ll explain lower down this message.

The normal problem with completely missing the square steel drive tube and resulting in no oil pressure: the car is jacked up, it is tilted either to one side, or tipped front to back. The square steel drive tube in the engine swings from a cotter pin through the upper end of the drive tube. So, with the car tilted, the tube does not hang down in the same spot where the oil pump drive shaft is, when the oil pump is held up and the cylindrical screen is lined up with the oil pan opening.

The shaft of the oil pump drive gear has a 1.25″ long round section, before the shaft changes to being square. You have to insert the round portion of the shaft into the square drive tube. You cannot see this insertion, it is 3.5″ up inside the oil pan, it has to be by feel. Once the round shaft is inside the square drive tube, I can feel the ‘rattle’ of the round shaft inside the square tube.

So: my technique: Jack the car up so that it is either lifted at the front, or lifted on the passenger side, Or put the car on a lift, so it is close to level. This minimizes the off-center ‘hang’ of the drive tube. There is more room to maneuver the pump and shaft when the drive shaft is hanging toward the driver’s side, or to the rear.

Hand crank the engine to align the square drive shaft such that one side of the square is parallel to the side of the engine, or the side of the oil pan. Then, hold the oil pump up lining up the pan’s studs with the holes in the pump body. Turn the pump shaft so that it is exactly the same as the drive tube: parallel to the side of the crankcase, or the side of the oil pan.

Put some axle grease on the pump gasket, and push it over the studs, pushing it against the pan’s gasket surface, the grease ‘glues’ the gasket up and in place.

Carefully slide the oil pump up into the oil pan opening, holding it aligned with the mounting studs. You MUST listen and feel for the round end of the oil pump drive shaft to touch the square drive shaft. it can touch on the outside of the tube, or butt up against the end of the tube, or slide inside the tube. You may have to try this several times to finally feel the round shaft inside the square drive tube. When it is inside, I can feel the tube ‘rattle’ around the shaft, and the rattle is the same on all sides of the drive shaft.

Then, continue to slide the pump up, the square of the drive shaft will offer some resistance or friction or ‘feel’ when it slides into the square drive tube. If you did not align the side of the drive tube and the pump drive shaft correctly, the shaft will not slide up into the drive tube.

If the pump drive shaft does not align with the square drive, there will be about 1/4″ of space or clearance between the end of the studs and the oil pump gasket surface. If the studs have been removed, this clearance will be about 3/4″. Any clearance is enough. Excess clearance does not help aligning the two squares, since that alignment is 3.5″ up, inside the oil pan, near the oil pan gasket surface.

The reason to not remove the studs is that then, each time the pump is dropped for cleaning the screen and wiping the bottom of the oil pan, the bolts will be wearing against the threads in the soft aluminum of the oil pan.

This is a significant problem. The studs are double threaded: 5/16″x18 coarse thread for the part threaded into the soft aluminum pan and 5/16″x24 threads for the pump retaining nuts. The reason is that the aluminum is SOFT, and the coarse threads are needed so that each thread is thicker and stronger. Pierce designed the studs and fasteners this way because the early aluminum was very soft, and does not take cross threading, or frequent tightening of a bolt very well. The threads being soft will wear rapidly from use. A stud is threaded in once, and usually sealed in place.

I have removed and replaced the oil pump on S80/81 engines with the original studs, and also with the studs removed, and short bolts replacing the studs. The insertion of the round drive shaft and the alignment of the square shape of each is not easier, at least not to me. And not having the studs to assist holding the gasket with grease up, out of the way makes the no-studs setup almost as difficult as with studs.

And, there is the very real problem with removing the steel studs that have been in the aluminum pan for nearly a century. Often they break off, then you have to drill them out, and put a Heli-coil or other thread repair insert in the pan. This is very difficult to do well when the pan is on the engine. I’d probably remove the oil pan if I found a broken stud, or stripped oil pan threads.

Try following the technique i outlined above. You will get it back together.

Oh, by the way, I’ve had to remove and re-try the insertion and alignment of the shaft and tube several times. it can be a bit frustrating. Persevere, there is no ‘easy out’.

Hope this helps.

Greg Long

Jim,

With all due respect to Greg’s significant mechanical prowess, I offer these comments.

Liberal amounts of PB Blaster (two or three times, a few days in advance), a touch of heat to the tips of the studs and a GOOD Stud Pulling Socket, should do the trick to remove the studs without a break.

You will likely not do this again in your lifetime, so wear on the threaded part of the aluminum crankcase caused by hex-head screws / bolts is not really an issue.

Also, if you use your brain, after removing the studs, you will measure the depth of the blind holes in the crankcase and determine the thickness of the base of the oil pump.

If you then buy hex-head machine screws / bolts that are slightly shorter than your full depth, including pump base thickness and lock washers, you will not reach the blind end of the bolt hole and will not crack the crankcase from inserting and torquing too long of a bolt.

Finally, if you do this prep work, the oil pump will just go in like a charm.

Proper Project Preparation Prevents Piss Poor Performance (the Seven Ps for Success).

Cheers,

Peter

Peter: With all that ‘work’. Why not just learn how to install the pump? I was done in the past, it can be done again, and again. Why risk broken studs, cracked oil pans, stripped threads ?

You just have to think, look, and do.

And even with the studs removed, and using cap screws [short bolts] it STILL requires some finesse. I”ve pulled and replaced the oil pumps on George’s engines more than once, and it still can be done wrong, or it can fight you.

Greg

George,

I believe that the number of angels that can dance on the head of an oil pump stud depends upon whether they are dancing a Waltz, a Fox Trot or the Charleston.

Regardless, the number is somewhere infinitely north of Avogadro’s number, which is of course, 6.022140857 × 10 to the 23rd.

Peter

DING DING DING DING……..just under the wire we have a winner for the most outstanding thread hijacking of 2018!!

Jim: Great News !! Glad to hear your wonderful Touring car is back on the road !!

Greg Long