Curbside PSA: Ford Pushrod V8 Oil Pump Driveshaft Orientation – Put Away Your Telescoping Magnets

There are few sounds in the garage that are more heart-wrenching than that familiar “thunk” a Ford oil pump driveshaft makes when the distributor extracts it from its home in the oil pump and deposits it in the oil pan.  If you’re lucky, it gets hung up on a surrounding hunk of iron and you can fish it out with a plastic tube or a telescoping magnet.  If you’re not, you’ll be reading up on how to remove the oil pan in-chassis.  Both of these unfortunate events can be avoided by simply installing the driveshaft as Ford Engineering intended, but you may not be so lucky if someone else built your engine.

I’ve suffered through this torment with two different Ford engines, a used 302 that lasted a few hundred miles and my ’63 Thunderbird’s 390.  Looking down where the distributor is normally located, you can see where the oil pump driveshaft waits to be engaged to the distributor through a boss that is cast into the block (which also serves to support the distributor shaft/driven gear).  The distributor drives the oil pump by engaging the hex of this shaft.  The shaft, however, loosely rides in the oil pump; in other words, it is free to be removed from said oil pump if appropriate precautions are not taken to avoid it.

Fortunately, Ford employed engineers who solved this problem when they designed their engines.  This is a Ford oil pump driveshaft.  The small collar is located on the distributor side of the engine, where it is designed to “grab” the aforementioned boss on the block when the distributor is removed, trapping the driveshaft between the block and the oil pump.  The distributor end is also beveled to ease the installation of the distributor.  Pretty simple.

Ford even explains how to position the collar in the shop manual (this one referring to the 1965 Comet, Falcon, Fairlane, and Mustang).  Motor Manuals also verify this method for installing the oil pump driveshaft.

The 1962 Thunderbird shop manual is inexplicably less clear in its text, but this diagram clearly shows that the collar should be oriented toward the distributor.

As a third source, I’ll cite Steve Christ’s How to Rebuild Big-Block Ford Engines.  His explanation verifies what the shop manual says, but with a warning tone that is closer to mine.

Unfortunately, at least two engine builders in the world have installed Ford oil pump driveshafts backward, and my Thunderbird is currently running around with this unfortunate mishap waiting to ruin my day at any turn.  I’ve been dealing with distributors in an effort to solve an ignition-related quirk in my T-Bird that I brought up last fall.  Honestly, I don’t know how an engine builder could possibly do this incorrectly, but I have proof that someone did: I’ve fished the driveshaft out of the depths of that 390 with a magnet at least twice by now.  (It’s like playing the old board game “Operation,” tongue hanging out on one side, one eye closed…Buzz!  Damn it!)

It would be easy for one to say, “Aaron, why don’t you simply remove the oil pan and make things right?”  Well, removing an oil pan in-chassis on a ’63 T-Bird involves a date with my engine hoist to, at the minimum, raise the engine up high enough to remove the pan.  On top of that, resealing the pan underneath the car is not as easy as one may hope.  Therefore, there’s a little laziness and inertia on my part, along with a little wariness.  I’m of the mindset that the fewer things you disturb on an old car (if it’s not absolutely necessary), the better off you are.

Regardless, this is a problem that is so easily avoided when building an engine that there’s no excuse for it, and it certainly makes one wonder what else the engine builder may have done incorrectly.

Many people have derided Ford’s method of driving the oil pump as being somewhat dinky, but that’s beside the point.  For decades, that spindly little driveshaft has done a perfectly serviceable job of keeping millions of Ford V8s on the road, and it should be foolproof under normal use and when installed as the factory intended.  Unfortunately, Ford has no control over who turns the wrenches on their vehicles, and this is one case where reading the directions can save someone from a pretty bad day in the garage.

Note: I am not a professional mechanic; I almost exclusively work on my own vehicles for my own satisfaction (and because I could never afford my fleet without being a reasonably competent mechanic).  The author and the website take no responsibility for your mechanical misfortunes.