In the leadup to the next Redline Rebuild video, the Hagerty video crew has released three videos documenting Davin Reckow’s rebuild of a Ford Model A four-cylinder. While Davin knows his way around a domestic V-8, each engine family tends to have its own quirks. These “banger” engines are a whole different animal entirely, since they predate most common pushrod V-8s by an entire generation.
“Something I’m picking up on with the Model A is, everything you’ve known and tried to understand from 1950s, let’s say, even up into the current day, you might as well just forget it and start over, because this stuff tends to be a little backwards,” Davin says.
One big difference in this four-cylinder is its use of babbitt bearings. Rather than an insert bearing that’s available off the shelf and drops in place, babbitt bearings are poured and machined in place and make for a very tight fit.
Take, for example, the much-loved small-block Chevy. The more modern engine will typically have .001-inch of clearance per inch of main journal diameter. The babbitt bearings on this banger engine, on the other hand, have zero clearance. In the first video, Davin notes that it takes 35 lb-ft of torque to rotate just the crankshaft of the banger—several times the rotational force required on a later insert-bearing engine. Once the pistons and rods go in, it will take three times as much effort. The system makes for a rotating assembly that doesn’t really care to rotate until it’s properly broken in, and the engine’s starter won’t even be able to overcome the drag of the bearings until that break-in process is complete.
The first video also includes installation of the pistons and rods. Luckily, the rings were all properly gapped straight out of the package, which saved lots of tedious ring filing and checking.
The second video kicks off with Davin making a tool to drive the cam—a specialized tool that he may not need again for several years until it’s time to freshen up the Model A once more.
The Model A’s four-cylinder uses tall valve springs and adjustable lifters for setting the lash. Davin goes over the time-consuming process before working on sealing up the Model A’s most leak-prone areas as the head goes on and the engine is buttoned up… all done, save for the accessories.
The final Redline Update includes some of the Model A banger’s most interesting features. After the months-long rebuild, the funky distributor goes in, the generator is mounted up front, and the heater box is bolted on (which uses fins cast into the exhaust manifold to warm the cabin air).
With the engine hoisted in place, bolted in, plumbed, and topped off, the Model A sedan gets a pull start with a flathead-powered ’46 Ford. After the four throws a few fits, Davin realizes the timing is off on the banger. A few laps around the garage, a couple of timing adjustments, and plenty of afterfires later, Davin swaps the distributor and then… leaves a giant cliffhanger for the final Redline Rebuild video to come.
Don’t worry. You’ll only have to wait until tomorrow to see what kind of stop-motion stunts the video team has pulled this time, and see and hear how the Model A’s four-cylinder has transformed.