Q: After rebuilding a 302 Ford EFI engine, I am having an issue getting my distributor to seat down all the way in the engine block. It’s about ¼-inch short. I’m using a heavy-duty shaft. Is it possible I got the wrong one?
A: Usually, distributor fitment problems stem from improper installation or adjustment of the oil pump driveshaft. Here are things to consider that might help to resolve your issue.
- 5.0L EFI distributors (and 5.8L EFI) have a longer shaft, extending approximately 0.575″ below the drive gear than the earlier Duraspark or points-type distributors. Additionally, the internal hex drive in the EFI distributor extends deeper into the shaft as well. There is no special-length oil pump drive shaft for EFI applications, be aware the longer distributor shaft may cause fitment issues with some aftermarket oil pump driveshafts.
- Ford 8.2-inch deck Windsor engines (221-302 c.i.d.) use a ¼-inch hex oil pump drive shaft and have a length of 7.45 inches. All other Ford oil pump driveshafts are considerably longer and use a 5/16-inch hex (except FE, those that is a ¼-inch hex), which are not interchangeable with a 302 base engine.
- Many aftermarket heavy-duty oil pump shafts are only hexed on the ends of the shaft with a larger diameter round section in the center. Most of these hexed shafts are long enough to accommodate a late model EFI distributor, although some of the earlier aftermarket heavy-duty oil pump shafts may not have enough hexed length to accommodate the longer EFI shaft causing a bottoming-out situation with the oil pump shaft’s shoulder. In this situation, trimming off some the bottom of the distributor shaft may be required, but only as a last resort. It’s best to find a shaft that fits properly.
- Ford oil pump driveshafts feature a retaining washer located near the distributor end, which prevents the shaft from pulling out of the oil pump during distributor removal. When the distributor is pulled from the engine, the washer contacts the engine block preventing it from disengaging the pump drive. If this washer is left off during installation, the shaft can be pulled out during distributor removal, and may result in the shaft falling into the oil pan, misaligning with the pump drive, or causing it to fall off to the side and onto the pump housing.
When building an engine or replacing a new oil pump and pump driveshaft, it’s essential to test fit the distributor, adjust the shaft retaining ring, and make any other modifications at this point.
This job becomes considerably more complex once the oil pan is on or the engine is in the engine bay.
After installing a new oil pump and shaft, insert the distributor into the engine block making sure it seats all the way. The retaining washer on the shaft should be far enough up to prevent the oil pump shaft from disengaging the pump drive with the distributor out, yet far enough down so the distributor will fit all the way the into the block without binding against the washer.
Once everything is installed correctly, there should be a small amount of up-and-down play in the oil pump shaft. If the oil pump shaft puts any force on the oil pump it can result in a major engine failure. Factory-style EFI distributor users may need to locate and use a “cupped”-style retaining washer that was used on factory Ford EFI engines to achieve the correct tolerances.