Can anyone identify this debris?

[HSSS427]

Found this in the oil pan. It is next to a 7/16ths nut for size reference. It appears to be a cap of some kind that is sheared in half. Am replacing the aluminum pan with a steel Aviad as the aluminum had cracked. Found this in the bottom of the pan.
Thanks!
Scott

[Pete Wolff]

If I don't miss my guess it's half of the keeper that retains your oil pump drive shaft in place when you remove the distributor. Question is.....where is the other half ? When intact this keeper lives about a inch or so from the top of your oil pump drive shaft.

[csx4769]

Bingo! Oil shaft retainer. Thats what I said as soon as I saw it. I haven't seen one of those since I left the Ford dealer in 1976. Good luck. Thanks for the memories! Randy HermansCSX4769

[RICK LAKE]

HSSS427 Scott where is the other half of the retainer? In the pickup? On the shaft? I think you need to find it Rick Lake

[HSSS427]

Thanks for the quick ID. Now at least I can figure out where to begin searching. I have had the distributor in and out a couple of times lately so maybe that's when it happened. Any tips on how to "repair" this situation?

Also, since I have the pan dropped - what else should I check and look at while I've got access to the bottom of the engine? At least I've taken a bunch of pics and identified my crank as a C5AE - 6300C - 1965 forged and cross drilled, and the rods as C6AE-E - 1966-70 427, 428SCJ.
Thanks!
Scott

[Michael C Henry]

It is a great time to replace the drive shaft.Check the ends of the shaft and the internal hex of the pump drive, They make better drive shafts these days. My shaft and oil drive were about to round out when I had my engine apart.They make a special pump and drive for trucks It has a 5/16" hex at the pump and a 1/4" at top for the distributor . I asked why only one end is larger and was told that the pump end is the end to always have a problem.
That would be a pump and drive combination. High volume= a taller gear and case , higher pressure = a shim in releif spring. I bought a blueprinted Melling high volume truck pump and driveshaft

[blykins]

Pull a couple bearing caps off also....check on how the bearings are doing.

Good time to change the oil pump also...cheap maintenance.

[HSSS427]

Took the pump and shaft out, but didn't yet find the other part of the retainer. However, since there was no retaining nut on the shaft it appears to confirm that's the culprit. I decided to order the Melling High Volume model pump and also ordered an ARP chromoly drive shaft. Also installing a steel Aviaid pan to replace the aluminum one that cracked and caused me to pull the pan in the first place. I guess I'm buying "insurance" given the going rate for side-oilers these days.

Since I can get a look at the bottom half of the cylinder walls and the rods and pistons, is there anything specific I should try to spot as a check-up?
Thanks!
Scott