304 eating distributor gears

[Retrorider]

Hey guys,

I'm starting again in car hobby world and what my grandpa referred to as a parts changer, not a mechanic. I have a basic understanding of taking stuff apart, marking it, changing things that look bad and buttoning it back up. Got a couple of projects to learn on but my well of automotive knowledge has passed on a couple years back and need some guidance.

I have a 81 Jeep CJ7 with an AMC 304 that seems hungry for distributors. It ran fine until it jumped time, pulled the distributor to see the gear eat up. Replaced with a new Mastercraft and it ran fine for about an hour and jumped time again with the same results. We replaced it the gear and noticed that it was dry as a bone. Oil pressure was fine until the engine got warm and dropped.

The plans so far was to replace the oil pump on the front of the engine but getting mixed info on this. Some say replace the pump and it will be fine. Some say just drill and tap a line that will spray oil on the cam/distributor gear. Some say just to drill a hole in one of the freeze plugs and let it squirt oil out other on the gears.

Any help will be appreciated because I want to keep the 304 in it.

Thanks in advance.

[nathanr15]

I also have a 304 jeep. I would say check and make sure there is enough clearance between the oil pump gears and the cover. Had a tolerance too tight and it ate the teeth off the distributor
Good luck

[401Spirit]

Guys...Let an AMC guru enlighten you. Cam gears have a keyway for timing and a half moon oil passage for lubing distributor gears. Every AMC engine I have built over the last 35 yrs. has had a restricted or blocked oil passage that MUST be opened up with a chain saw file. Also check to be sure the fuel pump eccentric is installed correctly. Look at the drive gear and make sure you have 4 unblocked holes.

[Retrorider]

Thank you guys! I'm fixing to start my shift for the week and when I get off next Wednesday I'm going to tear the front off to look. 401Sprit would it be extra insurance if I put in a tapped line to help with the oiling of the gears?

[AMC Racer]

Is engine original or rebuilt? Stock timing cover or aftermarket? What timing set? What distributor gears? Rarely will you get away with replacing just the distributor gear ... unless you run bronze. Could also be some debris periodically jamming up the oil pump which will fail the gears .... did you tear it down when you failed the first gear? If not, likely have bits floating around.

There have been lots of issues with aftermarket parts for AMCs made wrong - timing sets that don't have proper oiling slots, gears with incorrect or incompatible teeth, timing covers with distributor hole out-of-position. All will lead to failed gears. Bulltear.com offers matched gears, timing covers checked to be correct and some other oiling bits. Replacement timing sets are hit-and-miss ... Rollmaster seems to be one of the better ones.

Check amccars.net or theamcforum.com for more AMC specific info.

Hope this helps.