I'm getting tired of breaking distributor gear pins (4 in the last 2 years on two dif. motors). Is there some way of getting a better pin put in. Or should I go with a different distributor. I've been using remanufacutured ones from the parts store. Thanks for your suggestions.

 

Are you running an unusually heavy oil in cold weather or something? I haven't heard of this being a common problem. When there is a problem with the oil pump, it will usually strip the teeth off the gear before the pin breaks.

 

Okay I have been down this road too. Check to make sure your advance is working in the distributor. A faulty advance will not allow the distributor advance to work nor will the timing get advanced. This loads up the distributor when you accelerate and the pin shears. Had this happen on my 351M and my I-6 300. It will (does) drive you nuts. I used to carry a pin in my wallet for protection () most guys carry other protective items.

When you re-install a new pin and time the motor check the timing with a light. Have someone rev the engine and watch the timing mark and it should move freely.

Haven't broken one since.

Bob

 

OK Here's one more thing to check, When you install your dist. and get it to mesh with the cam, does it sit all the way down by it's self or does it sit just up a little. If it's not sitting all the way down and you jam it down with the dist. clamp, the gear is bottom out on the block and undue pressure is put on the pin.

Just one of those thing that gets over look when putting a motor together.

 

Here's another angle. I went through 3 pins before I figured out the problem. The valve stem seals break down, and get to the bottom of the oil pan. Being flat, the pieces can make it through the oil pump screen, and jam the oil pump up. Sometimes the piece will then go through the oil pump (so you won't find it,) other times it will lock the oil pump up solid. The solution is to replace the valve stem seals. If you need head work, go ahead and do it, if not, the seals can be replaced without removing the heads.

After 2 years of good running with new valve stem seal, the darned pin broke again. The overall problem is the oil pump screen has holes in the side large enough to pass crap through. This stuff (whatever it is) then jams the oil pump, and the shear pin breaks (or the whole cam gear breaks, this happened last time my pin broke. I just get a lifetime replacement distributor every time this happens.) To make a permanent solution, I went to the local hardware store, and bought some wire mesh screen (like for screen doors.) Make sure it isn't coated, just straight metal. Then wrap the oil pump screen, and use thick wire at the top of close it off (kinda like a bread bag.) Any particle would have to go through a pretty convoluted path to get through my double screen system.

fordmando
70 F-100 400 C6
78 F-150 4x4 400 NP435
George Selby

 

OK here's some more background. The first time this happened was on a 71 351c 4v with 150k miles on it going down the highway. The dist had about 15K miles on it. I run 10-30 weight oil by the way. The next time was last fall in a different 71 with 130K miles on it. I install a reman. dist. then. I just had a rebuilt motor put in. Everything is new or rebuilt. I have about 100 miles on it. I think it may have gone when I started it. It wasn't running quit as good as the day before and got worse as the day went on. I also had the same thing happen on my 390 truck. I had a fresh reman dist. put in when I had it rebuilt. 6 months later it brakes. The only explanation the parts place gives is the remanufaturer may have gotten a bad batch of pins.

Thanks again for your help.

 

I once had this problem. It turned out to be caused by a worn out distributor. It worn down the thrust bearing and started dragging on the case. Also if the bearings are galled or dragging for any reason.

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