what will cause this? I read that the oil pump will, but I turned mine with a drill so its not locked up. that was the only way I had to do it. How hard should it be to turn.

 

It depends on what pump you are using and what distributor you are using, although problems can occur with any combination.

Many FE's have a nylon coated cam gear. Over time pieces break off. Although there is a screen in the oil pick-up, some pick-ups have bypass hole and a piece of plastic can jam the pump. Now I'm not sure about this as I havn't looked at any FE stock pick-up screens in along time.

But here's what can happen. The roll pin sheared in my Mallory Distributor after about 1200 miles of use. I contacted Mallory and they said it was because I'm using a HV pump. I think it really depends on what value bypass spring you have in the pump, so it's a peak pressure thing, not volume.

But even then, that's not really addressing the problem. The fact is that Ford distributors have a press-on gear and Mallory distributors have a loose fitting gear. Both use a 1/8" roll pin. The Ford units seldom fail, while it's common for the Mallory units to fail.

What happens is the roll pin in the Mallory distributor fails from fatigue as it bends back and forth a bit as the distributor rotates. It can't do this with a Ford distributor. So in the Mallory case, it's not the shear strength that's the problem, it's the fatigue resistance.

In my case, I drilled out the 1/8" roll pin hole using a #22 drill. I then pressed in a 5/32" roll pin and then a 3/32" one nested inside the larger one. The "splits" were 180 degrees apart. That was over 5000 miles ago and it still works fine.

So if you have a Mallory distributor, you know the problem and the solution. If you have a Ford distributor, I guess something could have jammed the pump. I'm just not sure if the oil pump pick-up can pass a large chuck of "something". No doubt someone else can confirm or deny that possibility.

I suppose another possibility is the oil pump internal relief valve sticking. If it sticks shut, then the pressure could go very high putting an abnormal load on that roll pin. But again, some foreign object has to get in there, and I'm not sure that's possible. Plus I think if those valves stick, which is rare, they usually stick open so you have low oil pressure at lower rpms.

Edit: I looked at some pic of FE oil pump pick-ups and only see ones with screens, so large debris isn't likely. But here's one more thought. If debris did get in the pump and jam it (even temporarily), check your oil pump drive rod. It's a hex rod, and if stock, a bit light. A jammed pump can twist the shaft. If it's straight, then I'd start with the problem being at the distributor.

Mind you, listen to what he says about 0.40 seconds into it:

 

I have an crt performance billet distributer and a melling HV pump. I just drilled out the hole to 1/8 and put a larger pin in. we will see if it will hold up. I need to get the old truck back to making money. I will check to see if the shaft is twisted. as for the stuck relief valve when I instaled the pump it was stuck and blew up two oil filters before with help from fte I figured it out.

 

Depending on the distributor, is the pin a hardened roll pin or one of those rolled spring steel pins?

Yes, a HV pump will work on a distributor pin and I used to shear mine off in the hot rod 20 yrs ago. I ended up double drilling it(90* from the existing pin) and putting 2 pins in it. Still there to this day.

Don't drill it too large as you could weaken the shaft down there. Don't want the shaft splitting and falling apart.


My buddy broke two pins years back in a 460. It was a Napa rebuild distributor. Running down the highway, POP, it sheared and left us on the side of the road. Found a pin the race trailer and continue on. Did it again about 6 months later.

 

I had this happen on a SBF one time. Is this a newer Mallory? I've had a Mallory dual point in my 66 FE since 1972-74 when it was a 352 and still in there today after being built into a 390..

 

This happened in an older YL dual-point. I ordered a new shaft and gear, but the ETA was very long so I bought a newer YL (they had changed the P/N by then... same thing but I forget the new number).

Anyway, my old YL, the new YL and the spare parts that finally showed up, all had a sloppy fit concerning the gear and shaft.

There are other things that contribute to the problem. Is it a HV pump, what relief valve spring is in the pump, what viscosity oil is being used, how often you rev the engine, especially if cold. Plus there probably more factors I either don't know or can't think of at the moment.

Things were bad with mine. A very high pressure spring in a HV pump (which means very high max oil pressure) and 20W50 oil.

 

Would it be a bad idea to put the roll pin into the gear(so it is lined up) and then tack weld it to the shaft?

 

I wouldn't do it. Welding to a cast-iron gear probably isn't the best idea, and the heat will anneal the roll-pin (softening it).

 

Just an up date. the new larger roll pin seems to have fixed the issue.