I have a 86 f150 with a 351w 4V HO. I recently rebuilt the engine, being very careful. After rebuilding the engine ran well for awhile, but the first time I drove it, the cam shaft ate the cast iron distributor gear! When I rebuilt the engine I replaced the stock cam with a mild cam from PAW and replaced the cam thrust plate. When it ate the first drive gear I bought a new distributor and tried again with the same result. Next I disassembled the front of the engine and and inspected my work. There I discovered that the tab on the fuel pump eccentric had been bent by the cam shaft dowl pin and the the tab had actually scored the dowel pin end! I got PAW to replace the cam and lifters. It turned out that the cam was supposed to come with a long and short pin. My first cam only came with one pin. The replacement cam came with 2 pins, one long and one short. I bought a new fuel pump eccentric and reassembled the whole front of the engine carefully. It ran well, but today while doing some last minute adjustments before getting a smog inspection the engine just quit! I pulled the distributor again and the distribtor drive gear is gone again and this time the distributor is locked up! ( I think it bent the shaft this time!) Does anyone have any advice on what I am doing wrong!!!!
Dave

 

I have heard rumors and rumblings about dist gears being stripped by high volume aftermarket oil pumps. Does your engine run alot of oil pressure?

 

Dave, what brand of camshaft are you running ? At the shop where I work we had a 351W with a cam from Comp Cams. It chewed its way through 6 distributer gears before Comp 'fessed up to the problem. We knew that the cam and dizzy gear need to be made of the same material but after the first two gears were chewed we tried steel and bronze gears and had the same failures. It turns out that Comp incorrectly ground the gears on the end of some of their cam blanks. Who knows how many of their small block Ford cams are out there ? I would try a new cam from another manufacturer with a new dizzy gear. I have always had good luck with Crane. DF

 

I have a high volume oil pump and it does provide high oil pressure. In fact, when I prime the oil pump with my power dril, it only turns the pump until it fills with oil then stalls. I thought I had a wimpy drill, but maybe not!
dave

 

I am runig a PAW cam. when I complained to PAW they said that all the cams are ground by just a few companies. They did cave in and send me another cam of the same type. What do you think of the High performace oil pump theory?
Dave

 

OK if the oil pump stops your drill then I'd take a closer look at that, it should slow down your drill alittle but it should still turn.Here's something else I'd look at when you install your dist.does it sit flat on the block or does it sit up just a hair say 1/16" or so and then when you clamp down the dist. it's jamming the dist. gear into the block and causing it to jam-up there too and miss a line the gear to cam.Just something else to check .

ShaZam

 

I think the drill is raising a red flag too. But you know what's ahead now. Pulling the oil pan. What a pain!:-X23

 

Dave, the idea that a high volume oil pump can hurt your dizzy gear is an old wives tale, no truth to it. That said, your drill should be able to turn the pump, high volume or otherwise, but the HV pump would turn with some more resistance. If your drill can't do it, something is wrong somewhere. I'm afraid the above poster is right. You are going to have to pull the pan and look at whatever is happening in there. DF

 

I don't think this falls into the old wives tale category as it happened to me. I inquired with Ford on it and was told that was the problem. Actually it was about the first thing the Tech asked me. Did I put a HV pump in it? Tight Clearances? Yes on both accounts. Mine was chewed off in less than 30 miles of driving. Changed back to the stock pump and have not had a problem. Had exactly the same priming symptoms also, drill really lugged down when it picked up the oil. I thought it was just a weird thing, but now I know better.

Others have installed HV pumps without incident. So you'll have to decide for yourself.

 

Discussed on the 351W board awhile back...page 2,near bottom. #518.

 

I was searching for custom cam manufactures today on the web. I came across one in particular, i think Crow Cams and they specificaly said "do not use high volume oil pumps as they will eat the dist gear" for whats its worth.

 

 

You might want to make sure the distributor is dropping all the way in, have someone hand crank the engine while you push on the rotor until you feel the click.A breaker bar on the crank bolt should do it. Just a shot in the dark.