Rapid distributor gear wear on roller cam 351

[fxbill]

Hi,
I recently purchased a 67 Cobra replica with a 351 Windsor in it...(78 I believe. Since it was a sled... beautiful, but a dog nevertheless, I decided to pep things up a bit. The engine had only a few hundred miles on it so I opted to work with it. I pulled the Twist Wedge heads from my 85 Mustang and purchased an F303 roller cam after being told that I could simply drill and tap the holes for a stock spider lifter retainer and run with that cam. After installing the heads and cam I realized that the lifter bores were lower in the early 351 and the lifters came up too far anything to work...the oil holes in the lifters were exposed on the high side of the lift. I then purchased a set of crane roller lifters and that seemed to do the trick. I re assembled everything, installed a Weiand "stealth" manifold and Holley 750 carb. The thing ran like a rocketship for about 10 miles and then the problem began. The car just stalled the other day and after having to tow it home I discovered that the distributor gear had completely disintegrated! Actually it had worn down, but at an extraordinary rate. I checked with the local speed shop and was told that I needed a steel gear with the roller cam instead of the cast iron gear that came with the early engine. $40 for the new gear and 4 oil changes later to try to clean out the metal from the engine and I was ready to try it again. I cranked up the car and ran it for about 10 minutes, pulled the distributor again and it's already beginning to show signs of wear. Maybe it's just breaking in...haven't driven it long enough to really tell, but I have a bad felling about it.
My question to any of you is...Has anyone gone through a problem like this? Any suggestions would be greatly appreciated.
Thanks,
Bill

[faststang90]

i think u need a bronze gear. had the same problem when i put a roller motor in a truck that had a non roller motor before. call ford to make sure

[juiceman]

when you use a roller cam which has a billet steel gear you need to use either a bronze gear or a billet steel dist. gear. assuming you got the right gear this time( billet steel) for 351w you will need to check the cam gear now. it is important to get the proper mesh on the gears. since you used the cast iron gear first you may have damaged the cam gear also. take a look at the cam gear to be sure everything is good. what is the wear pattern on the dist gear. is it a shiny wear mark that is smooth and fairly even, or is it a ripply grinded look on the teeth. the last could be indicative of a bad or worn cam gear or bad gear mesh. even with improper gear mesh the gears will last a long time. always remember to do your homework before you change parts, this way you dont have problems later.

[fxbill]

Thanks,
I generally do quite a bit of research before any major project and even after building engines for many years, (my first was a tri-power 348 in a 58 Chevy...and it was new!lol), I still rely on my local speed shop for things pertaining to the exact make and model.....in this case all the info I got was bad and it has cost me.
The new gear seemed OK....wear hasn't been excessive, but I puched it a little today and the thing just stalled. I was afraid the gear had gone again, but since it sounded WAY advanced when I tried to restart it I retarded it....like almost 90 degrees and it fired right back up again and got me home. The wear pattern looks centered on the dist gear although it doesn't appear to be as deep as it could. The cam gear looks fine..no feathering on the gear edges, but now I have the problem that obviously the gear somehow jumped 6 or 7 teeth to produce the problem.....I'm baffled. I seem to be getting pretty good mesh, but there's no way to adjust that even if it was wrong.....I have no idea what could cause the thing to go a full 90 degrees out of time except for the gears jumping teeth and yet there's no sign of chipped teeth and the wear pattern is about halfway down the depth of the dist gear..more than enough bite.
Bill

[DirtKing]

I'd check the camshaft endplay.. If your cam is "walking" that might account for that but it is still bizaare. are you sure you had your distributor on one?? I've had them 180 out before and they will run; just not good. Saty with the steel gear though...the bronze one wear entirely too quickly for my taste.

[fxbill]

Thanks for the info...good to know. I did find the problem. I had marked the spot the roll pin had been drilled in and put the new hole at right angles to it. After more examination the other day I realized that the new hole and the line from the old hole were in line with each other....the roll pin had sheared. Cleaned everything out, installed a new roll pin and everything's been fine since.