Another Dist Gear Problem

[.boB]

I have been using Comp Cams rollers in this engine for the last 5 years. I've tried 3-4 cams until I found what I really wanted.

I've always used Mallory distributers. I do not change the gear, and run it as supplied. I've never had a problem with the gears. Never even sheared a pin.

In 11/09, I installed XFI 248HR-14, PN 35-776-8. I re installed the Mallory Unilite distributer that I had been using for the last few years, and did not change the gear.

In early March, I replaced the distributer with another Mallory, brand new out of the box. The "old" distributer showed a nice wear pattern on the gear teeth, with almost no actual wear of the gears. They were only slightly shiny.

After about 6 hours of run time - including a little dyno time and about 90 track minutes - the car quit running. When I removed the distributer, the gear was really chewed up and the pin came out in 3 pieces. I replaced that gear with the good one that was on the "old" distributer.

The engine would not start, and after only a few tries, I removed the distributer again. That gear is now chewed up, and the engine never ran.

Today I remove the cam, and this is what I found.

s13.photobucket.com/ albums/ a256/ bobcowan/

(you have to remove the blank spaces after the / to see the pictures)

I use a Ford Racing oil pump, SV/SP, an ARP drive shaft, and 10w-40 OIL.

What do you think the cause was? Am I using the correct gear? Or does this cam need something special? Is this cam Austempered?

I don't want to make the same mistake twice.

[amick]

This is an austempered camshaft and it does require a steel mealonized distributor gear. It would appear that you have put the wrong gear on the camshaft. One of the gears in your pictures looks to be a bronze gear which is not what we recommend using but it would work on the cam for a while untill it wore down as it is softer and designed to wear instead of wearing the cam gear. I am not sure what the material was on your other gear but it obviously is not going to work on our camshaft. You will need to insure you run the steel mealonized gear on your next cam. Also you want to check the distributor shaft for straightness. If it were bent that could casue a wear problem. You should alwasy check the wear pattern between the distributor gear and the cam gear. Running a high volume oil pump is also very hard on the gears as well, especially in a ford mmotor.

[.boB]

One gear looks a little like bronze. But that's just some copper based anti-seize. It was all I had at the track for lube.

Both gears are the standard steel gears from Mallory. The one that's really chewed up was on the brand new Unilite distributer. It had been in the car only a few hours.

The one that's on there now (in the picture) was the old one from the previous Unilite distributer. Again, that's all I had. But it had worked fine for a couple of years on previous cams. And it worked with this cam for about 3 months. It looked almost perfect when I removed in in March.

Could this new gear have been bad from Mallory? Is there a way to test them?

[amick]

You can test the hardness of the gear and see if it may have been bad. I don't want to say that Mallory gave you a bad gear but it is always possible that a new part is deffective. If the cam had run on another gear for 3mos and was fine with it then I would think that suggest the gear on the cam was fine. It could of still been an alignment issue with the distributor. Were you running the high volume oil pump the whole time or just with the new distributor?

[.boB]

I found the problem. It was not with the Comp Cams parts. And wasn't (really) with the Mallory part. It was my fault.

The new distributer I installed was for a '69-80 Ford 351W. That means it has a cast iron gear, and not steel. It clearly says that in the description from Summit Racing. But I didn't notice it. I'm so used to buying parts for a '70 Mustang for this engine, that I didn't think twice - as I should have. They look and fit exactly the same. But (obviously) they're not the same. When I get home tonight, I'll hit each gear with a grinding disc and see if they look the same.

Thanx for your help. I have the proper gears on order, to do the job right this time.

BTW, my entire valve train is Comp Cams parts, and has been for the last 5 years. I have never had any problems with any of your parts until now. And that was clearly my fault, and not yours or Mallory's. Thanx for the good products, and good support.

[amick]

You are very welcome and thank you for being a loyal customer. I am just glad to hear you got it figured out. If you need anything else just let me know. Thanks again.