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I recently replaced my distributor on my stock 460 with a reman Vatozone distributor. I installed it two months ago and didn't get to drive the truck until yesterday. I literally put 50 miles on it and the engine just died while on the highway. I later found out the gear was all chewed up on the distributor. Its a cast iron gear.

My engine was rebuilt about 650 miles ago and it drove fine with the old distributor for 600 of those. The only reason I replaced it was because I couldn't find the mechanical advance springs after i locked down the advance with safety wire (part of a failed efi swap).

Have any of you guys had similar problems with bad distributor gears?

I'm picking up the replacement distributor later today but I'm hoping my engine isn't done for.

Here's a picture of the damage..

Look in the hole and check the gear on the cam. The only time I have really seen a problem with Distributor gears getting eaten is when the engine has a roller cam and this would require a hardened or bronze gear. Check what year the distributor is for. Me personally, if the cam gear is still good then I would get a distributor gear from Ford for the correct year.

Oh man have I had distributor gear woes. I don't know what type of cam you have and what gear is supposed to go with it, but with the roller cam 5.0 and 5.8, you can only get the correct gear through Ford Motorsport. No on else!

All the reman distributors come with a cast gear which is not supposed to be used on roller cams. They even have a paper in the box telling you to replace the gear as required for your specific application.

I learned all this the hard (EXPENSIVE!) way.

Really good info Steve. Thanks!

Thanks for the advise guys. The engine is out of an 86 F250 HD 2wd truck. It was rebuilt as a stock motor. I would assume the cam is the original unit as well since I never bothered with a cam upgrade during the rebuild. As far as the paper in the box... Those wise guys at the parts store keep the box and instructions to put the core in there but I read about not mixing roller cams with cast iron gears. I'm not sure if I have a non roller cam or not.


I do have a distributor in the garage out of an old 351M ford truck. The gear pattern is the same from the looks of it.

Should I just install the gear from that one on the new distributor?

I'm seriously considering a body swap from my 79 to my 89 and call it good. TTB '79 Bronco with fuel injection and modern parts.. maybe even AC if I get that working too

DO IT!

good luck.. 3 cams and 4 distributors and 49 miles later i finally solved this problem. I blew it up and put it in recycling pile... reaaaaaaaly expensive 49 miles.

Also, how much oil pressure are you running? HP pumps can kill gears. Also check to make sure the pump actually turns. Crappy pumps will seize either taking out the gear or the drive rod.........

BDKW1 wrote:Also, how much oil pressure are you running? HP pumps can kill gears. Also check to make sure the pump actually turns. Crappy pumps will seize either taking out the gear or the drive rod.........

Yup. I'm all about stock oil pumps.

Oil pressure was on the high side of the Ford Normal range. The oil pressure sensor is from a 350 TBI Chevy motor (failed TBI swap)

I would imagine the pump is not a high volume pump but I guess it could also be that. I'm starting to think that if I keep it I'm going to swap in either an LS motor and trans w/ overdrive or a 5.8L with an E4OD.

mkiefer wrote:good luck.. 3 cams and 4 distributors and 49 miles later i finally solved this problem. I blew it up and put it in recycling pile... reaaaaaaaly expensive 49 miles.

Man, that sucks! Mine only lasted about 50 miles as well. I didn't get a chance to look at the cam gear yet but I'm almost certain it'll be thrashed. I built this 460 when I was a freshman in college and since my dad and I wrenched on it together, that was the reason I wanted to try to save the motor. Its looking like its either due for a motor and trans swap or it'll get cut up at which point its long arm kit, Dana 44 and NP205 will go to my dad's '56 F100.

The frame would end up getting sold but the body would and rear end would end up on a TTB Bronco frame.


I've got some serious bad luck lately. Every single one of my trucks has been sidelined at least twice during the last 2 weeks.

Here is a link to almost everything you wanted to know about Distributor Gears: Selecting the Correct Distributor Gear



Your Distributor Gear shows significant "knife edging". Could that even be a soft Bronze gear? At a minimum, inspect your cam gear and check your oil pan for metal particles. If the cam is good and everything made it to your oil pan you could flush with several frequent oil changes. Above all, be sure you have the correct distributor.

BTY, I am just finishing a complete rebuild due to a destroyed cam gear. I replaced the PIP and used the correct steel distributor gear for the roller cam, but clearly had bad gear mesh and no lube on installation. I learned to not be casual and impatient, especially with a performance engine. You live and learn...

Thanks for the link Ron. I'm going to pull the oil pan and clean it out real good and change the oil and filter. I might change the oil pump for one that I know isn't a high volume pump just to be on the safe side. I didn't know about checking the gear mesh pattern with white grease.. I'm going to check it on this next distributor. The gear was cast iron but I think the material might be very cheap.. I have a gear from a 351M (they use the same distributor as a 460) that I pulled from the junkyard and thinking about installing that gear on my distributor in case the autozone gear just poorly made.

They're identical but from what I can tell, the gear sits just a tiny hair higher on the shaft of the new distributor then it does on the old distributor from the 351M. The distributor that went out looked like the gear might have been just a bit higher up on the shaft than the new one they gave me which would explain why it knifed the gear until it chewed off a few teeth.

Haven't pulled the dizzy yet, but need to replace. How to check for steel or cast gear? I was told that NAPA makes a decent replacement. Thanks

95s had the roller cam, so the gear should be steel.

Thanks. Got it confirmed at the Napa store too.

When I went through some major distributor gear headaches a few years ago, Ford Racing was the ONLY source for the correct gear. Both NAPA and Carquest were able to get me a gear that was listed as being correct but neither was made of the correct material. After the mess (and expense) I went through, I will only use a Ford gear. I don't care who makes or sells an aftermarket replacement, there's no way it's as good as the O.E. unit.

SteveG wrote:When I went through some major distributor gear headaches a few years ago, Ford Racing was the ONLY source for the correct gear. Both NAPA and Carquest were able to get me a gear that was listed as being correct but neither was made of the correct material. After the mess (and expense) I went through, I will only use a Ford gear. I don't care who makes or sells an aftermarket replacement, there's no way it's as good as the O.E. unit.

That's for damn sure! If MSD suggest using the Ford Racing gear... there's probably a really good reason.

Autozone gave me a replacement distributor and I'm going to remove the gear that's on it and use a gear I have from a junkyard distributor I pulled so I could hack it up and make a Ford/GM duraspark-HEI dizzy (When my TBI swap failed I wanted to make sure it wasn't because of the Ford pick up coil so I welded a GM upper to a Ford lower... don't try that at home).

Anyway, back to the junkyard gear, I'm willing to bet the junkyard OEM gear is stronger than the parts store foreign sourced gear. I'm going to run the used OEM gear and eliminate the problem. I drained the oil and didn't find any shrapnel but I'm pulling the pan tomorrow morning and will check for any little bits that might be in there. I'm also going to run cheap autozone oil in it for about 2 minutes with a new oil filter and then drain it all out again and replace with a new filter and better oil.

So I was doing the gear swap today and wasn't really paying close attention when I was using the extractor and I broke off a small piece of the OEM gear (about 1/3 of a tooth). It didn't really phase me but then when I looked at the roll pin hole on the autozone dizzy that I was going to use, it was way bigger than the actual roll pin diameter. I compared it to my oem one and confirmed that the autozone distributor is just plain crap all around.

Now I'm highly considering going to an MSD distributor or possibly even a DUI distributor to just do away with all the problems. I'm guessing calling up Ford Racing for the correct gear for an '86 F250 460 V8 is probably the best thing to do since that's what my engine came out of.

Anyone know what part number I should be looking for for Ford Racing or could the MSD unit be good to go out of the box. I'm sure I don't have a roller cam since it's a 460 from 1986 so it's probably a hydraulic flat tappet cam.