Vintage Mustang Forums banner

1 - 20 of 30 Posts

·
Registered
Joined
·
91 Posts
Discussion Starter #1
So like a million other people on the planet I have been going round and round trying to figure out the proper distributor gear to get. I have a billet cam but it's made from 5150 steel not 8620. I don't want to use a bronze gear. thinking melonite one or composite. I trust real world advice on this one over the cam and distributor makers. I have a pertronix dist. Also! I pulled the gear off may dizzy and the shaft is made a little small. The gear slid off easy. Anyone come across that? I might center punch it to raise the diameter where the gear rides.
 

·
Registered
Joined
·
858 Posts
I don't have a pertronix distributor but I have heard they come with the melonized gear. Composite is supposed to be the best for all round use and will work with your cam for sure.
 

·
Registered
Joined
·
3,127 Posts
Ron, who manufactured your cam ? Lots of steel cams need a steel gear, but not all, there are steel cams with iron gears shrink fitted to the steel core. The best way to choose a gear is to call the company that made the camshaft you have. LSG
 

·
Registered
Joined
·
3,016 Posts
for a billet steel cam, you can use either a steel gear, available from most cam manufacturers, or a polymer gear, also available from most cam manufacturers. i second getting a hold of your cam manufacturer and asking them what gear you need to use.
 

·
Registered
Joined
·
91 Posts
Discussion Starter #5
I asked the cam manufacturer about it twice. first said use bronze or composite. The second time the answer was melonized. The pertronix site says their cam gears are compatible with all roller cams then I asked support about a billet roller cam and they said bronze. I changed my mind and bought a bronze gear that pertronix makes. It was only $40.99. I just need to remember in a couple years or when I have a couple thousand miles on it to check it.
 

·
Registered
Joined
·
5,217 Posts
best dizzy in the world is a stock ford unit set up by Danny @ GN
 

·
Registered
Joined
·
3,127 Posts
Ron, the bronze gears are sacrificial, I would never recommend one on anything but a drag race only that gets disassembled and checked often. If you have steel and are unsure, run the polymer gear. LSG
 

·
Registered
Joined
·
3,016 Posts
Ron, the bronze gears are sacrificial, I would never recommend one on anything but a drag race only that gets disassembled and checked often. If you have steel and are unsure, run the polymer gear. LSG
i have to agree here. for a daily driver, or even a weekend toy, the bronze gear is going to cause more problems than it solves. but if you are all head up to use it, then change your oil more often to keep the brass bits out, and buy two or three gears to have in stock. also when you note spark scatter, then change the gear, or check it regularly, say twice per year, at least until you get a feel for how the gear is wearing.

personally i would go with the polymer gear.
 

·
Registered
Joined
·
1,424 Posts
If the gear slides on , you will be shearing the roll pin very soon.
 

·
Registered
Joined
·
91 Posts
Discussion Starter #12
hopefully the gear I get is a little under-size on the bore. Was thinking about sending the dizzy back. I'm a machinist. I know what size it should be.
 

·
Registered
Joined
·
4,148 Posts
I ran the same melonized gear in my steel roller cam 331, then using a flat tappet cam on the original 289, then back to the 331 with no issues. The re-badged MSD distributor that came with my Pro-Flo 4 has what appears to be a melonized gear and Edelbrock says it will work with any cam.
 
  • Like
Reactions: Ron French

·
Registered
Joined
·
91 Posts
Discussion Starter #14
If the gear slides on , you will be shearing the roll pin very soon.

Stock Ford gears are a press fit because in original assembly they use a fixture to locate the gear when it is pressed on, and the press fit retains it while the roll pin hole is drilled. This is why every Ford has the roll pin in a different location. Because every Ford has the roll pin in a different location you cannot just line up the hole in the shaft with the hole in the gear, you must qualify the measurement as outlined in the Ford instructions.

Chevrolet distributors, on the other hand, do not use a press fit because the pin hole locations are manufactured with necessary precision, and also, because the end thrust is taken up against the housing instead of down against the block.

In any case, like a Chevy, the Ford gear is not required to have a press fit as long as the location is correct. Ford only used the press fit as a manufacturing convenience.

A larger pin gives more strength. You can use a larger pin. On occasion, I have corrected a miss-located pin hole by using a milling machine to precisely locate a 3/16” hole, offset from the incorrectly located original 1/8” hole, and used a 3/16” Chevy pin. A Chevy pin needs to be shortened

I have seen Ford distributor shafts that look like Swiss cheese from someone drilling multiple pin holes trying to get the gear located in the right spot. .






Top

I got this from somewhere from researching it. Makes sense. It is only a press fit because of poor manufacturing.
 

·
Registered
Joined
·
91 Posts
Discussion Starter #15
I ran the same melonized gear in my steel roller cam 331, then using a flat tappet cam on the original 289, then back to the 331 with no issues. The re-badged MSD distributor that came with my Pro-Flo 4 has what appears to be a melonized gear and Edelbrock says it will work with any cam.
might grab a melonized one and give it a shot.
 

·
Registered
Joined
·
4,148 Posts
might grab a melonized one and give it a shot.
The melonized and polymer gears are supposed to be good for any cam, the melonized being cheaper. That said, what does your cam maker say?
 

·
Registered
Joined
·
20,998 Posts
I had the same questions a few years ago. After talking with Howard's Cams, Ford Motorsports and MSD along with reading anything I could find. Melonized gears are the default gear for many distributor companies. It will work on factory 5150 billet, SADI or flat tappet. It will not work on mechanical roller cams as they are made from a harder 8620.

The gear must fit tight on the shaft. You can tap it off, you don't need a press. Very important too is that it's properly located and use assembly lube on the gear . MSD has a instruction sheet on installing the gear. I used MSD 85832
 

·
Registered
Joined
·
91 Posts
Discussion Starter #18
I had the same questions a few years ago. After talking with Howard's Cams, Ford Motorsports and MSD along with reading anything I could find. Melonized gears are the default gear for many distributor companies. It will work on factory 5150 billet, SADI or flat tappet. It will not work on mechanical roller cams as they are made from a harder 8620.

The gear must fit tight on the shaft. You can tap it off, you don't need a press. Very important too is that it's properly located and use assembly lube on the gear . MSD has a instruction sheet on installing the gear. I used MSD 85832
The shaft on the pertronix is a little undersize. was wondering if I should send it back. I just slid the gear off with my fingers.
 

·
Registered
Joined
·
1,424 Posts
The roll pin is NOT designed to take the shearing load "if" the gear is too loose. "Some" go to a larger roll pin but that only delays the inevitable.I use a factory steel gear on FMS hyd rollers. '85 gear for the "early" ones and later gear for the EFI 5.0 and 351Ws. I have an 8620 hyd roller in my 521 and am using a FMS steel gear. "Race" solid rollers use bronze gears. Gear alignment and material quality ( not cheap off shore) can give surprisingly long life in a bronze gear. The one in my race 331 has been there for 20+ years and looks great.
 
  • Like
Reactions: Ron French

·
Registered
Joined
·
91 Posts
Discussion Starter #20
The roll pin is NOT designed to take the shearing load "if" the gear is too loose. "Some" go to a larger roll pin but that only delays the inevitable.I use a factory steel gear on FMS hyd rollers. '85 gear for the "early" ones and later gear for the EFI 5.0 and 351Ws. I have an 8620 hyd roller in my 521 and am using a FMS steel gear. "Race" solid rollers use bronze gears. Gear alignment and material quality ( not cheap off shore) can give surprisingly long life in a bronze gear. The one in my race 331 has been there for 20+ years and looks great.
Thanks for the input. I think I'll send the dizzy back.
 
1 - 20 of 30 Posts
Top