New distributor gear when installing new cam?

SadbutTrue

Founding Member
May 1, 2002
2,391
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Thousand Oaks, California
Compcams' instructions recommend a new distributor gear when you are installing a new cam. Problem is... both the gears they recommend are $110!! (my distributor is not worth that much).

Are these necessary? My old gear is in good shape, near as I can tell. And if I have to get a new gear, might as well get a whole new aftermarket distributor (if thats the case, want to recommend a good, inexpensive one that comes with a gear and shoudl work with my pertronix unit?)...

Thanks
 
About the only time I'd swap out a good dizzy gear, would be; when installing an iron geared dizzy, with a roller cam. Then Ya do need change to a steel gear.
Other wise, not so much.


I did check on summit's webpage and it says that stock iron distributor gears are 'not compatible' with steel camshafts (which I'm assuming comp cams camshafts are). That sounds kinda ominous.

I looked up the less insane bronze gears and they're $50. Still way more than i want to spend on a dinky distributor gear, but...

A few more questions:
1) I see several 'sizes' for the gears (.467", .500", .530")... how do you tell which size is correct for your application?

2) If I were to get a sub-$200 distributor rather than spend all tha tmoney on a lame gear, do you have any recommendations (preferably one with an easy to adjust and reliable advance... and let me know whether mechanical or vacuum advances are better)?
 
Depends on your dist, look up yours and it should tell ya what shaft size you need.

Hm, k. To my knowledge my current one is some stock Ford or other no-name replacement distributor, nothing particularly outstanding about it. Where should I look on my distributor for the appropriate identifying marks?

Anyone with recommendations on a relatively inexpensive aftermarket distributor, if I decided to go that route?
 
If you have an iron cam, use an iron gear. If you have a roller cam (steel), use a steel gear. Pretty simple. An iron gear with a steel cam will self-destruct in short order, ruining your motor. So, yeah, that's ominous.

Bronze gears work with both but wear relatively quickly. OK for a race motor, not so great for a street motor that will see lots of miles.

I stick to the tried-and-true Duraspark distributor. For a roller motor (like I have), I use the '85 Mustang version (manual), which is the only year the Duraspark came with a steel gear (AFAIK). Its avail at your Autozone.
 
+1 on the Duraspark. You can either hook it up to a GM 4-pin HEI module to control the coil or use the Duraspark box. The HEI module is painfully simple, but the Duraspark has a cranking ignition retard for easier starting(especially with high compression). However, I don't know what vehicles came a Duraspark for a 351W.

As a general rule, flat-tappet cams are iron and need an iron gear. When in doubt, Call Competition Cams or check their site.
 
If you have an iron cam, use an iron gear. If you have a roller cam (steel), use a steel gear. Pretty simple. An iron gear with a steel cam will self-destruct in short order, ruining your motor. So, yeah, that's ominous.

Bronze gears work with both but wear relatively quickly. OK for a race motor, not so great for a street motor that will see lots of miles.

I stick to the tried-and-true Duraspark distributor. For a roller motor (like I have), I use the '85 Mustang version (manual), which is the only year the Duraspark came with a steel gear (AFAIK). Its avail at your Autozone.

Will those duraspark distributors/steel gears work with hydraulic flat tappet cams as well? A few of those distributors i'm looking at also advertise that they work with roller cams, which hope doesn't mean that my cam won't work with them (sorry for the double negative there).

I might take a look at the duraspark distributor. Do other chains have it than autozone (nearest autozone isn't close, but we have a pep boys and a napa...)?
 
Will those duraspark distributors/steel gears work with hydraulic flat tappet cams as well? A few of those distributors i'm looking at also advertise that they work with roller cams, which hope doesn't mean that my cam won't work with them (sorry for the double negative there).

I might take a look at the duraspark distributor. Do other chains have it than autozone (nearest autozone isn't close, but we have a pep boys and a napa...)?

steel gears will not work with iron cams, just like the iron gear on the steel cam it will ruin the gears very quickly. what cam are you going to use?
 
+1 on the Duraspark. You can either hook it up to a GM 4-pin HEI module to control the coil or use the Duraspark box. The HEI module is painfully simple, but the Duraspark has a cranking ignition retard for easier starting(especially with high compression). However, I don't know what vehicles came a Duraspark for a 351W.

As a general rule, flat-tappet cams are iron and need an iron gear. When in doubt, Call Competition Cams or check their site.

Gonna call them in a bit when my phone charges. If my new cam (compcams xtreme energy hyd flat tappet) is iron, then I don't think I'll bother with the new cam gear unless I see visual wear or anything tonight when I look at it. If I do need a new gear, I'll probably just get a new distributor while I'm at it, hopefully one thats easy to adjust as far as advance goes. Thanks, I'll let you know what I learn.
 
steel gears will not work with iron cams, just like the iron gear on the steel cam it will ruin the gears very quickly. what cam are you going to use?

XE274H, hydraulic flat tappet. I understand the previous poster saying iron and steel don't mix. I'm wondering if my new cam is iron or steel. It is a new(er) cam design and compcams does make a point of saying they don't want you using your old gear, so it might be steel despite being a hyd. flat tappet. If its iron, I'm not gonna worry about it. If its steel, I'll get a new dist. with a steel gear.

I figure someone here should know whether that cam is iron or steel, but like i said, if not i'll be calling compcams in a little while.
 
Ok, I'll jump in and clear a few things up here. I was also looking at your other thread about a new distributor.

First of all, EVERY flat tappet cam is iron, including your new one, and EVERY hydraulic roller cam is steel. Solid rollers are also steel, but billet steel maybe? Some have a harder metal, I don't know much about solid rollers. With that being said, use an iron gear, which you already have, but only if it is in good shape, and you say it is. The reason Comp tells you to change the gear is to cover their own butts.

Now, I have been over this and over this with comp's tech line, and they have told me that you can use an iron gear on a iron camshaft only, but you can use a steel gear on a steel (roller) cam as well has a flat tappet (iron) cam. They say the way the camshafts are hardened these days, they are compatible, but the iron distributor gears are softer than the cams are. With that being said, I see no reason to take the chance with a steel gear on an iron camshaft, especially since you have an iron gear already and iron gears are less expensive.

So if I were you, I would just stick with your current distributor if it is working ok. Maybe get a new cap and rotor and such like you were talking about. Maybe do the HEI conversion, that works pretty good and is relatively cheap.
 
XE274H, hydraulic flat tappet. I understand the previous poster saying iron and steel don't mix. I'm wondering if my new cam is iron or steel. It is a new(er) cam design and compcams does make a point of saying they don't want you using your old gear, so it might be steel despite being a hyd. flat tappet. If its iron, I'm not gonna worry about it. If its steel, I'll get a new dist. with a steel gear.

I figure someone here should know whether that cam is iron or steel, but like i said, if not i'll be calling compcams in a little while.

ok the cam you have selected is an iron cam, thus needs an iron gear. what i recommend is using a rebuilt distributor from say checker or autozone. they come with a new gear, and are inexpensive to buy. remember to use plenty of assembly lube on the gears, both cam and dist gear when putting them together.
 
ok the cam you have selected is an iron cam, thus needs an iron gear. what i recommend is using a rebuilt distributor from say checker or autozone. they come with a new gear, and are inexpensive to buy. remember to use plenty of assembly lube on the gears, both cam and dist gear when putting them together.

Okay, I'll look into it. Any details on how tod o the HEI conversion I've heard a few people mention?

edit: And is the Duraspark an option for a 351w? What cars came with them? But I guess they come with steel gears anyway, so probably just best to go with a rebuilt reman unit with iron gear and use my pertronix with it.
 
edit: And is the Duraspark an option for a 351w? What cars came with them? But I guess they come with steel gears anyway, so probably just best to go with a rebuilt reman unit with iron gear and use my pertronix with it.

absolutely an option. any non efi truck with a 351w can provide a donor like an 84 bronco. They were all flat tappet so the gear will be compatible.

no need to buy an hei module since you already have an msd box
just plug the dizzy to a msd box magnetic trigger with the adapter harness or splice it and roll.
 
Okay, I'll look into it. Any details on how tod o the HEI conversion I've heard a few people mention?

edit: And is the Duraspark an option for a 351w? What cars came with them? But I guess they come with steel gears anyway, so probably just best to go with a rebuilt reman unit with iron gear and use my pertronix with it.

I think you're under the wrong conception as to what distrbutors came with a steel gear for a roller cam. The ONLY factory Duraspark distributor to have a steel gear was the 85 Mustang GT unit and only with a manual transmission.The 86-up Stang 5.0 used a TFI distributor. The only 351W distributor that would have a steel gear is the 94-97 TFI distributor, and that's only if the motor had the roller cam.
 
I think you're under the wrong conception as to what distrbutors came with a steel gear for a roller cam. The ONLY factory Duraspark distributor to have a steel gear was the 85 Mustang GT unit and only with a manual transmission.The 86-up Stang 5.0 used a TFI distributor. The only 351W distributor that would have a steel gear is the 94-97 TFI distributor, and that's only if the motor had the roller cam.

You are right on the 302 but he is running a flat tappet cam in his 351w so basically any duraspark 351w dizzy for a carbed application (mid 1970's to mid 1980's) will work for him.

For me I am running a roller cam 351w so I removed the steel gear from a 302 efi/ TFI style dizzy and installed it on my 351w duraspark.

You can tell the factory steel gears from the factory iron gears in that the surface where the dowel pin goes through is a really smooth machined surface on the steel gears. The iron gear have a rough cast finish to them.