Alternator pulley diameter

The place to talk Slicks. All we ask is that discussion has something to do with slicks...

Moderators: Kid, Casey 65

Post Reply
9Fingers
Posts: 189
Joined: September 26, 2015, 8:14 pm
Location: Virginia
United States of America

Alternator pulley diameter

Post by 9Fingers »

Hey everyone. I'm trying to find the alternator pulley diameter for the slower revving 300 inline six cylinder. I'm going to use a one wire alternator rated at 63 amps with a rear mounted tach drive, but need to know correct pulley diameter. The one that comes with this alternator is 1/2" wide and 3-3/4 in diameter.

I searched this site and with Google with no success.

Thanks, Bradshaw
Always know where you will be, when you get where you're going - Jerry Clower
slick4x4
Posts: 5721
Joined: April 19, 2008, 10:01 pm
Location: kipp kansas
United States of America

Re: Alternator pulley diameter

Post by slick4x4 »

That will probably be fine...
they usally won't start charging until
They hit a certain rpm, then they will
Keep charging at lower rpms

Measure your drive pulley... figure out your ratio
and go with this info ...

"· An alternator has a normal range of operation.
Most alternators need to spin at about 2,400 rpm at idle,
have their maximum output above 6,000 rpm,
and should never exceed 18,000 rpm."
.
.
.
[b]'' I think what scares me the most about you guys is that I understand you '' ..... KID
'' lookin good, a little paint adds at least 100hp!'' ....... COOTER
'' well an old guy can dream cant he? ''............ICEMAN
''I would donate organs before selling my slick''........ HOOFBEAT RACER
User avatar
Toyz
Posts: 4333
Joined: March 22, 2011, 6:23 pm
Location: Baja Houston Taxes
United States of America

Re: Alternator pulley diameter

Post by Toyz »

General rule is three to one, You CAN go a bit lower to ensure the "one wire" self-energizes. But, any change in operating speed will also affect the tach drive, possibly resulting in an incorrect reading, if it is in fact a match for your particular tachometer.
Paul
The Ford Orphanage
Life's too short for boring vehicles!
My quest to develop a universal solvent is held up by the lack of a storage container.
Paul
slick4x4
Posts: 5721
Joined: April 19, 2008, 10:01 pm
Location: kipp kansas
United States of America

Re: Alternator pulley diameter

Post by slick4x4 »

I did not catch the "tach drive"

Rpm definitly important for that feature
.
.
.
[b]'' I think what scares me the most about you guys is that I understand you '' ..... KID
'' lookin good, a little paint adds at least 100hp!'' ....... COOTER
'' well an old guy can dream cant he? ''............ICEMAN
''I would donate organs before selling my slick''........ HOOFBEAT RACER
User avatar
Toyz
Posts: 4333
Joined: March 22, 2011, 6:23 pm
Location: Baja Houston Taxes
United States of America

Re: Alternator pulley diameter

Post by Toyz »

Figured you would be the one on top of that, Pat!
Bradshaw, since old tractors and go-carts are the ONLY things I use a "one-wire" on, several thoughts come to mind. I am sure there are direct drive tach adapters to fit the ancient Delcos, but the ones I am familiar with using on Masseys and Fords have a gear drive to reverse rotation of the tach cable.
So, be sure to check those factors,and please, post your findings. I probably would never use the "one-wire" myself, but likely could finagle a correct tach drive adapter to a real alternator.
Paul
The Ford Orphanage
Life's too short for boring vehicles!
My quest to develop a universal solvent is held up by the lack of a storage container.
Paul
9Fingers
Posts: 189
Joined: September 26, 2015, 8:14 pm
Location: Virginia
United States of America

Re: Alternator pulley diameter

Post by 9Fingers »

Paul and Pat,

I hope to make this work for one of the 0-4000 rpm mechanical tachs from the bigger Ford Trucks from this era(F600), I bought one from Michelle.

The alternator is advertised as an upgrade for older Ford tractors and does appear to have the gear set you speak of, which would reverse the rotation. I also have found some folks that I hope will be able to make an adapter to correct input/output and if using one set of gears this would reverse the rotation again back to the same as the alternator before the gear set.

I will keep you posted and write it all up if I can make it work.

Thanks, Bradshaw
Always know where you will be, when you get where you're going - Jerry Clower
slick4x4
Posts: 5721
Joined: April 19, 2008, 10:01 pm
Location: kipp kansas
United States of America

Re: Alternator pulley diameter

Post by slick4x4 »

Paul, how hard is it to find a distributor
That has a tach drive...

I'm thinking I've seen them on 352s
But I might be imagining things
.
.
.
[b]'' I think what scares me the most about you guys is that I understand you '' ..... KID
'' lookin good, a little paint adds at least 100hp!'' ....... COOTER
'' well an old guy can dream cant he? ''............ICEMAN
''I would donate organs before selling my slick''........ HOOFBEAT RACER
User avatar
Toyz
Posts: 4333
Joined: March 22, 2011, 6:23 pm
Location: Baja Houston Taxes
United States of America

Re: Alternator pulley diameter

Post by Toyz »

Pat, I "think" I've seen 'em on FT's, so housings might be swappable. IME, most do as Bradshaw plans.
Just have a speedo shop set up and calibrate for the gauge, regardless of drive source.
Since a 4000 max would do me little good, I have considered changing the drive ratio and have Andrew Bauer make me an 8000 rpm overlay for the stock gauge.
Paul
The Ford Orphanage
Life's too short for boring vehicles!
My quest to develop a universal solvent is held up by the lack of a storage container.
Paul
9Fingers
Posts: 189
Joined: September 26, 2015, 8:14 pm
Location: Virginia
United States of America

Re: Alternator pulley diameter

Post by 9Fingers »

I have seen two possible sources for a distributor with a mechanical tach drive.

Mallory made these at one time for the Ford 240/300 inline six. I have not been able to source a used one.

Joe Hunt makes a self contained magneto driven distributor for the Ford 240/300 inline six that can be upgraded to have a mechanical tach drive. They do not require a battery hookup and work from the magneto generating the current. It requires special spark plug wires supplied by them. I like the concept of being able to push start and drive a truck with NO battery in an emergency. I would have purchased one of these but for two reasons. The expense is out of my range and I found out they create unusually high amounts of electrical noise that would render a radio useless in the truck.

So I dropped back to plan B, hoping to make mechanical tach drive alternator work.
Always know where you will be, when you get where you're going - Jerry Clower
9Fingers
Posts: 189
Joined: September 26, 2015, 8:14 pm
Location: Virginia
United States of America

Re: Alternator pulley diameter

Post by 9Fingers »

The alternator arrived yesterday. I measured the outside diameter of the pulley, approximately 3-11/16". Crankshaft pulley approximately 6-11/16".

3.75 turns of the alternator = 1 turn of the tachometer output.

Check my math.

6.6875÷3.6875÷3.75= 0.4836

Looks like one revolution of the crank gets 0.4836 revs of the tachometer cable.

Output for tach drive at the alternator is the correct direction for the Ford tachometer input.

Need to find my hand held mechanical tachometer to test electric drill speed, then run the drill to turn the Ford tachometer and check it's reading to hopefully be able to estimate if it's going to be anywhere near correct.
Always know where you will be, when you get where you're going - Jerry Clower
Post Reply