DZAUTO

Well, I just saw something today that many of you have asked about and it does not exist------------------------BUT IT DOES!
Several people have asked about converting their 55-61 Vette from a generator to an alternater and if there is such a thing as an alternator with a tach drive. Well, we all thought there is no such thing as a tach drive alternator. WRONG!
At the Okla NCRS chapter meet today, one of the members brought his 57 WHICH HAS A GENUINE, DELCO, TACH DRIVE ALTERNATOR!!!!!!!!!!!!!
I took a couple of pictures, but it will be a while before I have them developed.
The owner said that the alternator (it's a Delco) came on Ferguson tractors back in the 70s. It may take some searching, but apparently they DO exist! And it is NOT a crappy looking unit. It looks like your average Delco alternator with a offset housing for the gears (smaller than the gear housing on the generator). It has the fitting for screwing the cable nut onto the gear housing.

AZDoug

That would be cool to get.

It would give me an excuse to get rid of the SW Stage III tach that inhabits my instrument cluster and put back the original mech tach that I took out in 1977.

As a side note, all of my instruments are rubber stamped with a date of May3, 1961 on the cases, though the 9141 VIN would suggest late May, or maybe June as a build.

Doug

PS: i see a lot of phone calls on Monday to the Ferguson tractor dealers.

AZDoug

Well, I ordered one of these tach drive alternators today.

I will let y'all know about it when it shows up later this week.

Doug

wesmigletz

Doug, could you post contact info and price for the tach drive alternator you ordered? Thank you, Wes

AZDoug

After I check this puppy out, I am going to did a little deeper into where it is coming from and start selling these.

All I will tell you right now is it is being drop shipped to me from a supplier of the place I found that retails these, which means, i can become a retailer and cut out the middle man, and you get the parts at the same price.

I will tell you price was less than $200

Doug

JoesC5

You might want to check the accuracy of your tach after you make the change. On the old generator/tach cars the generator is driven at twice engine speed (the pitch diameter of the crank pulley is twice the pitch diameter of the generator pulley). In order for the tach, which is calibrated for a 1:1 reading, to read correctly, there is a 2:1 gear reduction (that gearbox mounted on the rear of the generator) between the generator and the tach drive cable. Do you know what the alternator's pulley's pitch diameter is and the gear reduction is on the alternator you are installing? The vettes with the distributor driven tachs have the drive cable running at 1/2 crank RPM (because the distributor is running at 1/2 crank RPM) and their tach is calibrated to read double the cable speed.

AZDoug

I had already taken all that into consideration.

61 and earlier cars were cable speed=tach readout, except FI distributor drive cars which were tach speed was twice cable speed.

If there are any variances, cable speed multipliers are readily available.

Doug

DZAUTO

Also, to some extent, you can also make speed changes with different size alt pulleys.

AZDoug

This brings up the questions, what were the original size generator and crank pulleys?

I have the old generator sitting around(not Corvette) that has a 3.7" OD pulley(No idea what the pitch diameter is), and my crankshaft/balancer pulley is 6.4" OD, and I know that pulley is not original to the car.

Doug

dazvet

OK, I know this is an old post but for me it's a current problem, where did everything wash out on this alternator with a tach drive - I need one.

DZAUTO

This is not the best, but it is the ONLY picture that I have of a tach drive alternator which is from a tractor. This is on a friend's 57 in Tulsa, OK. The last time I saw the car was 2-3yrs ago.



Tom Parsons

dazvet

Thanks Tom, sure would be nice to hear from someone with particulars on this. AZDoug did you ever advance your efforts to sell these?
Larry

AZDoug

No, too much work for too little return.

It works nice, though. I ended up using a 1.12:1 (or real close) ratio adapter to make the FI tach read exactly correct, you can see the adapter in the pic



Doug

DZAUTO

If I wanted to convert my 56 from a generator to an alternator (and I DO NOT, it works too well), the tach drive alternator would be the way I would go.

Tom Parsons

dazvet

Great, That's what I'm looking for, where do I get one.
Larry

AZDoug

I don't remember.

I found via an online search. Google tach drive alternator ford tractor

Mid 1960's Ford tractors, some anyway, used these alternators. i found mine at a tractor supply shop.

The drive that attaches to the alternator, (not the same as the ratio adapter) you need the plastic gear that goes in the back of the alternator and the drive, i found these at the same shop, but some large speedo shop in Riverside, CA, United Speedo, maybe, said they had a bunch of the output drives when I was buying the ratio adapter.

I had to make the standoffs to mount the tach drive to the alternator, real simple, they are just hollow spacers. Use Loctite on the machine screws that hold the drive to the alternator case.

If I ever get ambitious and hook my Accel Dual Sync dizzy up to my tach, my alternator will be for sale.

Good luck

Doug

dazvet

Thanks Doug, appreciate you sharing your groundwork.
Larry

Frankie the Fink

My old tach-drive generator is humming right along and has never given me a bit of trouble....might be time to look at the brushes and put a drop of oil in the bearings come to think of it!

mechron

maybe i'm just to old and decreped.... but i remember all C1 tach drives gens were on the drivers side on C1s ( maybe not now as i remember) so the tach cable had a more or less a straight shot to the gauge.
i also realize this an old thread, BUT come one guys, alternators never appeared until the early 60s. slap them on and "forget about it" those old gens always needed a jumper from the BAT to the F terminal
to "polarise/energize them" that was fun on any old gen install, how much spark do you need, not enough to burn out anything, but as i remember a farking big spark for only an instant. then the gen was good to go "charging from then on" ...

AZDoug

Nope.

Doug