options for hooking up a mechanical tach on a flathead...

flathead 6 or 8, in general... are there spots in the blocks or ??? that are set up to drive a tach gear... have a retired tool & die buddy that could probably fab me up the drive mechanism, fit to a standard cable, but curious what to look for on the engine for hook ups...

would like to switch out the new electric 6 volt positive ground tach in my 38 Nash with the flat head 6, to a mechanical unit, & or find a set up for my old school truck project, that will likely be powered by a flat head Ford 8 cylinder ( when I'm shopping for the "8" are there model years or specific parts I need to find to drive the tach ???

any suggestions would be great...thanks

 

I'm interested in the same answer. Best as I know, all mechanical tachs are run off the distributor housing and I've never seen one for a ford flathead application (except magnetos).

Oops, on second glance, you said Nash flathead, not Ford. Anyway good luck.

 

thought most were driven from sowhere around the distributor, but also have never noticed a mechanical hook up... my truck project will have a Ford flathead 8 so if I can start out with the right parts, rather than buying the wrong thing 1st would be great

 

Contact GMC bubba here... he's a distributor specialist!!!

 

Older mechanical tach applications were driven off the front of crank. apparently the drive parts still exist (someone posted a Formual Ford site with these), bracket to support the thing in front would have been a homemade on odd motors, a special cast one on Fords and possibly others commonly used in industrial apps.
Some fifties cars had drive off back of generator...easily transplanted, probably dodgy at best on accuracy even with proper pulley ratio.
I have here somewhere a Corvette distributor cut to fit a LATE flathead Ford. For oddballs...Mallory made a pretty wide range of tach drive distributors, you might luck out and find one with dimensions and rotation allowing it to be cut to fit your app.

 

The easiest way for the Ford flathead is to use an 8BA flatty, then adapt a SBC distributor with tach drive in the base. An early Mallory would be cool. GMC Bubba can cut it down for you.

All other drives will probably end up co$ting you more, and will be a tighter fit in already tight areas.

Maybe the same thing can be done for the Nash? Is there a common 6 cyl aftermarket distributor (with built-in tach drive) that can be cut by Bubba to fit your Nash?

 

get a tractor generator, run it off the back of the gen.

http://www.steinertractor.com/FDS403-12-volt-generator-complete-with-tachometer-drive

 

a quick check of "evil bay" shows there are alot of Chevy small block / Corvette distributors with a tach drive...

I didn't know these were that convertable to fit the Flat Head 8...

what basic changes need to be made???

 

I have seen them with a doubler driven off the cam snout. You may do a search on cam driven tach drives.

 

how accurate would a generator tach drive have the potential to be ???

granted this won't be a bracket racer or anything, but I would like it to be more than just a pretty accessory

 

the only cam driven tach drives that come up in a search of such, on evil bay, are for motorcycles

 

Do a google search.

Generator driven tachs are accurate enough to keep you from grenading your engine. I like mechanical tachs, but unless one is really up to par it will never be as smooth as your eletric tach. They have a tendency to be a little bouncy.

 

What your are looking for is this:





This is the tach drive that bolts to the front of the 8BA engine. It's driven off the crank pulley.



HellRaiser

 

Here's another couple of the same, and a place that you could get a later front mounted mechanical tach drive. I only have the one bracket, but got two of the 90 degree outputs...but no more Flathead





View attachment yanmar_mda flathead tach adapter.pdf


HellRaiser

 

When you do find your mechanical tach drive. This is also what you might be hunting for. This is a S W mechanical tach in a heavy Eelco alumn base with the mech oil and water gauges.







HellRaiser

 

And lastly if you're not happy with all that, then go with a Vertex mag that is already set up to go in a 8BA, without having to modify some GM dizzy to make it work.







This is all I know about mechanical stuff

HellRaiser

 

Over the pst few years we have done quite a few tach drives for the flathead engines.
The corvette is a good option as its cast iron and looks very nice in the engine also there are tons of other options using Mallory tach drives with different cap options etc. Heres a couple from a week or so ago... and a Vertex as well....
Just find something you think is a cool tach drive look and we can make it fit the flathead.

 

P.S.


Bubba's good.....



HellRaiser

 

And he makes something that seems difficult so easy.

 

There are 2 types of mechanical tachs.
Magnetic driven like old speedometers and these are "bouncy" sometimes.
Chronometric driven like a Jones. There are no magnets in these. They have a mechanism
similar to a hand wound watch. These do not bounce and they are the most accurate of the mechanical tachs.

 

Can anyone locate the old post giving a current source for the crank (or cam) drive units? The bracketry can be fabricated. The source had to do with Formula Ford cars and offered drives for both crank and cam speed takeoff. Drive to speedometer cable type tachs...

 

Bruce,

In that one post of mine above, I have that link to Yanmar MDA that makes them. Is that the one??? Click on that and see if it is......


HellRaiser

 

we have a short convo going on here:
http://www.jalopyjournal.com/forum/showthread.php?t=705820

the old drive units by SW are brass or brass cast looking. Most of the new units seem to come from aircraft units and are aluminum (maybe) or polished steel

 

Ive been playing with the idea of designing a worm drive adapter that would go between the block and the distributor on earlier engines.
But the fact that I have no engineering, cad, or machiningeducation may hold this idea up a bit...
If someone steals my idea I want at least 6 bucks!!

 

I found a tach drive adapter that goes under the Mallory on my Mopar flat 6. It came from a fire truck with the bigger Chrysler 6. Were there any industrial applications of the Nash motors? Might be somewhere to look.

Willy- sign me up for some moustache wax!

 

HAHA! Another soon to be sastisfied customer!

 

Do you mean this? https://www.pegasusautoracing.com/productdetails.asp?RecID=254

 

Correct me please if I am wrong, but shouldnt the drive be a 1:1 ratio to mount to the crank?
Or does it involve more math depending on the tach that you want to use??

 

1 to 1 off the crank.
1 to 2 off the cam.

This setup used a 1 to 2 besides a set of bevel gears.