The Ford Barn

36tudordeluxe · 01-01-2017, 05:23 PM

Have a 12V negative ground electronic tach, will it work in a 6V positive ground application?
UPDATE: Been checking around, don't think it can be done.

Drbrown · 01-03-2017, 12:59 AM

Would think it either won't read or won't read correctly.

tubman · 01-03-2017, 11:45 AM

Yeah, this is more complicated than it sounds. My friend and I are working on a cheap "Black Box" that would allow the use of a 12 volt, negative ground tach on old Fords. We got the tach circuitry to work quite easily, but then discovered that we had to change the polarity of the input impulse signal as well. That project has stagnated because of our "Big Brass Condenser" project (that also turned out to be more complicated than we ever thought), but should be back on track next spring.

36tudordeluxe · 01-03-2017, 02:53 PM

Westberg Manufacturing makes a tach. for a 2" hole that will work pos. or neg. with a points type distributor. A little pricey at about $125.

tubman · 01-03-2017, 03:44 PM

That's why we are trying to copme up with a universal "Black Box". Our target selling price is $20-$30 depending on component cost. There are a LOT of 12V tachs out there for less than $50.

adileo · 01-03-2017, 03:49 PM

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Quote:

Originally Posted by tubman

That's why we are trying to copme up with a universal "Black Box". Our target selling price is $20-$30 depending on component cost. There are a LOT of 12V tachs out there for less than $50.

Tub put me on your waiting list

tubman · 01-03-2017, 07:04 PM

You guys will be the first to know.

Terry,OH · 01-04-2017, 06:53 AM

Switch your box from 8 to 6 to 4 cyl with a jumper wire, would also be very good.

01-01-2017, 05:23 PM	#1
36tudordeluxe Senior Member Join Date: Feb 2012 Location: Las Vegas, NV Posts: 1,260	Tach. For '36 engine? Have a 12V negative ground electronic tach, will it work in a 6V positive ground application? UPDATE: Been checking around, don't think it can be done. Last edited by 36tudordeluxe; 01-01-2017 at 09:35 PM.

01-03-2017, 12:59 AM	#2
Drbrown Senior Member Join Date: Oct 2013 Location: Glens Falls NY Posts: 1,267	Re: Tach. For '36 engine? Would think it either won't read or won't read correctly.

01-03-2017, 11:45 AM	#3
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 10,358	Re: Tach. For '36 engine? Yeah, this is more complicated than it sounds. My friend and I are working on a cheap "Black Box" that would allow the use of a 12 volt, negative ground tach on old Fords. We got the tach circuitry to work quite easily, but then discovered that we had to change the polarity of the input impulse signal as well. That project has stagnated because of our "Big Brass Condenser" project (that also turned out to be more complicated than we ever thought), but should be back on track next spring.

01-03-2017, 02:53 PM	#4
36tudordeluxe Senior Member Join Date: Feb 2012 Location: Las Vegas, NV Posts: 1,260	Re: Tach. For '36 engine? Westberg Manufacturing makes a tach. for a 2" hole that will work pos. or neg. with a points type distributor. A little pricey at about $125.

01-03-2017, 03:44 PM	#5
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 10,358	Re: Tach. For '36 engine? That's why we are trying to copme up with a universal "Black Box". Our target selling price is $20-$30 depending on component cost. There are a LOT of 12V tachs out there for less than $50.

01-03-2017, 07:04 PM	#7
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 10,358	Re: Tach. For '36 engine? You guys will be the first to know.

01-04-2017, 06:53 AM	#8
Terry,OH Senior Member Join Date: May 2010 Posts: 4,771	Re: Tach. For '36 engine? Switch your box from 8 to 6 to 4 cyl with a jumper wire, would also be very good.