Tach Filter - The 1947 - Present Chevrolet & GMC Truck Message Board Network

byates2 · 03-13-2013, 06:40 PM

The tach filter wires are a much smaller wire than the actual harness for the tach. If i put the filter in line will that pose a problem as the smaller wires may heat too much? Does the tach harness get that much electrical current through it to make those smaller wires on the tach filter heat??

byates2 · 03-15-2013, 02:55 PM

Anybody have any advice
Posted via Mobile Device

**john** · 03-15-2013, 05:09 PM

What kind of tach.? I have a aftermarket factory type that woks good and does not use a filter. Also have HEI dist.

byates2 · 03-15-2013, 07:34 PM

It's a repro of the original. They say on the website you need a filter with hei
Posted via Mobile Device

ray_mcavoy · 03-15-2013, 09:02 PM

On the original GM tachs, the filter was only used to prevent interference with the radio. I've hooked original tachs up to HEI distributors without a filter and haven't had any problems. But if the manufacturer of the reproduction tach says to use a filter it would definitely be a good idea.

There is very little current flowing through the tach signal wire. So the smaller gauge wire on the filter shouldn't be a problem at all. I fact, the only reason I can think of for GM to have used such a heavy gauge wire on the factory tach harness was for durability. Even the +12V power wire is oversized for the amount of current drawn by the tach.

03-13-2013, 06:40 PM	#1
byates2 Registered User Join Date: Feb 2007 Location: Acton Posts: 158	Tach Filter The tach filter wires are a much smaller wire than the actual harness for the tach. If i put the filter in line will that pose a problem as the smaller wires may heat too much? Does the tach harness get that much electrical current through it to make those smaller wires on the tach filter heat?? __________________ 1967 C10 Long Bed, Soon to have a 350 1997 Chevy 2500 454 BB

03-15-2013, 02:55 PM	#2
byates2 Registered User Join Date: Feb 2007 Location: Acton Posts: 158	Re: Tach Filter Anybody have any advice Posted via Mobile Device __________________ 1967 C10 Long Bed, Soon to have a 350 1997 Chevy 2500 454 BB

03-15-2013, 05:09 PM	#3
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Re: Tach Filter What kind of tach.? I have a aftermarket factory type that woks good and does not use a filter. Also have HEI dist. __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/

03-15-2013, 07:34 PM	#4
byates2 Registered User Join Date: Feb 2007 Location: Acton Posts: 158	Re: Tach Filter It's a repro of the original. They say on the website you need a filter with hei Posted via Mobile Device __________________ 1967 C10 Long Bed, Soon to have a 350 1997 Chevy 2500 454 BB

03-15-2013, 09:02 PM	#5
ray_mcavoy Registered User Join Date: Nov 2009 Location: Sherman, ME Posts: 2,359	Re: Tach Filter On the original GM tachs, the filter was only used to prevent interference with the radio. I've hooked original tachs up to HEI distributors without a filter and haven't had any problems. But if the manufacturer of the reproduction tach says to use a filter it would definitely be a good idea. There is very little current flowing through the tach signal wire. So the smaller gauge wire on the filter shouldn't be a problem at all. I fact, the only reason I can think of for GM to have used such a heavy gauge wire on the factory tach harness was for durability. Even the +12V power wire is oversized for the amount of current drawn by the tach.



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