Technical SUN TRANSMITTER TACHOMETER

my dad was parting out this old f7 truck and I noticed the cool vintage tach in it. now that tach would go perfect in my traditional half ton truck im building, so I asked him if I could have it and to my surprise he said yes! so I was wondering if anyone else has got one of these in there hot rod? it looks really simple to wire. the terminals are labeled. what I found really interesting when I opened it up was the size D battery inside. I also question its accuracy when I do hook it up. any input?

 

Not sure that is a Battery. Maybe some sort of other electrical component?

 

You SURE it was a D battery? The batteries in these are often oddballs.

 

http://www.jalopyjournal.com/forum/threads/found-batteries-for-sun-tach-transmitters.37497/

 

If there's actually a "D" battery in there, it isn't original. Probably a shade tree repair.

 

well I found this old ray-o-vac flashlight battery in this cylinder than is part of the cover. than in the cover at the end of the cylinder there is a brass sheet that connects to a screw connector that was screwed on to a wire that connected to a component in the box. here is what it looks like

 

I've got one of those tach's....thought it was off something military.....

 

How old is the truck that it came out of?

 

it was an old 1945ish f7. not 100% sure.

 

Its not the correct battery. If it does work, it will be the wrong voltage and read incorrectly.

 

The transmitter boxes are marked for their specific use,,,,AE,,8 cyl,6 volt---8 cyl,12 volt---and etc..the battery is special to them also,,,Williamsons in Chester,Ark is the best to repair these old units.

 

this tach was being used on a big f7 truck with a 337ci flathead. in my truck I just got a little 221ci. will it still work?

 

the tag says model e-1, 6 volts, 8 cylinders

 

It will work providing you are running 6 volts and the batteries inside the EB1 box are correct,,and still good

 

I am running the 6 cylinder version of that sending unit in my 53 Chevrolet.
Williamson's changed it to 12 volts and eliminated the battery. It works great!!

 

Yes, the D sized battery is correct. You have the earliest style Sun transmitter (E-series)...very rare. Later transmitters (EB series) used the oddball batts.

Your transmitter should show the specifics on cylinders and voltage.

Here's my old transmitter (also used a D sized battery);

 

how could I check its accuracy? just hook up one I know is accurate at the same time I run this one?

 

Yeah, that might be the best way...My tach (identical to yours) was off a couple hundred RPMs. Ran it like that for years, then realized that under the light bulb 'pod' there is an adjustment wheel - uses a flat blade screwdriver. Not sure how much adjustability is there, but worth a shot.

 

Early 60s Chevy truck shop manual shows how to check accuracy using a battery charger. Later units used 1.30 volt batteries AA batteries are 1.6 when new. run them down to 1.35 volts and install they should last a year.

 

As suggested by wbrw32, send it to Williamson's Instrument Service and have them give it the once over. They do fantastic work and can convert it to function properly with any ignition and without having to use a battery.

 

They do great work. Hope your not in a hurry thou!

 

I'd try it with the D-cell battery before sending it out for modern guts to be installed. Mine worked, tach just needed adjustment.

 

so the other day i mounted the tach and the box and started wiring but i cant figure where to hook the distributor stud to. where on the distributor is it? i know its not the same one that you count the ignition.