OEM Sun tachometer help
 

Hello , Can anyone tell me from looking at this picture if this Tach will need a transmitter. I cant seem to get anywhere with the model #. I do not have the Tach in my hands yet so i cant tell if the guage has the electronics in it or not. I read that if its the older style that needs a transmitter it will have a + and - on the back. As you can see this one has Ign.sw., dist. and grnd. Any help would be appreciated.Thanks, Scott
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Re: OEM Sun tachometer help
 

Look here and see if you can figure it out.
I guess not. :chevy:

https://www.jalopyjournal.com/forum/...ctions.467635/

Re: OEM Sun tachometer help
 

With that tach having the terminals marked "Ign Sw", "Dist", and "Grd", it will have it's own internal electronics and not require a transmitter box.

As you mentioned, the older tachs that just have the 2 terminals marked + and - are the ones that need the transmitter box.

I don't think I've ever seen any sources documenting the OE-x model numbers for the factory installed Sun tachometers. But I know they did have a few different ones for 6 vs. 8 cyl as well as standard vs. transistor ignition.

The old GM parts catalogs list the following numbers for 63-66:
GM #3852111 for 6-cyl gas engines.
GM #3839947 for V8 gas engines with standard ignition.
GM #3885480 for V8 gas engines with RPO K66 transistor ignition (only available in 1966 medium/heavy duty trucks).

Unfortunately, they don't show any cross reference to the Sun OE model number that's indicated on the back of the tach. The few examples I have seen in person were Sun OE-6 models that also had "8-cyl 12 volts" printed on the label (where the one in your example just says "Sun Electric Corp"). And they were also printed with "STD IGN" directly below that, which would indicate a match up with GM #3839947.

Re: OEM Sun tachometer help
 

Ray, Thanks for your input.I have located a NOS 6cyl. 12v Sun transmitter But I thing I'll wait until my new used cluster shows up to see what i have. there is no marking on the cluster indicating 6 or 8 cyl. The man i bought the cluster from said he pulled it from a larger truck years ago and cant remember what engine it had. whats odd is the cluster is the older style before 63 ive attached a picture my truck is a 61 K10 with the 235 6 and idiot lights so im wanting to install the cluster with guages and a tach. Ive read that I can buy a tach adapter the will correct the signal if its a different engine than what i have.

Re: OEM Sun tachometer help
 

You're welcome Scott! Yeah, that sounds like a good plan to hold off on buying the transmitter until you receive the cluster to see exactly what tach you're dealing with.

Even though the clusters are different for 60-63 vs. 64-66, the section where the tach is located stayed pretty much the same. So there is a possibility that the original 60-62 tach has been swapped out for a 63-66 tach that doesn't need the transmitter.

If the tach in question ends up being a 63-66 version with the built-in electronics and happens to be for an 8cyl, an alternative option to an adapter would be to send the tach to a repair shop and have it re-calibrated for your 6.