1986 El Camino Tachometer Swap [Archive] - El Camino Central Forum : Chevrolet El Camino Forums

: 1986 El Camino Tachometer Swap


~JM~
04-06-2012, 03:29 PM
What all is needed to make a Tach work in an '86?

I have an '86 that came from the factory with gauges & speedo. The lighting circuit went bad & I replaced the whole cluster with another G-Body cluster that I had. The new cluster has a tachometer that I'd also like to hook up.

What will it take?

Thank you
~JM~

ccc
04-06-2012, 03:50 PM
you will need the resister that goes to the tach terminal in the dist.it screws to the firewall between the dist and brake booster.a junkyard part as its not available from gm any more.any third gen camaro will work as long as it has a v8.then you will need to run the white tach wire to the cluster plug i believe pin 17. the hot and ground are already in the printed circuit

elkper1771
04-06-2012, 04:04 PM
JM, Have you the checked the green circuit board also? Last time I attempted this on my old '86, in addition to the wiring connections CCC has mentioned, that circuit board was always a problem for me. I changed the board with a used one, and it only worked on occasions. I abandoned a final fix & ignored it, since it came on when it wanted to,.. - George

~JM~
04-07-2012, 12:12 PM
The circuit board looks good & seems to be functioning at least with the rest of the panel. It looks like the Tach is ready to go, it just needs the information signal.

Thank you
~JM~

Rally169
04-07-2012, 02:55 PM
First, you need to get a tach filter. There are several available on E-bay. Search for a 87 monte carlo tach filter. This mounts on the fire wall and connects to the tach output on the HEI distributor. Look Under the dash on the drivers side by the radio and you should find a white wire with a brown single lug connector clipped to the forward edge of the dash. The tach filter will plug into this connector an the tach should work.

randycamino52
04-07-2012, 06:31 PM
Maybe that is what I need to make mine work right. It started to work again today after not working for about a year, but it reads about 4000 at idle and pegs out at cruising speed. What does a tach filter look like and would it work for an 84 with the comp and stuff removed?

ccc
04-07-2012, 06:56 PM
it looks like a capacitor with a wire comeing from each end of it and bolts to the firewall between the dist and the brake booster.it has a plug for the dist and a connector for the dash plug.without it the tach reads all crazy.you can get them from any 80s g body or camaro/firebird with a v8 and tach

O. D. Showtime
04-07-2012, 07:03 PM
Here's a pic (not the greatest) of a tach filter...actually I see it's the complete wiring right from the cluster connection...


http://img833.imageshack.us/img833/1200/pc040001e.jpg

87GMCCab
04-09-2012, 05:53 PM
Following this thread. I have a 87 Caballero. The printed circuit has Gnd 12V and Coil as well as Bat. Pin 17 contains a white wire. I am assuming I need to find the connection under the dash and run the wire to the distributor. (I have the tach filter). What I really need to know is what am I looking for at the distributor to connect to?

~JM~
04-10-2012, 12:48 PM
Thanks for all the replies. By any chance does anyone have an extra Tach Filter & Line that they'd like to sell? Please reply here or by PM.

Thank you
~JM~

Beepster
04-10-2012, 03:15 PM
Fastest way would be to go to a Chebby dealer, BUT be prepared to pay thru the nose, and any other orface.

greywolf
04-10-2012, 06:40 PM
Following this thread. I have a 87 Caballero. The printed circuit has Gnd 12V and Coil as well as Bat. Pin 17 contains a white wire. I am assuming I need to find the connection under the dash and run the wire to the distributor. (I have the tach filter). What I really need to know is what am I looking for at the distributor to connect to?
Distributor has a second terminal next to the ignition terminal for the tach. Mine was even marked tach.

~JM~
04-10-2012, 08:50 PM
What should I be prepared to spend for a Tach Filter?

Thanks
~JM~

O. D. Showtime
04-11-2012, 06:35 AM
What should I be prepared to spend for a Tach Filter?

Thanks
~JM~


I've seen them on ebay from time to time anywhere from $20-$75.

The pic I posted above is one I have as an extra. I could look tonight I may have a couple extra extras here.

~JM~
04-12-2012, 01:08 PM
Well I got lucky & found a Tach Filter on eBay. http://www.ebay.com/itm/270951866746

Now I just have to wait for it to arrive & then start poking around under the dash to see if I can find where it hooks up.

Thank you
~JM~

O. D. Showtime
04-12-2012, 03:09 PM
Well I got lucky & found a Tach Filter on eBay. http://rover.ebay.com/ar/1/711-53200-19255-0/1?mpt=1176758226&adtype=1&size=1x1&type=3&campid=5336121877&toolid=10001 http://www.ebay.com/itm/270951866746 (http://rover.ebay.com/rover/1/711-53200-19255-0/1?type=3&campid=5336121877&toolid=10001&mpre=http%3A%2F%2Fwww.ebay.com%2Fitm%2F27095186674 6)

Now I just have to wait for it to arrive & then start poking around under the dash to see if I can find where it hooks up.

Thank you
~JM~

Sorry I didn't get a chance to reply sooner...but looks like you've found what you need.

~JM~
04-12-2012, 03:27 PM
Sorry I didn't get a chance to reply sooner...but looks like you've found what you need.

Please don't sweat it. You've been very helpful. Thanks.

I was surprised to find one as easily as I did. I hope its a good one.

~JM~

~JM~
04-13-2012, 11:32 AM
Well... I think I may have a new problem.

I think I have a Tach intended for a 6-cylinder vs. my V-8. My redline begins at 4500rpm & the Tach ends at 6K.

I don't suppose there is anything that can be done about this other than to find another Tach?

Thank you again
~JM~

O. D. Showtime
04-13-2012, 12:09 PM
Well... I think I may have a new problem.

I think I have a Tach intended for a 6-cylinder vs. my V-8. My redline begins at 4500rpm & the Tach ends at 6K.

I don't suppose there is anything that can be done about this other than to find another Tach?

Thank you again
~JM~

Actually some of the V8 tachs did start with a lower redline. Other members have posted up indicating they've been one owners of crucks with that tach.

Nicholas J . Hornickle
04-13-2012, 01:20 PM
I also installed a tach, pre 86, so not sure if its' from a V-6 or V-8, which I am told is critital to know. This tach has the small clock, so once hooked up to the posts it's working. The Tach stays at zero a idle, but moves & stays at 4,000. Does not register after that and may move slightly. When engine is off, may still rest at 4K. I did not have this talked about resister wire or filter, so may have discovered my problem. As you asked, where does this connect? Thanks, N

~JM~
04-13-2012, 01:35 PM
The Tach that I have now has a small clock also. So far the clock is keeping time.

~JM~

~JM~
04-13-2012, 01:43 PM
http://i127.photobucket.com/albums/p124/Northwet/1-8.jpg

Here is a pic of the gauge cluster. Hopefully it will show up.

~JM~

~JM~
04-13-2012, 02:33 PM
Here is a slightly better pic. The glare off the curved plastic cover makes it difficult to take a nice pic.

http://i127.photobucket.com/albums/p124/Northwet/A.jpg

~JM~

~JM~
04-13-2012, 02:46 PM
I found this pic in another post. It shows the white wire that is supposed to be hidden near the top.

http://i127.photobucket.com/albums/p124/Northwet/tach_con.jpg

~JM~

~JM~
04-14-2012, 10:43 AM
Can anyone tell me if this is a 6 cylinder Tach or an 8 cylinder model?

Do I just need to hook it up & see if it works correctly? I have heard of using a resistor or potentiometer in line to make a 4 cylinder tach work for a V-8. Any idea if this will work in this case?

Thank you
~JM~

Jack_K
04-15-2012, 06:31 AM
Here's a schematic of what's inside the tach filter. You could easily build one from Radio Shack parts.

Stick the parts inside a piece of PVC or plastic pipe with thye two wires coming out. Crimp a push-on lug on the wire that connects to the distributor. Then fill it with electronic-safe silicone rubber. Use a clamp to mount it to the firewall.

Jack
BTW, the capacitor values are not critical. Anything close will do fine.

~JM~
04-15-2012, 12:16 PM
What is the purpose of the Tach Filter? Is it to reduce signal strength before it enters the cabin?

I was finally able to locate the under dash plug in. (white wire with brown connector) I ended up using a dental mirror to find it. Everything snapped into position after that. Where did the factory originally route the wire through the firewall? I used the grommet that the speedo cable runs through to avoid having to drill another hole.

The tach appears to be functioning correctly. It idles around 750-800rpm & free revs to about 2500. I haven't taken the car for a drive yet. If this is a 6-cylinder tach how will I be able to tell? Will the readings be grossly off?

Thank you
~JM~

~JM~
04-18-2012, 12:13 PM
Well... I found an eBay auction for a Tach that looks just like mine. This eBay Tach was reportedly removed from a Monte Carlo SS with the 305. It appears that there are 8-cylinder Tachs out there where the redline (or orange line) begins at 4400rpm.

Anyone else want to weigh in with more info? This is a nice post for anyone looking to perform this swap. There is still some unverified info out there on the various Tach configurations & how to ID them.

Thank you
~JM~