Your thoughts on this idea

[Skunksmash]

This thread is for those of you who are familiar with the gauge cluster innards. 87 model. I'm not happy with the way I currently have my gauges set up. I don't have them mounted like I want them. Well, I think I can get them all recessed behind the factory bezel, using the factory printed circuit if I do this right. The printed circuit will bend, unlike other setups where they use one of those green PCB boards. That is the only reason this method will work. I think...

Anyway, I plan to take the appropriate grit of sand paper, and sand off a couple of very small spots on the printed circuit, to expose the copper filament underneath. Just enough to make a place to solder. Then solder the wire that I'm needing to run, to that copper thing. Then throw down some clear silicon or something on the solder point to sort of strengthen the solder point. If the sanding part is even necessary. It might not be necessary if I can just solder to the already exposed copper points on the printed circuit, that were originally open so that they could contact the lights and various power points and signal emitters and stuff.

To make a hole in the factory gauge housing, I'm going to just cut a hole in it large enough to fit the new 5" tach. I've checked and there appears to be room. I will lose the "fasten seat belt" and "Parking Brake" lights that come factory in the dash, but I don't really care. So since the printed circuit can bend, I can just bend it and fasten it over somehow. That way my big tach can fit where it needs to go, and so I don't have to ditch the stock setup for the rest of the gauges. Can't really afford to buy all new gauges right now but I did get a few of the necessary ones. Necessary at least, in my opinion. So what do you think? Can you forsee any problems with this idea?

[Da67goatman]

Not having a fuel gauge...

[1MCP7.3/87GMC]

Why not just get a factory gauge cluster with a tach and not have to cut the circits at all?

[Skunksmash]

Factory tach looks kinda...abnormal with zeros after the numbers. Looks like some kind of other speedometer or something. But I wasn't going to cut the circuit, I was going to fold it over a little and leave it that way. Also, the fuel gauge will be replaced with a smaller one that I have, which will be fitted into the clock's old spot.

[jaredts]

Maybe I'm misunderstanding, but a new aftermarket tach will require a bat. pos., lighted pos. from dimmer (for backlight), ground, and tach signal wire.  None of those would I get from the printed circuit, so I don't see the need to sand and solder to the pcb.  You just have to run a few wires and figure out how to physically fit it in there.

[Captkaos]

Ditto on what jaredts posted.  Of course I am still confused as to what you want to do...

[Skunksmash]

Sorry I should have been more clear on that. Yeah the tach will have to have its own wiring of course, but the new autometer fuel gauge and the digital water temp gauge might be able to benefit from just having their wiring (some of their wiring at least) soldered to the correct spots on the factory PCB. That way, I don't have to deal with the dimmer aspect of things, which I was never able to get working on any more my gauges. Didn't try real hard though. Also, if I am stuffing this tach in there, the PCB does have to be folded over simply because there is no longer room for it with that big tach in there. So that presents a couple of minor issues. I'll post up a couple of pics tomorrow.

[Skunksmash]

Ok here are some pics that might help explain what I want to do. I'd like yall to look at them and tell me what you think. Good, bad, or ugly. And maybe some recommendations.

[Captkaos]

Are you planning on keeping all the other stock gauges?  I started down this path and you will end up hacking that cluster housing to death. 

Honestly you would be better off going this route:
http://73-87.com/7387garage/interior/gauges_recessed.htm

[Skunksmash]

Yeah I'd like to do that, but only working part time due to school I simply can't afford to buy everything necessary. I can only do a little here, a little there. And for now, yes I do plan on keeping the other stock gauges.

[jaredts]

Why would you have to fold the printed circuit over?  Couldn't the tach just bulge out the back and push it back a little?

[Skunksmash]

I guess you could, but it does still need to be secured some kinda way. Cause I don't want it just being loose back there.

[Captkaos]

If you are worried about the printed circuit, just tape it down, just don't crease it.

[Skunksmash]

Ok now I have to drag this topic back up. Is there some kind of tach lead wire on the coil of an 87? I am about to wire up my tach properly, and it looks like there is some little wire coming off the coil. Just a little 4 inch wire with a little plug on the end of it, coming right out of one side of the plug that plugs into the coil. I thought this could be awful convenient for me, if its just a negative test lead that goes straight to the coil. I could just wire my tach signal wire, right to the little plug looking thing on the end of the wire. Its not plugged into anything, so I have no idea what its for.

[Captkaos]

The HEI has a plug for TACH, just use that.