Tachometer replacement thoughts

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,742
Reaction score
11,319
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
So back when I bought this truck 4 or 5 years ago it didn't have a tach in it. After the first time I towed my trailer with a load on I decided I needed a tach, so I bought a cheapie Equus unit, knowing that it was kind of stop gap, not the best quality but would perform the function. Well now it's starting to fail, occasionally it'll stop reading for a short time. I've checked the connections and believe that the tach is starting to fail.

Option #1, replacing it with another aftermarket tach, which is fine with me, but it needs to be a traditionally or classic styled instrument that fits in with the rest of the truck and does not standout as looking to modern.

Option #2 The other option would be to get a factory tach kit from LMC. I'd be curious to hear from other folks that have done the LMC kit. I actually kind of wanted to do this back when I got the aftermarket unit, and while I'm in there I could fix a couple other issues with the instrumentation. Biggest con with this is cost

What you guys think? Thanks.
 

Redfish

Full Access Member
Joined
Nov 6, 2021
Posts
2,392
Reaction score
12,866
Location
Prairieville, LA
First Name
Andrew
Truck Year
1987
Truck Model
V1500
Engine Size
350/5.7
I am very interested in this as I have been considering this myself. I would love to have a factory looking setup, just buy the small fuel gauge and move it down to the left. Of course I would have to remove the QUARTZ!!! clock...I have no idea why they made such a big deal about that Quartz Clock but they made it sound like a great thing.

Do you have to replace the entire printed circuit board?
What wire/where does the tach get its input?
 

PeteJr

Full Access Member
Joined
Jan 12, 2021
Posts
827
Reaction score
3,034
Location
NW MS
First Name
Jim
Truck Year
1983
Truck Model
GMC Sierra Classic 1500
Engine Size
350
Last summer I replaced the big gas gauge with a tach and moved the gas gauge to where the clock was.
I tried to order the "kit" to do this from LMC. It was backordered for 6 - 8 months. I finally got tired of waiting and ordered all the individual pieces which "amazingly" they had. Paid about $100 more than the "kit" price. I ended up having to get the back panel also as the new, small gas gauge didn't mount in the place where the clock was on the old one.
You will need the correct printed circuit for sure.

I have pics and can list the items I bought if anyone needs it. I have an '83 GMC Sierra Classic SB.
 

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,742
Reaction score
11,319
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
I am very interested in this as I have been considering this myself. I would love to have a factory looking setup, just buy the small fuel gauge and move it down to the left. Of course I would have to remove the QUARTZ!!! clock...I have no idea why they made such a big deal about that Quartz Clock but they made it sound like a great thing.

Do you have to replace the entire printed circuit board?
What wire/where does the tach get its input?
LMC sells a kit and their kit includes a new circuit board so I would think that's a requirement.

As for the clock is you think about the time period when these trucks came out, no other truck had a built in clock. What a luxury! My clock is dead and the aftermarket radio has a clock as does my GPS so I won't miss that at all. I have wondered though if I would miss having the large fuel gauge.

My oil pressure gauge isn't the best any more so I'd change that while I'm in there and I think replacing the circuit board could only do me good. But the kit is like $315 that's money I could put towards a bed cover if I go with a less expensive aftermarket tach.
 

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,742
Reaction score
11,319
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
Last summer I replaced the big gas gauge with a tach and moved the gas gauge to where the clock was.
I tried to order the "kit" to do this from LMC. It was backordered for 6 - 8 months. I finally got tired of waiting and ordered all the individual pieces which "amazingly" they had. Paid about $100 more than the "kit" price. I ended up having to get the back panel also as the new, small gas gauge didn't mount in the place where the clock was on the old one.
You will need the correct printed circuit for sure.

I have pics and can list the items I bought if anyone needs it. I have an '83 GMC Sierra Classic SB.
The pics for sure would be great to see for me at least. I always seem to get into a time crunch on projects like that so seeing it would be helpful for me. Thanks.
 

Catbox

Full Access Member
Joined
Jul 12, 2018
Posts
3,992
Reaction score
14,572
Location
Just Outside of Portland Oregon
First Name
Peter
Truck Year
1979
Truck Model
C20 Silverado Camper Special
Engine Size
461
This is the tach in my truck.
You must be registered for see images attach


You must be registered for see images attach

I have too much torso, so I can never see it through the steering wheel when I drive it.
Soon I will be replacing it with a used Autogage unit that I picked from a swap meet.
These 3-3/4 inch tachs have always done well for me.
You must be registered for see images attach

I have a few of them to choose from as I always snap them up from the swaps when I spot them for $5-$10 each.
 

PeteJr

Full Access Member
Joined
Jan 12, 2021
Posts
827
Reaction score
3,034
Location
NW MS
First Name
Jim
Truck Year
1983
Truck Model
GMC Sierra Classic 1500
Engine Size
350
Here's the list of parts I ordered from LMC.
My truck is an '83 GMC Sierra Classic. Parts differ for other years.
This process isn't too hard to do. I removed the dash pad, helps a lot.
Make sure the speedo and tach wires go in correctly so you don't have to remove the cluster after installing it. (Lesson learned)
I used some Testors model car paint for the older gauge needles.
I also, used a small rubber plug for the hole in the lens when the clock stem was. Just to keep dust out.........

36-2042 Tach - 7,000 RPM
36-3104 Tach wiring harness
38-8069 Tach bracket (didn't need it)
36-1858 Small fuel gauge
38-8101 Gauge cluster backing plate
38-8041 Printed circuit
38-1103 Dash bezel - brushed aluminum (handle with care or it will crease very easily)
36-0190 Instrument bulb holders - as needed
38-8042 Retainer clips for printed circuit - as needed
As for the clear lens over the gauges, I polished mine and it looks fine
There's other items you may need like spacers, clips, screws and headlight lens, etc.

Hope this helps !

You must be registered for see images attach


You must be registered for see images attach


You must be registered for see images attach


You must be registered for see images attach
 
Last edited:

Soundmound

Supporting Member
Supporting Member
Joined
Feb 15, 2022
Posts
1,773
Reaction score
5,327
Location
North Central Washington
First Name
Dave
Truck Year
1984
Truck Model
Scottsdale
Engine Size
305
I've been eyeballing the LMC kit but it's been out for months. I had them send me the parts list and I built it in my cart where I realized it would be almost $200 more doing it this way. I went as far as to buy a set of used gauges to try and rebuild what I had. However, what I got was for a different year than I needed as when it arrived it had a mechanical oil pressure gauge. I'm at the point now where I just want gauges back and will probably skip the tach conversion to do a like kind replacement, but will definitely NOT be reconnecting the clock as it is a parasitic drain that I don't want to deal with
 

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,742
Reaction score
11,319
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
want to keep your clock? here ya go! :)
Tell me about that installation. I've seen those gauges I think out of medium duty trucks? I'd like that actually even more than the LMC kit, but my clock would go and my trans temp gauge would go in it's place. So how much work is that installation?
 

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,742
Reaction score
11,319
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
Here's the list of parts I ordered from LMC.
My truck is an '83 GMC Sierra Classic. Parts differ for other years.
This process isn't too hard to do. I removed the dash pad, helps a lot.
Make sure the speedo and tach wires go in correctly so you don't have to remove the cluster after installing it. (Lesson learned)
I used some Testors model car paint for the older gauge needles.
I also, used a small rubber plug for the hole in the lens when the clock stem was. Just to keep dust out.........

36-2042 Tach - 7,000 RPM
36-3104 Tach wiring harness
38-8069 Tach bracket (didn't need it)
36-1858 Small fuel gauge
38-8101 Gauge cluster backing plate
38-8041 Printed circuit
38-1103 Dash bezel - brushed aluminum (handle with care or it will crease very easily)
36-0190 Instrument bulb holders - as needed
38-8042 Retainer clips for printed circuit - as needed
As for the clear lens over the gauges, I polished mine and it looks fine
There's other items you may need like spacers, clips, screws and headlight lens, etc.

Hope this helps !

You must be registered for see images attach


You must be registered for see images attach


You must be registered for see images attach


You must be registered for see images attach
That's awesome. Any chance you'd be able to give a rough time estimate on the job?
 

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,742
Reaction score
11,319
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
I used an Autometer #2891 (2 5/8"). I screwed it to the shifter column. When I'm in drive it's straight up.
I like the gauge but not the installation. I can see the appeal to do it like that, but my current tach is attached to the dash pad screw by the ash tray and that location is fine for me.
This is the tach in my truck.



I have too much torso, so I can never see it through the steering wheel when I drive it.
Soon I will be replacing it with a used Autogage unit that I picked from a swap meet.
These 3-3/4 inch tachs have always done well for me.

I have a few of them to choose from as I always snap them up from the swaps when I spot them for $5-$10 each.
I like the autogage and will keep that one in mind thanks.
 

Kurnacopia

Full Access Member
Joined
Jan 19, 2021
Posts
259
Reaction score
268
Location
Tucson, AZ
First Name
Mike
Truck Year
1978
Truck Model
Scottsdale
Engine Size
383
I did a complete bezel swap on my 74 K5. I found a guy that had a 73 suburban with a newer model cluster in it. BUT, the problem I am finding with getting things used is the plastic is so very brittle and can break off in a heartbeat when putting things together. Many companies sell the Cluster Backing Plate but never the one you need and LMC does too, but not all of them. So I highly recommend the LMC kit because all of the plastics are brand new, as well as the print out. Things will go in and seat perfectly and be solid for years to come. Thats my 2 cents.
 

StickyLifter

Supporting Member
Supporting Member
Joined
May 28, 2022
Posts
144
Reaction score
250
Location
N/A
First Name
Screw You Homophobes
Truck Year
N/A
Truck Model
N/A
Engine Size
N/A
I've been eyeing the LMC kit, but I may got with a Dakota Digital unit instead. Probably won't do either until next spring.
 

Latest posts

Forum statistics

Threads
42,137
Posts
909,894
Members
33,634
Latest member
prenrag
Top