Vega Tachometer - "I killed 2 over 35 years ago"

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Vega Tachometer - "I killed 2 over 35 years ago"

Postby 74_Vega_GT » Tue Jan 02, 2018 11:35 am

Yes, I did it, I only found out recently. So, waaaayyy back when we upgraded the Vega 4 banger to high energy electronic ignition and removed the points distributor, no one told me that this would kill the tachometer. We went to the junk yard where they were plentiful back then and put in another tach, I vaguelly remember that it worked only for a few seconds and then died like the one before it. I drove it many years with no tach.
Fast forward to the resto-mod project, the one that was in this Cos. dash (8,000) rpm looks the same as far as the electronics on the board go. It will fit into the 74 GT instrument carrier with one exception. There is a split window for the oil light indicator on this one and a single window on the 74 GT tach, we are using the instrument harness from the 74. The Monzas were available in 4,6, and 8 cylinders and switched to electronic ignition at some point. I am wondering if there is a tach that will fit the 74 carrier and work with the 4.3 V6 vortec which has a spot on the cap for the tachometer wire. The 74 harness has a 3 hole connector for the tach.
I am told that the reason the points tach quit was because the points type breaks the negative to get the pulse and high energy systems break the positive side to get the pulse or vice versa.
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Re: Vega Tachometer - "I killed 2 over 35 years ago"

Postby dindin » Tue Jan 02, 2018 3:25 pm

I don't see how points would cause a tach to stop working, the tach simply connects to the negative side of the coil..or the tach wire on the distributor..

Al
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Re: Vega Tachometer - "I killed 2 over 35 years ago"

Postby spencerforhire » Tue Jan 02, 2018 6:42 pm

I also have experienced failures of older style points-ignition tachometers when upgrading to HEI or MSD ignition. And not just 50 year old OEM units, but brand new reproduction ones as well. There are adapter available from MSD(#8920) and other sources, but you have to know you need one BEFORE you try to hook up the tach. It was explained to me that the old style GM tachs do not like the 12v square wave signal that newer ignitions produce to drive an aftermarket or newer style tach. Fords are a completely different problem, and I won't bother explaining that on this forum.
As to what other OEM tachs might fit, you're pretty well limited to one from a 1975 Monza, and AFAIK, the V6 was not offered that year.
The "fleet"-
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
03 Silverado 2WD ex.cab (work truck/parts hauler)
04 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
93 Suburban- 350/4L60(retired)
00 Saturn SW2- wife's car
01 Saturn SC2- younger son's project
00 Saturn SL2- daughter's car
98 Saturn SW2- spare
and 3 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

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Re: Vega Tachometer - "I killed 2 over 35 years ago"

Postby Brad C » Tue Jan 02, 2018 10:46 pm

spencerforhire wrote:.
As to what other OEM tachs might fit, you're pretty well limited to one from a 1975 Monza, and AFAIK, the V6 was not offered that year.


What about the Skyhawk or Starfire? They had the same dash in 1975 and both only had V6's for powertrains.
Brad C. 75 Skyhawk, 70 Buick GSX, 71 Buick GSX, 87 Buick GNX, 2 86 Buick Grand Nationals and a host of other Buicks.
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Re: Vega Tachometer - "I killed 2 over 35 years ago"

Postby dindin » Wed Jan 03, 2018 10:38 am

I see I misread this..Its the HEI thats the killer not the points..I googled lots of HEI filters, I wonder if they would work with a basic vega tach that does not have HEI?..

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Re: Vega Tachometer - "I killed 2 over 35 years ago"

Postby Smiley » Wed Jan 03, 2018 5:15 pm

I used a 73 Vega GT tach with an HEI for years with no issues.
TimMcCabe could probably recalibrate it for a V6.
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Re: Vega Tachometer - "I killed 2 over 35 years ago"

Postby spencerforhire » Thu Jan 04, 2018 7:51 am

I am not exactly sure what 1975 H-bodies had the Vega-style cluster and which ones had the Monza type. I do know that I "harvested" the tach from every V8 one I found and sold them along with the motor mounts and other swap pieces.
The "fleet"-
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
03 Silverado 2WD ex.cab (work truck/parts hauler)
04 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
93 Suburban- 350/4L60(retired)
00 Saturn SW2- wife's car
01 Saturn SC2- younger son's project
00 Saturn SL2- daughter's car
98 Saturn SW2- spare
and 3 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
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Re: Vega Tachometer - "I killed 2 over 35 years ago"

Postby spencerforhire » Thu Jan 04, 2018 8:04 am

May have just found the answer; I was Googling different year H-body clusters, and this is supposed to be a pic of a 1975 Skyhawk dash with most likely a V6 tach.
Attachments
Skyhawk 75.jpg
Skyhawk 75.jpg (102.51 KiB) Viewed 389 times
The "fleet"-
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
03 Silverado 2WD ex.cab (work truck/parts hauler)
04 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
93 Suburban- 350/4L60(retired)
00 Saturn SW2- wife's car
01 Saturn SC2- younger son's project
00 Saturn SL2- daughter's car
98 Saturn SW2- spare
and 3 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
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1972 Chevrolet Vega Hatchback

Re: Vega Tachometer - "I killed 2 over 35 years ago"

Postby Brad C » Thu Jan 04, 2018 12:04 pm

spencerforhire wrote:May have just found the answer; I was Googling different year H-body clusters, and this is supposed to be a pic of a 1975 Skyhawk dash with most likely a V6 tach.



Uhhh, yea. See my post above about Skyhawk's and Starfire's. In 1975, they both had that style of dash and were available only with V6's.
Brad C. 75 Skyhawk, 70 Buick GSX, 71 Buick GSX, 87 Buick GNX, 2 86 Buick Grand Nationals and a host of other Buicks.
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Re: Vega Tachometer - "I killed 2 over 35 years ago"

Postby spencerforhire » Thu Jan 04, 2018 1:45 pm

Glad Brad reminded us of the Skyhawk thing. I remember seeing a post about the 1975 Town Coupe having the later style Monza dash; is that correct? Never owned one.....
The "fleet"-
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
03 Silverado 2WD ex.cab (work truck/parts hauler)
04 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
93 Suburban- 350/4L60(retired)
00 Saturn SW2- wife's car
01 Saturn SC2- younger son's project
00 Saturn SL2- daughter's car
98 Saturn SW2- spare
and 3 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
User avatar
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1972 Chevrolet Vega Hatchback

Re: Vega Tachometer - "I killed 2 over 35 years ago"

Postby Brad C » Thu Jan 04, 2018 4:03 pm

All 75 Hatchbacks had the "Vega" style dash. All 75 notchback's had the "new" style dash. All 1976 and later had the new dash, hatch's or notchbacks.
Brad C. 75 Skyhawk, 70 Buick GSX, 71 Buick GSX, 87 Buick GNX, 2 86 Buick Grand Nationals and a host of other Buicks.
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Re: Vega Tachometer - "I killed 2 over 35 years ago"

Postby spencerforhire » Thu Jan 04, 2018 4:59 pm

I still remember the "ah hah!" moment back in about 1983 or so when I discovered that the V8 tach and 120 mph speedo out of the 1975 Monza donor car would fit into the 1976 GT cluster.
The "fleet"-
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
03 Silverado 2WD ex.cab (work truck/parts hauler)
04 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
93 Suburban- 350/4L60(retired)
00 Saturn SW2- wife's car
01 Saturn SC2- younger son's project
00 Saturn SL2- daughter's car
98 Saturn SW2- spare
and 3 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
User avatar
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1972 Chevrolet Vega Hatchback

Re: Vega Tachometer - "I killed 2 over 35 years ago"

Postby Monza Harry » Sat Jan 06, 2018 9:50 pm

Spencer "Somebody Loves You" I went to eBay for the first time in about ~6 mos. and "looky see" what I found!
https://www.ebay.com/itm/Chevy-Monza-OE ... 2x&vxp=mtr
Harry
120MPH Speedo.jpg
Now we're Makin' TIME!
120MPH Speedo.jpg (146.94 KiB) Viewed 355 times
I'm not a hoarder I'm a preservationist 78 Monza Spyder (Soon To Be 2+2 with Spoilers)
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Re: Vega Tachometer - "I killed 2 over 35 years ago"

Postby spencerforhire » Sun Jan 07, 2018 5:56 pm

It could use a refurb, Harry, but that's the one.
And I am forced to admit that I didn't realize how woefully inadequate the 85MPH Vega speedo was until AFTER the engine swap.....
The "fleet"-
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
03 Silverado 2WD ex.cab (work truck/parts hauler)
04 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
93 Suburban- 350/4L60(retired)
00 Saturn SW2- wife's car
01 Saturn SC2- younger son's project
00 Saturn SL2- daughter's car
98 Saturn SW2- spare
and 3 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
User avatar
spencerforhire
 
Posts: 2442
Joined: Mon Jul 03, 2006 9:02 pm
Location: Halifax, Nova Scotia

1972 Chevrolet Vega Hatchback

Re: Vega Tachometer - "I killed 2 over 35 years ago"

Postby 74_Vega_GT » Wed Jan 10, 2018 10:56 am

Thanks for the info 'yall. I think I know where one of those speedos is...if the cantankerous junkyard owner will come off of it....So, was the 75 Cosw. an H.E.I. type signal going to the tach? I have one of those that will fit into the 74 carrier and could use that one. I suppose the 4.3 Vortec v6 is of the HEI tach. signal type as well? Thanks in advance.
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