Tach jumping

Reply Subscribe

Thread Tools

Search this Thread

Mar 19, 2006 | 06:11 PM

mkflanagan

Thread Starter

Melting Slicks

Joined: Mar 2006

Posts: 3,443

Likes: 2

From: McDonough Georgia

Tach jumping

Okay guys,between idle and 1500 my tach just jumps back and forth then around 1500 and beyond it works great,the connections at the distributor are fine.The kicker is it doesnt do it all the time,most of the time it works perfect.

Its a 76 L48

Mar 19, 2006 | 07:59 PM

mkflanagan

Thread Starter

Melting Slicks

Joined: Mar 2006

Posts: 3,443

Likes: 2

From: McDonough Georgia

Anybody?I need some help on this.

Mar 19, 2006 | 08:05 PM

carl a

Safety Car

Joined: Jun 2002

Posts: 4,135

Likes: 1

i put 2 or 3 tach drives and side gears in my old mech tach drive ,,all blew,,then i looked at a diagram and there is a 4 dollar ''thrust washer ''that must be installed or the side gear gets eaten up,,,the gear wants to move outward,,,the thrust washer keeps it aligned,,,they would last anywhere from 15 miles to 150 miles then go,,,make sure that washer is in,,,then i went with m s d tach drive destributer ,,, 6 al box,,, ect never have to mess with it again,,used to find mosture under old cap!!! sux pushing a corvette so i went msd after that

Mar 19, 2006 | 08:17 PM

mkflanagan

Thread Starter

Melting Slicks

Joined: Mar 2006

Posts: 3,443

Likes: 2

From: McDonough Georgia

Thx carl,i'll take a look and see what i find and then i will pick up the phone and call summit

Mar 19, 2006 | 08:22 PM

carl a

Safety Car

Joined: Jun 2002

Posts: 4,135

Likes: 1

i think its a gm part# not that they wont have it i would call a dealer,,,some parts are still available,,,like the insulation blanket for my 73, i got the thrust washer from d&m corvette in downers grove ill...also found a nos a/c bracket at a dealer in wheaton ill,,been sittin around on a shelf,,,also check the catalogs like corvette central gotta be in there

Mar 19, 2006 | 08:34 PM

c69vete

Drifting

Joined: Jul 2004

Posts: 1,695

Likes: 64

From: Kissimmee fl

Finalist 2021 C3 of the Year - Modified

2017 C3 of Year Finalist

Cruise-In VIII Veteran

St. Jude Donor '07

tach

I think that 76 has an electrical tach not a mechanical tach as talked about above. You will not have the gears that he is talking about. as far as what could be causing your problem,

Mar 19, 2006 | 08:36 PM

carl a

Safety Car

Joined: Jun 2002

Posts: 4,135

Likes: 1

Quote:

Originally Posted by c69vete

I think that 76 has an electrical tach not a mechanical tach as talked about above. You will not have the gears that he is talking about. as far as what could be causing your problem,

if its is sorry i didnt think they changed over till 77..

Mar 19, 2006 | 08:57 PM

70ZZ3 96LT4

Burning Brakes

Joined: Oct 2001

Posts: 911

Likes: 5

From: TN

tach jumping

1975 was the first year for the electronic tacks. The filter and electronics are now available to repair the electronic tacks. GM does not have the parts.