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tach gear install

Jim B

Well-known member
Joined
Feb 26, 2006
Messages
62
Location
Illinois
Corvette
1974 L82 Grey coupe
Hey guys, Thanks for the help on my last project... Now , Need to replace a tach gear on my '74. Do I need to pull the dist. to do an install?
 

Johan

Well-known member
Joined
Feb 20, 2002
Messages
247
Location
Eksjo, Sweden
Corvette
1974 red coupe, 1969 yellow vert
Not really, but if your tach gear is shot, there is a good chance that the gear on the distributor axle is also damaged, so I would advice you to pull the distributor and check that out. (I dont remember if you need to disassemble the distributor to check the axle gear, maybe someone else knows? I think you can see the axle gear through the hole where the tach gear goes)

/Johan
 
Joined
Jan 1, 2002
Messages
7,246
Location
Washington, Michigan
Corvette
'67 Marina Blue Convertible
If the cross gear is damaged, chances are the mating mainshaft gear is too - if you just replace the cross gear, it will be toast very shortly. Pull the distributor and inspect the gear teeth very closely - if either the cross gear teeth or mainshaft gear teeth look like the photo below, it's time for a new mainshaft AND cross gear.



:beer
 

motorman

Well-known member
Joined
Mar 7, 2002
Messages
849
Location
pa
Corvette
2008 Crystal Red Tint Coat
JohnZ said:
If the cross gear is damaged, chances are the mating mainshaft gear is too - if you just replace the cross gear, it will be toast very shortly. Pull the distributor and inspect the gear teeth very closely - if either the cross gear teeth or mainshaft gear teeth look like the photo below, it's time for a new mainshaft AND cross gear.

http://img.villagephotos.com/p/2002-2/13522/TachDriveFailure.jpg

:beer
good time to shim the up and down play in the main shaft to .005/.008. this will also help prevent the gear teeth from chewing up. make sure the little shim is on the cross gear to prevent excess back and forth movement
 

bobs78

Well-known member
Joined
Jun 6, 2004
Messages
90
Location
Hot AZ
Corvette
50th AE vert - 25th SA - 54 Polo White
Johan said:
Not really, but if your tach gear is shot, there is a good chance that the gear on the distributor axle is also damaged, so I would advice you to pull the distributor and check that out. (I dont remember if you need to disassemble the distributor to check the axle gear, maybe someone else knows? I think you can see the axle gear through the hole where the tach gear goes)

/Johan

Definitely check out your tach too!

I had the same problem. I only replaced the shaft and side gear then within a month the tach froze-up totally!!! So I had to do the whole thing over again and have the tach rebuilt :mad
 

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