Tach questions
Thread Starter
Pro
Joined: Apr 2008
Posts: 681
Likes: 11
From: Carson City MI
Tach questions
Bought my 74 L-82 a couple months ago. The tach cable is hanging freely in the engine bay and the connection on the distributer was covered with grime, so obviously had not been connected in a long time. I have verified the cable and gauge are good with a drill in reverse and carried about 700 rpm. I can assume two different scenarios. 1. the gear set in the distributer is shot. 2. someone had it apart and just chose not to hook it back up. I can see that as a viable option as there is no way in hell there is enough room to connect it due to the connection directly facing the firewall and only having a couple inches of clearance. So my question is, do I rotate the distributer enough to connect it and force it back to verify whether it actually works, or buy the 90 degree adapter. And if still not working, then is it wise to upgrade to the needle bearing gear sets? And what is the difference in the stainless or bronze sets? I assume that I don't have to remove the distributer to install this gear set, correct? And lastly, what is the "button" that shows in the catalogs?
Thanks for your help.
Thanks for your help.
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,481
From: Southbound
Cruise-In II Veteran
If you correctly index the distributor, no adapters of any type are required for the tach cable.
Before going to all the trouble, you can reasonably assume the PO disconnected the tach cable because the crosshaft and mainshaft gears in the distributor are probably stripped.
Do you have the assembly instruction manual (AIM)? The AIM shows the correct orientation for the distributor based on the stake marks on the stock intake manifold and housing of the distributor.
You do not need needle bearings. You may or may not need the button. Some model years use the button, other years do not.
Before going to all the trouble, you can reasonably assume the PO disconnected the tach cable because the crosshaft and mainshaft gears in the distributor are probably stripped.
Do you have the assembly instruction manual (AIM)? The AIM shows the correct orientation for the distributor based on the stake marks on the stock intake manifold and housing of the distributor.
You do not need needle bearings. You may or may not need the button. Some model years use the button, other years do not.
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Email Lars for his distributor install papers. IT sounds like the last person that had it out didn't install it so the cable would reach. If you can get to the cable connection on the distributor as it is now, use a small screwdriver and see if you can turn the driven gear, or start the engine and see if the driven gear is turning.
If it needs help, there are several options, but pretty much all of them are a distributor rebuild with a new mainshaft and driven gear.
If it needs help, there are several options, but pretty much all of them are a distributor rebuild with a new mainshaft and driven gear.
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
The distributor is not correctly oriented. Bubba has visited your car. If the housing is correctly positioned as per GM design, no 90* adapters are required.
I'll bet that the gears have failed and Bubba made a half-*ss attempt to fix it. Replacement of the side gear and main shaft is required.
I'll bet that the gears have failed and Bubba made a half-*ss attempt to fix it. Replacement of the side gear and main shaft is required.
Thread Starter
Pro
Joined: Apr 2008
Posts: 681
Likes: 11
From: Carson City MI
If you correctly index the distributor, no adapters of any type are required for the tach cable.
Before going to all the trouble, you can reasonably assume the PO disconnected the tach cable because the crosshaft and mainshaft gears in the distributor are probably stripped.
Do you have the assembly instruction manual (AIM)? The AIM shows the correct orientation for the distributor based on the stake marks on the stock intake manifold and housing of the distributor.
You do not need needle bearings. You may or may not need the button. Some model years use the button, other years do not.
Before going to all the trouble, you can reasonably assume the PO disconnected the tach cable because the crosshaft and mainshaft gears in the distributor are probably stripped.
Do you have the assembly instruction manual (AIM)? The AIM shows the correct orientation for the distributor based on the stake marks on the stock intake manifold and housing of the distributor.
You do not need needle bearings. You may or may not need the button. Some model years use the button, other years do not.
Race Director
Joined: May 2006
Posts: 18,731
Likes: 2,582
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
Not sure if the '74 AIM has the updated positioning or not. There is a GM bulletin revising the housing orientation to reduce the stress on the cable. The vacuum canister nipple and hose should be behind the upright for the ignition shielding and not in front as per previous design.
Thread Starter
Pro
Joined: Apr 2008
Posts: 681
Likes: 11
From: Carson City MI
Thanks for your replies..
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From: New Or-leens Loo-z-anna
I was just wondering (since my project is in a similar situation) if it would help to disassemble the distributor/clean out the old grease/replace worn parts/add new grease/reassemble/drive car for 20 more years ?