Can someone dumb it way down?
Thread Starter
Pro
Joined: Apr 2012
Posts: 526
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From: Maine
Can someone dumb it way down?
I have a 74 convertible 350 automatic.
The former owner changed from points to electronic ignition when he did the tachometer stopped working. He thought the cable needed to be changed but never bothered since it was an automatic. I’ve read here that isn’t the case, I don’t want to go back to points so how do I get the tach to work?
Thanks in advance.
The former owner changed from points to electronic ignition when he did the tachometer stopped working. He thought the cable needed to be changed but never bothered since it was an automatic. I’ve read here that isn’t the case, I don’t want to go back to points so how do I get the tach to work?
Thanks in advance.
Race Director
Joined: Jul 2001
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Whether you have an automatic or 4 speed transmission is irrelevant. The stock distributor has a cable drive that operates the tachometer. If the cable is broken or left unattached, obviously it won't work. If the previous owner swapped the complete distributor assembly with one that has no cable drive mechanism, you're out of luck.
Drifting
Joined: Dec 2004
Posts: 1,714
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From: Austin Texas
I have a 74 and converted to HEI. I sent my tach to Roger at http://www.corvetteclocks.com/ He converted it to electric.
Pro
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Tech Contributor
Joined: Aug 1999
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From: At my Bar drinking and wrenching in Lafayette Colorado
Whether you have an automatic or 4 speed transmission is irrelevant. The stock distributor has a cable drive that operates the tachometer. If the cable is broken or left unattached, obviously it won't work. If the previous owner swapped the complete distributor assembly with one that has no cable drive mechanism, you're out of luck.
That's the correct answer. It doesn't matter if he swapped the internals with electronic internals - the cable drive remains unchanged. If your tach isn't working, it's because:- The cable is broken or not hooked up
- The crossgear is stripped out
- the entire distributor has been swapped with a non-tach drive distributor.
Thread Starter
Pro
Joined: Apr 2012
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From: Maine
I found the old post about the tachometer problem Mike Ward you posted on that thread:
"You'll first have to choose whether you want a mechanical tach with mechanical distributor (original equipment for your '73(same with 74 I've been told)) or convert to an electronic tach with electronic distributor like on a '75. Can't have a mix of the two. The points conversion thingmys won't help one way or the other."
The last owner told me he changed to an electronic ignition and at the sametime the tach stopped so if I read what you posted right a 1974 mechanical tach won't work??
"You'll first have to choose whether you want a mechanical tach with mechanical distributor (original equipment for your '73(same with 74 I've been told)) or convert to an electronic tach with electronic distributor like on a '75. Can't have a mix of the two. The points conversion thingmys won't help one way or the other."
The last owner told me he changed to an electronic ignition and at the sametime the tach stopped so if I read what you posted right a 1974 mechanical tach won't work??
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Le Mans Master
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not to flog a dead horse, but, thats where a pic of yours would come in handy, you dont seem to know which version you have, there's more than one and less than 100 versions, if its been converted with a kit internally on your original dist. you may only need the cable or a drive piece. If it was converted to a aftermarket dist. you'll need something else. without actually knowing what you have all these are is educated guesses
Race Director
Joined: Jul 2001
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I found the old post about the tachometer problem Mike Ward you posted on that thread:
"You'll first have to choose whether you want a mechanical tach with mechanical distributor (original equipment for your '73(same with 74 I've been told)) or convert to an electronic tach with electronic distributor like on a '75. Can't have a mix of the two. The points conversion thingmys won't help one way or the other."
The last owner told me he changed to an electronic ignition and at the sametime the tach stopped so if I read what you posted right a 1974 mechanical tach won't work??
"You'll first have to choose whether you want a mechanical tach with mechanical distributor (original equipment for your '73(same with 74 I've been told)) or convert to an electronic tach with electronic distributor like on a '75. Can't have a mix of the two. The points conversion thingmys won't help one way or the other."
The last owner told me he changed to an electronic ignition and at the sametime the tach stopped so if I read what you posted right a 1974 mechanical tach won't work??
Team Owner
Joined: Aug 1999
Posts: 30,995
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From: Ontario
I suspect that someone dropped in a GM HEI and you have no mechanical hook-up.
Last edited by Paul L; Jun 2, 2012 at 08:30 PM.
Race Director
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Thread Starter
Pro
Joined: Apr 2012
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From: Maine
Melting Slicks
Joined: Apr 2001
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From: Olmsted Falls, Ohio
Well, that does look like an external coil, so probably a points distributer. But it would have been nice to take off the distributor chrome sheild/cover so we could actually see if it had a tach cable attached.
Race Director
Joined: Jul 2001
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definitely not an HEI system- but in this pic, and not related to the tach issue, someone has inexplicably added an aftermarket ballast resistor (?)
Best thing is to remove the upper shielding cover and root around to see if the tach cable is attached to the distributor housing or not.
Thread Starter
Pro
Joined: Apr 2012
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From: Maine
I added photos.
One of the differences between me, and the former owner is I want to do it once,(or more likely have it done) and do it right. I’ve found in the past if I walk into a garage and say it doesn’t work fix it I find out later that I got hosed. So I’ll be asking a lot of stupid questions along the way.
Since the former owner lived in Florida, with no inspection needed why fix the emergency brakes its an automatic so he ripped them out. Hey its an automatic who needs a tachometer so he didn’t bother to fix it. I guess I’m lucky he took his wife for a ride now and then or I would be looking for a passenger seat.
One of the differences between me, and the former owner is I want to do it once,(or more likely have it done) and do it right. I’ve found in the past if I walk into a garage and say it doesn’t work fix it I find out later that I got hosed. So I’ll be asking a lot of stupid questions along the way.
Since the former owner lived in Florida, with no inspection needed why fix the emergency brakes its an automatic so he ripped them out. Hey its an automatic who needs a tachometer so he didn’t bother to fix it. I guess I’m lucky he took his wife for a ride now and then or I would be looking for a passenger seat.
Last edited by mxz800; Jun 3, 2012 at 12:41 PM. Reason: need to add a comment