11-10-2008, 08:22 PM | #1 |
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HEI and A factory tac
Has any one had a issue with installing a factory tac with a HEI distributor?
I installed a used one and at idle everything reads ok. But as the RPMs go up the error gets larger. I know this because I had a autometer tac and it wiorked fine. Somewhere I think read that there may be a issue with using a hei distributer on a factory tac. The bottom line is should just go and buy a new tac or would I just be wasting my money? Lastly the adjustment pot on the back of the factory tac can that be used to calberate it. Thanks
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11-10-2008, 08:40 PM | #2 |
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Re: HEI and A factory tac
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I just put one in a '72 GMC with HEI, no problems on it.... I don't think you can get a lot of adjustment out of the pot. maybe someone else will have some other ideas for you. Oh, and . LockDoc
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Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 - Last edited by LockDoc; 11-10-2008 at 08:40 PM. |
11-10-2008, 08:41 PM | #3 |
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Re: HEI and A factory tac
I am running HEI with a factory tach, no problems so far, and it has been several years now.
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11-10-2008, 08:42 PM | #4 |
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Re: HEI and A factory tac
Mine works just fine also---no issues
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11-10-2008, 08:54 PM | #5 |
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Re: HEI and A factory tac
We have several tachs with HEI and they have worked well for years.
Jim
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11-10-2008, 11:19 PM | #6 |
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Re: HEI and A factory tac
You may have some bad resisitors on your Tach, they are 36+ yrs old and they do go out.
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11-11-2008, 10:39 AM | #7 |
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Re: HEI and A factory tac
Are you positive you have the correct tach for the engine, V8 and 6 cylinder tachs, are different.
Shawn
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11-11-2008, 06:14 PM | #8 |
its all about the +6 inches
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Re: HEI and A factory tac
lets not forget, these tachs were not real acurate 40 years ago...
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11-12-2008, 07:48 AM | #9 |
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Re: HEI and A factory tac
And they have gotten a lot worse over the years. I have heard that it is the capacitors that drift over time.
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11-12-2008, 09:40 AM | #10 |
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Re: HEI and A factory tac
Mine works just fine also.
But take jorgensensc advice and check the stamp on the back to see if it's the right one.
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Nigel. An American living in a British body. 1971 Chevy Cheyenne 10 454 "In a time of universal deceit, telling the truth becomes a revolutionary act." - George Orwell "When injustice becomes law, resistance becomes duty" - Thomas Jefferson No more pain. 03.12.60 -- 12.28.10 http://www.youtube.com/Eightbanger Last edited by eightbanger; 11-12-2008 at 03:49 PM. |
11-12-2008, 11:43 AM | #11 |
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Re: HEI and A factory tac
Dang Longhorn, you get the credit for everything!
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11-12-2008, 03:54 PM | #12 |
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Re: HEI and A factory tac
It's the names they're just so similar...jorgensensc, Longhorn Man
I'm sorry jorgensensc, it's been a long hard week.
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Nigel. An American living in a British body. 1971 Chevy Cheyenne 10 454 "In a time of universal deceit, telling the truth becomes a revolutionary act." - George Orwell "When injustice becomes law, resistance becomes duty" - Thomas Jefferson No more pain. 03.12.60 -- 12.28.10 http://www.youtube.com/Eightbanger |
11-12-2008, 04:21 PM | #13 |
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Re: HEI and A factory tac
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11-12-2008, 04:58 PM | #14 |
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Re: HEI and A factory tac
Just to clarify, I had to edit my first post as I credited Andy for sugesting he check to see if it were the correct Tach. When it was jorgensensc.
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Nigel. An American living in a British body. 1971 Chevy Cheyenne 10 454 "In a time of universal deceit, telling the truth becomes a revolutionary act." - George Orwell "When injustice becomes law, resistance becomes duty" - Thomas Jefferson No more pain. 03.12.60 -- 12.28.10 http://www.youtube.com/Eightbanger |
11-12-2008, 05:07 PM | #15 |
its all about the +6 inches
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Re: HEI and A factory tac
LOL!
A LOT of the info that I have, came from THIS board. |
11-12-2008, 06:38 PM | #16 |
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Re: HEI and A factory tac
Oh Geez!! I meant it as a joke, and now you guys have made me feel like a real a$$! And to think, I wasa on here with Longhorn Man when he was just a wee little Longhorn Boy with a mere 20k posts! Ha.
SHawn
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11-12-2008, 06:51 PM | #17 |
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Re: HEI and A factory tac
A lot of info on here does get recycled...just makes it easier to find when you need it. Everybody here contributes...just that I haven't seen anyone else with 70K posts! No offense was intended towards anybody.
Last edited by leddzepp; 11-12-2008 at 06:53 PM. |
11-12-2008, 06:57 PM | #18 |
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Re: HEI and A factory tac
None was taken! It was all a bit of a joke.
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11-12-2008, 07:03 PM | #19 |
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Re: HEI and A factory tac
The wave length of the signal is different between HEI and original ignition which the tach's were designed to work with. There are some things that can be done but---reality is that in stock form, they are far from accurate. If it is within a hundred or so rpm, consider it OK for driving purposes. You can tweek the pot on the back for closer readings, but realize when you go one way, you are flipping readings on the other end. Huck
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11-16-2008, 12:58 AM | #20 |
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Re: HEI and A factory tac
thanks all for your input I think I will be buying a new factory tac and see what happens
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