The Tach of my 58' Corvette always shows approx.the double RPM of the
electronic tester,
I have changed to an other/new one,it is the same. How can I fix it?
Thank you for any information
Hotchrome Austria/Europe
Eugene Blanchard - 21 Jul 2006 05:41 GMT
I thought that the 58 Vette tach was distributer drive not electric? Now it
is interesting that the tach shows 2x the rpm of the tester. The tach drive
is connected to the distributer which is connected to the camshaft which is
driven at 1/2 the speed of the crankshaft rpm...... So the tach will show
twice the speed of the distributer/crankshaft.
Here's my website that shows you how to verify your electric tach using a
battrey charger:
http://www.cadvision.com/blanchas/54pontiac/tach.html
> The Tach of my 58' Corvette always shows approx.the double RPM of the
> electronic tester,
> I have changed to an other/new one,it is the same. How can I fix it?
> Thank you for any information
> Hotchrome Austria/Europe
Barking Rats - 21 Jul 2006 08:04 GMT
> I thought that the 58 Vette tach was distributer drive not electric? Now it
> is interesting that the tach shows 2x the rpm of the tester. The tach drive
[quoted text clipped - 6 lines]
>
> http://www.cadvision.com/blanchas/54pontiac/tach.html
Well, no, Eugene. The factory '58 tach runs off the generator - it bolts
to the rear of the housing with the cable running from there to the
dash. *IF* hotchrome still has the original, then perhaps someone
substituted pulley diameters somewhere in the "fan" belt setup and
that's why it shows double speed.
Here's waving to ya - \||||
Owen
___
'67BB & '72BB
-- not affiliated with JLA forum in any way -- alt.autos.corvette is
original posting --
___
"To know the world intimately is the beginning of caring."
-- Ann Hayman Zwinger
Eugene Blanchard - 22 Jul 2006 04:45 GMT
> Well, no, Eugene. The factory '58 tach runs off the generator - it bolts
> to the rear of the housing with the cable running from there to the
[quoted text clipped - 3 lines]
>
> Here's waving to ya - \||||
Well isn't that the dumbest thing I've heard yet. A generator drive tach..
Barking Rats - 22 Jul 2006 07:41 GMT
> Well isn't that the dumbest thing I've heard yet. A generator drive tach..
Strange but True.
Perhaps it was a gimmicky thing in the beginning - made it more sports
car for the image crowd like but saved money. Does anyone know if other
GM vehicles of that era used a direct engine connected tach? Maybe it
was not engineered as distributor driven yet.
"Who Knows?"
-Donald Rumsfeld
Here's waving to ya - \||||
Owen
___
'67BB & '72BB
-- not affiliated with JLA forum in any way -- alt.autos.corvette is
original posting --
___
"To know the world intimately is the beginning of caring."
-- Ann Hayman Zwinger
Dad - 22 Jul 2006 17:33 GMT
>> Well, no, Eugene. The factory '58 tach runs off the generator - it bolts
>> to the rear of the housing with the cable running from there to the
[quoted text clipped - 5 lines]
>
> Well isn't that the dumbest thing I've heard yet. A generator drive tach..
And the correct way to do that in 1958 was?

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Eugene Blanchard - 23 Jul 2006 04:24 GMT
>>> Well, no, Eugene. The factory '58 tach runs off the generator - it bolts
>>> to the rear of the housing with the cable running from there to the
[quoted text clipped - 8 lines]
>
> And the correct way to do that in 1958 was?
Maybe the correct way for Chevies but the rest of the world didn't do it
that way.. btw I was waiting for someone to get their shackles up over my
comment...
Dad - 23 Jul 2006 05:22 GMT
>>> Well isn't that the dumbest thing I've heard yet. A generator drive
>>> tach..
[quoted text clipped - 4 lines]
> that way.. btw I was waiting for someone to get their shackles up over my
> comment...
Doesn't bother me, just wanted to know the right way that it should have been
done. So by what you're saying you don't know the right way. Don't believe that
there were very many cars with tachometers back then to compare it to.
By the way, isn't it "hackles" and not "shackles", or is that the right way
where you come from?

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Dad
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Eugene Blanchard - 23 Jul 2006 18:46 GMT
Hackles is right - its just me screwing up another phrase again...
I did a search on tach drive generators and found they are used quite often
in airplane engines - quite surprising. I guess I should of used "unusual"
instead of "dumbest"
>>>> Well isn't that the dumbest thing I've heard yet. A generator drive
>>>> tach..
[quoted text clipped - 12 lines]
> By the way, isn't it "hackles" and not "shackles", or is that the right
> way where you come from?
Dad - 23 Jul 2006 20:16 GMT
> Hackles is right - its just me screwing up another phrase again...
>
> I did a search on tach drive generators and found they are used quite often
> in airplane engines - quite surprising. I guess I should of used "unusual"
> instead of "dumbest"
Actually it was an easy way to use the current technology, and parts available
to slap together a cheap tach for the Corvette just as it was to use the
standard sedan chassis. GMs way of leading the field of automotive advancement.
Eugene Blanchard - 24 Jul 2006 08:09 GMT
>> Hackles is right - its just me screwing up another phrase again...
>>
[quoted text clipped - 6 lines]
> use the standard sedan chassis. GMs way of leading the field of automotive
> advancement.
I did a lot of measuring of the standard Chevy kingpin suspension while
machining my own replacement balljoint suspension (lots of work) and was
very surprised to find that the kingpin suspension was a horrible design
concerning bumpsteer. Here's my webpage on my measurements:
http://www.cadvision.com/blanchas/54pontiac/rnp.html
hotchrome - 21 Jul 2006 13:30 GMT
My Tach is generator mounted,not distributor.
Thank you, Hotchrome
hotchrome schrieb:
> The Tach of my 58' Corvette always shows approx.the double RPM of the
> electronic tester,
> I have changed to an other/new one,it is the same. How can I fix it?
> Thank you for any information
> Hotchrome Austria/Europe
hotchrome - 21 Jul 2006 13:49 GMT
The lower and upper pulley are 17cm diam.,generator pulley is 9,3cm
(3-5/8'') diam.,
the bigger one of the two originals 58' pulleys,the two generator
transm.wheels are
new but original diam. 58' Vettes had generator and distributor
tachs,on the tach
magnetic gear(inside tach housing) there is a number ,,2'' , double
rotation???
Thanks to all, Hotchrome/Austria
hotchrome schrieb:
> The Tach of my 58' Corvette always shows approx.the double RPM of the
> electronic tester,
> I have changed to an other/new one,it is the same. How can I fix it?
> Thank you for any information
> Hotchrome Austria/Europe