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Posted by: Dr. Roger Feb 6 2008, 11:08 PM

Looking for details on the V8 tach modification.

A "how to" and a pic would be awesome. Maybe even borderline stupendous.

=)

On a side note:
I hooked up my ancient speedo tonight and an interesting thing happened. At 15 MPH it read 30. At 60 it went to 100. Then got stuck at 30 and never moved from there. I guess it's due for a tune-up/cleaning. So in the mean time I have a 911 gauge I'll install tomorrow morning and try it out. Hookup looks exactly the same.

Still need that tach mod though.


Peace,
Roger

Posted by: jkeyzer Feb 7 2008, 01:06 AM

one way to do it:
(scroll down)
http://www.914world.com/bbs2/index.php?showtopic=49598&hl=tach++face

Posted by: brer Feb 7 2008, 02:14 AM

I have a VDO tach for an 8 cyl. if you find the need for one.
cheap.

Posted by: rick 918-S Feb 7 2008, 09:07 AM

Here ya go! Contact Mark (Marks914) He'll do what ever you like.

http://www.914world.com/bbs2/index.php?showtopic=72389&hl=

Posted by: marks914 Feb 7 2008, 12:02 PM

Send it to me, I will not only make it into a V8 tach, but it gets fully refurbished and a redline of whatever style and placement you want
only $150

Mark

http://rides.webshots.com/photo/2001892860057582025WizfCm

http://rides.webshots.com/photo/2851033840057582025XSkKDd

http://rides.webshots.com/photo/2179585910057582025xxRqQn

http://rides.webshots.com/photo/2570480490057582025wNFBAV

Posted by: Dr. Roger Feb 7 2008, 04:32 PM

Thank you all,

I am really just looking for the tach modification. If that doesn't work out I will probably be going to eitherMarks product or a creation of my own. =)

Posted by: cobra94563 Feb 7 2008, 05:35 PM

(I could use that tach mod as well, if anyone has the info.)

Right now using a autometer that fits in fine, but wouldn't mine the stock unit.

Also, if there is an adjustment screw on the speedometer anyone knows of?

Posted by: Dr. Roger Feb 7 2008, 11:26 PM

Bob B. (BIGKAT_83) is the author of this solution.

This is the newer style 914 tachometer with the single turn signal indicator light. You can calibrate this for a V8 engine by adding a 15k ohm resistor in parallel with the existing 15k ohm resistor. This then gives you enough adjustment with the pot to calibrate this for the V8. Before I put the tach back together, I wired the tachometer up with jumpers and adjusted pot with the engine running and compared to another (auto meter) tach.

The older style tachometer with the dual turn signal indicator lights has a different calibration board. There is not an adjustment pot for it. I’ve got an extra early tach in working order and the first chance I get I’m going to try to recalibrate it.


Thank you Bob!




Attached image(s)

Posted by: BRAVE_HELIOS Jul 16 2010, 10:13 AM

QUOTE(Dr. Roger @ Feb 7 2008, 11:26 PM)

Bob B. (BIGKAT_83) is the author of this solution.

This is the newer style 914 tachometer with the single turn signal indicator light. You can calibrate this for a V8 engine by adding a 15k ohm resistor in parallel with the existing 15k ohm resistor. This then gives you enough adjustment with the pot to calibrate this for the V8. Before I put the tach back together, I wired the tachometer up with jumpers and adjusted pot with the engine running and compared to another (auto meter) tach.

The older style tachometer with the dual turn signal indicator lights has a different calibration board. There is not an adjustment pot for it. I’ve got an extra early tach in working order and the first chance I get I’m going to try to recalibrate it.


Thank you Bob!

Posted by: roadster fan Jul 17 2010, 01:39 AM

the gauge you have pictured is not the later style that Dr. Roger refers to. The 1975 and 1976 tach has one indicator light for the turn signal and the needle is different. The pic below is the gauge he is using i believe. Your tach may be a transition year old style with adj. pot, but no really sure.

If you look closely the layout of the two circuit boards is different with different components.

Posted by: BRAVE_HELIOS Jul 17 2010, 08:32 AM

QUOTE(roadster fan @ Jul 17 2010, 01:39 AM)

the gauge you have pictured is not the later style that Dr. Roger refers to. The 1975 and 1976 tach has one indicator light for the turn signal and the needle is different. The pic below is the gauge he is using i believe. Your tach may be a transition year old style with adj. pot, but no really sure.

If you look closely the layout of the two circuit boards is different with different components.