0Willcox Corvette

Ron.. is it necessary.. In IMHO, no...

The function of the filter is to knock off the edge of the square signal before it hits the board chip. It will also prevent spikes from knocking out the board. But.. the chip (on both the original and repro boards) is capable of reading both squared and rounded signal so it's not necessary and there are plenty of people out there using it without a filter.

Spike insurance, maybe.. but a must.. no..

Willcox

Factor

Thanks Wilcox! Great info!

Do you reommend owners replace the board if the dash is completely out if they had only a few issues? or do you chalk it up to bad/dirty connections?

BTW, are the tach needles for the 75-77 the same as 68-74?
(i have one from a 69 was thinking of using on my 76 elect)

Thanks!
Ron

0Willcox Corvette

Another good questions.... for us, it's not that big of a deal to pull the drivers side pad.
Corvette Left Hand Dash Pad Removal Made Easy 1968-1977

But.. for us it's a job we've done over and over and over.

For the average customer it's not that easy and pulling the tach back out is a real pita.... I would surely test the tach before installing it in the car new board or not, and it's very easy to do. With the tach in hand, run power and ground to it from the car and then run a jumper wire to the distributor for signal. You can then start the car and see if it's working. I'm in the shop right now and our guy that does this job say's the hardest part is going back together and keeping the bulbs plugged in. The main harness is huge behind that dash pad and he said it will in most cases knock a socket out going back in.

In todays world.. I would also take a picture with your cell phone of the back of the cluster because once you are putting the pad in place it's hard to remember which bulb goes where. The back of the metal gauge housings are all marked which color goes where.

Factor

AWESOME info Wilcox!!!

Lastly!...are the tach needles the same for 68-74 and 75-77?
(since the later did not have removable faces, wondering if they are the same needle)

thankS!!!

Ron

EasyEd

Filter "prevents spikes from knocking out the board". That seems to me to make it a necessity. I sure don't want to have to remove the lower dash pad again any time soon to re-board the tach. For the few bucks it costs, I'm putting it in.
Found one at Volvetts that has the brown wire and they have the connectors, both male and female to hook into the tach and tach wire on my '75. (Sorry Willcox, we talked about that.)
Ed

Factor

Thanks Easy Ed!

R

resdoggie

FWIW, I upgraded my original HEI with the MSD super HEI upgrade kit. It has a rev limiter. When you turn the ignition to the 'on' position, the tach needle will sweep to the rev limit value you set. I couldn't get this feature to work until I removed the tach filter. The tach works as it always has.

Factor

resdoggie! HOLY COW! YES. I am upgrading mine to HEI with MSD ready-to-run pro billet kit with the built in rev limiter!

That solves that...no tach filter.

thanks all!