3 3/8" (85mm) tach in 4" housing

[260Alpine]

This is how I adapted a 3 3/8" (85mm) tach to fit a 4" housing. If you use a black rim tach it would be less noticeable. I think it looks good though. Might do a cheap GPS speedometer the same way.

 

[Tom H]

Jim, just to be sure I understand, I assume you mechanically anchored the smaller case inside the larger one and used the foam tape to fill the gap between the two circumferences. Or is the foam tape THE anchor? Looks quite nice. I do not see the foam in the photo, so again, I assume there is almost zero gap between the two chrome rings, but enough that you want to seal that gap, right?

Tom

 

[260Alpine]

Tom, the foam strip is wrapped right under the chrome rim of the tach. Tight fit. The chrome rim sits a little bit on the larger chrome rim. I cut the mounting studs off the back of the tach to push down enough to fit flush.

 

[260Alpine]

Got the matching GPS speedo mounted. Had to drill a hole for the coax cable in the back. Also, using the existing bulb feature is red LED. I'll carefully use a hole saw to use the existing bulb in the 4" can.

 

[Mikeflbmer]

I am in process of doing similar as my t5 will not hook up to speedo cable

 

[olson1950]

Anyone know if the electronic series 5 tach can be modified to switch to a 6 cylinder? Otherwise in the past I took a small tach out of its enclosure and glued it to the back of the bezel and put the original needle on it and fit the origin cover back on. I can't seem to find the small tach I used ~5 years ago and am looking for a similar one.I like to keep the original look and works great on my bugeye sprite.

 

[sunalp]

Anyone know if the electronic series 5 tach can be modified to switch to a 6 cylinder?

Yes it can. Contact Tom H on this forum as he does wonders for our old tachs.

 

[todd reid]

While getting a Tom H tach update is certainly a good thing, if your tach is in good working order you can do it yourself if you (or your mechanic) has access to a tach. The Series V tach is just counting firing pulses. There is an adjustment screw on the back of the tach. You will probably have to remove the tach from the case and drill an access hole if there isn't one there already. Should be about 10 o'clock if you are looking at the back of the case. Use the adjustment screw to adjust your tach to the known good one (3 pulses per revolution instead of 2 means your tach should be reading about 50% high when you start).

 

[Knightowl61]

I just put a similar GPS gauge in with extra tach, turn, and high beam. My Speedometer quit and was inaccurate when it did work (Toyota trans).
I could never see the turn signal indicators in daylight, and the tach (rebuilt with Tom H instructions) still varied a few hundred rpms intermittently.
The new unit pressed very snugly in an old tach case, and has a button for settings (odometer, tach, +).
Original tach still functions but the car is heavily modified and is showing wear from being rebuilt 14 years ago so why not a weird gauge.

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