Opel Tachometer Board

[namba209]

Hi folks, I could use a little bit of help from someone that has a loose GT tach laying around. I need to know the sizes of the two mounting holes in the tach printed circuit board, and the center hole for the pointer shaft. The reason is, I have had some folks that wanted a tach board for their various engine swaps. I have the latest and greatest schematic by P. J. Hall, who spent many days getting Willit?'s board to work, and Nathan Acree has offered to get new tach boards made with the printed circuits, so that all that is needed is to solder the componenets to the board. In order to get the boards made, I need the sizes of those three holes in the boards. These schematic has been designed, as I said, by P.J. Hall and can be used on any engine swap with any configuration. ie., battery-coil, computer tach output, 4-6-8 cylinder engines, just by changing a resistor. Nathan has told me he needs a minimum of three large boards to be made, that will have multiple tach circuit boards on each one. So I also would like to see how many of you would like to have one of these tach boards that you put the components in. One other thing, these are gonna be a non-profit item, only the initial cost and shipping will be applied to the price once we find out who wants/needs one.

[tomking]

If you dont get an answer by thursday let me know and can check one of mine when I get back home.

[heimue]

If you also want to make one for the Manta, I'm in.

Dieter

[namba209]

Thanx, Tom, I misplaced the original tach board, can't find it anywhere. I sure don't want to pull the instrument panel and tach if I can help it.

Dieter, these boards are just gonna have printed circuits on them, you'd have to purchase the components and solder them to the board. Kinda DIY for those that can't use the Opel tach in their application.

[Killer Texas GT]

Mount hole Center to Needle center is 14 mm, to mount hole center 14 mm -mount to mount is 28mm, the center hole is 17 mm, the post (mount) holes are 7 mm hope that is what you need. I will go and see if I have a Manta and a Kadett torn down.

Just went and checked they are all the same, Manta, Kadett and Ascona

[namba209]

Hey, that's good news Rodney, and it is exactly what I needed. It means folks that are contemplating or doing an engine swap in those models won't be left out in the cold, so to speak. One question for you. On the circuit board I got from P.J. Hall, the nylon bushings for the mount holes kept falling out, but the flanges held them in until I turned the board over. Can the holes be made a silly milly smaller or is it possible my holes were a tad larger than 7mm? Just an eyeball guess would work here.

[Killer Texas GT]

Ron, when I took the face plate off the nylon "bushings" set on top of the board and the face plate screws when installed hold the nylon "bushings" in order to hold the board down and in place. I can get a picture of the nylon spacer for you this evening when I get in from work. The holes in the board could be made smaller as the mount dia. is 6.4 mm and the centre where the needle isolator board is measures 14.6 mm, both these measurements are tight with no room for error. Note the nylon busing flares out to 10 mm, the inside dia. of the busing is 6.89 mm the outer is 7 mm with the mount hole in the board 6.9 mm and the centre hole tight is 16.76 mm. These last set of measurements where taken using a plastic caliper, while the previous measurements where taken using a ruler. The center to center dimension are correct by both ruler and caliper. Let me know if you need a picture of the nylon spacer/"bushing".

[namba209]

Thanx Rodney, I don't need a pic of the bushings, you answered my ? about the hole diameter and the bushing OD. Mine were slotted lengthwise and I guess had lost the "spring" tension and kept slipping out of the hole. So a 7mm hole to put a slotted 10mm bushing in, works just fine. Thanx again. I'll pass the info to Nathan, so he can layout the components for the PC on the boards.