So I posted some stuff on this project already - on the "shelter in place" project thread - but thought I'd summarize here.
The goal was to fabricate replicas of two of the GT factory gauges - Oil pressure and temp, and the 66mm fuel gauge. Real ones, as you may imagine are pretty rare, collectable and fetch high dollar amounts.
FUEL GAUGE
So I found an 80's 60mm VDO fuel gauge NOS on eBay - which I bought for for $32. Wrong fascia, no "empty" light - but the casing, bezel and glass form a good basis.
As you may know, the 914/6 GT cars used a black faced, chrome dot, 60mm VDO fuel gauge with an "empty" indicator. It looks way cool and is one of those collection of things that people in the know will look for as they glance into any GT cockpit, to see how far the owner/builder went in their search to be truthful to the factory cars. I've seen recreations of these listed for $1500 on eBay. Which is ridiculous.
In order to duplicate this piece from what I had, I needed to:
- change the fascia from white to black, with correct lettering / ticks
- change the black dot indicator to chrome dot
- add a second bulb assembly for the EMPTY indicator
- change the electrical working range from 0-180 ohms to the 914 sender (70-0ohms)
- paint the internal bezel ring black
pics of the process follow:
Also for reference this is the VDO part number on the core:
With the casing basically done, I drew the fascia in PowerPoint, copying the fonts, tick marks, etc. then sent a out PDF to have a vinyl sticker printed and mailed to me. Seems a little ghetto, but it came out OK:
- Tony
Love details like these. Nicely done!
OIL PRESSURE / TEMP
I purchased a 911 oil gauge from a member here on the world; nice condition and out of a Sportomatic optioned vehicle. The gauges tested functional, the only detail is that the fascia and gauge scales were incorrect for the GT version.
These items were secured from Heiler in Germany; then it becomes a simple reassembly task (no casing mods, or electronic mods like with the fuel gauge). Pictures show progress:
I needed a different sender to match the gauge, as my previous one only had the pressure switch, not the combo switch/sender. North Hollywood Speedometer were awesome in identifying the correct VDO sender and shipping it the same day. Good to go.
- Tony
I had to make up a cowling to position the fuel gauge. I went back and forth on where to mount it - the factory GTs had several options - but I decided on having it peek out of the glove box area, as it meant the least disruption to the dash and the existing switch gear / circuit breakers.
Some CAD (Cardboard Aided Design), aluminum sheet and some matching black felt covering that I had left over from when I did the dash:
- Tony
Great looking gauges Tony.
@http://www.914world.com/bbs2/index.php?showuser=9712 @http://www.914world.com/bbs2/index.php?showuser=2058
Thanks guys!
Also if anyone has questions or wants help/hints about how to work on these wonderful VDO units, feel free to ping me. For instance, I don't have any special tools to remove/replace the bezels, but I have arrived at a technique that works without excessive damage or deformation,
- Tony
How did you do the 10k RPM Tach? I'm planning on putting in an engine with an 8300 RPM redline.. eventually haha.
@http://www.914world.com/bbs2/index.php?showuser=22593 : Original thread to make your own:
http://www.914world.com/bbs2/index.php?showtopic=334521&hl=10K+tach
I've since made (and sold on) a small batch of similar ones:
http://www.914world.com/bbs2/index.php?showtopic=341379&hl=10K+tach
There was significant interest from various folks on here after I sold these; I may be tempted to do another batch at some future point. FYI.
- Tony
@http://www.914world.com/bbs2/index.php?showuser=22593 , Tony is using a Bosch / Sunpro tach as his source for the conversion. Nice thing is the Tach has a switch that allows you to select 4, 6, 8 cylinder cars. What that does mean is if yours is going to be 4 you will still want to go and test and make sure it is accurately hitting the numbers you expect on the new 10K face.
BTW, Tony great job - @http://www.914world.com/bbs2/index.php?showuser=5176 Rory, this was the gauge I was telling you about.
That's absolutely perfect. Now is just a question of gauge faces... does anyone in the US make them? Or just that german site?
I would ideally like a tach where 0 RPM starts at 6 o clock, but in the font and style of classic 914/911 gauges. And I'd probably want the red line too. Not trying to make a replica car or anything. (although if I did... it'd probably be an 11k RPM tach heheh)
Great looking parts and nice attention to detail.
Retroracer, nice work. Can you describe the circuit mods required to work with the 914 sender and also to drive the low-fuel lamp?
Tony, would you make the fuel gauge for sale? Mark
"I'm not sure what the second coil is intended to do. Maybe linearize the meter movement somehow? And in the case of the temp meters, what role does the choke have? Used as a LP filter? Why? Thermal systems already have limited bandwidth."
I have almost zero knowledge of moving coil meter design, but am thinking the secondary coil has no DC effect, but acts as a damping circuit to control the dynamics of the needle movement. In other words stops the needle "trembling" after transients. Guessing. As you say, no need for lightning fast response for things like fuel, thermal, etc.
The older VDO tachs seem to have tweaks in them to help the non-linearity, with a metal disc of which some tabs are cut and can be manually bent to be closer to / further away from a fixed magnet as the needle moves. The tachs have far more angular movement than the mini gauges though. Interestingly the Bosch tachs I use in the 10K conversions have a very different coil layering design again - and the damping is great on those movements.
- Tony
Powered by Invision Power Board (http://www.invisionboard.com)
© Invision Power Services (http://www.invisionpower.com)