Modern Rodding Tech

InTheGarageMedia.com

1. Colin and Sue Radford’s T roadster is outfitted with an art deco Diamond T instrument panel with Classic instruments Classic Series 2-5/8-inch gauges and a matching 3-3/8-inch speedometer and tachometer.

By Ron Ceridono Photography by Brian Brennan

Everything New is Old Again Typography
Everything New is Old Again
Classic Instruments’ 2-5/8-Inch Gauges Combine Vintage Style and Modern Technology
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ne of the modifications that many hot rodders in the ’40s made to the austere dashboard of an early car was the installation of an assortment of gauges. And while the common 2-1/8-inch-diameter gauges were often used, the larger 2-5/8-inch versions had much more visual impact. One practical advantage was they were easier to read, and as a result were often found in competition cars. However, the fact that they looked way cool was the real reason they were a popular choice for hot rods that spent more time on the street than the track.

Over the years trends changed and 2-5/8-inch instruments became less common. Then came the welcome resurgence of traditional build styles, and along with that came the demand for equally traditional components, such as those vintage, large-diameter dials. It seemed what the world needed was a line of 2-5/8-inch gauges with the nostalgic styling and contemporary movements, and thanks to Classic Instruments we’ve got them.

Classic Series from Classic Instruments have a vintage look with polished stainless steel bezels, curved glass lenses, crescent moon pointers, and black dial faces with white numbers and letters. On the inside these gauges have the latest air core movements for accuracy and reliability. Oil pressure, water temperature, volts, and fuel gauges are 2-5/8 inches in diameter, speedometers and tachometers are offered in 3-3/8- and 4-5/8-inch sizes, and all are available as individual instruments or as part of a five set without a tachometer or a six-gauge set that includes an 8,000-rpm tachometer. Turn signal and high-beam indicator lights are available as an upgrade option with either Halo lighting or surface-mounted indicators.

As all Classic Series instruments are electric, they require a good ground to the chassis for proper operation and all require a switched 12V source. Connecting the remaining wiring is simple, however one precaution to be observed is disconnecting the ground lead from the battery. Voltmeters do not require a sender, so all that’s necessary is a source wire and a ground and power for the internal light. The tachometer is similar, a 12V source, power for the light, and a signal from the minus side of the coil.

Both the oil pressure and temp gauges require senders, which are included with the gauges. It should be noted that Classic Instruments advises that the single-wire temperature sender has tapered threads, which are designed to be self-sealing. Using sealant may cause a poor ground, causing inaccurate readings. The three-wire transducer used with the oil pressure gauge may have sealer designated for senders applied to the threads.

All electric instruments rely on a compatible sending unit for proper operation, and that is certainly true of the fuel gauge. Classic Instruments supplies the appropriate fuel level sender in their complete kits, however in some cases a different sender may already be in place. Senders are rated by their resistance, measured in ohms, when empty and full, and Classic Instruments offers fuel gauges calibrated to work with the most common senders: 240-ohm empty, 33-ohm full (Stewart-Warner and Auto Meter); 75-ohm empty, 10-ohm full (pre-’87 Ford); 0 empty, 30-ohm full (early Chevy); and 0 ohm empty, 90-ohm full (’66 and later GM).

When it comes to speedometers, cable drives are as outdated as the leisure suit hanging in Brennan’s closet. The Classic Series electronic speedometers rely on an electrical pulse signal sender that mounts where the cable would normally attach. Using Classic Instruments’ ZST technology, these speedometers will hook directly to any ECT (electronically controlled transmission) or VSS (vehicle speed sensor) of a modern transmission. This simple arrangement uses easy-to-route wires rather than a bulky cable and eliminates the maintenance and periodic replacement that cables often require. Electronic speedometers make calibration simple—no more doing math in your head to account for an inaccurate mechanically driven speedometer when you see a police car.

While electronic speedometers are vastly superior to the cable-driven variety, another leap in technology from Classic Instruments is the SkyDrive GPS satellite system. An antenna generates a signal from GPS satellite for the speedometer, which is particularly useful when a pulse generator is impractical, or impossible, to install.

The best location for the SkyDrive antenna to guarantee a good satellite signal and trouble-free speedometer operation is inside the car where it will have a clear view of the sky. In some cases, this may not be possible, so if the antenna is hidden Classic Instruments recommends testing the SkyDrive in that location before permanently mounting it. Once a suitable mounting location is determined, the SkyDrive can be mounted using Velcro or double-sided tape.

Classic Instruments Classic Series gauges have combined today’s technology for reliable and accurate performance with the traditional look of a bygone era. Nostalgia just doesn’t get any better.

Tate Radford installs the Classic Series electronic speedometer, a process simplified by the elimination of a bulky mechanical drive cable.
2. Tate Radford installs the Classic Series electronic speedometer, a process simplified by the elimination of a bulky mechanical drive cable.
The Classic Series instruments are available in a six-gauge set (shown), five gauges without the tachometer, or individually.
3. The Classic Series instruments are available in a six-gauge set (shown), five gauges without the tachometer, or individually.
This is the workings of a vintage mechanical pressure gauge. The curved brass tube (arrow) straightens when pressure is applied and moves the dial.
4. This is the workings of a vintage mechanical pressure gauge. The curved brass tube (arrow) straightens when pressure is applied and moves the dial.
By comparison, this is state-of-the-art Classic Instruments air core movement found in the Classic Series gauges. These rugged electronic components are reliable and accurate.
5. By comparison, this is state-of-the-art Classic Instruments air core movement found in the Classic Series gauges. These rugged electronic components are reliable and accurate.
Air core movements are unique in that they make it possible for an electric gauge to have a full sweep needle movement of 270 degrees.
6. Air core movements are unique in that they make it possible for an electric gauge to have a full sweep needle movement of 270 degrees.
Although it’s difficult to tell in this photo, Classic Series gauges have vintage-style curved lenses.
7. Although it’s difficult to tell in this photo, Classic Series gauges have vintage-style curved lenses.
Supplied with the Classic Series electronic speedometer is an SN16 pulse generator and cable.
8. Supplied with the Classic Series electronic speedometer is an SN16 pulse generator and cable.
The Classic Series electronic distributor and the SkyDrive GPS antenna are a high-tech combination with vintage appeal.
9. The Classic Series electronic distributor and the SkyDrive GPS antenna are a high-tech combination with vintage appeal.
On the end of the SkyDrive antenna is a status indicator.
10. On the end of the SkyDrive antenna is a status indicator. The status LED will be red when the SkyDrive is powered but has not acquired a satellite signal. The status LED will be green when the SkyDrive is powered and has acquired a satellite signal.
This is the oil pressure sender, or transducer. It has three contacts and does not rely on grounding to the block to operate. An approved sealer for senders may be used on the threads.
11. This is the oil pressure sender, or transducer. It has three contacts and does not rely on grounding to the block to operate. An approved sealer for senders may be used on the threads.
Gas gauges and senders must be matched for proper operation. Classic Series gas gauges are available in configurations that are compatible with popular fuel tank senders.
12. Gas gauges and senders must be matched for proper operation. Classic Series gas gauges are available in configurations that are compatible with popular fuel tank senders.
The Classic Instruments fuel tank sender is adjustable to accommodate tank depths of 6 to 15-1/2 inches.
13. The Classic Instruments fuel tank sender is adjustable to accommodate tank depths of 6 to 15-1/2 inches.
With the pivot point of the sending unit at half the tank’s depth, the float arm is adjusted so the float is approximately 1/8 inch below the bottom of the mounting bracket.
14. With the pivot point of the sending unit at half the tank’s depth, the float arm is adjusted so the float is approximately 1/8 inch below the bottom of the mounting bracket.
While the temperature gauge requires a sender, the voltmeter simply requires a switched 12V source and a ground. To prevent damage, no other electrical connections can be made to the voltmeter.
15. While the temperature gauge requires a sender, the voltmeter simply requires a switched 12V source and a ground. To prevent damage, no other electrical connections can be made to the voltmeter.
This is the Classic Series temperature gauge sender. Note the tapered threads and the single-wire connection.
16. This is the Classic Series temperature gauge sender. Note the tapered threads and the single-wire connection.
While Classic Instruments cautions against using Teflon tape on the threads of temperature senders, there are paste sealers available that do not interfere with the proper grounding of the sender. Choose carefully.
17. While Classic Instruments cautions against using Teflon tape on the threads of temperature senders, there are paste sealers available that do not interfere with the proper grounding of the sender. Choose carefully.
Colin puts the finishing touch on wiring the Classic Series gauges. One of the critical aspects for the proper operation of these instruments is a good ground to clean, bare metal.
18. Colin puts the finishing touch on wiring the Classic Series gauges. One of the critical aspects for the proper operation of these instruments is a good ground to clean, bare metal.
To simplify wiring, Classic Instruments offers a universal gauge wire harness with quick disconnect connectors. The harness has connections for up to six gauges.
19. To simplify wiring, Classic Instruments offers a universal gauge wire harness with quick disconnect connectors. The harness has connections for up to six gauges. 
Most aftermarket wiring harnesses have a keyed source on the fuse panel to power the gauges.
20. Most aftermarket wiring harnesses have a keyed source on the fuse panel to power the gauges.
When installing electronic components, such as a SkyDrive, there may be wires that aren’t used. To prevent issues, fold the end of the wire 180 degrees and slip into a section of shrink tubing.
21. When installing electronic components, such as a SkyDrive, there may be wires that aren’t used. To prevent issues, fold the end of the wire 180 degrees and slip into a section of shrink tubing.
There are several methods to heat shrink tubing, the most effective, and safest, is a heat gun.
22. There are several methods to heat shrink tubing, the most effective, and safest, is a heat gun.
Here are two unused leads that have been protected from possibly shorting out.
23. Here are two unused leads that have been protected from possibly shorting out.
Connecting Classic Series gauges is a simple matter of plug-and-play. All the wires are color-coded to simplify connections.
24. Connecting Classic Series gauges is a simple matter of plug-and-play. All the wires are color-coded to simplify connections.
A unique feature of the Classic Series is the adjustable lighting. Push buttons allow changing from the bright white light of LEDs to the softer look of incandescent bulbs.
25. A unique feature of the Classic Series is the adjustable lighting. Push buttons allow changing from the bright white light of LEDs to the softer look of incandescent bulbs.
Another cool feature are warnings that make the gauge faces turn red when oil pressure or water temperature are outside of normal readings (set points are adjustable).
26. Another cool feature are warnings that make the gauge faces turn red when oil pressure or water temperature are outside of normal readings (set points are adjustable).
Classic Instruments does offer high beam and turn signal indicators as an option. Colin opted for vintage warning lights with jeweled lenses.
27. Classic Instruments does offer high beam and turn signal indicators as an option. Colin opted for vintage warning lights with jeweled lenses.
Also available is the Classic Series 2 5/8-inch clock. It also features a stainless radial bezel, curved glass lens, and nostalgia white hands.
28. Also available is the Classic Series 2 5/8-inch clock. It also features a stainless radial bezel, curved glass lens, and nostalgia white hands.
Classic Instruments
(800) 575-0461
classicinstruments.com
Radford Auto
(208) 745-1350
Modern Rodding

VOLUME 3 • ISSUE 18 • 2022

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