Diesel Gauges for the F250

Anyone who’s messed with a mechanically injected diesel knows that things melt quickly if the wick is turned up without additional monitoring. The defueling that a modern engine management system will initiate when temps get too high is done in a purely mechanical environment with a lifting of the right foot.

Unfortunately, there typically isn’t much room to install extra gauges, and this necessitates jamming them under the dash, on the pillar, on top of the dash, or a homely combination of the three that causes the driver’s compartment to take on the appearance of the cockpit of a wrecked DC-9.

“No, officer, nothing to drink. Was just looking for my oil pressure reading when I hit that parked car.”

Good news here is that the aftermarket for 73-79 Ford truck interior retrofits has perked up in the last couple years. The instrument cluster can be replaced with units that house aftermarket Auto Meter or similar gauges. LMC and Classic Dash are two places that sell them. While I love the look of the round gauges in the previous generation, their look in this model doesn’t work. Dakota Digital has the nicest match with the original styling, and were I amenable to spending the money, I’d seriously consider that route. But the goal here is just to add enough additional gauges to monitor the Cummins for as little as possible, especially since I already have 2 of the 3 gauges from a previous project.

The three gauges are: mechanical oil pressure, pyrometer, and boost. A tachometer would be nice, but it’s an old 4-banger Cummins. When your fillings fall out, shift. A pyrometer is a must for pulling any load and becomes even more important with performance upgrades. Check both boxes here. We’re turning the fuel up to match the upgraded turbo and intercooler and towing a travel trailer when we’re done.

Now for placement. I never liked hunting for gauges in the standard retrofit place, which is hanging under the dash. As it happens, this model truck has the radio located close to the driver, rather than in the center of the cockpit, in a pocket right next to the instrument cluster. The current resident was a cool looking but completely useless original Philco AM radio. While I’d been hoping to get by without modifying the dash bezel or anything else, this was clearly the solution even though I’d have to cut the radio cover out. This was made all the more appealing by the fact that our Lord and Savior Gale Banks has introduced a standard 2 1/16 size gauge that is selectable and programmable If 3 gauges turn out to be too few, 1 or 2 of these will give all the information I could ever want by just swapping them into this setup.

So, off with the dash bezel. Unfortunately the video of the process didn’t save due to camera malfunction, but the nice thing about these cheap plastic bezels is that it really is as easy as a few files, a scuff pad and a metal sawzall blade for hand cutting:

Out with the AM radio, right, and in with the gauges, left. The bracket is used to hold the radio and the heater controls above it, and simply needed some notching to accommodate the left and right side gauges.

Gauge backing plate: The one other piece needed for this is a piece of sheet metal to hold the gauges. Use a thicker than standard 18 gauge, as the sides near the holes bends quite easily due to lack of material. Find the center of the space in the bezel, not the sheet metal, as things are not quite centered, and mark the corresponding spot on the sheet metal. That will be the middle gauge. Then find the outside edges that the 2 outer gauges will form. Then measure 1 1/16″ in from there to get the centers of the 2 outer gauges, since we’re drilling 2 1/8″ holes, and have at it with your 2 1/8 hole saw.

Bezel: Anyone who has worked on old American cars is familiar with the oversize 2-knob radio chassis that necessitates cutting to replace with anything other than an oversize, 2-knob radio. I’d never come out of this exercise looking like I used anything other than a rabid pit bull to do the cutting, but I seem to have made progress with this attempt. Here’s how:

  1. Ditched any power tools, even a Dremel. I grabbed a metal cutting sawzall blade to cut the big pieces of the bezel that blocked the gauges.
  2. Like with woodworking, cut proud and sanded or file down to target shape. The bigger file was for the long edges, and the smaller was for corners. Next time, I’d even add a finer file than the ones in the picture to slow down as I closed in on the final shape
After cut, before filing.
After. Not perfect, but won’t jump out, either. A small sanding block will finish this, but I’m not worried about it here given the use of the truck and the overall condition of the bezel.
Loosely mocked up, ready for wiring and installation.

The sheet metal backing plate is coated with Dupli-Color aerosol bed liner. Not sure how it works in an actual truck bed, but I’ve had great results spraying an entire dash to get rid of that cheap looking fake leather texture. Here, it camouflages imperfections in the hand-cut hole in the bezel.

Now the biggest challenge is not knocking it off the bench in the 2 or so weeks before I can get it back to the truck, which is stored elsewhere. Meanwhile, there’s a big section of exhaust to tend to next.

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