Hewitt Pyro:

[Rob]

How common were these things in the 3.375" diameter style in Macks? I have one NOS in the box from the speedo shop I worked at and purchased another off of ebay to use in my 1977 R model when the V12 goes in. Mostly I've seen the 2.063 diameter gauges installed into the dashboards, but have seen a few of these also.

The larger ones will certainly be easier to view.

Rob

[Lmackattack]

Rob, I have seen alot of the larger pyro in The R models. Most of them were in the OTR trucks. I dont know what brand they were but know they were larger than the standard ???? 2 1/8" ???? gauges. Think there is one of the larger ones in one of the junk Kanzker trucks?

[Rob]

Rob, I have seen alot of the larger pyro in The R models. Most of them were in the OTR trucks. I dont know what brand they were but know they were larger than the standard ???? 2 1/8" ???? gauges. Think there is one of the larger ones in one of the junk Kanzker trucks?

My 12V-71 did have 12 thermocouples installed into the exhaust manifolds, but the left side cracked back in 1989 and the replacement manifold was not drilled and tapped. Shortly after the replacement, the maintenance proceedures changed and we no longer had to monitor each cylinders' temperature so they were never reinstalled. I still have the rotary switch and meter panel for selection of each cylinder. I was thinking of incorporating this setup into the dash of the truck using the larger pyrometer.

Rob