IVR for 6v - 12v conversion

Park_W

This for those of you who have my 6 to 12 conversion notes. I recently learned, via Forum member Richard Dryman, that in my tech notes the suggested Instrument voltage regulator (IVR) from Dennis Carpenter Ford Parts, has at some point been replaced with a different item with the same part number, and that part doesn't work for our Hudson conversions. So here's what does work:
Dennis Carpenter part nr. B9MZ-10804-C. Price is $19.95 plus shipping. Listed for Fords for '57 and several years beyond. The unit looks almost identical to the one I've run in my Hornet for several years. I have just completed testing this unit compared to my proven accurate one, and the readings are the same.

NAPA stopped carrying a replacement Ford unit many years ago, but you may find this one or a like item from other parts stores, by asking for the IVR for '57 and later Fords. (Yes, I know Ford went to 12v in '56, but they used a different solution that first year).

Park_W

Ken, when I did my conversion my original one worked fine too.  Except that the gauges read about I/4 of the scale too high.  So I installed an appropriate 12v version which got the gauges back to reading accurately.

DavidC

Experienced this problem on my 53HH after putting it on the road.  Temp gauge red 'HOT' while my underhood temp gauge read 165-174 on several outings.  Temp has never been above 174, car idling on 90+ day in VA.  Was planning on trying to find an appropriate resistor but now I don't have to!  Thanks guys for discovering this part change.  Clearly I got the new incorrect version from Dennis Carpenter.

With a quick 'net search I see the appropriate IVR was used in 57-72 Fords, so there should be no problem getting a replacement- they are all over the place.

Hudsonly,

Dave

RichardD

Dave, the D-10800 can be used as a normal solid state voltage reducer 12VDC>>6VDC.  The instruction says to insert a 5 amp fuse so perhaps that is ampacity.

DavidC

Thanks!  Will just replace the IVR

ShaneStone1964

Park,

I believe everything except the radio and clock was changed over to 12V during a previous restoration of our Hornet. Both the clock and radio were simply left disconnected. I'd love to get the clock running again. The radio would be great, but I'd be shocked if it worked after 63 years.    Would one IVR be sufficient to run both the clock and radio, or would one be required for each instrument?

Thanks in advance.

shane

Park_W

Shane . . . the IVR stands for instrument voltage regulator, and it's just for the fuel and temp gauges.  It puts out a steady 5v, which is what those gauges operate on.  So it's not suitable for other applications.  The good news is that for the clock, you needn't worry about the 12v, as the very quick pulse of voltage every couple of minutes is so brief that it's not going to hurt the clock.  This told to me by a couple of the good clock restoring shops.  I agree with you on the radio.  Get a modern one, mount it under the dash or in the glove box.  There might even be one that fits in the Hudson dash!

ShaneStone1964

Thanks, Park! I appreciate your wealth of knowledge and your willingness to share it.

I did not see anything resembling an IVR when I disconnected the gauges. As I said earlier, the car had been updated to a 12V before we got it. I do know that the temp and fuel gauge appeared to be working before the ignition problem popped up that prompted this re-wire. I haven't removed any of the existing wiring as yet. I'll double check the dash area once I get started again this weekend. Would the gauges have been working on straight 12V, but reading incorrectly if there isn't an IVR in the dash? The gauges look to be original.

ShaneStone1964

Thank you, Ken! I'll take a much closer look soon.

Park_W

Shane, the gauges will work on 12v of course, but some close bench-testing when I did my conversion showed that the gauges indicated about 25% high on 14v (what the alternator will be putting out) using the original IVR.  Others have seen very little difference.  The one thing we know is that they show pretty accurate with the Carpenter IVR.

ShaneStone1964

Thanks, Park. I'm feeling my way along. Your advice is invaluable.

HudsonBob

vintagecarradio.comI just got a 1953 Hudson radio that doesnt work.  I checked eBay but was unable to locate one.  Does anyone know where they sell them? Thanks in advance.

Park_W

Suggest you send it to Steve Engel in CA for repair and upgrade of power supply, etc.  Excellent work on Hudson radios.

Engel Bros. Auto Radio

17355 Jackson Ave.

Fontana, CA 92336

(909) 543-6078