Why won't the 12v to 6v ceramic reducers work for gauges?

[Mike B]

My '42 had one in there, but in chasing down a voltage draw, I found this reducer being the cause...anyways, searches led to to several alternatives...one led to to Speedway Motors and Runtz reducers...in Speedway's listing it said "DO NOT use ceramic reducers for gauges, only blower motors-and something else...anyway, I have another of these 12 to 6 reducers...wondering why it shouldn't be used with gauges?

Here's what Speedway said:

"Note: Never, ever use ceramic block style reducers for gauges, radios or lighting. A power surge will destroy the electronics when first turned on. Ceramic block reducers should only be used to operate 6 volt DC motors and fans on 12 volt DC."

Is this true? Or is speedway trying to sell additional items?

I know about he other options, but would like to use what I have on hand.

Thanks

[ford38v8]

The Runtz is what you want for gauges, they deliver 6v, while the ceramics will vary depending on the available voltage. You need the constant voltage for accurate gauges.

[Mike B]

I should be fairly constant with a Alternator, Ya think? Being that both Gennies I had were dead, and on a budget, I made an Alt bracket for a GM 10si earlier this week...anyways, a modern Alt should eliminate "surges"...pure accuracy of the gauges isn't a big concern to me, I just don't want to burn them out.

What you think...heck, for all I know they could be dead by now anyways...lol!

[Barry-ct]

Use the Runtz. Ford used them from 57-86 on everything. Guages were still 6 volt until 1987. They were 12 volt after 86.

[Barry-ct]

THe ceramic also generate alot of heat. You don't want that under the dash. THey are usually where they can get alot of air over them to keep them cooler. Bite the bullet and buy the Runtz. Don't get cheap where safety is involved. Hate to see your project go up in flames!

[Mike B]

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Yes, I know about the Ford gauges, seems Napa still carries the reducer via Echlin that should handle all three gauges...but have come across several posts on the HAMB and other sites (didn't search for it here) that the Runtz and Echlin parts are not of the best quality these days.

[Mike B]

Excellent point on safety...I didn't see it mentioned, but will the Runtz reducer handle all three gauges, or is one needed per?

Thanks

[51 MERC-CT]

Originally Posted by Mike B

Excellent point on safety...I didn't see it mentioned, but will the Runtz reducer handle all three gauges, or is one needed per?

Thanks

You need one Runtz for each gauge. Have been running the Napa Echlin Ford reducer on all three for the past 8 or ten years with no problems.

[Mike B]

Originally Posted by 51 MERC-CT

You need one Runtz for each gauge. Have been running the Napa Echlin Ford reducer on all three for the past 8 or ten years with no problems.

Thanks, seems like a good option there, I noticed the "NapaOnline" site doesn't list it, is it the Echlin IV1, or do I have the p/n off?

[TJ]

The part # used to be IR-1, but those numbers do change on occasion. I have had issues with the Runtz reducersand had more than one failure. I've used the Ford unit for most of my conversions. There's also a guy on e-Bay that sells an electronic reducer for the gauges and it's not a bad price. He has been selling them for awhile and he has good feedback.

[joe plumber]

From what I read,the ceramic reducer will not handle the power surge when the power is turned on ,the power surge will destroy the electronics of the gauges.Transistorized reducers will handle the power surge.

[Ross F-1]

Hard to imagine what "power surge" there is going to be to stock gauges that draw less than an amp each??

I used a NAPA IR-1 for a couple of years, but I could watch the gauges cycle up and down under steady conditions as the thermal element pulsed. Their newer ones seem to have been cheapened up considerably. So I bought one of these, and it is excellent:

http://www.ebay.com/itm/Ford-Instrum...item4175acd131

[41ford1]

The ceramic resistor, about 1 ohm, provides an equal voltage drop for a motor. 6 volts with about 10 amps current flow. Each gauge uses something less than 1 amp. With a ceramic the gauges are powered with about 9 volts. A 7806 3pin regulator wired to each gauge will provide a constant 6 volts from the 12 volt source.

This link is very informative: http://www.studebaker-info.org/tech/6-12V/6-12-6.html

[Mike B]

Thanks, have decided on the regulator route (very similar to the stude link) I hope my gauges are still okay, truck was converted to 12v before I acquired it and gauges run through a ceramic drop...so hoping all is well with them...seesm like 15 bucks and a bit of time (via RadioShack) will be the way I go...I'd called my two local Auto wreckers, they won't let me pull the Ford part from the gauges they have...I can understand that..., I've several chunks of AL here, so easy to make a heat sink...besides, the gauges can draw too much power (I'd think) to worry about mounting it out side the cab?

Thanks for all the input gents!!

[joe plumber]

Thus the ceramic reducers ,when used on a12volt system ,provide more volts than the gauges ,that we're designed for a 6 volt system can handle ,therefore damaging the gauges caused by an increase or surge in power.

[41ford1]

If you wire up a 7806 with the two filter caps on each gauge you will not need a heat sink. this is what a $15 to $20 Runtz is. Your "Radioshack" cost will be around $20 to do all 4 gauges.

[Mike B]

Just have the 3 gauges...but as mentioned before I'd have to use a Runtz "per gauge", I'll still sink them to dissipate heat from the regulator and have something to mount it all on...I hate dangling stuff

Edit:

I think what you were saying is like I was thinking, much more cost effective to make it myself.

[Mike B]

Originally Posted by joe plumber

Thus the ceramic reducers ,when used on a12volt system ,provide more volts than the gauges ,that we're designed for a 6 volt system can handle ,therefore damaging the gauges caused by an increase or surge in power.

I just hope mine are okay...no idea how long it was run with the 12-6v drop it had...hopefully it'll be fine.

[41ford1]

Originally Posted by Mike B

Just have the 3 gauges...but as mentioned before I'd have to use a Runtz "per gauge", I'll still sink them to dissipate heat from the regulator and have something to mount it all on...I hate dangling stuff

Edit:

I think what you were saying is like I was thinking, much more cost effective to make it myself.

Nothing will dangle. The tab with the hole is ground. Just mount the regulator to the instrument case with a gauge mounting screw. 12 v to the in pin and 6v from the out pin to the Gauge power lug. Solder one filter cap from the in to ground pin and one from the out pin to ground pin. Electrically insulate these connections and you are good to go.

[deucemac]

Originally Posted by Barry-ct

Use the Runtz. Ford used them from 57-86 on everything. Guages were still 6 volt until 1987. They were 12 volt after 86.

Ford NEVER used Runtz reducers. Ford used their own IVR/CVR (instrument voltage regulator) which supplied a pulsed 6v feed to all three gauges. It wires in series to the gauges and is trouble free. Millions of cars and truck can't be wrong. Napa and various old Ford parts houses sell them. Just make sure you get one that fits a 1959 Ford because it has spade terminals as opposed to later ones that had "snap" connections for a printed circuit system.