How to hook up an oil pressure gauge

[Chris Belyea]

Hello all,

I've been reading how to install an pressure gauge so I can get an accurate reading of where my oil pressure is but I'm a little confused about thread sizes and where to install it on my '59 356A.

I have read that I need a fitting that has an 1/8" pipe thread, to remove the oil pressure switch and install the gauge but the threads don't seem to match. I've also read that the pressure switch screws into a 10x1 thread hex coupling. I cannot find anyone in town that has a metric fitting.

Here's how I installed the gauge. Started the car but oil leaked out around the fitting.

Am I doing something wrong here?

Thanks

Chris

[Jim Beam]

Chris-
Years ago I installed a VDO oil pressure gauge in my 1963B. At that time there was available a dual pole pressure sender which simply screwed in and replaced the stock single pole sender which operated the green idiot light. I hooked up the idiot light to one pole and the VDO gauge to the other pole. Both have been working for me for 20 years or so. Not sure from your post if you are just trying to get a one-time pressure read or install or a permanent oil pressure gauge.
Regards.
Jim Beam

[Chris Belyea]

Jim

My first objective was to hook up a pressure gauge temporally but I like what you are describing.

Is this what you installed?

http://www.egauges.com/vdo_indS.asp?Sen ... PN=360-006

Chris

[Alex Mestas]

Chris:
Here is a picture of what the sender looks like installed. It appears to be the same one that I purchased from North Hollywood Speedo for my 63 B coupe when I installed a oil pressure gauge. I installed mine in the place of the clock.

The dual wire oil pressure sender mounts on the engine. You plug the idiot wire into one side then run a new wire through the tunnel and up the wall behind the pedal boards to the gauge. It’s best to use a ground close to the new gauge.

The dual wire pressure sender fits fine but you have to watch the orientation so it doesn't interfere with the distributor.

[Jim Beam]

Chris:
Yes, that unit looks very much like the one I installed. I used the dual pole sender with one pole feeding the idiot light and the other going to the VDO gauge. Has worked great over the years. By the way, at the same time I installed a VDO oil temp gauge with the sender positioned in the oil sump plate. VDO had an angled mounting bracket which I placed below the glove box, on the lip of the dash. No modifications to the dash and it has worked fine.
Jim

[Chris Belyea]

Thanks for the info. A quick follow up question. Since I don't have a good place to install the gauge, I was thinking about tucking it away and just getting pressure readings under certain driving conditions. I still want to rely on the idiot light. If I swap out the old switch for the new sending unit, will the "green" idiot light still work properly or does the gauge need to be recalibrate?

Chris

[Phil Planck]

I installed my gauge in the rubber holder that I think VDO made, along with a spacer standoff from the steering column.

[Dave Overington]

Can't help with the oil sender stuff, but I can suggest how to cheaply fix your horn ring. Get some of that metal putty in a tube. With the horn ends held in the right place, work the metal putty into the groove at the back of the ring. Once set, all's good.

[Phil Planck]

Dave

What! You don't like my tape? Well it has been on there a while. Tell you what, I will put some fresh tape on there before driving to WCH.

[Albert Tiedemann]

chris belyea wrote:
.
>
> Here's how I installed the gauge. Started the car but oil leaked out
> around the fitting.
>
> Am I doing something wrong here?
>
> Thanks
>
> Chris
Could you post a picture of the gage installtion--that is the mounting of the gage in the engine compartment.

[Albert Tiedemann]

To Chris and all:

Metric hydraulic thread sealing relies on a tapered and straight thread interface. For the application under discussion, the Factory sending unit for the idiot light screws into a "double nut" M10 x 1mm pitch thread. At one end of the double nut, sealing is effected by a copper seal and the other end by the interference geometry caused by the tapered and straight thread. Ordinarily, the sending unit used with a gage is provided with a M10 x 1 tapered thread. Some very early genuine VDO sending units for gages with metal housings had M12 threads with a short length of tubing and fittings for remote mounting. This may have been required because early sending units were larger in diameter than they are today--much like the early oil pressure switches have a 27 mm hex and the later ones a 24mm one. Oh yes, Concours Police will nick you in the seriously judged event. Anyway, back in the early sixties I made an adapter using the housing of an old pressure switch, the 12 mm fitting that was provided and sealed the sending unit with a face o-ring design. The adapter was then just screwed into the double nut as before. This worked well for many years but there was always interference with the distributor cap at the maximum sending unit dimension. A local grind on the distributor cap solved the interference and no one seemed to mind since it was so dark down there with all the black paint that you could not see the locale modification that well. The original adapter was replaced with one that used the same principle to seal the 12mm threads since they were straight, but the adapter was made tall enough to clear the distributor and, as a seridepitous benefit, the capacitor as well for setting the initial static timing.

Today I manufacture an oil pressure standoff adapter that is a special variation of the original double nut. It seals one end as original, is the 17 mm hex as original and is plated as original. The end accepting the sending unit is a 10x 1 thread, but could be any thread to match the sending unit [most now are tapered]. It alleviates the interference problem many have cited in the past.

[Conrad Carter]

Does anyone make an adapter for 2-3/8” VDO oil pressure gauge? The straight threads on the gauge are challenge!
Conrad

[Al Zim]

A) do not cut a hole in the dash for the gauge. B) story time! Most of the cars when I started Porsche work had the oil pressure light come on at an idle. You do not need much oil pressure when the engine is at 1,000. This was single velocity 30 weight Kendall oil (1962) The customers would complain! We removed the oil pressure sender, there was a screw on the inside of the fitting that screws into the top of the tree that allows the oil movement to the filter. Thus the light came on at a lower pressure and the customer was satisfied. As far as I know none of the engines exploded because of this modification. All air cooled VW'S used a idiot light for the pressure and no temperature gauge. Probably 65 years. zim

[Hugo Karasawa]

Does anyone make an adapter for 2-3/8” VDO oil pressure gauge? The straight threads on the gauge are challenge!
Conrad

Sorry, did not understand your question.

Are you looking for an adapter to substitute the large "nut" ?

Or are you looking for something like this ?

[Jim Liberty]

I'm big on gauges, but not on idiot lights. This is my set-up on my '64 C. .........Jim.