Oil Pressure Senders?

[SailingTerrapin]

Hi all,

I have a pilothouse and currently the oil pressure sender is a single and is only active at the lower helm. I would like to upgrade this to a dual sender unit so that I can get pressure at both helms. My question is this: Are senders (and gauges) universal or are they specific to the engine? I have a perkins 4.236 and I am seeing generic units for much cheaper than perkins parts. Thanks!

[model 10]

Originally Posted by SailingTerrapin

Hi all,

I have a pilothouse and currently the oil pressure sender is a single and is only active at the lower helm. I would like to upgrade this to a dual sender unit so that I can get pressure at both helms. My question is this: Are senders (and gauges) universal or are they specific to the engine? I have a perkins 4.236 and I am seeing generic units for much cheaper than perkins parts. Thanks!

Anything will work as long as you get a kit with gage and sender. You can mix and match but you would need to do your homework on the sender.

[SailingTerrapin]

Thanks Guy!

[Jesse]

The sending unit and guage are a matched pair, so simply adding another guage will not give you what you want. The least expensive way to go would be with a mechanical guage at the helm nearest the engine and the electric guage at the more remote location. The added advantage would be the ability to compare true pressure readings with electronic pressure readings. A "Tee" fitting and mech pressure guage will be less than $30 while a marine dual-station pressure guage will usually be over $100.

[SailingTerrapin]

Thanks Jesse. So it seems that more often than not senders are sold by themselves without accompanying gauges. Do I need to buy the same brand of gauge if I buy the unit separately? Is there a way to know what gauges are compatible with specific senders? Thanks!

[model 10]

It's not a brand thing but a resistance thing. There is a range of Ohms for a model of gage. The Standard Parts catalog at a good auto parts store will have dozens of senders with different sizes, threads, configurations etc. Often times, you only need to worry that you buy a sender for a gage not a low pressure light sender which is only a switch.

[Jesse]

Guy is right. This is why a two guage setup with a single sender is usually expensive, because it's usually made for the marine industry and you know $pendy that can get. The sender must have the proper resistance value to accommodate both gauges. If one of them fails or looses connection with the sender the other will read double the true pressure. It seems a bit vulnerable and lacks backup.

[Blue Stocking]

Ask the sales tech for a dual station kit. Quite common item.

[GuidoY]

I know this thread is a year old but am currently looking to match some senders to new gauges that came with my boat.

So as far as I can tell this is what you have to look out for:

1) Range, i.e., 0-80psi, 120°-240° F, etc.
2) Resistance, i.e., 240-33ohm, 10-180ohm, etc.
3) Dual or single station, i.e., for one gauge or two in separate locations.

As long as these match up, brand is generally a non-issue (except maybe where proprietary software is involved?)

What is the difference between a standard and floating ground?
Also, are the same gauges able to be used for single and dual station as long as you connect one or two respectively?

Thanks for any clarification

[Lepke]

Unless you're using a gauge made for an oem, the senders at a parts store probably will work. Oem gauges are for mass production and changes are made to save money and to force owners to buy replacement senders worth $3 for $40 because no one else has one.
I have dual stations w/2 mains and run independent gauges. In the engine room I have mechanical gauges. So 3 sets of gauges. The gauges at remote stations are electric and each has it's own sender. That way if one fails I still can check it against the other station. Also, it makes trouble shooting easier. My mains are easy to add extra senders. On some engines you need to add a tee, etc.
When I setup electric gauges, I check them against a mechanical gauge before I depend on them. Mechanical oil pressure gauges need the air in the oil line bled to be accurate.
Standard ground is a ground to earth like house current. Ground is a steel rod driven in the dirt. Floating ground is without a connection to earth. Airplanes have floating grounds. Cars also. Boats usually have a ground to the engine that connected to the shaft and to earth via water.

[Wotname]

Originally Posted by GuidoY

.....
What is the difference between a standard and floating ground?
.....

Thanks for any clarification

With respect to senders, a standard ground uses the outer case of the sender for the return side of the circuit (almost always the negative). IE, the outer case is screwed into the engine and as the engine is also connected to the battery negative, so the sender case is thus connected the negative of the battery.

A floating ground sender will have a terminal on it for the return side of the circuit. You connect this back to the battery either directly or by way of the engine etc. Thus a floating ground sender will always have at least two terminals for a single circuit sender and at least three for a 2 circuit sender.

And for the record, cars and metal aircraft use standard grounds.

[GuidoY]

Got it!

Thanks for the explanations