Oil Pressure gauges

[Plan B2]

I am concerned that my oil pressure gauges are not reading correct pressures. What is the proper trouble shooting procedure to determine the connections are correct and the sending units are actually intended for dual gauge application?
32V system, running 8V714Ti engines

 

[SKYCHENEY]

I installed mechanical gauges mounted in each engine room. Only a mechanical gauge can be trusted.

 

[SEVEN]

I did the same as Sky, I added mechanical gauges. On the helm and fly bridge my transmission pressure read 200 psi. Once I added the mechanical gauges in each engine room the reading is 125 psi where it should be.

 

[KPTIM]

You will most likely find that the gauges are powered by 12 VDC (From one of the DC to DC converters). The converter is energized when you turn the ignition switch(s) on. One DC to DC converter for the STB and one for the Port engine instruments.

On my 1979 53' MY the DC to DC converters are located located under the fold back lower helm station.

It is the sending unit (at least on mine and most of the others boats I have worked on) that is the difference between single and dual station gauge setups. The actual analog gauge is the same for both.

I also have and agree with most here you should have a separate mechanical oil pressure, water temp and gear/drive oil pressure gauge in the engine room. They should be located easy to view just opening the engine room door and looking in.

 

[Photolomy]

Any recommendations for buying mechanical gauges?

 

[KPTIM]

I personally like VDO or Stewart Warner.
You can view and buy from:

www.summitracing.com
www.jegs.com

There are other places including eBay, your local higher end auto parts store and such.

 

[Photolomy]

Thanks. Do you T them off of the sender, or is there a better place to connected them?

 

[KPTIM]

The water temperature gauge you should not T in because you want the sensor bulb directly in the coolant flow. There is typically more than one place to pick this up especially in a V engine.

The oil pressure and transmission pressure can be T'ed in.

 

[SEVEN]

I personally like VDO or Stewart Warner.
You can view and buy from:

www.summitracing.com
www.jegs.com

There are other places including eBay, your local higher end auto parts store and such.

Sent you a PM Tim.

 

[SKYCHENEY]

Thanks. Do you T them off of the sender, or is there a better place to connected them?

The point of a mechanical gauge is that there is no "sender". The oil pressure directly moves the needle on the gauge and the water heats a bulb that heats a gas that directly moves the needle. You can T into the ports, but not the senders. If you're not familiar with how to do this, you should probably get a mechanic to install them for you.

 

[Photolomy]

The point of a mechanical gauge is that there is no "sender". The oil pressure directly moves the needle on the gauge and the water heats a bulb that heats a gas that directly moves the needle. You can T into the ports, but not the senders. If you're not familiar with how to do this, you should probably get a mechanic to install them for you.

I meant the ports. I'll T an Arduino off the resistive sender unit. My main purpose for the mechanical gauge, besides as backup, is to calibrate everything else. I didn't buy the boat to let someone else have all the fun.

 

[dsharp]

You may have the wrong sender. They make senders for single gauges and dual gauges. To check if the gauge is functioning you can ground the sender wire and the gauge will peg all the way over. Stewart Warner used to make a good gauge but I’ve heard the quality is not what it was. You may already have a switch t’d in to trigger an alarm or an alternator. 71 series Detroit’s aren’t really known for high oil pressure. what are you showing after it reaches operating temp?

 

[Boatsb]

I meant the ports. I'll T an Arduino off the resistive sender unit. My main purpose for the mechanical gauge, besides as backup, is to calibrate everything else. I didn't buy the boat to let someone else have all the fun.

Give it time. You'll want to share the fun soon enough.

 

[Photolomy]

One of the gauges in the helm isn't working, but they are checking it on the fly bridge. They have been recording oil pressure every few hours, but I don't have the logs yet. So far she has been running textbook, like new. I do plan on networking the sensors to a server and recording/reviewing trends.

 

[Boatsb]

Sounds like a lot of work. Detroits just run and run. 10 psi at idle is fine.

Spend the time using the boat before you spend 100 hours tweaking her.