Adding Instruments

Have a Volvo TAMD40B engine and would like to add oil pressure, water temp, and volt gauges to my fly bridge panel. Can this be done without changing all the sending units? All I have up there is a tach and idiot lights.

Most senders are designed to operate either one or two gauges. So if you want to add a second set of gauges you'd need to change senders. Or add a second set of senders just for the bridge gauges.

A Volvo dealer should be able to answer that question for you.

Let me expand on my boatdiesel response or was it a Yanmar guy who asked the same question, can't remember.


Most idiot light senders which is what you have are on/off. They ground the lead to the engine when activated, ie oil pressure is low or they are open circuit when ok. So they cannot be used as a gauge sender. Also various gauge manufacturer's like Faria and VDO can use different resistance ranges.


So to install a gauge you will need a new sender and to retain your idiot gauge sender you will need to install a tee so both can use the same block port. When you do this you will want to keep the hardware to a minimum so: it doesn't stick out and catch on things, and it doesn't have a large mass that can vibrate and crack the fitting. If you can fit it in, a street tee would be the best. Screw the male end of the tee in the block and then screw your two senders in to the female ends. Or use a regular tee and a short nipple.


David

ddalme said:

Have a Volvo TAMD40B engine and would like to add oil pressure, water temp, and volt gauges to my fly bridge panel. Can this be done without changing all the sending units? All I have up there is a tach and idiot lights.

Click to expand...

I assume you want to duplicate the lower station gauges on the bridge. Up top there's only a tach and warning horn... I don't know if the factory harness to the bridge duplicates the lower station harness to allow a full set up top. If so it might be a simple plug and play if you can determine the wiring.
I have the full install manual but won't be able to get to the boat til next week...

djmarchand said:

So to install a gauge you will need a new sender and to retain your idiot gauge sender you will need to install a tee so both can use the same block port. When you do this you will want to keep the hardware to a minimum so: it doesn't stick out and catch on things, and it doesn't have a large mass that can vibrate and crack the fitting. If you can fit it in, a street tee would be the best. Screw the male end of the tee in the block and then screw your two senders in to the female ends. Or use a regular tee and a short nipple.

Click to expand...

Agreed. I wanted to install an oil pressure gauge on my Phasor generator and the port where the low oil pressure shutdown sensor was located didn't lend itself to the necessary Christmas tree of fittings. In fact it was a poor piece of design by Phasor, as the sensor touched the coolant hose. My solution was a small bore hydraulic hose with the Christmas tree mounted remotely on the engine block.

The big arrow is the port in the cylinder block. The small arrows are the sender and sensor mounted on a piece of GRP.

Mike:


Nice installation, but... That oil pressure idiot light sender is probably a normally closed switch that closes the circuit to engine ground to indicate low oil pressure. It opens the circuit when the engine oil pressure rises. So did you provide a ground to that sender in your new setup? Otherwise it will always indicate good oil pressure because there is no ground.


Can't tell from your pic.


David

David: Hmm, good observation. Yes, both sender/sensors get their ground from the curved black wire going to the middle of the fat sender unit. The hose clamp is what keeps the ground wire in firm contact. Not elegant, but secure.

Mike:

I see it now, the black wire going to the starter lug for a ground. Sorry to doubt your installation.

David

David: You make a very good point though; without a ground wire it is possible to be living in a fool's paradise.