Options for adding gauges to Yanmar 3GM30F

[stormalong]

Originally Posted by Wotname

You forgot to refute the essential bit which was "Now drive it with a varying voltage source that is current limited to 1uA, the pointer remain at 1% deflection regardless of the voltage supplied"

FWIW, the first bit was simply a demonstration that the moving coil responds to current. The bit above demonstrates it doesn't respond to voltage.

OK Wotname you refuse to accept basic principles of electronics so it is time to end this discussion. Adios.

[Scubaseas]

So which way does the smoke in the wires travel and how do you put the smoke back in when things stop working? I know you used to be able to get smoke replacement kits but haven't seen them in an while.

[Wotname]

Originally Posted by stormalong

OK Wotname you refuse to accept basic principles of electronics so it is time to end this discussion. Adios.

I am very firm believer in the basic principles of electronics and a card carrying life long member of the purity of ohms law. But a simple application of it doesn't explain everything - one has to look deeper at times.

I think (but maybe wrongly) that you have forgotten that a moving coil meter needs a certain amount of power (watts) to move the pointer. As you know, P=E.I.

If the I is not enough, it doesn't matter what the E is, the pointer doesn't respond correctly. There are many occasions where the E can be high but the I is low.

Anyhow, it has been an interesting discussion and if you have better things to do then adios and thank you.

[Scubaseas]

I would not use a tee fitting for oil pressure senders on a diesel if mounted on the engine. A remote/off engine tee with a pressure hose to it is fine. Tee fittings have a nasty habit of cranking due to vibration. You can easily get warning light/senders for OP gauges from most manufacturers. You can also buy adapter bushings if needed to convert NPT to BSP and vice versa.

[stormalong]

Originally Posted by Wotname

I am very firm believer in the basic principles of electronics and a card carrying life long member of the purity of ohms law. But a simple application of it doesn't explain everything - one has to look deeper at times.

I think (but maybe wrongly) that you have forgotten that a moving coil meter needs a certain amount of power (watts) to move the pointer. As you know, P=E.I.

If the I is not enough, it doesn't matter what the E is, the pointer doesn't respond correctly. There are many occasions where the E can be high but the I is low.

Anyhow, it has been an interesting discussion and if you have better things to do then adios and thank you.

Well Wotname, time for remedial electronic theory. All current flow is regulated by voltage and circuit resistance. Any active circuit has both voltage and current so to say that the current moves the meter is a given. However, the amount of current flowing through a load - in this case and electromagnet coil in a mechanical meter is dependent on the voltage. The current flowing through the resistance is directly proportional to the voltage. The voltage across the resistance is the only voltage that counts. Your example of a 1ma current at 100 volts is irrelevant because the voltage across the resistance of the coil is not 100 volts. Example: E=IR, if the resistance of the meter is 100 ohms and the current is .001 Amps (1 ma) then the voltage drop across the coil is .1 volt. .0001 times 100 volts. No ifs ands or buts. There is no 100 volts as seen by the meter movement. If you don't believe it, build it yourself and see what happens.

All meter movements are inherently voltmeters. To measure current you are measuring voltage drop across a shunt, either external or internal. Open up your ammeter and you will find a shunt. Using an external shunt you can read the current with a volt meter - that is exactly what the ammeter is doing.

It is 2:00am here and I am going to bed. Good night.

[GordMay]

Originally Posted by Scubaseas

So which way does the smoke in the wires travel and how do you put the smoke back in when things stop working? I know you used to be able to get smoke replacement kits but haven't seen them in an while.

Here is presented for your perusal one Lucas Replacement Wiring Harness Smoke kit, P/N 530433, along with the very rare Churchill Tool 18G548BS adapter tube and metering valve. These kits were supplied surreptitiously to Lucas factory technicians as a trouble-shooting and repair aid for the rectification of chronic electrical problems on a plethora of British cars. The smoke is metered, through the fuse box, into the circuit which has released it's original smoke until the leak is located and repaired. The affected circuit is then rectified and the replacement smoke re-introduced. An advantage over the cheap repro smoke kits currently available is the exceptionally rare Churchill metering valve and fuse box adapter. It enables the intrepid and highly skilled British Car Technician to meter the precise amount of genuine Lucas smoke required by the circuit.

Unlike the cheap, far-eastern replacement DIYsmoke offered by the "usual suppliers", this kit includes a filter to ensure that all the smoke is of consistent size, It has been our experience in our shop that the reproduction Taiwanese smoke is often "lumpy", which will cause excessive resistance in our finely-engineered British harnesses and components. This is often the cause of failure in the repro electrical parts currently available, causing much consternation and misplaced cursing of the big three suppliers.

***

ELECTRICAL THEORY BY JOSEPH LUCAS - The Demon of Darkness

Positive ground depends on proper circuit functioning, which is the transmission of negative ions by retention of the visible spectral manifestation known as "smoke". Smoke is the thing that makes electrical circuits work. We know this to be true because every time one lets the smoke out of an electrical circuit, it stops working. This can be verified repeatedly through empirical testing.

For example, if one places a copper bar across the terminals of a battery, prodigious quantities of smoke are liberated and the battery shortly ceases to function. In addition, if one observes smoke escaping from an electrical component such as a Lucas voltage regulator, it will also be observed that the component no longer functions. The logic is elementary and inescapable!

The function of the wiring harness is to conduct the smoke from one device to another. When the wiring springs a leak and lets all the smoke out of the system, nothing works afterward.

Starter motors were considered unsuitable for British motorcycles for some time largely because they consumed large quantities of smoke, requiring very unsightly large wires.

It has been reported that Lucas electrical components are possibly more prone to electrical leakage than their Bosch, Japanese or American counterparts. Experts point out that this is because Lucas is British, and all things British leak. British engines leak oil, British shock absorbers, hydraulic forks and disk brake systems leak fluid, British tires leak air and British Intelligence leaks national defense secrets.

Therefore, it follows that British electrical systems must leak smoke. Once again, the logic is clear and inescapable.

In conclusion, the basic concept of transmission of electrical energy in the form of smoke provides a logical explanation of the mysteries of electrical components especially British units manufactured by Joseph Lucas, Ltd.

And remember: "A gentleman does not motor about after dark."

Joseph Lucas "The Prince of Darkness" 1842-1903

[FAST FRED]

My Yanmar 3GM30F only has idiot lights for the oil and temp indicators.

This is because most boat owners do not observe the gauges constantly , so need an alarm to tell them something is happening.

The best gauges for most folks are Murphy Alarm gauges.

These are mechanical gauges that have an operator adjustable sensor that can ring a bell, blow a horn , to create an alert.


Mechanical Gauges (Pressure) | FW Murphy Production ...

www.fwmurphy.com › prod

Larger more complex boats can even install a set that will automatically secure the engine is a limit is reached.

[NorthCoastJoe]

On my Yanmar 3GM30F I added a VDO temp gauge sender to one of the extra ports on the thermostat housing no problem with threads they were NPT.

I also have a VDO oil pressure sender for the idiot light and gauge, the same sender used on old VW bus, it fits ok but you have to cut the nuts that hold the terminals down to clear the alternator belt, a very easy thing to do.

I would not bother with oil temp on these engines if the oil hot is enough to notice on a gauge the coolant would be long gone. I will try to get some pictures.

[Wotname]

Originally Posted by stormalong

Well Wotname, time for remedial electronic theory. All current flow is regulated by voltage and circuit resistance. Any active circuit has both voltage and current so to say that the current moves the meter is a given. However, the amount of current flowing through a load - in this case and electromagnet coil in a mechanical meter is dependent on the voltage. The current flowing through the resistance is directly proportional to the voltage. The voltage across the resistance is the only voltage that counts. Your example of a 1ma current at 100 volts is irrelevant because the voltage across the resistance of the coil is not 100 volts. Example: E=IR, if the resistance of the meter is 100 ohms and the current is .001 Amps (1 ma) then the voltage drop across the coil is .1 volt. .0001 times 100 volts. No ifs ands or buts. There is no 100 volts as seen by the meter movement. If you don't believe it, build it yourself and see what happens.

All meter movements are inherently voltmeters. To measure current you are measuring voltage drop across a shunt, either external or internal. Open up your ammeter and you will find a shunt. Using an external shunt you can read the current with a volt meter - that is exactly what the ammeter is doing.

It is 2:00am here and I am going to bed. Good night.

Happy New Year Stormalong and may it be both prosperous and Covid free.

Obviously all current flow is dependent (and proportional to) the EMF. I sort of assumed that was a given. While EMF can exist without current flow, current can't exist without an EMF present. As you say, Ohm's law always applies to electrical theory - no ifs and no buts.

Where we differ (apparently) is how we define the terms ammeter and voltmeter. If I understand your position correctly, your understanding is that all current measuring devices are essentially voltmeters. I find this untenable, it is saying the clamp ammeter is just a voltmeter in disguise etc. I get your logic - current is always dependant on EMF and so any measuring of current is a default measuring of EMF. I just don't see how this is useful is any meaningful analysis of any electrical circuit. Sometimes we need to measure the current and so we use an ammeter; other times we need to know the values of the EMF so we reach for a voltmeter.

Rather than write a lot ATM, this link is more like how I define the terms. Of course it is a simple explanation but the general thrust of it is how I would explain the terms to most people. https://circuitglobe.com/difference-...voltmeter.html

In simple terms, a perfect voltmeter has an infinite input resistance while a perfect ammeter has a zero insertion resistance.

The moving coil meter movement makes for poor voltmeter (due to its necessary current requirements to operate) while other types of voltmeters are way better e.g. VTVM, CRO, Transistor etc. In fact, the moving coil is totally unsuitable for measuring EMF in low voltage solid state circuits. Yet it is quite good for measuring current flow (in part due to the usual parallel resistance AKA shunt).

This is why I suggest the moving coil movement is best understood as a ammeter rather than a voltmeter.

But hey, you don't need to agree and I am happy to politely disagree - I am sure we can still both solve the electrical questions raised on CF as long as we continue to use Ohm's law as the guiding gospel.

[Dalliance]

I recently added whole new panels from AC/DC marine with oil pressure, water temp and watert temp and oil pressure alarms. (My engines are 3YM30AE) 1. The stock yanmar harness did not come with the oil pressure wire or an water temp wire. 2.Sensors that provide the alarm and data are Relatively cheap But I had to buy a BSP adapter for the oil pressure/warning sensor on $6 Amazon. 3. Yanmar does not use conventional wire colors so a “secret decoder ring” provided by AC/DC Marine saved my bacon. (Ramsey provided excellent over the phone advice) I didn’t intend for this post to be an infomercial but I am very satisfied with the performance of the system as we cruise on our catamaran.

[ripmiata]

In 2004 a genius named Roy Mosteller posted complete directions for adding Oil Pressure and Water Temperature analog gauges to a Yanmar 2GM20F diesel engine in a 30 foot Hunter. He ended up sending the directions to a bunch of people on the Hunter Owners Website including me. I followed his directions and installed the gauges. They have worked great for 15 years and do not interfere with the idiot lights. I would be very happy to pass the instructions on to anyone who wants them. They include photos and part numbers for the needed sensors. I would be happy to post them on this Board as long as Roy gets credit (intellectual Property) but I don't know how.

[Capt. Mike Maurice]

Originally Posted by Scubaseas

I would not use a tee fitting for oil pressure senders on a diesel if mounted on the engine. A remote/off engine tee with a pressure hose to it is fine. Tee fittings have a nasty habit of cranking due to vibration. You can easily get warning light/senders for OP gauges from most manufacturers. You can also buy adapter bushings if needed to convert NPT to BSP and vice versa.

Failure to isolate sensors from engine vibration as noted above is one quick way to compromise a perfectly good engine. Such a defect can go undetected for years and then bite you when some other danger threatens. The original manufacture most likely took this into account when building/designing the engine.
Many owners have such an issue lurking in their engine rooms, from past jury rigging by a previous owner.
Fact is any such modification may subtly compromise the engine. Such mechanical modifications need careful consideration.

[ripmiata]

I just added an Album called "Mosteller Analog Gauges for Yanmar 2Gm20F diesel engines". It has directions from Roy Mosteller from 2000. I have had them on my engine for 15 years without a moments' trouble. My marina asked to look at it and have installed a number of them on other peoples' boats.

[Spot]

Originally Posted by ripmiata

In 2004 a genius named Roy Mosteller posted complete directions for adding Oil Pressure and Water Temperature analog gauges to a Yanmar 2GM20F diesel engine in a 30 foot Hunter. He ended up sending the directions to a bunch of people on the Hunter Owners Website including me. I followed his directions and installed the gauges. They have worked great for 15 years and do not interfere with the idiot lights. I would be very happy to pass the instructions on to anyone who wants them. They include photos and part numbers for the needed sensors. I would be happy to post them on this Board as long as Roy gets credit (intellectual Property) but I don't know how.

Hi Rip, that sounds like a great resource for this project.

Maybe a PDF document with a watermark giving him credit would work.
Even better if he was reachable to give permission.

[eroc]

can't dispute the advantage of a separate gauge for water temp, which I added , but finding a mounting place easily visible from the helm was not handy on the sailboat. Depending on the vintage of the 3GM, it may have an extra un-used idiot light if it is a shaft drive. That would be the water intrusion sensor for the saildrive . I added a flow sensor on the raw water intake ( sorry can't recall the make- the boat is 600 miles away) which activates the panel alarm when the intake flow is restricted. This alarm is adjustable and I have it tweaked so it just twitters ever so slightly when the engine is at idle. A reliable check on the system being operational.
The primary cause of engine overheating is raw water flow loss and this system gives you warning BEFORE the engine temp goes up, (such as when we leave the dock without checking that the raw water thru hull is open.) because there are often times when stopping the engine to sort out the overheat is not handy. Should that happen however, say in the middle of a tidal passage there is a short term stop gap measure that helps for a few minutes. Start running hot water if you have a engine heated water tank.
Happy sailing