Engine temp display / alarm

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Avocet

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Can anyone recommend a cheap engine temperature display and alarm unit please? It's a raw water cooled single cylinder which normally runs pretty cold. There are any number of blanking plugs in the water jacket / head / exhaust elbow that I could drill and epoxy a thermocouple into, but I could do with the alarm side of it being programmable so I can just see whatever temperature the engine normally runs at, and then set the alarm a bit higher.

I was wondering about this...

http://www.ebay.co.uk/itm/Digital-A...3?pt=UK_Pet_Supplies_Fish&hash=item417d050ab7

...although the alarm probably wouldn't be loud enough!

Also, does anyone have a feel for the maximum temperature a wet exhaust should get up to? I might see if I can get something similar for the exhaust!
 
A few people have used these:
http://www.ebay.co.uk/itm/10A-12V-D...ial_Automation_Control_ET&hash=item1e863d9409

The alarm is a closing relay, so you can connect whatever klaxons, whistles and gongs you want :)

My only concern would be that you're relying on a relatively complex yet cheaply-made piece of electronics to protect your engine from damage, if there's no other alarm. Although, if it improves the situation from as it is now, that can only be a good thing, and what are the odds of the temperature unit failing on the same day you have an overheat?

Pete
 
Avocet

I was about to google Vetus wet exhaust and it added "alarm". With such a critical item I would rely on just anything but Vwtus has a good name surely?.
 
Why use a water-injected “wet”
exhaust system?
The following factors are of great importance:
1) Exhaust gas temperatures can reach very high levels. A diesel
engine can easily produce an exhaust gas temperature of
600°C(1100°F) or more.
2) The speed with which sound can be transmitted through air
is dependent on the temperature of the air. This applies to
exhaust gases as well. The higher the exhaust temperature,
the higher the speed of sound through the gas.
3) The sound level , i.e. the relative volume of sound as
experienced by the human ear, is in turn dependent on the
speed of sound. As the speed of sound transmission reduces,
so the sound level will reduce proportionally.
In the past, many boats used a “dry” exhaust system, in which
the exhaust gases were transported to outside the hull without
any form of cooling. The resultant hot exhaust pipe had to be
thoroughly insulated, but even so, it produced a tremendous
amount of noise. However, reduction of exhaust gas temperature
to about 40° or 50°C (104°F or 122°F ) can be achieved by
injecting the engine cooling water into the exhaust line. This
is how a “wet” exhaust system works. In addition, the typical
diesel exhaust smell is also considerably reduced. A further
major advantage of reducing the temperature, is the fact th
 
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A bit more money but worth considering,
anchormarine.org.uk/maritime-products/rapid-response-overheat-alarm‎
The Anchor Marine Rapid Response Overheat Alarm.
Its made in UK as well.
 
prv said:
A few people have used these:
http://www.ebay.co.uk/itm/10A-12V-D...ial_Automation_Control_ET&hash=item1e863d9409

The alarm is a closing relay, so you can connect whatever klaxons, whistles and gongs you want :)

My only concern would be that you're relying on a relatively complex yet cheaply-made piece of electronics to protect your engine from damage, if there's no other alarm. Although, if it improves the situation from as it is now, that can only be a good thing, and what are the odds of the temperature unit failing on the same day you have an overheat?

Pete
Click to expand...

+1 for the Chinese temp controllers. Cost effective would be my description IMHO the days of 'Cheap rubbish' from China are for the most part past.
 
prv said:
A few people have used these:
http://www.ebay.co.uk/itm/10A-12V-D...ial_Automation_Control_ET&hash=item1e863d9409

The alarm is a closing relay, so you can connect whatever klaxons, whistles and gongs you want :)

My only concern would be that you're relying on a relatively complex yet cheaply-made piece of electronics to protect your engine from damage, if there's no other alarm. Although, if it improves the situation from as it is now, that can only be a good thing, and what are the odds of the temperature unit failing on the same day you have an overheat?

Pete
Click to expand...

That looks excellent - thanks! Just the job! Just to put this into perspective, Avocet's engine is a 12hp raw water cooled, 25 year old, obsolete and discontinued lump, which never had a temperature gauge (never mind an alarm!), just a light on the engine panel in the cabin. It hasn't overheated in the last quarter of a century, so I'm fairly sanguine about the chances of it happening. I take the point that others have made about the reliability of cheap stuff, but for what this costs, I could buy two and still be quids-in over the cost of a "proper" one! I might even use the second one as an exhaust alarm. I'm pretty happy about the chances of overheating in the first place being very low, and the chances of overheating on the day the unit breaks, being incredibly low. As for overheating on the day that both units break...

Only slight worry is that the write-up says the working voltage is 12V +/- 10%. When the engine is running, the alternator chucks out about 14.5V (which is more than 10% over the nominal 12V). Has anyone had any problems with that?
 
Avocet said:
...
Only slight worry is that the write-up says the working voltage is 12V +/- 10%. When the engine is running, the alternator chucks out about 14.5V (which is more than 10% over the nominal 12V). Has anyone had any problems with that?
Click to expand...

No, mine work just fine at alternator output voltage above 14 v.
 
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