Temp Alarm Development report.

[haydn callow]

Some of you may be aware that over the past 2 months We have with the help of 2 B/F members been trying to produce a cheap "add on" to the Low Coolant Alarm that will warn you that your Cylinder head temp is reaching critical levels. This is a extreamly simple "add on" consisting of a Bi Metal thermostat switch which connects into the Low Coolant Alarm sensor wire. We tried 3 thermostats 90/100/110 degree C. The 100 C switch seemed ideal and would sound a warning if the head temp ever reached this temp. The downside was that, whilst running this temp was rarely reached, but on stopping the temp rises and would set the alarm off on restarting. No big deal you might think..the problem was it could take 20 mins for the switch to drop down to a low enough temp to reset itself. So, that was no good....The answer seems to be to fit the 110 C switch and then forget about it. 110 degrees seems to still be a safe temp to reach and at this temp your temp gauge will still not have moved from it's 11 o'clock position. So by all means fit one of these and treat it as a "Armageddon" warning device. Of course you need to have a Low Coolant Alarm in the first place. I would be happy to put a small kit together and supply them as cheap as possible. But it is such a simple device and the componants can be bought for about £3. Again I will be happy to make details of what to get and where from and how to, to forum members.
All this caused us to look for a more sensitive/accurate switch..We have not been able to come up with one that will stand the heat/vibration at a sensible price.
What we have managed to do is get the Engine Saver company and the Engine Watchdog TM-2 company to put their tecnology together and we have produced a combined unit that covers...Low Coolant Alarm.....Digital temp gauge with High Temp Alarm......Low Oil Pressure Alarm.
If there is any member out there who is considering fitting these alarms as separate units (a separate Low Coolant Alarm & a separate TM-2) these would cost about £125....as one of the companies has donated a couple of "test samples" for evaluation. It would be good if a B/F member with a bit of Bongo experience would step forward and fit/evaluate/report on this new product. Anyone interested please PM me. When this has been done I will put up a new post to that effect.

BIG Thanks are due to Helen&Tony...&...francophile1947 for all the testing they have done to get this project to where it is. Their input has been invaluable

I will post a photo of the new system shortly.

[haydn callow]

[haydn callow]

Had a couple of pm's.....If you are interested in fitting one of these...No point if you already have alarms fitted and please only offer if your Bongo is a Diesel.

[haydn callow]

O.K. got my crash test dummy....you all know him and I know he will give a unbiased report.

[haydn callow]

http://uk.rs-online.com/web/search/sear ... &R=2282620



To put this switch into the Coolant Alarm circuit..simply make up 2 wires..both with a female spade connector on one end...put a male bullet on the other end of one wire and a female bullet on the other....then disconnect the bullet connector on your coolant alarm sensor wire(near the module) and plug in your two new wires...run these to the cylinder head where you have located the thermal switch and plug in the female spades.
What will now happen is...your coolant alarm will function exactly as before...but if...the thermal switch is activated by the cylinder head reaching 110 degrees C ( +/- 3 degs) the switch will break the circuit and your coolant alarm will sound....Stop at once and find out if it has gone off because of Low Coolant in the header tank or the thermal switch has activated. At any time you can simply disconnect the switch from the alarm and plug the sensor wire back as it was.


I have the above Prototype kit left over....If anyone would like it FOC please let me know (remember you need to have already fitted a Coolant alarm)
I have decided to forget about putting kits together...It's such a simple cheap project for anyone to DIY...Just bolt/rivet the switch to a bit of metal bar to act as a heat sink (as in photo's) and put it under a rocker cover bolt.

[mikeonb4c]

http://uk.rs-online.com/web/search/sear ... &R=2282620



To put this switch into the Coolant Alarm circuit..simply make up 2 wires..both with a female spade connector on one end...put a male bullet on the other end of one wire and a female bullet on the other....then disconnect the bullet connector on your coolant alarm sensor wire(near the module) and plug in your two new wires...run these to the cylinder head where you have located the thermal switch and plug in the female spades.
What will now happen is...your coolant alarm will function exactly as before...but if...the thermal switch is activated by the cylinder head reaching 110 degrees C ( +/- 3 degs) the switch will break the circuit and your coolant alarm will sound....Stop at once and find out if it has gone off because of Low Coolant in the header tank or the thermal switch has activated. At any time you can simply disconnect the switch from the alarm and plug the sensor wire back as it was.


I have the above Prototype kit left over....If anyone would like it FOC please let me know (remember you need to have already fitted a Coolant alarm)
I have decided to forget about putting kits together...It's such a simple cheap project for anyone to DIY...Just bolt/rivet the switch to a bit of metal bar to act as a heat sink (as in photo's) and put it under a rocker cover bolt.

Oooh - I could be tempted Haydn, if no other takers. One query though . Is there a risk the jolly thing will start going off simply because the engine is working hard, in which case it could prove to be an irritation?

But if it is going begging, I'd be tempted to try it as have not dosh for the full monty right now.

Mike

[haydn callow]

Mike...pm me your address and I will get it in the post. I have one on mine and it has never gone off..The day it does you know you have a problem and it just might give you time to stop..Should go off just before the bongo gauge moves.

[missfixit70]

Nice one Haydn where are you fitting the sensor?

[mikeonb4c]

Nice one Haydn where are you fitting the sensor?

Yea. Get yer butt up here and fix it for me Haydn. Only kidding

[haydn callow]

Inlet side rocker cover bolt.
One test one is exaust side ..Threaded hole in block.
Yer takes yer choice !!