Alarm/immobilizer

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jagiron
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Joined: Tue Sep 27, 2011 1:52 pm

Alarm/immobilizer

#1 Post by jagiron » Wed Jun 24, 2015 5:05 am

Just bought an MGB roadster,(1978). wondering about alarm/immobiliser,any suggestions on best to use

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TerryG
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Location: East Midlands

Re: Alarm/immobilizer

#2 Post by TerryG » Wed Jun 24, 2015 7:23 am

I have Toad 606 alarms fitted to all my classics (and skytag trackers). Any alarm can be a bit fiddly but it is a DIY job if you are handy with a soldering iron and can read a wiring diagram :)
Understeer: when you hit the wall with the front of the car.
Oversteer: when you hit the wall with the back of the car.
Horsepower: how fast you hit the wall.
Torque: how far you take the wall with you.

mr rusty
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Location: Harlow, the birthplace of fibreoptic communication, as the town sign says.

Re: Alarm/immobilizer

#3 Post by mr rusty » Wed Jun 24, 2015 10:35 am

Any immobilser fitted to an old car can be easily bypassed, so i wouldnt bother actually buying anything. The best thing you can do is also very cheap, hidden switch to your fuel pump supply, maybe another to ground your coil supply/starter solenoid circuit, that's all an immobiliser will do anyway. Fleabay is awash with cheap alarms, they all seem to be much of a muchness.
1968 Triumph Vitesse Mk1 2 litre convertible, Junior Miss rusty has a 1989 998cc Mk2 Metro, Mrs Rusty has a modern common rail diesel thing.

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TerryG
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Location: East Midlands

Re: Alarm/immobilizer

#4 Post by TerryG » Wed Jun 24, 2015 11:23 am

The trick is stealth. Hiding the alarm itself and running wires so they look factory. Harder on a classic in some ways with the small number of electrical items but if you pull the clocks out of the dash the rats nest of BMC cabling makes it easier in others.
Some well hidden relays and you can disable:
The complete ignition circuit
power to the coil
fuel pump.
No two relays in the same place and it makes finding and bypassing them harder.

Avoiding the alarm all together, the cheapest method of immobilising your car is to swap the king lead with any other HT or pull out the rotor arm (or fit a broken one).

I have alarms because once upon a time my insurance company insisted on it. Now I'm less concerned with stopping the car getting stolen (as all it takes is someone with a recovery lorry and they can take anything) and more concerned with getting it back afterwards hence tracker.
Understeer: when you hit the wall with the front of the car.
Oversteer: when you hit the wall with the back of the car.
Horsepower: how fast you hit the wall.
Torque: how far you take the wall with you.

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JPB
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Re: Alarm/immobilizer

#5 Post by JPB » Wed Jun 24, 2015 5:27 pm

mr rusty wrote:Any immobilser fitted to an old car can be easily bypassed, so i wouldnt bother actually buying anything. The best thing you can do is also very cheap, hidden switch to your fuel pump supply, maybe another to ground your coil supply/starter solenoid circuit, that's all an immobiliser will do anyway. Fleabay is awash with cheap alarms, they all seem to be much of a muchness.
That's pretty much the way I see it, a battery cutoff switch operated by a key will buy you plenty of time to prevent the casual scrote from starting the car, a tracking device (easily built using the R/F board and SIM reader from an otherwise obsolete mobile phone) is more useful when the car's wiring isn't protected to the same standards as that on a modern motor with its shielded ignition wiring and yes, if someone turns up with a truck then even the best "protected" car can be heisted so it's far better be able to know where it is than to worry about primary devices.
J
"Home is where you park it", so the saying goes. That may yet come true.. :oops:

jagiron
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Joined: Tue Sep 27, 2011 1:52 pm

Re: Alarm/immobilizer

#6 Post by jagiron » Wed Jun 24, 2015 6:45 pm

Hi Folks, thanks for all the advice, consensus seems to be do`nt fit one but immobilise coil,fuel etc
Thanks again :D

History
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Re: Alarm/immobilizer

#7 Post by History » Wed Jun 24, 2015 8:25 pm

Every after market alarm immobiliser I have seen has never worth the money. Nobody pays attention to the alarms, its just another noise.

On fuel injected cars a simple switch across the fuel pump relay. On carbs and points a switch to earth the cb side of the coil.

Selmar used to make a pendulum alarm system. It was cheap and cheerful and reliable.

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