Ignition light going off and on while driving

Alternator output should be 14+ volts with a few revs up. If it isn't I'd be suspecting a dodgy diode or connection in the alternator first then the 4tr
 
If it's going from 12v to 6v I'd blame the 4tr though I'd think 6v would also cause the IGN light to be on, But first, check the battery cable bolt where it goes through the floor (drivers side floor where the high beam switch used to be on a holden. Outside end comes from the starter motor) and make sure the surfaces are clean and the nuts on both sides tight as a dodgy connection there will give similar results.
 
If you have a v8 you can fit a range rover alternator and get a built in regulator to take away all this shenanigans, provide improved efficiency and have higher power charging...
 
I replaced the alternator of my %over P5B with a Lucas A127 which has an internal rectifier and voltage regulator and if you look at Ebay, these can be bought for GBP 55,- to 60,- and the A127 gives a much better output then the original alternator and is a direct replacement. It also doesn't require much changer to the loom

Peter
 
This is a right positioned one and you need the left positioned one and this is the one with the 3 pin connector and you need the one with the separate electrical connection pointes

Peter
 
Just get an 18 ACR alternator if you wish to keep to Rover Parts ( this is the unit that series 2 cars use) it has an inbuilt regulator and will have the appropriate mounts.
 
roverp5Bcoupe said:
I replaced the alternator of my %over P5B with a Lucas A127 which has an internal rectifier and voltage regulator and if you look at Ebay, these can be bought for GBP 55,- to 60,- and the A127 gives a much better output then the original alternator and is a direct replacement. It also doesn't require much changer to the loom

Peter
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I have one of these, nice and compact. I've polished mine and swapped the fan blades for an aluminium piece and serpentine pulley :D
Jim
 
Hang on a second? an 18ACR alternator, my car is a 1971 3500 auto series 2 and that has a 11ACR so make sure first, I think perhaps the later series 2 will have the 18ACR type (when British Leyland took over - not sure on this though). Good luck
DAV8
Dave
 
Early Series 2 had the 11AC, and that changed to the ACR around the same time that the BW35 changed to the BW65, but the ACR uses a different mounting bracket to the 11AC.
 
I think Harvey has got it spot on (my 1971 3500 auto does indeed have the BW35 box and of course the 11AC)
I've had the car since 1975 and it was completely original then so I know there has been no mods.
DAV8
Dave.
 
It was during February 1973 that the 18ACR replaced the 11AC. The 35 was replaced by the 65 along with the introduction of the 9.25 : 1 engine plus numerous other changes for the 1974 model year within the U.K. In Australia the story was somewhat different with 1974 models having either the 1973 specifications or the later 1974 specifications, depending upon when they left the factory during 1974.

For an 18ACR equipped car, an ignition light alternating between illuminated or not is usually attributed to either brushes in need of replacement (or at least one of them) or the voltage regulator.

Ron.
 
SydneyRoverP6B said:
It was during February 1973 that the 18ACR replaced the 11AC. The 35 was replaced by the 65 along with the introduction of the 9.25 : 1 engine plus numerous other changes for the 1974 model year within the U.K. In Australia the story was somewhat different with 1974 models having either the 1973 specifications or the later 1974 specifications, depending upon when they left the factory during 1974.

For an 18ACR equipped car, an ignition light alternating between illuminated or not is usually attributed to either brushes in need of replacement (or at least one of them) or the voltage regulator.

Ron.
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Can I confirm...between a 10.5:1 and 9.25:1 V8, does the 10.5 have more bhp? Meaning the bigger the CR is, the more bhp it can produce. And since my engine is a 10.5:1 and it supposed to run on RON100, can I still use 95 since I can't get 100 here in NZ?
 
Also if anyone can take the time to share their thoughts on the effect and damage to the 3500 engine if RON 91 or 95 were used? Since the engine does not have knock detection sensor. I am curious to understand and learn and also worried if previous owners have used lower RON fuel and what effect on the engine should I be looking for. thx u guys.
 
10.5:1 is more powerful on the correct fuel. In the UK we have standard 95RON and also 'super unleaded' which varies from 97-99 RON depending on supplier. The latter is what i run my 10.5:1 engine on.

if you have a 10.5:1 engine and you run it on 95RON it will be down on power as you'll have to retard the timing to run it.

A good trick is to replace the head gaskets with the composite type. This will lower the compression down to 10.1:1 and mean you have to retard the ignition less. Also fitting a richer carb needle can help with this.

So yes 10.5:1 can be more powerful, but in the modern world you may need a few alterations to get anywhere with this.

Hope that helps.
 
rockdemon said:
10.5:1 is more powerful on the correct fuel. In the UK we have standard 95RON and also 'super unleaded' which varies from 97-99 RON depending on supplier. The latter is what i run my 10.5:1 engine on.

if you have a 10.5:1 engine and you run it on 95RON it will be down on power as you'll have to retard the timing to run it.

A good trick is to replace the head gaskets with the composite type. This will lower the compression down to 10.1:1 and mean you have to retard the ignition less. Also fitting a richer carb needle can help with this.

So yes 10.5:1 can be more powerful, but in the modern world you may need a few alterations to get anywhere with this.

Hope that helps.
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Thanks mate, that's helpful. The best we can get is 98 which I use although not all stations have this. There are also 2 types of 98, the bio-ethanol mineral E10 and Mineral fuel, any idea which is best? I'm guessing the latter which is from BP/Mobil.

Also I did use 95 before, half a tank, does this damage the engine?

From AA NZ site:
At many BP and some Mobil service stations, and at all Gull sites, they offer a 98 octane grade instead of 95. In Gull’s case, the 98 grade is an E10 bioethanol-mineral blend. Of the 280 BP stations nationwide, 99 sell 98 octane, while 31 of Mobil’s 190 sites sell 98 octane mineral fuel.
 
Mineral is best...

95 won't hurt... It'll just pink when you put your foot down. If it doesn't you can probably get away with advancing the timing for more power/ economy.
 
rockdemon said:
Mineral is best...

95 won't hurt... It'll just pink when you put your foot down. If it doesn't you can probably get away with advancing the timing for more power/ economy.
Click to expand...

Thanks RD, will stick to E10 98 from now on..
 
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