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Dodgeman
Re: It seemed like a good idea at the time
#1
No life (a.k.a. DattoMaster)
Joined:
2003/6/27 14:53
From Southern Tablelands N.S.W. Australia
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Posts: 8287
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According to my original 120Y owners manual, the headlights in these cars were rated at 50/40 when they left the showroom, but lord only knows whats in there now.

If we assume a 'nominal' 12.5 volts in the electrical system, then the lights draw a paltry 4 amps each & there's two of them, so there's a nominal 8 amps flowing through the switch for the headlights.

Now Datsun engineers are not fools, they know that using wiring & switchgear that handles much more than this is only going to cost more money, so the system is engineered to safely handle the current draw needed by a stock lighting system, but not much more.

Next, we switch to the QH lights with the standard 55/60 bulbs. The current draw is now only 4.8 amps per light with a new total of 9.6 amps. Doesn't look like a lot more, but it represents a 20% increase in current flow.
The system would handle this just fine when the car was new, but after 30 years many electrical connections have developed a little corrosion & the electrical resistance may not let all the current reach the headlights. The end result is less than satisfactory performance & sometimes a switch or fuse connestion that gets a bit hot.
Many people, like me, don't mind a further upgrade to 100/90 bulbs & the resulting 16 amp draw is going to send the lighting system into a [metaphoric] meltdown.

The recomended fix is the relays, but for the store bloke to say that the current draw is the same shows a lack of understanding of both the subject, & of 30 year old cars from the low cost end of the market.

Just make sure that the bulbs get all the current they need, & make sure they have a good earth & as I have said before, even those standard QH lights will really light up your life.

Oh yeah, check the voltage across the battery terminals with the engine running at about 2,000 rpm & headlights on. You are looking for more than 14 volts. If it's down, then have your regulator checked [if you have an adjustable regulator] to ensure that the system is running at full rated voltage. That should brighten things up.

Posted on: 2007/4/23 7:00
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Subject Poster Date
     It seemed like a good idea at the time Dodgeman 2007/4/21 9:20
       Re: It seemed like a good idea at the time pager 2007/4/21 9:43
         Re: It seemed like a good idea at the time Dodgeman 2007/4/21 9:47
           Re: It seemed like a good idea at the time pager 2007/4/21 9:50
           Re: It seemed like a good idea at the time dog160 2007/4/22 10:15
             Re: It seemed like a good idea at the time shirley 2007/4/23 5:49
               Re: It seemed like a good idea at the time benny 2007/4/23 6:21
                 Re: It seemed like a good idea at the time Dodgeman 2007/4/23 7:00
                   Re: It seemed like a good idea at the time short-coupe 2007/4/23 7:46
                     Re: It seemed like a good idea at the time pepper 2007/4/23 8:03
         Re: It seemed like a good idea at the time beattie 2007/4/21 9:52
           Re: It seemed like a good idea at the time shirley 2007/4/22 9:26
             Re: It seemed like a good idea at the time pepper 2007/4/22 9:55
               Re: It seemed like a good idea at the time Dodgeman 2007/4/22 10:05
         Re: It seemed like a good idea at the time benny 2007/4/21 9:58
           Re: It seemed like a good idea at the time B210sleeper 2007/4/22 3:47
             Re: It seemed like a good idea at the time 1000collector 2007/4/22 4:25
       Re: It seemed like a good idea at the time Dundee1000 2007/4/23 9:17
         Re: It seemed like a good idea at the time Dodgeman 2007/4/23 9:48
           Re: It seemed like a good idea at the time b310gx 2007/4/24 7:59
             Re: It seemed like a good idea at the time Dodgeman 2007/4/24 8:17
               Re: It seemed like a good idea at the time shirley 2007/4/26 5:01
                 Re: It seemed like a good idea at the time b310gx 2007/4/26 5:22
                   Re: It seemed like a good idea at the time shirley 2007/4/26 5:58




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