Headlamp relays

[davbat]

Hi All,
Quick question, I have halogen headlamps fitted by PO and there are no relays fitted , this has never really been an issue as I generally use the car for summer & day light use only.

Well I've been thinking that I should now get some relays wired in, just in case... A quick search & for that correct 'period look' Lucas 6RA are the ones (I believe). Question is what variant of these is the right one?

Some are listed as # 33302

http://www.ebay.co.uk/itm/261473609294? ... EBIDX%3AIT

Others as as # 33258

http://www.ebay.co.uk/itm/281878067445? ... EBIDX%3AIT

and these at # 33311, listed for a Dolomite

http://www.ebay.co.uk/itm/NOS-GENUINE-L ... xy9X5TaQp5

Can anyone with Lucas 6RA relays fitted, tell me what ones they have fitted?

I will be at Stoneleigh on the 21st Feb, so hopefully will find a 'correct' pair at perhaps a more reasonable price than those listed above...

Thanks in advance,

Dave

[cliftyhanger]

If the bulbs are std 55w halogoens they pull no more current than the old sealed beams.
So no relay required.

However, bear in mind the electrics on the car are pretty old, and switches harder to get (at least decent quality) fitting relays is pretty simple and not only protects the wiring, it also gives you brighter headlights (less voltage drop)

As to which relay, I use the std plastic box ones for a couple of pounds each. Not period, but you should be able to tuck them away somewhere, besides how you going to hide the new wiring?

[sprint95m]

Dave, I have used (and indeed still am using) Lucas 6RA relays without problems.
These I found secondhand (and cheaply) from T2000 mark 2 (horn and overdrive) or Rover P6 (starter).

Nowadays, however, I use the compact type like this
http://www.carbuildersolutions.com/uk/s ... gral-mount.
I concur with Clive, it should be possible to wire these in discretely so as not to detract from your car's originality.


This is a rare occasion, because on his first point
I disagree with Clive, having had the main beam fail on a T2500S years ago due to a knackered stalk switch, I play safe nowadays,
believing that relays should have been employed when our cars were built.




Ian.

[Mahesh]

I was never one for relays (and still have to fit mine) but after seeing the car in the garage,
whereby how much smoke was generated inside the car on a short circuit, its a must for all.

Been looking, there are some ready made looms for this purpose, however a better quality of
product will be diy, also found fused relays.

[cliftyhanger]

[quote="sprint95m"

This is a rare occasion, because on his first point
I disagree with Clive, having had the main beam fail on a T2500S years ago due to a knackered stalk switch, I play safe nowadays,
believing that relays should have been employed when our cars were built.




Ian.[/quote]

Oh come on old chap. I did add the second paragraph with the "however"!

In fact just yesterday I added a relay setup to the car lights. Today I added spotlights via an additional relay, and now my lights wont work. Well, they will, but rather dull as I think I have poor connection issues. So tomorrow is crawl under the car and do the job properly, with some new decent connectors as opposed to 45 year old crusty ones. Let alone some of the wiring mods done by previous owners!
For the headlight relays I used this. but cut the bulb connectors off and used bullets so it fitted to the existing wiring. Good value I reckon.
http://www.ebay.co.uk/itm/H4-9003-Halog ... SwDNdVjgCM

[soe8m]

For originality you can fit two normal relays under the column cover. It does fit and i have it on all my dollies. Just to "override" the switch. You do not need to alter the wiring. It is thick enough. Only the switch does burn or cause extra resistance after time. Just cut and connect behind the licht switch. You maybe only have to pull through the loom through the column guide to have a bit more lenght but it's long enough to do that.

Jeroen

[tinweevil]

To answer the original question - none of them. There was no relay so none of those are 'the right one'. OTOH they are all genuine period relays, the only difference is the can style which was chosen by the OE user according to the fitment location. If your wallet runs to it use any of them.

Like the others I would (and did) use modern relays. I fitted them in the gap between the inner & outer front panels where they are invisible. The current path for the lights then remains entirely at the front of the car which at the lights gives a useful increase in the voltage, and hence power - See Tony's posts in the fuses thread.

[shaunroche]

Whereabouts in the loom should the relay go, or rather which wire feeds it?...I'm going to put halogens in my sprint but am confused where to put the relay feed wire, not the permanent relay feed from the battery, but the 87 wire?

[Galileo]

Seem a bit expensive those ebay ones, as to the 6RA part numbers, this might help (stolen from http://www.autoelectricalspares.co.uk/)

Lucas 33157 , 33209 , 33213 , 33218 , 33250 , 33251 , 33293 , 33294 , 33302 , 33315 , 33359
12v 20A normally open
5 x terminals 2 x C1 , C2 , W1 , W2

Lucas SRB146 33222 , 33222F , SRB143 , 33307
12v 20A Change over relay
5 x terminals W1, W2, C1 , C2 , C3

Lucas SRB131 33258
12v Normally closed
4 x terminals W1 , W2 , C2 , C3

W1/W2 - Coil winding
C1/2/3 - Contacts

[markas]

I was just googling the same thing myself as I'm intending to fit Lucas Square 8 Spots and, at the same time, protect the main lighting switch & stalk and future-proof the headlamps against having to convert to halogen as sealed beam units seem to be unavailable.
Galileo, thanks for your useful post on all the different versions of 6RA type relay. So which of these would be the correct one to use for headlamp and spot lamp circuits?

[Galileo]

If I was going to use a 6RA type for the looks then I'd use the SRB111 (33302 etc), at 20 amp it's perfect for headlights or spots as it is normally open, with two outputs for each spotlight.

The new Lucas relays in a 6RA can are potted with a resin to keep out moisture so should be happier under a damp bonnet than the original 70/80's stuff, get one here for £18 (inc vat) http://www.autoelectricalspares.co.uk/l ... -978-p.asp

Of course for just £4 you could use a solid state relay instead http://www.12voltplanet.co.uk/make-and- ... 0-amp.html

Connectors
85 - to earth (body)
86 - to dashboard switch (low current positive)
30 - Positive (battery, or other high current source via fused supply)
87 - Lefthand Spot positive
87b - Right hand Spot positive

Use as many as you need to control the lights, perhaps use a relay box for neatness? http://www.12voltplanet.co.uk/4-way-rel ... elays.html

Hope that helps, I'm not an auto electrician but I've never understood the mystique around electrical systems and haven't blown anything up yet, and my Dad's intermittent wiper circuit I built for his Triumph in 1981 is still going strong!

Edited: Typo with 87a that should have read 87b

[Mad Mart]

You can't use 87 & 87a like that. 87 is 'normally open' 87a is 'normally closed' and vice versa when ignition is on.

[markas]

If I was going to use a 6RA type for the looks then I'd use the SRB111 (33302 etc), at 20 amp it's perfect for headlights or spots as it is normally open, with two outputs for each spotlight.

The new Lucas relays in a 6RA can are potted with a resin to keep out moisture so should be happier under a damp bonnet than the original 70/80's stuff, get one here for £18 (inc vat) http://www.autoelectricalspares.co.uk/l ... -978-p.asp

Of course for just £4 you could use a solid state relay instead http://www.12voltplanet.co.uk/make-and- ... 0-amp.html

Connectors
85 - to earth (body)
86 - to dashboard switch (low current positive)
30 - Positive (battery, or other high current source via fused supply)
87 - Lefthand Spot positive
87a - Right hand Spot positive

Use as many as you need to control the lights, perhaps use a relay box for neatness? http://www.12voltplanet.co.uk/4-way-rel ... elays.html

Hope that helps, I'm not an auto electrician but I've never understood the mystique around electrical systems and haven't blown anything up yet, and my Dad's intermittent wiper circuit I built for his Triumph in 1981 is still going strong!

That's really helpful Galileo, thanks a lot.
As an auto-electrical ignoramus, I take it you mean that one lamp can be connected to each C1 terminal, so just one relay will be needed for both spots?
This is probably a really stupid question, but will I need one relay for the dipped beams and one for mains?

[Galileo]

You can't use 87 & 87a like that. 87 is 'normally open' 87a is 'normally closed' and vice versa when ignition is on.

Sorry Mart, my mistake, I was talking about a make and break relay that wouldn't have an 87a anyway as it belongs on a changeover relay, but that would not have helped the confusion. I've corrected my post in case someone stumbles across it and doesn't read on.

[Galileo]

As an auto-electrical ignoramus, I take it you mean that one lamp can be connected to each C1 terminal, so just one relay will be needed for both spots?
This is probably a really stupid question, but will I need one relay for the dipped beams and one for mains?

What you say is spot on(!) and that one relay is all you need for a pair of spots. It's a 20 amp relay, so using Amps x Volts = Watts means 20 x 12 = 240 watts, which should cover a pair of 100w Cibie Oscars so I think your Lucas Square 8's will be just fine.

Pictures might help, so I've gone and stolen some!

Here's the SRB111, you can see that one of the outputs at the bottom right is just a double Lucar, that's C1 and the output for your lights:

srb111.jpg (14.23 KiB) Viewed 3054 times

And here is a what it actually looks like 'under the hood', and you can see that C2 is your main feed, the equivalent of a modern 30 pin, and C1 is the equivalent of 87 and 87b.

relais-standard-type-lucas-srb111-srb-113.jpg (15.83 KiB) Viewed 3054 times