When I was putting my rebuilt servo back, I noticed that my relays (horn, alternator, a/c) were looking tired. They’ve been opened and the points dressed more times than I can remember. NOS relays are obscenely expensive, and DIN cube relays just don’t look right, so I bought me three of these:
Spent some time installing them with all those fiddly nuts and screws. Turned the key on and the horn started blasting. Alternator wouldn’t charge. Spent more time rechecking the wiring. Finally took them out and bench tested. Two of the three relays were bad. It struck me that the “click” was very quiet when they turned on. Thinking that they were copies of Lucas relays and could be adjusted, I opened one up. And what a surprise. What they had done was to use an electronics grade micro relay which was small enough to fit in the can. This was crudely soldered to the Lucas base plate. It’s a so-so idea to begin with, but the cause of failure was faulty execution. The relays were unsalvageable. I returned them and now I have store credit, which means that I get to spend that money on something else I probably don’t need.
Soooo…before I install a set of DIN cubes, has anyone recently found a cosmetic emulation of a Lucas relay that actually works?
Michael, what about gutting the Lucas internals, placing the DIN relay in the empty container and wiring that to the spade connectors? Looks the same as original, but will work like new.
I assume the reason they die is the coil winding perishes? I wonder if anyone’s tried getting a spool of copper wire thread and rewinding them while watching a movie? Some people hand wind guitar pickups. This can’t be much different.
If you can find one that fits sure. Those cases are rather narrow. I have one original one, and the fan is an obvious cube. I figured no harm no foul since it didn’t come with a fan relay to begin with.
That’s what I was thinking. You are likely a better fabricator than the folks who assembled the relays you returned. Assuming one is put together properly with good solder work and tight rivets are there any other downsides to doing what Scot suggested?
Michael, how close to the one in your first post are you looking? I may know of one that is a similar can, but the bracket sticks out the top, not the sides? Do you care if it is coil or solid state?
Tom
I meant replace the original relay in its entirety - waterproof cube relay and receptacle.
I did this for my horn, hi beams and low beams, all mounted on the back of the splash panel. Same for the fans. For me reliability and availability trump originality.
I have had 100% failure rate on these “new” relays either right out of the box or shortly thereafter and end up with a warranty situation. Modern box relays are better made and much more reliable. I still have a stash of originals in good shape. Some rewiring might be required but only use those on the cars that want to be Concours correct.
Try googling “Omron High-Current Micro 280 Automotive Relay G8V-RH”. I used these in a fuse block for my EFI setup On my SIII E Type. Some of them are rated to 35 amps and it looks like they would fit inside the Lucas case. The pdf I have shows them to be 36 mm tall(including terminals, body is 25 mm) x 15 mm x 22.5 mm. These might do the trick.
I have crates of DIN relays which would work, that’s not the point. I happen to like the look of the three relays on the splashguard. There’s no design issue with the original Lucas relays, and the DIN relays aren’t going to work any better. I was hoping to retain this little bit of bling by using repro relays, but they just aren’t right. The sad thing is that the manufacturer accomplished the hardest parts: stamping and plating the cans and laying out the terminal board. And then screwed it up with a soldering iron.
The problem with loading a small relay inside the can is that heat will build up without air circulation. 10 watts isn’t a problem in open air. But it’s a guess whether the microrelay can function indefinitely inside the can. And there’s the problem of mounting, as the photos illustrate.
The reason I posted this here is that I suspected that a lot of these were being sold, and a lot of people may be getting burned. Electrical issues seem to be a puzzlement for many, and getting bad parts doesn’t help. The industry has to be capable of better. I don’t think the vendors are complaining to their sources, and I would encourage anyone who has problems with these relays to push them back across the counter. And the question remains: has anyone had success with Lucas look-alike relays?
Tom, are you talking abut a repro Lucas relay, or an American-style relay? Contemporary American relays are available, but generally had a common 12V pin for winding and contact.
The first is a switchover relay with an internal diode. The bracket would need to be cut off and a new bracket welded to the back. It’s not impossible to make this work, but it’s not an out of the box solution.
The second is a vintage style American relay…SPST, with a common 12V+ terminal for winding and contact. I think the only place relays like this are used by Jaguar is in the S2 A/C fan overide. They aren’t really appropriate for anything else.
I’m still wondering if ANY of the aftermarket Lucas clones are workable. There are an awful lot of British cars that use these relays, I can’t believe there are no authentic-looking replacements available. Are the Lucas-labeled relays from the UK any better?
The relays in my '68 still function well. I’ve taken one apart maybe 15 years ago to clean up the points but otherwise no issues. I do have a Lucas branded NOS spare but have never had the need to take it out of the box. Given these relays are 52 years old and still functioning it seems to me the better recourse would be to rebuild the originals to spec rather than taking a flyer on a repro.
Michael, yes, as I said, the bracket would not be the same. On the first one- just curious, what do you mean by a switchover relay? It appears to be a standard relay with both NO and NC tips. I did see the diode, but that should cause no issue, and may help tip life.
Of my other three choices, one is NLA, the other is a 3 post horn relay. But the last one is possible:
Also bracket on top.
I do not know if it is solid state. I believe it is about $65.
Just suggestions.
One thing to be aware of with relays is there are intermittent and continuous duty coils. Typically a horn or starter relay will be intermittent. They pull in at a lower voltage and draw more current on the coil. Do not interchange the two as you will overheat and burn out an intermittent relay if used continuously.
Among Lucas relays, you can identify continuous or intermittent rating by measuring the resistance of the winding. Continuous relays have 72 ohm windings, intermittents have 15 ohm windings. This is another question I have about the current crop of replacements, which seem to be one size fits all.
Thanks, Tom. None of these are appealing. If is was to just about making it work, I’d reach into a box and pull out a set of DIN relays. Appearance and plug compatibility counts. I trying to figure out the state of the art in replacement Lucas relays, and so far I’m not impressed.
I understand. Just out of curiosity, I have seen these types of relays priced anywhere from $10 to $150. How much do you think you or the average E Type owner would pay for a reliable original look relay. And no, I am not planning on making any.
Tom
