• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Dash light bulbs

Share this page

Brosky

Brosky

Great Pumpkin
Offline
One of my upcoming winter projects is going to be to change out the bulbs in all of my dash lights and clean all of the gauges at the same time. I've been trying to find higher wattage bulbs that didn't cost a ridiculous amount and wasn't having much luck. I've only found bulbs that were $6.00-8.00 per bulb and the wattage was too high at 8.8W

By dumb luck today, I received a catalog from a company called Interlight (www.interlight.biz) 800-743-0005 and spoke to a really nice gal whose name I just lost, but will be on my invoice later. In any event, I was able to get replacement 12V bulbs at 3.125W rather than the 2.2W that TRF and the others sell as OEM replacements. The best part is that they only cost $0.95 each plus shipping. I bought the last 24 that they had on stock, but she said more are due in any day.

I thought that this would be a good increase in power for light without going overboard and melting anything or drawing the Lucas demons into battle.

Just in case anyone is trying to light up the night a bit!!
 
Excellent information. Not to trying to be funny, but how much brighter is basically 1 watt going to make? I have taken all my gauges apart and cleaned them but would like them brighter. I was thinking about coverting them to white LED's, plenty bright and don't have to worry about too much draw on the wiring harness.

The hole for the light socket is 10mm for the small gauges and 12mm for the tach and speedo.

Off ebay I can get 100, 10 mm Led's with resistors for $20 shipped and they are as bright as you want to buy them.

If you can, let us know what the difference is when you get them, I may not go the LED route.

Thanks
 
I plan to swap out the oil or volt guage bulb and take a pic comparing it to the old and post. If you think about it, if the 2.2 is OK, but low, then a 45-50% increase should be a lot better.
 
I thought that the bulb sockets are all the same size on TR6's. The cars require 12 bulbs total. Is the socket bigger on the speedo and tach?
 
Hi Paul:
That is great info. I happen to be working on my dash as we speak, so to speak, heh. Mine is a 60 TR-3 my bulbs are screw in type, is that true of yours also? Mine seem to be all 10mm.
Thanks, Tinkerman
 
Hi,

I was thinking about the led route as well. One setback is the size of the led versus the size of the socket for the bulb. I wonder if I could take a bulb and remove the glass and innards and solder the led with a resistor into the bulb directly. That would make installing them into the sockets reasonable easy as opposed to putting the led's directly into the sockets some how. But them getting them out when you need to replace them might be a pain.
 
[ QUOTE ]
...Excellent information. Not to trying to be funny, but how much brighter is basically 1 watt going to make? ...

[/ QUOTE ]

You're going from 2.2 watts to 3.125 watts. A bit of math gives you about a 42% increase. That's pretty significant.
 
Yes, they are screw in or "SE Single End" bulbs. And the size is .376" which is close enough to be called 10MM.

The part number for these bulbs at Interlight is #428.

I just guess-timated a 45-50% increase, so I think that they should work pretty well without having to rewire sockets or anything complicated. Screw an old one out, screw a new one in.

Pics to follow as soon as I get them next week.
 
Not to dampen your enthusiasm, but I think the real problem is not the bulb. These are the same bulbs that worked very well when new. The only difference between now and then is that the harness has a lot of resistance through poor connections (positive and ground side) and general crud in the wire itself. But, am hoping to hear of good results after your change.
 
Very good point(s). I'll be sure to check all connections while I'm in there. If I get them clean and the wiring resistance isn't too bad, these should be better than or equal to new condition.
 
Paul/Brosky- an experiment of sorts with interesting
results.

I am at the final stages of completing the refurbished
dash gauges, all new wires and a new wood dash.

I have a brand new Dan Master wire harness and 100%
brand new Lucas 2.2W dash lights. Plus two aftermarket
gauges with 3W bulbs. The dash is 100% wired but not
installed in the car yet.

The two aftermarket gauges with 3W are very much brighter
than the new Lucas 2.2W bulbs. So just a minute ago, I
swapped them out into two original gauges out of curiosity.

Guess what?? The original gauges with 3W bulbs went
very dim while the 2.2W Lucas bulbs in the new gauges
glowed brightly. The tack and speedo with new wires and
new 2.2W barely can be seen at nigh.

Since I have had all my gauges apart and refurbished them
well, I believe there must be a design problem in the
path of light thru the gauges themselves.

Way too much effort to take apart the refurbished gauges
again just to discover why they are dim regarless of bulb
wattage.

Maybe someone in the middle of refurbishing gauges can
take a look at the path of light.

If so, please "enlighten" us all.

tinster
 
Very interesting, and thanks for the information. What puzzles me though, is that when these cars were new, the dash lights were just as good as anyone else's. I always had the rheostat turned down in fact. Maybe it was just younger eyes.
 
When these cars were new... gas was well under a dollar a gallon and radial tires were a great new thing. Times change, hopefully things improve. I think if you looked at a 1960s American car its dash might look a little dim compared to today's cars.

Good luck to those of you planning on LED conversions. The problem with most LEDs (even high-intensity ones) is that unless they are mounted in diffusers, their light is too focused to illuminate a gauge well. I play with discrete LEDs for gauge lights every now and then but have only had limited success.

Tinster, that's really good information regarding the performance of high-watt bulbs with a new harness. Thanks. I think you're right, there just isn't a great path for the light inside the gauges.

Once you introduce the LEDs into the comparison it becomes painfully apparent that manufacturers of incandescent lamps and LEDs need to use the same units for both. Watts is a power measurement and doesn't do a good job of describing brightness or light power. LEDs on the other hand are typically rated in MCD (which I think stands for Millicandella... correct me if I'm wrong). That unit of measurement is a lot more useful for comparing brightness.
 
I have a spare set of gauges, all, except for the gas and if I could get some sockets from Erik, I may do some bench testing with one of my ham radio 12V power supplies. I haven't taken these apart yet, so I may just try some of the new 2.2 bulbs and do a comparison of the new 3.125's when they arrive later this week.

I'm hoping that Her Majesty's may have an extra harness laying around that I could get a few spare sockets from.
 
The brightness of a bulb is measured in lumens. You can have a 60 watt bulb or an 18 watt bulb give off the same amount of light. Use the lumens measurement Paul and you will see the light.
 
This subject pops up from time to time. I have replaced all of the bulbs in my dash with LED's and it is very bright. I got them from here.....https://www.autolumination.com/
www.autolumination.com Tail Light Brake Light Turn Signal LED Bulbs They have every possible bulb you could want and their prices are good. Hope this helps
 
[ QUOTE ]
The brightness of a bulb is measured in lumens. You can have a 60 watt bulb or an 18 watt bulb give off the same amount of light. Use the lumens measurement Paul and you will see the light.

[/ QUOTE ]

This is very true. However, if you are comparing the brightness of the same types of bulbs, such as flourescent or incandescent, wattage is a good indicator of how bright one bulb will be when compared to another of the same type.
 
As soon as the bulbs arrive, I'll try to set up for a "Mr. Wizard" comparison. Let's see how many out there are old enough to remember that show.
 
I had the same challenge, so I took all my gauges apart, sanded the insides, primed and painted with gloss white paint, removed those plastic light covers right on the inside where the lights come in. also made sure the light actually protruded into the gauge, replace all light bulbs with new OEM bulb and they are bright and you can see all of them even in town under street lights
 
Back
Top