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MG TD TF 1500 - LED replacement for H4 bulbs

Electrics is not my strong point but my question is what are the good/bad points directly replacing the halogen (H4) front headlamp bulbs with an LED replacement. I see that buying direct from China they have become quite cheap. This is an example
which at some 30 pounds ($50 ish) for a set seems like a deal. I would appreciate some help with everybody's thoughts on lumens(?), power (?) etc. My current lights are the old Lucas 700's which would first require a change to halogen. So am I dreaming or will this work? ..... Chris
Chris Malcolm (TD29228)

Dunno..... I'm thinking about trying these in my '34. I'll wait til the first 'rod and custom show in the spring and ask around first.

I'm leary of parts that should be easily replacable in a hotel parking lot (plugs, bulbs, oil) that can't be found at a NAPA store, so you can get home. Carrying a spare set at nearly $50.00.......

Firstly, the are NOT LEGAL. In fine print you will see they say for off-road use. NO HID or LED plug in is legal (in the US anyway), it does not meet DOT standards.
That being said, no policeman will ever cite you for running HID or LEDs, so it's not really a worry.
The advantage of directly replacing your H4 bulbs are a) LEDs are probably brighter than stock, depending on the unit b) LEDs will last far longer, tens of thousands of hours.. and c) LEDs draw far fewer amps, freeing up power for other applications.
The disadvantage is that ... well, there aren't any disadvantages, unless you don't like the look of the bulb in the holder, or the color it puts out. They should be available in a variety of shades of white; these days they have pretty close matches in color to halogens anyway.
If you want LEGAL LEDs, go look at Truck-Lite round LEDs. They are pricey (about $300/pr on ebay) but look to be ultra-tough and meet DOT standards.
Geoffrey M Baker

One other consideaton is, will thay be legal where you are? Dont they have to have a kite symbol or something to state they are road legal?

I see someone got to that question as well :)
R. D. Jones

Wouldn't it be a major modification to convert the headlamps into something that would accept an H4 lamp's mounting configuration? Bud
Bud Krueger

I put a set of these on the 72 B and they work great! Direct replacement. Thought about putting a set on the TF. Moss has them. Of course their not period looking. PJ

Paul S Jennings

Bud, I don't think it's a difficult conversion. These are all standard 7 inch round headlamps, and you can buy 7" shells to fit H4 bulbs in many places. I see Moss sells H4 replacement bulbs to fit TD/C/Fs so it has to be pretty straightforward. I know my motorcycle had a 7 inch headlamp and I bought the shell to fit a H4 lamp for it. Adds another fifty bucks or so to the price tag though...
I've not done it so I can't say definitively, but I'm pretty sure you can get the aftermarket shells that will fit.
Geoffrey M Baker

There are plenty of 7 inch headlamp conversions available (at least in the UK) to convert from the original Lucas 700 to halogen (H4 bulb). Looking through the archives there is a mention from Jan in Scotland about a set of Lucas conversions he bought. The beauty of these is that they look the part (original). My first thoughts were to do the conversion to Halogen and leave it there - but as I have (hopefully!) sorted out an LED system for all other exterior lights I was hoping to take it one step further - LED. Paul, what you have for the B is exactly what I wanted to do except as you point out, not quite period. If these drop in LED bulbs will work then the period look problem would be solved. My problem though is if all the bits will fit into the shell, will they overheat in the shell, and of course what is the true lifespan on the unit. As an example of my concern, I have converted/changed all the lighting in our old house to LED's. I used the cheapest ones I could find (from China). The system works great but I do have about a 10 - 15% failure rate for the bulbs after a few months usage. This would be unacceptable in the car. Geoffrey, it appears that depending on the colour of the lights they would be legal here - although as you have said, I'm not too worried about it :)
Chris Malcolm (TD29228)

Certainly there is a potential problem... The drop in LEDs may not fit every shell. I recall that the first HID unit I bought didn't fit, I had to search for a shorter unit. It could be the same thing with LEDs. Caveat emptor...
I've had the same problem as Chris, with the new generation of cheap household LEDs... Some have failed. I hope this is not the case with the automotive LEDs. Another reason to opt for the more expensive Truck-Lite versions perhaps?
Geoffrey M Baker

I meant to say that the LEDs might not fit in the headlamp bucket, if they protrude too much in the rear. They should fit in any shell which fits H4 bulbs...
Geoffrey M Baker

I stuck HID bulbs in generic 7" H4 headlight using the compact ballast. The ballast fit inside the bucket too.

Cheap, only about 35 watts/bulb and very bright.

It is intersting to watch the price of LEDs coming down to the HID price range.

There was a thread not too long ago on the MGA forum...

The long and short of it is, most (all, some are too dim) of these H4 conversion will be brighter than what is legal, in the wrong places... ie blinding on coming drivers. Last summer, I had my co-op buy about 8 of these different lights off ebay and ran them through all the goniometric (beam pattern, intensity ) testing and they all failed, not one of them even put the LED in the proper focal point in the reflector!

The 6024 conversions from the legitimate lamp companies are legal... peterson, trucklite, osram / sylvania, ge... I had them in my TD for a while, but they don't look right, so they are in the B. The price of the Sylvania lamps was reduced lately, they are now $179 each

It is possible that by having too much light in the wrong spot can reduce your night vision... if you have too much light in your near field, your irises close down and in turn reduces your night time vision.

When I was a kid, 30 some odd years ago I had an MGB, I used to run aircraft landing lights for headlamps... I thought I was the shizz, but nobody ever complained because the B was so low to the ground, the glare never made it high enough for people to complain. Knowing what I know about automotive lighting I was probably reducing my night vision.

Product Development Engineer
Big Automotive Lighting Company that starts with O (or S in the states)

Blair Weiss

Is there any issue with the LEDs being positive or negative earth? Are they made both ways?
John Quilter (TD8986)

John almost all LEDs are intended for negative ground. You can of course wire them to fit positive ground vehicles if you know what you are doing. Still I would not recommend doing it in a positive ground vehicle because a short would destroy them.
Geoffrey M Baker

Blair's got it. Night blindness due to putting too much light in the wrong place.

Blair, Thank you very much for the comments and link to the mga topic - It has more or less answered all my questions (I think!). .... Chris
Chris Malcolm (TD29228)

Blair, thanks for the link and the comments. It bears out what I have suspected, that the drop-in LEDs are not merely not DOT legal, but also will not direct the light where you want it... much like the HIDs that have been on the market for years now.
I'm still waiting for the DOT legal versions to drop in price before considering LED headlamps.
I was only aware of the Truck-Lite versions, can you post numbers or links for other DOT legal LED headlamps?
Thanks for your expertise!
Geoffrey M Baker

Here are some links...

Peterson and





John Quilter brought up a good question... positive ground / negative ground... The high and low beam +12 terminals are the vertical terminals and the horizontal terminal is ground. I know of one car (Datsun 240Z) that supplies power on the ground lug and switches the HB/LB terminals to ground. Coils don't care about such nonsense, diodes do. I believe these are reverse polarity protected... they won't light, but they won't fry...

Blair Weiss

This thread was discussed between 02/03/2015 and 05/03/2015

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