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H4 bulbs ??
Posted: 14 Oct 2010, 02:52
by Dantes
Was thinking the earth of my high beam headlights were failing on one side, so I had a look. The H3 bulb looked fine, but the contacts on the inner bracket were moving slightly past each other. So while I was tinkering around the garage found a H4 bulb where the low beam filament had already snuffed it (from my GSX1100f), and thought it'd be great if this fitted my T3 as I have a few H4 bulbs like this kicking around (and instead of soldering the H3 contct disc on properly).
So I took out the inner holder from the seperate full beam headlight, and then positioned the H4 bulb which sat more-or-less in place (few bends with pliers). Anyways then used stiff wire to make a clamp and presto !! All seems good as gold.
My question though is: will the H4 bulbs generate more heat, and could this be an issue for the T3 headlights I have only done this with one side thus far, but on comparison with the original bulb just putting your hand over both lenses the H4 is slightly hotter at standstill
Any thoughts on the matter??
Cheers.
Re: H4 bulbs ??
Posted: 14 Oct 2010, 05:41
by Red Westie
H4 bulbs have two fillaments, 55/60watts dip/fulll, but only one illuminates at a time and as you say, yours have one fillament blown.
The wattage/power of the single fillament in a H4 & H3 is more or less the same and so the heat generated will also be similar.
My concerns would be the positioning of the fillament within the lamp, as this is critical to beam pattern and how the reflector 'reflects' the light forwards through the glass which shapes the light (obviously not as critical as the outter full/dip beam which has to have the fillament very accurately located within the lamp to create the required cut off and kick beam pattern)
The sealing of the lamp and security of the bulb mount may also be an issue (poss water ingress and movement through vibration)...considering the relatively low cost of H3 bulbs, carrying out this particular mod isn't something I would recommend, especially as it could lead to a possible MOT failure if it were noticed.
Martin
Re: H4 bulbs ??
Posted: 17 Oct 2010, 09:58
by Dantes
Cheers for the reply. I ended up doing this mod to only one of the two full beam headlights as every petrol station I went to here in Spain only stocked the H4. And never wanting to be caught out I wanted to make sure I always had lights (had a scare when I was much younger in an old Ford Sierra when the electrics suddenly cut out for all the lights at night driving ).
The clamp I made seems very secure so it cant move. The dip filament in H4 bulbs seem to be very prone to fusing, whereas the Full beam filament must be rock hard. For that reason I have a tiny stock of old bulbs with the full beam filament intact (as a tinkerer by nature I never through anything away). At night the beam seems correct and the position of the bulb is dead centre without touching any part of the lens or glass. All in all I keep the old bracket for the H3 bulb in the van as a backup so can revert to that if needs be.
I think as you say the dip lights require good directional postioning so don't think I'd ever mod that. But all-in-all I'm happy to have modded the headlight for H4 (of course this wouldn't work for older T3s with only one main headlight for Full and dip.
Cheers.
Re: H4 bulbs ??
Posted: 27 Mar 2011, 12:40
by naskeet
Dantes wrote:Cheers for the reply. I ended up doing this mod to only one of the two full beam headlights as every petrol station I went to here in Spain only stocked the H4. And never wanting to be caught out I wanted to make sure I always had lights (had a scare when I was much younger in an old . . Sierra when the electrics suddenly cut out for all the lights at night driving ).
The clamp I made seems very secure so it cant move. The dip filament in H4 bulbs seem to be very prone to fusing, whereas the Full beam filament must be rock hard. For that reason I have a tiny stock of old bulbs with the full beam filament intact (as a tinkerer by nature I never through anything away). At night the beam seems correct and the position of the bulb is dead centre without touching any part of the lens or glass. All in all I keep the old bracket for the H3 bulb in the van as a backup so can revert to that if needs be.
I think as you say the dip lights require good directional postioning so don't think I'd ever mod that. But all-in-all I'm happy to have modded the headlight for H4 (of course this wouldn't work for older T3s with only one main headlight for Full and dip.
Cheers.
You might find that your modified main beam, with H4 bulb, substituted in place of an H3, does not comply with alignment and/or beam focus requirements.
If you passed through France, on your way to Spain, you would be committing an offence by
not carrying a complete set of spare bulbs!
It's always useful to carry spare bulbs, plus other essential touring spares.