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Thread: SEV Marchal 900 series retromod

  1. #1

    Default SEV Marchal 900 series retromod

    Hello everyone,

    I just received some SEV Marchal 900 series lights that I am looking to modify to fit my 1990 Mazda Miata. The most trouble that I am having is finding out what bulbs will fit and what holder is needed to keep the bulbs in place. There is not a lot of information online so I figured that I would turn to this forum for help. If you need an images, I'll make a gallery and link it in this thread.

    Thanks,

    miataguy

  2. #2

    Default Re: SEV Marchal 900 series retromod

    Hi, Miataguy, and welcome to this board.

    The Marchal 900 is a large auxiliary lamp. They were made as fog lamps, "driving" (auxiliary high beam) lamps, and spot lamps. I have trouble thinking of where you're going to fit such a large pair of auxiliary lamps on a Miata, but your word "retromod" makes me wonder if you're thinking of putting them in place of the headlamps, is that your plan?

    As far as the bulb holder: uh-oh, you don't have them? Which one you need depends on the production date of your Marchal 900s, there were a few different holders over the years. All of them are long since out of production with no substitution possible.

    (Also, the fact that you don't have the bulb holders makes me wonder if your lamps are new or used...if used, it's likely they aren't in as good a condition, optically, as you might think.)

  3. #3

    Default Re: SEV Marchal 900 series retromod

    Quote Originally Posted by -Virgil- View Post
    Hi, Miataguy, and welcome to this board.

    The Marchal 900 is a large auxiliary lamp. They were made as fog lamps, "driving" (auxiliary high beam) lamps, and spot lamps. I have trouble thinking of where you're going to fit such a large pair of auxiliary lamps on a Miata, but your word "retromod" makes me wonder if you're thinking of putting them in place of the headlamps, is that your plan?
    Thanks for your response. Currently, they actually sit very well in place of the stock headlamps and are only a smidge bigger. I didn't find out they were not standard driving lights until I got them in. As for the condition, they seem to be in very good condition even without having the bulb holders. I have no idea what the beam pattern will be if I am able to fit a normal H4 bulb to them but I am hoping that it will be usable. If not, I can always sell them and try and find a better pair for normal driving.
    Last edited by Alaric Darconville; 06-30-2020 at 01:13 PM. Reason: Pared down quote

  4. #4
    Moderator Alaric Darconville's Avatar
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    Default Re: SEV Marchal 900 series retromod

    Quote Originally Posted by Miataguy View Post
    Thanks for your response. Currently, they actually sit very well in place of the stock headlamps and are only a smidge bigger. I didn't find out they were not standard driving lights until I got them in. As for the condition, they seem to be in very good condition even without having the bulb holders. I have no idea what the beam pattern will be if I am able to fit a normal H4 bulb to them but I am hoping that it will be usable. If not, I can always sell them and try and find a better pair for normal driving.
    None of their design functions make them a suitable replacement for the Miata's factory headlamps; you will not have headlamps if you do this. Remember, this Miata has 7" round headlamps performing both high and low beam functions. If you replace them with the SEV Marchal lamps you will have one of the following outcomes:

    * Just fog lamps (no low or high beam functions)
    * Just high beams (no low beam function)
    * Just pencil beams (a less-usable high beam function compared to factory high beams, and again, no low beam function)

    None of these outcomes are wise, safe, effective, or legal.

    And putting in a dual-filament bulb in place of whatever single filament bulb they normally take will not produce a safe high/low beam function, rather you'll have two very different but still wrong beam patterns that way.
    Last edited by Alaric Darconville; 06-30-2020 at 01:49 PM.

  5. #5

    Default Re: SEV Marchal 900 series retromod

    Yeah, no, I'm sorry to have to break the news, but this is not going to work -- period. The optics of a lamp, its reflector and lens, are very highly specific to one kind of light source (bulb) and to particular beam patterns. This isn't something that can successfully be reworked or overridden after the lamp is made. Even if you were to figure out how to hack/cram an H4 in place of the intended bulb, that would only address the physical fit. The optical incompatibility is total and cannot be worked around. Fog lamps, "driving" lamps, and spot lamps are not high and low beam headlamps. Alaric's comment is correct but doesn't go far enough: you won't have beam patterns out of these lamps if you hack in an H4 or other non-intended bulb, you'll have random streaks of light, blotches and shadows...totally unusable.

    You really need high/low beam headlamps in your Miata's headlight mounts if you are driving it on public roads at all; nothing else is going to be safe, effective and legal. That doesn't mean you have to put up with the weak original headlamps; there are a lot of good options for what to put instead, but there's also a lot of garbage on the market (all hyped up as an "upgrade" of course) so be skeptical and cautious, and ask a dependable expert -- don't just rely on internet "reviews" or recommendations on Miata forums.

  6. #6

    Default Re: SEV Marchal 900 series retromod

    Thank you again for your responses. I am definitely rethinking my purchase of these headlamps for the use that I had intended. I clearly did not have a good understanding on how vehicle headlamps operated. I'm going to see what I can do with these lights now that I have them. Maybe I'll just put them back up for sale and get some normal H4 lights.

  7. #7
    Moderator Alaric Darconville's Avatar
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    Default Re: SEV Marchal 900 series retromod

    Quote Originally Posted by Miataguy View Post
    Thank you again for your responses.
    You're welcome!

    I am definitely rethinking my purchase of these headlamps for the use that I had intended. I clearly did not have a good understanding on how vehicle headlamps operated.
    It's a very complicated subject and many think it's much simpler than it is, then come here to argue about it. Thank YOU for recognizing the complexity.

    I'm going to see what I can do with these lights now that I have them. Maybe I'll just put them back up for sale and get some normal H4 lights.
    Sell 'em for enough, and those JW Speaker Model 8700 headlamps might be more affordable. (Other excellent and less-expensive 7" round LED headlamps are out there, of course.)

  8. #8

    Default Re: SEV Marchal 900 series retromod

    Alaric's right again, but if you don't want to spend a pile of money on good name-brand LED headlamps, don't get cheap LED headlamps (junk), get good-quality halogens -- check with Daniel Stern about it for guidance.
    Last edited by -Virgil-; 06-30-2020 at 03:10 PM.

  9. #9
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    Default Re: SEV Marchal 900 series retromod

    Virgil is right, those JWS 8700s are the best money can buy, but if you want something more period looking, contact Daniel Stern for some Koito 7" H4s & 60/55W Tungsram +120 bulbs.

    According to Dan:
    The very best replaceable-bulb (H4) headlamps in the 7"
    round size you'd need are made by Koito, another of
    Porsche's OE headlamp suppliers. They
    are the most efficient (greatest amount of light on the
    road), best focused (most useful distribution of light),
    best-built (sturdiest glass and metal materials, most
    careful build quality) lamps of their type in this size.

    A fairly sizeable step down from there is the Cibie H4
    units.
    Before the Koitos were available I put the Cibies in our '64 Plymouth and Jeep Wrangler with a relay harness and a good set of bulbs. It looks 100% original, and night-time vision was much improved.
    Last edited by Mr. Merk; 07-01-2020 at 06:23 AM.

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