Installing 430 Daytona seats in 355 Spider | FerrariChat
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Installing 430 Daytona seats in 355 Spider

Discussion in '348/355' started by Carmellini, Aug 17, 2020.

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  1. Carmellini

    Carmellini Formula 3

    Jul 16, 2019
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    #1 Carmellini, Aug 17, 2020
    This is going to take a little time, but I am going to install these gorgeous 430 Daytona seats in my 355 Spider. The seat frames appear to be the same as 360 seats, so I hope this thread can help anyone interested in upgrading their seats. We shall see......

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    Hoping I might get some feedback from the community regarding some of the dilemmas I am about to face. A big thanks to Qavion (Ian) for his detailed and concise help with electrical concerns, which I will explain.

    There are a number of hurtles to get over.

    The seat mounting and attachment to the floor is the first. The 430 frame rails, which is similar in construction and form to the 355, are about 1 7/8" wider, so the existing mounting holes cannot be used. Also, 355 bolts are M8, while the 430 bolts are M10.

    Does anyone have a good idea on how to install a flush mount threaded nut or insert for the new seats. It would be easy to weld a nut directly on the floor, but of concern will be the taller height of the seat bottom. Measurements "seem" to show that the seats will not be too tall. Won't know with certainty until I am able to get in the mud.

    Next step is the electrical which Qavion has done a brilliant job of solving. I will be rewiring the console convertible top switch with the wires from the emergency top switch. This will take the seat potentiometers out of the loop. The new seats have very simple 12v+ and negative connections with the power seat controls on the seat. It will be very easy to wire up. With this set up, I will need move each seat forward, and probably move each seat back down for the top to fold down properly. (once I complete the wiring, I will post details and diagrams of what Ian has done)

    Final issue will be the seat belts. This may be the most daunting 355 seats have the spool and guide built into the seats, while the 430 does not. I have a nice idea for the guide, but locating the spool and its housing will be tricky. I don't see how I could attach it to the new seats so the only other choices would be the engine firewall, or the floor. No idea if the the spool would be in the way for the seat to be in the most rearward position? Hoping someone might have a good idea for this one?
     
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  2. 355OXO

    355OXO Karting

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    Simon
    #2 355OXO, Aug 17, 2020
    Why not use a 5mm alloy plate under seat with built in seat belt holder and bolt into original seat fittings and then bolt new seat to plate?
     
  3. Carmellini

    Carmellini Formula 3

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    #3 Carmellini, Aug 17, 2020
    Great idea. Will put this one on my list. Thanks.
     
  4. Carmellini

    Carmellini Formula 3

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    #4 Carmellini, Aug 19, 2020
    I think I found a nice solution for the seat belt guide, however I am not sure how to attach without taking the whole seat apart. 355 GTB seats and 575M seats share the same style of guide bolted to the top of the seat back, just next to the head rest:

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    From the parts diagrams it looks like it is held in place with a single allen head cap screw. (can anyone confirm?) Might be tricky to feel for a solid piece of the seat frame? These are cheap at less than $10. Interesting to note, the same looking guides for 550 cars are about $140. each...LOL
     
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  5. Qavion

    Qavion F1 World Champ
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    #5 Qavion, Aug 19, 2020
    Just wondering if seat belt length would be an issue if the mounting point varies too much from the original (too short or too long).
     
  6. Carmellini

    Carmellini Formula 3

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    #6 Carmellini, Aug 19, 2020
    Good point. Will need to research, but guessing that belt needs to cover a wide range of body types and "should" not present an issue?
     
  7. Ferrarium

    Ferrarium F1 Veteran
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    #7 Ferrarium, Aug 19, 2020
    Belts usually have way more material that needed, some pull the belts and cut off a few feet then rewind it so the spring spool strength is faster on various cars.
     
  8. Qavion

    Qavion F1 World Champ
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    #8 Qavion, Aug 19, 2020
    I vaguely recall that I had a problem with a seatbelt being too long on one (non-F) car. There was simply too much belt on the reel and it jammed up inside the reel housing before fully retracting. Not a big problem, just looked messy. I guess the biggest problem would be a too short belt.
     
  9. INTMD8

    INTMD8 F1 Veteran
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    #9 INTMD8, Aug 19, 2020
    If you use that type of guide the reel must be mounted in a similar location to gtb/gts and those mounting points properly reinforced. Would not have enough strength in a collision if you had a floor mounted reel and likely break your back from compression.

    Only way to floor mount the reel is to have it go through a seat made to take the compression load in a collision.
     
  10. Ferrarium

    Ferrarium F1 Veteran
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    #10 Ferrarium, Aug 19, 2020
    Just fabricate new brackets, or modify current brackets, its pretty simple to do, little measure, little cut, little drill, little weld, done.
     
  11. Carmellini

    Carmellini Formula 3

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    #11 Carmellini, Aug 20, 2020
    That does not sound good. Can't you expand a little more on this? Not sure I am fully understanding. If the spool is properly secured to any fixed point, why would it matter?
     
  12. INTMD8

    INTMD8 F1 Veteran
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    #12 INTMD8, Aug 20, 2020
    Ideally the belt mounting is 90 degrees in relation to your spine. Any downward angle from that point starts to compress your body while restraining forward motion.

    Straight down to the floor behind the seat would shear off a plastic guide like nothing, leaving your back to take all of the severe downward compression.

    Tons of info out there, here is some about racing harnesses but the same dynamics apply to seat belts.

    http://teinusa-blog.com/using-racing-harnesses/
     
  13. Carmellini

    Carmellini Formula 3

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    #13 Carmellini, Aug 20, 2020
    ^^^^^^thank you.
     
  14. Carmellini

    Carmellini Formula 3

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    #14 Carmellini, Aug 20, 2020
    The 355 guides cannot be used or modified to fit on the 430 seats. The 355 seats have a relief cut out that the 430 does not have. I am open to ALL ideas. Been down the fabricating road many times and know its always best to proceed very slowly and gather as much intel as possible before diving in.
     
  15. Carmellini

    Carmellini Formula 3

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    #15 Carmellini, Aug 21, 2020
    Calling all fabricating ideas:

    It may be a little tricky to mount the triangular seat belt guides on the top shoulder of each 430 seat. I believe that the frame back, item #16, in this picture, is most likely an ABS or a plastic composite? and #34 is metal?

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    In order ta attach the seat guide, I will need to drill and tap into whatever is underneath. If everything is metal, I don't think it will be a big deal, but if that seat back is plastic, I am not sure what I will do.

    A toggle would "work" but I have never seen one that big, and if they exist, the hole needed would probably be too large.

    Is it possible to affix a rivet nut to plastic? Plan B might be to go deeper to guarantee I reach metal and use a large sheet metal screw?
     

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