330 GTC Koni shock oil??? | FerrariChat
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330 GTC Koni shock oil???

Discussion in 'Vintage (thru 365 GTC4)' started by machineryhill, Apr 24, 2024.

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  1. machineryhill

    machineryhill Karting

    Nov 11, 2011
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    Dan
    #1 machineryhill, Apr 24, 2024
    Hello,

    I took the shocks out of my 330 GTC so I can adjust them. They were set at the factory setting of 2 half turns and I'll try them at an additional half turn stiffer. They feel great, but I'd like to put fresh oil in them.

    Image Unavailable, Please Login Have seen some discussions about this but would like a definite answer on the viscosity and amount of oil that should be used.

    The best reference I found was posted by Dino_Bob, who said: "Regarding oil, the owners manual and workshop manual says that 190ml Agip Oso 35 oil should be used. This is no longer available, but Agip Oso 32 is. That has a dynamic viscosity of 30centi stokes (cst) @40C, and 5,3 cst @100C. I used Putoline Hpx 7,5 suspension fluid with a a dynamic viscosity of 32,1centi stokes (cst) @40C, and 6,31 cst @100C."

    Any info would be greatly appreciated.

    Thanks
     
  2. DWR46

    DWR46 Formula 3
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    #2 DWR46, Apr 24, 2024
    Dan: You will have to fabricate a special tool to loosen the upper retaining ring. They are not rocket science, but keep careful track of how they come apart and keep the pieces in order. We have used ATF as fluid for 45 years with no problems. Many years ago, the Koni North America Shop Manager told me they used a "special" fluid and he could not tell me about it, but he did say they had a lot of ATF on their shelves.
     
  3. machineryhill

    machineryhill Karting

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    #3 machineryhill, Apr 24, 2024
    It's funny that he suggested they use ATF. I know from experience that a small change in viscosity can be too much in some shocks though, and it's kind of lame that they won't tell us what should be used to service their shocks. You can buy Bilstein shock oil.

    I guess I'm trying not to do this by trial and error. I'd plan on using motorcycle fork oil, which is available in various viscosity ratings. I do have a pin wrench that will work, and ended up ordering shock eye bushings and the funny flat bump stops.

    Thanks
     
  4. DWR46

    DWR46 Formula 3
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    #4 DWR46, Apr 24, 2024
    Dan: Read my post again, he didn't "suggest", he "told" me what Koni North America used.
     
  5. machineryhill

    machineryhill Karting

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    #5 machineryhill, Apr 24, 2024
    Do you know how much oil should go in these shocks? They must need an air space?
     
  6. DWR46

    DWR46 Formula 3
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    #6 DWR46, Apr 24, 2024
    Dan: Drain the oil into a container and measure the volume. Usually you will find about 8 oz. If is more than that, put back in the amount that came out. Koni's produced up to about the early 1980s (there is a date stamped on the shock body), used a fluid that attacked the internal plastic limiters. Don't be surprised to find lots of black goo plugging the passageways. Clean everything very carefully, refill the shock and reassemble. You do not need the plastic limiters and you can find matching upper O-rings at your local hardware store. Make sure the foot valve has not been crushed by somebody bottoming out the suspension. If it is, you can bend up the tabs to free the valve and you will be good to go. There are no plastic valves in a Koni of this era, so very rarely are any parts needed, just a careful cleaning.
     
  7. machineryhill

    machineryhill Karting

    Nov 11, 2011
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    #7 machineryhill, Apr 24, 2024
    Thanks, I appreciate the good info. I thought about measuring it too but was worried it could be pretty low.
     
  8. John Vardanian

    John Vardanian F1 Rookie

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    #8 John Vardanian, Apr 24, 2024
  9. machineryhill

    machineryhill Karting

    Nov 11, 2011
    66
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    Dan
    #9 machineryhill, Apr 28, 2024
    The table in the 330 GTC handbook lists the shock oil as Shell Donax A1; from what I've found, this appears to cross reference to Shell Advance Fork Oil 10.

    The handbook lists front 0.220 liter, rear 0.300 liter.
     
  10. machineryhill

    machineryhill Karting

    Nov 11, 2011
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    Dan
    #10 machineryhill, Apr 28, 2024
    In a published table, the Shell advance fork oil 10 looks to be 6.5 wt at 100C (cSt). That's about what regular ATF like Dexron, and what the Oso 32 would be.
     
  11. DWR46

    DWR46 Formula 3
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    #11 DWR46, Apr 28, 2024
    I am glad you with me that Koni North America knew what they were doing.
     
  12. machineryhill

    machineryhill Karting

    Nov 11, 2011
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    #12 machineryhill, Apr 28, 2024
    I never said that KONI didn't know what they were doing, just want to know what they were doing. Just saying to use ATF or hydraulic oil isn't what I was trying to figure out. I wanted to know the amount and viscosity that they used so I'd have a good baseline. Kind of dumb that I didn't see it in the manual fluid table initially.

    These old adjustable KONI shocks may not be as sensitive as motorcycle shocks of the era can be, but now I think I know what they used. I have some Belray 10W fork oil that I think will be very close to the original viscosity.

    Thanks for the help.
     

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