Testarossa distributor cap button replacement | FerrariChat

Testarossa distributor cap button replacement

Discussion in 'Boxers/TR/M' started by c4b4the04, Jul 5, 2019.

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  1. c4b4the04

    c4b4the04 Formula Junior
    Silver Subscribed

    Jun 9, 2017
    383
    Northern Virginia
    Full Name:
    Cassidy
    #1 c4b4the04, Jul 5, 2019
    Long story short...owned my 88 Euro spec less than two weeks. Motor has already been out for critical timing belt updates and tensioners.

    I never drove the car car before the belts so I assumed it ran fine. When I did the belts car was only running on driver side bank of 6 cylinders. Non cat model, smelled of fuel. Heavily.

    Checked for spark with a timing gun, yup. Decided to take cap off to find that the internal button had dissolved and someone years ago took the gasket out of the distributor. Do I need a new cap and rotor? I’d say so. Both are date stamped 1987.

    My fix to enjoy my car for the weekend? Get another internal carbon button.

    Went to Advanced Auto and dug through every distributor cap they had. Turns out the carbon center buttons have been revised by Borg Warner into two sizes: 0.19” diameter and 0.24” diameter. The TR cap opening is 0.22” diameter so the .19 is the way to go. Turns out the cap for a 1994 Toyota 6 cylinder pickup is about 13 bucks. Pop that
    piece into your TR and you’re back on the road. Super quick fix. Parts pics below for reference. Check any 3.0L Toyota motor from the mid 90’s and you’re all set.

    Hope this helps someone else. I will order caps and rotors this summer. For now it’s pulling strong on all 12.


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  2. C1C7M

    C1C7M Karting

    Jun 11, 2018
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    Chris
    #2 C1C7M, Jul 5, 2019
    Good info, thanks for sharing. FYI - You may wish to post this in the Testarossa Cross Reference Thread.
     
  3. Motob

    Motob Formula 3
    Professional Ferrari Technician

    Nov 11, 2003
    2,238
    Frederick, Maryland
    Full Name:
    Brian Brown
    #3 Motob, Jul 7, 2019
    If you have original Marelli caps, I would just clean them up and reuse them. The quality of the only available replacement reproduction caps is marginal. I have had many issues with them.
     
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  4. c4b4the04

    c4b4the04 Formula Junior
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    Jun 9, 2017
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    Cassidy
    #4 c4b4the04, Jul 8, 2019
    Actually great advice. Thank you. The new ones appear to be aluminum which wears and oxidizes differently than the copper ones from Marelli. In domestic cap designs, we used to scrap and sand smooth the contacts. The small amount of material removed was inconsequential to the delivery of the spark. My wires and caps are original I believe but appear to all be working. 25k miles and climate control may have saved the day on this one. Thank you for reaffirmation I’m on a right path! Cheers.


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