308 Distributor problem | FerrariChat

308 Distributor problem

Discussion in '308/328' started by Paul308GTSi, May 31, 2011.

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  1. Paul308GTSi

    Paul308GTSi Formula 3

    Oct 26, 2008
    1,003
    Queensland Australia
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    Paul D
    #1 Paul308GTSi, May 31, 2011
    Last edited by a moderator: Sep 7, 2017
    I was just in the process of removing the distributors so that I could reseal the cam covers when I discovered a mess inside the front distributor. Obviously there should not be a pile of brass shavings inside the cover.
    It appears the rotor has been rubbing on the contacts for ages .......... should this be happening ??

    I'm used to electronic ignitions and am a little lost with this old technology ......Help !
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  2. PAP 348

    PAP 348 Nine Time F1 World Champ
    Lifetime Rossa Owner

    Dec 10, 2005
    99,174
    Mount Isa, Australia
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    Pap
    Is there any lateral movement there Paul when you move the shaft up and down?

    Looks like the shaft bush is worn out, causing the rotor button to "wobble" and wear out 1 of those 4 posts inside the dizzy cap. Although it looks like they have all copped a hammering over time it seems.

    If there is movement there, remove the dizzy's and overhaul them. Or have a pro do them both and have them bench tested while he is at it. :):)

    The rotor button does not (should not) touch the posts. As it comes past the post, the spark jumps from rotor button to post to send spark to the lead/spark plug and into the cylinder.

    Have the dizzy's overhauled and replace both dizzy caps and rotor buttons while you are it. :):)
     
  3. mwr4440

    mwr4440 Five Time F1 World Champ
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    Jun 8, 2007
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    To the best of my limited but growing knowledge in this area, PAP is "All over it."


    GREEN rotor buttons?????? Hmmmmmmmmmmm ....

    Never seen those before. Got ANY markings on them?
     
  4. Sledge4.2

    Sledge4.2 F1 Rookie

    Oct 19, 2007
    4,779
    Marin
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    Geno
    #4 Sledge4.2, May 31, 2011
    Last edited by a moderator: Sep 7, 2017
    My old dizzy caps looked much worse. I had my distributors rebuilt (new bearings) when I did the pertronix setup. a few months later, I noticed the caps had huge grooves in the terminals (worse than yours), so I bought new ones. Prior to rebuilding the distributors they were spinning out of round causing the grooves in the caps. When I later replaced the caps there was no change in the way the car ran. While those grooves arent good, in my case they didnt seem to affect the spark that I could tell.

    agree with earlier response you should rebuild the distributors including new bearings.
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  5. miketuason

    miketuason F1 World Champ
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    Feb 24, 2006
    15,517
    Cerritos, CA.
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    Looks like you need to replace the oil seal too.
     
  6. Jonny Law

    Jonny Law F1 Rookie
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    May 6, 2008
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    More then likely the brass shavings are a result of the rotor head being too far away from one of the posts. When I opened mine the hammer head of the rotor was laying on the bottom of the cap, and the inside of the cap looked like it had been painted in gold metal flake. Since the normal fraction of an inch clearance was now 1/4 inch, every rotation arched off a little brass.

    superformance.co.uk has replacement rotors and caps for £99.00 ($150ish) each.
     
  7. mikael82

    mikael82 Formula Junior

    Nov 18, 2007
    869
    Finland
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    Mikael
    I just opened my i-model distributor to change ignition wires and was little surprising to find that it got QV rotors in.
     
  8. Paul308GTSi

    Paul308GTSi Formula 3

    Oct 26, 2008
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    Queensland Australia
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    #8 Paul308GTSi, Jun 1, 2011
    Last edited: Jun 1, 2011
    Oh Yeah ! :)

    I didn't mention the other end of the camshaft where the seals are so bad it looks like a memorial to the Exxon Valdez !
     
  9. Paul308GTSi

    Paul308GTSi Formula 3

    Oct 26, 2008
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    Queensland Australia
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    I hadn't noticed any problem with spark either , she'd rev out easily with no stuttering or problems.
    I'm certain in time it would have had problems for sure.
     
  10. mwr4440

    mwr4440 Five Time F1 World Champ
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    Oh yeah? How did it run with those in?
     
  11. mikael82

    mikael82 Formula Junior

    Nov 18, 2007
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    #11 mikael82, Jun 1, 2011
    Last edited: Jun 1, 2011
    Well, I had no idea that it got QV rotors until, few week ago as I was browsing Superformance homepage and almost write there that they got it wrong with rotors.
    Otherwise 308 GTBi (I like when people make clear note for what model they have not just "308") has both original distributor caps (9/80) and until last week, original ignition wires.
    I have no idea when rotors had been instaled, they look very old.

    So I would say; It runs excatly how it should and not burnig distributor caps or connectors.

    (btw, car is originally sold in Germany)
     
  12. Yoric

    Yoric Formula Junior
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    Jan 8, 2005
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    My rear cam cover is leaking noticeably and, though I've already bought the correct (green) gasket from Ricambi, I'm now a bit hesitant to remove the cover, scrape off the old gasket and replace it (with Hylomar or Hondabond in the right places). I'd do it in a heartbeat if I didn't have to remove the rear distributor--or do I? It took me many tries to get the timing and distributor setup just right, and the thought of going through it all again is giving me pause. By the way, my car is a '77 GTB.
     
  13. Paul308GTSi

    Paul308GTSi Formula 3

    Oct 26, 2008
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    Well it looks like I have to replace a couple of distributor caps , fair enough.

    I might as well replace the ignition wires also , , at this point I would prefer to change the huge long straight plug leads for the angled ones like QV's have ...... not because they are QV parts but because the angled end means they do not stick up in the way when I am fixing something else.
    Will QV plug leads also 7mm like a 2 valve GTSi distributor cap ? I'm trying to find black leads and caps also ........ so what fits , , I recall somewhere on here someone modified Honda / Accel plug caps.
     
  14. Jonny Law

    Jonny Law F1 Rookie
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    May 6, 2008
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    Here is a link to Birdman's solution.

    http://www.birdmanferrari.com/service/spark_plug_article/spark_plug_wire.htm
    308 GT4/GTB/GTS Spark Plug wire replacement

    The only problem I ran in to was the back of the motor, #1 wire came up a little short. Also you will not be able to get the rubber boots back on, but I have not had mine on in over a year, and have had no issues.
     
  15. Paul308GTSi

    Paul308GTSi Formula 3

    Oct 26, 2008
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    They are marked " Magnetti Marelli " " Made in Italy " there is also a B with a circle around it. No other marking visible anywhere.
     
  16. Paul308GTSi

    Paul308GTSi Formula 3

    Oct 26, 2008
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    Paul D
    #16 Paul308GTSi, Aug 20, 2011
    Last edited by a moderator: Sep 7, 2017
    Can anyone tell me what the gap between the rotor and the brass contact in the distributor cap should be please. I'm chasing a dimension for the distance between the red lines drawn onto the photo.

    I have found a considerable difference between an original cap and a replacement !

    I will measure both soon


    ............ I would just like to know what the gap SHOULD be

    :)
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  17. Fairview

    Fairview Formula 3

    Mar 16, 2009
    1,109
    Waynesboro, Virginia
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    Jeff Ward
    Hi Paul,

    I measured for you. Using a used Marelli distributor cap, and a Marelli rotor, both removed from my running 78 GTS, I measured all way across from one terminal face to the other- 59.2mm. This means half the distance (from terminal face to middle of center coil terminal) is 29.6 mm.

    I then measured the rotor from the tip to the center of the wear pattern for the carbon coil contact- 29 mm.

    So, the gap between the rotor and the terminals on my 308 is .6 mm (or about .024 inches). Yours looks wider than that, doesn't it?

    Hope this helps. Jeff
     
  18. Tifosi100

    Tifosi100 Karting

    Sep 26, 2006
    52
    Montana
    I went through 2 set of rotors and caps at quite an expense... Had the same issues as you, even broke one rotor under full throttle, lost one bank... Was a little scary at the time! Found out after market parts are not the best quality. I bit the bullet and put on an elecronic ignition system and all ignition problems solved, car runs much better too. Wasn't cheap and wasn't the simplest task either (but not too bad really), but in my opinion is the single best upgrade for the old 308's you can do to improve driveability and reliability. My 2 cents. I've got a bunch of picture of the install somewhere if you're interested I can post them later... Good luck!!
     

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