Distributor blanking plate bolts stripped... help | FerrariChat
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Distributor blanking plate bolts stripped... help

Discussion in '308/328' started by samba-lee, Jul 8, 2007.

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  1. samba-lee

    samba-lee Formula Junior

    Aug 28, 2006
    677
    Manchester, UK
    Full Name:
    Lee Griffiths
    #1 samba-lee, Jul 8, 2007
    Hi all,

    I've been addressing some oil leaks from the cam cover end caps and found that the PO had stripped two of the M8 threads that hold the distributor blanking plate on. It seems they tried to "repair" them with some kind of liquid thread glue.

    I managed to fashion a nut so I could get a long stud on the top forward one, but the lower casting doesn't allow for a nut so needs a proper repair. I can get hold of a helicoil kit, but my question is what size?

    The lower hole appears to be stepped with a 10mm diameter hold reducing to M8 thread. This seems a little odd as I would expect simply M8 tapped right into the head. Can anyone confirm what the lower thread hole should look like. I imagine that the PO may have drilled the hole to 10mm diameter in which case I'll have to use an M12 helicoil - I can make a special stud which is M12 on one end and M8 on the outer so it looks stock in the end.

    Csan anyone advise ?

    thanks

    Lee

    '77 GT4
     
  2. gearheadken

    gearheadken Rookie

    Aug 12, 2006
    12
    #2 gearheadken, Jul 8, 2007
    You are probably looking at the larger diameter counter bore drilling where the hollow alignment dowel used to be. These had two hollow dowels with studs and one hole that had a bolt on it. Hope this helps.
     
  3. samba-lee

    samba-lee Formula Junior

    Aug 28, 2006
    677
    Manchester, UK
    Full Name:
    Lee Griffiths
    #3 samba-lee, Jul 9, 2007
    Ahh yes that makes sense. I thought there was something going on as the gasket also has two large holes and a small one.

    I guess I can just work on the deeper M8 part of the hole then, and remake some dowels too. Are the dowels stepped at all ?

    Lee
     
  4. samba-lee

    samba-lee Formula Junior

    Aug 28, 2006
    677
    Manchester, UK
    Full Name:
    Lee Griffiths
    #4 samba-lee, Jul 12, 2007
    Just completed helicoil-ing the two M8 "studed" fixings in the rear head for the ex-2nd distriubutor blanking plate.

    I very much wanted to do the job in situ so bought a right angle drive ($15 from ebay) so I could drill the holes out to the helicoil tapping size (8.3mm). This was mainly to clear the oil cooler. Helicoils went in easily and now the blanking plate is held in place better than factory.

    Will be pulling the arch liner to inspect the forward bank for cam cover leaks next.

    Lee

    '77 RHD GT4
     
  5. FasterIsBetter

    FasterIsBetter F1 Veteran

    Jul 22, 2004
    5,855
    NoNJ/Jupiter FL
    Full Name:
    Steve W.
    #5 FasterIsBetter, Jul 12, 2007
    Just a thought, but before doing the helicoil thing, did you try re-tapping the holes? You don't need a lot of torque to hold the blanking plate, so if you can revive the threads for the stock bolt enough to get it to hold, you might be better off than drilling it out. It's worth a shot. Just be sure you use a metric tap with the correct thread pitch for the stock bolt.
     
  6. samba-lee

    samba-lee Formula Junior

    Aug 28, 2006
    677
    Manchester, UK
    Full Name:
    Lee Griffiths
    #6 samba-lee, Jul 12, 2007
    Yeah, I had a good look before hand, one was really shot, but I ran a plug tap down the other, but wasn't happy with the result and wanted something I could rely on. The cam cover bolt of the three already had a helicoil fitted so I guess it had happened before. The helicoil looked the best option - better than tapped straight into alloy. VW used an M10 helicoil in their blocks to hold the cylinder head studs so I feel confident it won't budge now and really only took about 0.5mm material out of the hole.

    : )

    Lee
     

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