Tapping the Block

Discussion in 'General Tech' started by blackdemon007, Feb 18, 2016.

  1. blackdemon007

    blackdemon007 Active Member

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    Aug 31, 2013
    I'd like to re-tap/chase the threads in the engine before it goes to the builder.

    Anybody have a list of thread sizes for the 4.6 romeo iron block?
    I believe the oil pan is M10 x 1.5.

    Mainly looking for head bolts, main bearings, side cap bolts, but any info will be helpful.
  2. 96blak54

    96blak54 Legend

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    Feb 21, 2011
    Not busting on you here and I like your ideas, but I believe the term your looking for is cleaning the threads and with that youre gonna want to make some thread cleaner bolts or dull up some taps. The idea is to not remove material by using sharp taps, which it will do.

    Take a junk bolt for each hole size and grind out a notched key at the end. Notch back about 3threads and youll be ready to go! The notch will scrape the thread, holding any dirt. Remove clean repeat. If you encounter a buggered up thread, your cleaner bolt will most likely form the thread back into place. If the thread entry is damaged, still try using the bolt before the tap. Using a sharp tap to recut an entry with aready existing threads threads can be tricky to start without making another seat of threads within the same hole. Hope this helps