I have a crank pin cavity that is 9.5mm.

I have a screw-driver I'm using as a pin, with shaft that is 6mm in diameter.

I want to be sure that the pin width is sufficient to lock the engine whilst I loosen the crank pulley bolt.

Is there a general rule of thumb to minimize any risk to engine internal parts e.g. crank journals?

For example what if the bolt is a bit stiff? Perhaps a torque wrench would help to guage whether I'm applying too much pressure to loosening the crank bolt.

  • This is a K7M engine (renault sandero, nissan np200), 1.6l, 8valve, 2012 model.
    – Jim
    Commented Dec 29, 2022 at 12:20
  • Any input, @Paulster2 or @HandyHowie?
    – Jim
    Commented Dec 30, 2022 at 6:40

1 Answer 1


My advice is to get a correctly-sized pin and use that instead of your 6mm screw driver.

You asked, "is it possible" and the answer is yes, it is possible, although not likely in my opinion, for the engine to be damaged by using the wrong sized pin.

  • I made enquiries, and was told "that's not a part we stock... probably a dealer-only item".
    – Jim
    Commented Dec 29, 2022 at 13:02
  • I think you should have no trouble finding some 9.5mm round stock somewhere. Chances are you might even find a suitable screwdriver with a shaft having that diameter.
    – jwh20
    Commented Dec 29, 2022 at 14:57
  • Found an 8mm bolt. It's a bit more snug so having trouble going as far in as the 6mm shaft. I think it's far in enough now, so it's just a case of how much strain to put on a wrench or breaker-bar.
    – Jim
    Commented Dec 29, 2022 at 15:56
  • Crank bolt loose! But now crank gear is not budging.
    – Jim
    Commented Jan 1, 2023 at 14:07

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