Crank gear bolt - how much torque? - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• Crank gear bolt - how much torque? by nime01 on 15 Dec, 2009 11:40
• Just bought a new crank gear bolt (p/n N-901-120-01) for my 1991 Golf 1.6TD Eco Diesel. I had to remove the whole crank pulley & crank gear assembly, as I couldn't loosen the crank pulley alone.
  
  Does anyone know how much torque should be used for tightening the new bolt?
  
  
• #1 by nime01 on 17 Dec, 2009 06:37
• Anyone? 
• #2 by boxer246 on 17 Dec, 2009 07:50
• This is from an earlier post regarding same thing.
  
  "Bentley for 85-92:
  Crankshaft sprocket to crankshaft (lubricated)
       6 sided bolt with washer                    180 Nm  (137 ft. lb.)
       Hex head bolt with washer                 150 Nm  (111 ft. lb.)
       12 sided bolt with collar (no washer     90 Nm   (66 ft. lb.) + 1/2 turn (180 deg.)"
  
  Seems as though depending on when your Bentley manual was published there was varying numbers.
  I only have a later AAZ and TDI Bentley on my hands at the moment so that doesn't help.
  
  The general consensus is to buy the new style twelve point bolt which is a one time use stretch type bolt.
  Some use Loctite, some dont.  I do.  I would say definitely use Blue Loctite....some even use Red.  With the Red Loctite you would maybe have to heat the bolt if you ever wanted to get it out again.
  
  
  
  
• #3 by dieselweasel on 17 Dec, 2009 08:02
• Quote from: boxer246 on 17 Dec, 2009 07:50

  This is from an earlier post regarding same thing.
  
  "Bentley for 85-92:
  Crankshaft sprocket to crankshaft (lubricated)
       6 sided bolt with washer                    180 Nm  (137 ft. lb.)
       Hex head bolt with washer                 150 Nm  (111 ft. lb.)
       12 sided bolt with collar (no washer     90 Nm   (66 ft. lb.) + 1/2 turn (180 deg.)"
  
  Seems as though depending on when your Bentley manual was published there was varying numbers.
  I only have a later AAZ and TDI Bentley on my hands at the moment so that doesn't help.
  
  The general consensus is to buy the new style twelve point bolt which is a one time use stretch type bolt.
  Some use Loctite, some dont.  I do.  I would say definitely use Blue Loctite....some even use Red.  With the Red Loctite you would maybe have to heat the bolt if you ever wanted to get it out again.
  

  
  Careful...the torque for the 12 point bolt is 66 ft-lbs + 1/4 turn (90 deg) for an AAZ anyway...it's gotta be the same for a 1.6.
• #4 by boxer246 on 17 Dec, 2009 09:28
• Quote from: libbybapa on 17 Dec, 2009 09:03

  Are you looking in the Bentley or Haynes?  Mk2 Bentley says 66 ft-lbs + 1/2 turn (180°).
  
  I have the ALH Bentley and it says 89 ft-lbs + 1/4 turn (90°) for the same bolt.  Maybe you should use 77.5 ft-lbs + 3/8ths turn (135°)??   
  

  
  Yeah see these Bentleys are different depending on when they are published I found out.  1/4 turn, 1/2 turn.....who the heck knows. 
• #5 by dieselweasel on 17 Dec, 2009 09:29
• Quote

  Careful...the torque for the 12 point bolt is 66 ft-lbs + 1/4 turn (90 deg) for an AAZ anyway...it's gotta be the same for a 1.6.
  

  
  Ahh I see...this spec is from my mk3 Bentley.  The 1/4 turn is plenty tight...I've run crank bolts torqued this way for several 100 thousand kms ok.
• #6 by RadoTD on 17 Dec, 2009 10:45
• Just to confuse everyone even more, on the gasser side with the same shaft nose and bolt, the ABA's spec is 66ft-lbs + 1/4 turn and the G60 says 66ft-lbs + 1/2 turn, both from the Bentley.
  
  I don't think VW has any clue how tight that bolt should be...
• #7 by burn_your_money on 17 Dec, 2009 15:46
• Quote from: dieselweasel on 17 Dec, 2009 08:02

  Careful...the torque for the 12 point bolt is 66 ft-lbs + 1/4 turn (90 deg) for an AAZ anyway...it's gotta be the same for a 1.6.
  

  
  Just checked my MK3 Bentley (covering the AAZ and AHU, ABA and AAC) and it says all 4 cylinder engines, 66 ft-lbs + 1/4 turn.
  
  I think RadoTD hit the nail on the head....
• #8 by nime01 on 21 Dec, 2009 15:15
• Seems there is some confusion about how much torque should be used on a 1.6TD 1V engine.. I think I'll have to go for 90nm/66ft.lb as I have the 12 sided bolt with collar (no washer)
  
  Now, I guess I should be using some thread lock, such as Loctite 243 - or do you guys recommend anything else?
• #9 by burn_your_money on 21 Dec, 2009 18:58
• I'm personally against thread lock on the crank bolts. I don't see it offering any benefit.
• #10 by Vincent Waldon on 22 Dec, 2009 10:02
• Quote from: burn_your_money on 21 Dec, 2009 18:58

  I'm personally against thread lock on the crank bolts. I don't see it offering any benefit.
  

  
  I'm in the same camp... it's darn tight anyway, the bible doesn't call for it, and you will want to loosen it someday perhaps.