Another use for your Dial Indicator--Finding TDC with it - FAQ/Tech Tips/Please Read First - VWDiesel.net The IDI, TDI, and mTDI source.

• Another use for your Dial Indicator--Finding TDC with it by AudiVWguy on 30 Mar, 2010 00:43
• A couple of years ago when I installed the 16v lightened flywheel I found out it didn't have the right TDC mark. Here's what I did to check TDC. Rotate the engine to the TDC mark on the flywheel (cyl #1). Pull the #1 injector. Loosen the nut on the glow plug a little. Unscrew the glow plug most of the way out to get it out of the way. Extend your dial indicator with a piece of coat hanger or similar of metal. Preload to about 2.5 mm. Now, rotate the crank. the dial indicator will stop at TDC, and then move again as you pass that point. In my case, TDC on the dial was not correct on the flywheel (the pointer in the transmission hole). I made a new mark with my Dremmel tool and was good to go.This is critical for very accurate pump timing.
  I hope this helps.
  Cheers,
  -JB
  
  
  
  
  
  
  
  
  
  
  
   
• #1 by Vincent Waldon on 30 Mar, 2010 00:51
• Good one... thanks for posting... "don't have a reliable mark on my flywheel" comes up often.
  
  Moved to the FAQ section.
• #2 by lovinthedeez on 30 Mar, 2010 01:16
• i've never seen a magnetic vise like that before.  that's awesome
• #3 by moTthediesel on 31 Mar, 2010 10:01
• That's a great tip!
  
  I have a hybrid flywheel on my engine (Kennedy A/C VW) and I've never been absolutely sure of my TDC mark. This winter I made a "mental note" to check it before I put the head back on.
  
  Of course, as we all know, "mental notes" are not worth the paper they're not written on, which lead to another Homer Simpson "DOHH!" moment shortly after torquing the head 
• #4 by vako on 08 Sep, 2010 16:16
• will it be possible to use this method on 1.9td (aaz)? because am going to use suzuki flywheel on my engine and i will no more have tdc mark on it. 
  
• #5 by goomicoo on 16 May, 2015 21:08
• Doesn't the piston linger at TDC for a couple of degrees of crank movement?
• #6 by vanbcguy on 16 May, 2015 23:55
• Yes. You're better off using something as a piston stop (say a valve) and then turning the crank till it makes contact, marking, turning it back the other way till it makes contact, marking again. True TDC will be directly in the center of your two marks.
• #7 by libbydiesel on 17 May, 2015 14:48
• I've used the liquid and clear tube method a couple times and find it to be incredibly accurate and very easy.  That way just one glow plug or injector needs to be removed.  Glow plug #4 is easiest and has the same crank TDC as #1.