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Engine Specific Info and Questions => TDI Engine -General Info => Topic started by: dlnd5d on January 27, 2016, 01:58:56 am

Title: AHU Timing
Post by: dlnd5d on January 27, 2016, 01:58:56 am

I just bought an AHU out of a 98 Jetta that came without a transmission or flywheel so I can't immediately identify TDC. Without tearing into the engine and putting a special rig on the number 1 cylinder, how do I find TDC? Would it work if I lock the pump and then mark the other pullers? Or is there enough slop/tension in the belt that could throw it off? I want to convert it over to an MTDI as soon as I can financially so I need to find TDC.

Title: Re: AHU Timing
Post by: libbydiesel on January 27, 2016, 09:20:46 am

There is waaaaayyyyyyyy too much slop in the pump lock to use it to make a TDC mark.  It's also possible that the pump is off any number of teeth so using it to determine TDC is utterly unreliable.  Doing so would be just asking for a ruined engine with bent valves, broken lifters, bent rods, etc...

There are various ways to accurately determine TDC and they have been discussed quite a few times on this forum.  I don't have the time or gumption right now to go into the details or find links.