timing belt tensioning question regarding tdc

[IASM]

In following the wiki artical on prime in combination with the factory manual i seem to have a conflict. The wiki request rotating the crank one turn to tdc then moving to the blue mark. This would be 9 teeth past tdc on the exaust stroke. The manual states to just rotate to the blue mark with would be 9 teeth past true tdc on th power stroke. I have read some threads but there seems to be confusion on rotating the crank one turn and thinking it bdc.Can someone clarify if i am missreading the guides?
Thanks

 

[greenberet]

Have you seen this thread? Post #44 in particular may help.

 

[ftuhy]

Hmm. I did two timing belts in 2007 (mine and someone else's), and I can't remember if I followed the plus "1 turn" in the wiki, or followed page 6-14 in the manual. However, there is a greasy thumbprint in page 6-14 of my manual as a hint that I followed it. I also made supplemental notes of my own, and noticed that after completion I turned the crank 4 more full turns and checked all alignment marks again.

Unless the tension on the belt due to cam/valve spring push-back is identical for both the power and exhaust stroke, it seems this is an important issue.

Both cars I did in 2007 are running quite well, so it sure would be nice to know what I did (my write-only memory is definitely problematic here) so I get it right when I do my timing belt again in a few more years.

I wonder if this is the hidden issue in the above noted thread??? I'll PM Larry B, since he's done more than a few timing belts.

I just got the following reply back from Larry B:
I always start at true TDC #1 Compression Stroke, then go to the blue mark.:wink:

The key is having the tension tight from the crank pulley through the rear exhaust cam, then all the "slop" in the belt is between the exhaust cam and the tensioner pulley.

My conclusion: I'd follow Larry & do it on the compression stroke, per the service manual.

 

[Kaz-kzukNA1]

Not sure from where this ‘1 turn’ requirement came from but when the manual refers as ‘TDC’, it is the #1 cyl compression TDC.
If the crank was rotated ‘1 turn’, the #1 piston is at the same position as TDC because it’s simply 360deg from crank point of view but it is #1 cyl exhaust stage and we don’t call it as #1 TDC.
In fact, it’s #5 cyl TDC.

For adjusting the TB tension, you will count 9 cam teeth from #1 cyl compression TDC.
This is when all markings (outer and inner faces) on the four cam pulleys line up and you will clearly see the engraved number ‘ 1 ‘ on the outer face of front bank intake cam pulley so you can’t miss it.

Kaz

 

[IASM]

Thanks for the replys. I will use the factory manual and just rotate to the blue mark after tdc. The wiki article shoud be changed.