Let me present here the following information collected from web concerning the Z20NET tensioner and its initialization.
this topic here (vocky):
some of the internals appear to be shared between the two types of tensioner - z22se and z20net
the z20net requires much more effort to compress than the z22se when tested on the bench
the z20net uses the same spring as the z22se but it has more tension - probably because the area where the spring sits has less room.
http://www.ecotecforum.com/forums/showthread.php?13604-Timing-Chain-Tensioner (Cavillac)
this tensioner is the same design as the original, cept its "guts" are held in the bore with a snap ring. to reset it, u have to remove the snap ring, and reset it just like the original tensioner. when i took mine apart when i had a valve spring break, i had no idea how to reset this unit, i just took it apart and discovered it was the same as the old one.
http://www.ecotecforum.com/forums/showthread.php?14849-Timing-chain-tensioners (AYl redline)
you have to compress it before install, then once it is screwed into the head and in place, you have to hit it with something through the access under the valve cover, once you hit it it will expand and tension the chain.
http://www.ecotecforum.com/forums/showthread.php?13604-Timing-Chain-Tensioner/page2 (mike)
when i changed out just the timing tensioner on one of these engines ... i installed the new one which was a new style tensioner ... i could physically see the v-groove line up with the ridge in the tensioner guide.
From these, the advice "remove the snap ring, and reset it just like the original tensioner" seems to be quite reasonable.
However, my attempt to confirm such a Z20NET tensioner related information directly from Opel head office in Rüsselsheim am Main Germany failed, regardless the Opel directive (Opel 2366 Feldabhilfe) on Z20NET tensioner - see the info on web here http://kleinanzeigen.ebay.de/anzeigen/s-anzeige/spanner-steuerkette-opel-z22se-y22yh-z20net-gm-12608580/25401281
should exist.
Field remedy 2366 (Opel Feldabhilfe 2366 equivalent given by Rhil Harisson expert on http://www.justanswer.com):
Subject: Engine Z22SE/Z22YH, tensioner timing chain - Rattling noise from timing chain
Models:
Vectra-B 2001...2003,Astra-G 2001...2004,Zafira 2001...2004,Speedster 2001...2004,VX220 2001...2004,Zafira-B 2005...2009,Astra-H 2007...2009,Vectra-C 2004...2009,Signum 2003...2009
Engines: Z22SE,Z22SE,Z22SE,Z22SE,Z22SE,Z22YH,Z22YH,Z22YH,Z22YH
Complaint: Rattling noise from timing chain, often together with elongated timing chain.
Cause: Blocked timing chain tensioner.
Production: A modified Z20NET tensioner will be introduced in production with MY 2009.
Remedy:
Note: For Z22SE engines please first take note of Quick Information 1532.
In case of customer complaint exchange timing chain and install Z20NET timing chain tensioner part-no.: 12608580 / catalogue-no.: 48 07 839.
(I am from Slovakia, therefore addressing GM Opel).
My questions that Opel is not willing to answer, are the following:
- Opel statement to using the Z20NET tensioner in Z22SE type engines
- Opel ordering code for the Z20NET type tensioner
- Opel ordering code for the Timing Chain Kit containing the Z20NET type tensioner
- Functional principle of the Z20NET tensioner - is its function dependent on spring only or engine oil pressure is engaged as well ?
- Way of initialization of the Z20NET tensioner before its installation and after installing it into the engine camchain drive.
So, except the above introduced Field Remedy 2366 info, it is further possible to use the unofficial information only as it may be found on web.
