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      05-07-2022, 09:36 AM   #28
GuidoK
#buildnotbought
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Drives: Z4 3.0i ESS TS2+
Join Date: Jul 2012
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Quote:
Originally Posted by Tambohamilton View Post
Timing chain tensioners are sprung by oil pressure.
There is afaik always a spring to back it up, or another mechanism (I've seen ratcheting systems on tensioners, so that it can only tension up, not tension down). Otherwise you'd risk jumping the chain/timing belt at sheer startup
So that chance the chain/belt jumps due to low oil pressure is pretty remote imho.

I just saw the post the TS made before my post.


My guess is that the vanos (or whatever it's called on this engine) on this engine has sprung loaded retention pins to set a base advance/retard in the vanos, that are acutated/released by oil pressure.
I've seen such things in toyota's, which look pretty similar. The function of these retention pins is to start the car
However, this is a function of the car/system, so I don't really understand why this could be broken by no oil pressure. Maybe a weak point of this particular engine.

However, that the dealer didn't do a compression test, which is maybe 5 min. work, is questionable.
A compression test is next to listening to the engine the easiest test and first to do; only the spark plugs need to be removed....
If there's compression, only then you know the valves are allright... now it's speculation.
That it doesn't start is concerning...
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Z4 3.0i | ESS TS2+ supercharger | Quaife ATB LSD | Brembo/BMW performance BBK front/rear | Schrick FI cams | Schmiedmann headers+cats | Powerflex/strongflex PU bushings | Vibra-technics engine mounts | H&R anti rollbars | KW V3 coilovers/KW camber plates | Sachs race engineering clutch | tons of custom sh#t

Last edited by GuidoK; 05-07-2022 at 10:06 AM..
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