Quote:
Originally Posted by CobraMarty
The rectangular 'support' in the 3rd picture (that is what BMW calls it) is the piece that gets modified, machined and needs to get changed out. Unfortunately it is not a simple unbolt and replace. It just doesn't slip out when unbolted.
N52 + N55 – Twin cam, 4 valves per cylinder, valvetronic engines produced from mid 2000s to current (US), Cylinder numbering is from front to rear; 1 at the front and 6 at the rear.
Ignition firing order is 1-5-3-6-2-4.
Use this order sequence to minimize the amount of crank rotation
Sequence that I have found works reliably is-
1- remove valve cover, there are plenty of write ups about how to do this
2- rotate engine CLOCKWISE until #1 intake cam lobe center is pointing just above the eccentric cam, this will put a slight downward pressure on the intermediate rocker lower roller wheel
3- loosen the bolt holding the spring in place exactly 5 turns. NO MORE! or you risk the bolt coming out and spring coming off and MAJOR hassle to replace spring back into place without spending $300 for a special tool. Be warned
4- insert spacer under spring and tighten. COUNT how many turns to tighten. This will raise the spring 'coils' up enough to allow for the 'support' to be removed.
5- remove the 2 bolts holding the 'support' in place
6- wiggle free and remove the stock 'support' and replace with modified 'support'
8- while pushing 'support' towards the exhaust cam, tighten 'support' bolts to spec
7- loosen spring bolt exactly the same number of turns required to tighten in step 4. This will keep the spring bolt still only loosened 5 turns total
8- remove spacer under spring and tighten spring bolt to spec.
9- repeat for other 'supports' Use sequence cylinder 1-5-3-6-2-4.
10- replace valve cover. NOW is a good time to use a NEW valve cover gasket kit
MOST Important is to turn over the engine CW to get the intake cam lobe into the proper position and ONLY loosen the spring bolt a MAXIMUM of 5 turns.
'Special' tools required- (I sourced all these online)
1- E8 external torx socket and short 1/4" extension and 1/4" ratchet or 3/8" adapter to remove 'support' and loosen spring bolts
2- 22mm socket for crank bolt to rotate engine clock wise
3- 1/4" torque wrench to tighten 'support' and spring to spec
4- spring spacer to lift the spring and it's coils to allow the 'support' to be removed
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Fantastic!
When are we going to do some live testing?