WHY ARE SPECIAL INSTRUCTIONS NECESSARY for Z4 E85/86 INSTALLATION?

Because there isn’t enough clearance in the engine bay between the VANOS body and the radiator fan cross brace to do it the way you would with an M3 E46 engine bay:

  • Specifically, you can’t preinstall the splined shafts with pistons joined and fully inserted fully into the VANOS body BEFORE you begin reattaching the VANOS assembly to the cylinder head as done with an M3 E46 (depicted in picture below).
  • You will need to join the splined shafts to the pistons AFTER you begin mating the VANOS body to the cylinder head. This is outlined step-by-step below.

BEFORE YOU BEGIN

You’ll need the following special tools in addition to those listed by Beisan here https://beisansystems.com/s54-vanos-rattle-procedure/.

1. SHORTENED 5mm ALLEN (HEX) KEY – DIY MODIFICATION

  • Saw off the short end of the key so there is about 1/4 inch left to the elbow bend, enough to seat into and turn a hex bolt.
  • You will need to carefully file the raw edges.
  • This will be used to put the two cam caps back on the VANOS body once it’s positioned on the cylinder head and with very little clearance to the radiator cross brace.

2. CROW’S FOOT 10mm WRENCH ATTACHEMENT

  • These usually come in multi packs ranging from 6mm – 12mm at a hardware or auto parts shop.
  • You’ll attach it to your torque wrench when tightening the exhaust hub bolts (intake hub bolts can otherwise be done with a standard socket on the torque wrench).
  • **Secure the crows foot with masking tape so it won’t come off and fall into the engine block.

3. A SMALL RUBBER MALLET

  • Such as that used in flooring with a harder and softer head. You’ll want to use the SOFTER side in STEP 2 below.

STEP-BY-STEP INSTRUCTIONS FOR Z4M E85/E86 VANOS REINSTALLATION

STEP 1

  • On the work bench, remove the lower solenoid assembly(RED arrow) from the upper VANOS body but leave the coil pack joined to the metal plenum(GREEN arrow). Caution: internal oil will gush out.
    • This involves removing three 10mm and two short 10mm bolts from the top of the VANOS body to separate the two parts. DO NOT remove the four E-5 Torx mounting bolts from the bottom of the coil pack.

STEP 2

  • On the work bench, remove the two exterior caps that house the cam actuator pistons.
    • After you remove the six T25 Torx bolts,
    • Use the softer end of a small mallet to tap, tap, tap on the cap housing until sufficiently loosened.
    • Then you can just grip the caps off.

(Picture shows the old, used VANOS unit for illustration. You’ll do this on the rebuilt Beisan unit before reinstallation.)

WHY ARE STEP 1 AND STEP 2 NECESSARY?

You will need to have zero internal back pressures (oil and air) to perform the reassembly of the VANOS body onto the cylinder head:

  • Without doing this, you will not be able to fully recess the cam splines/pistons to the correct position inside the VANOS body because of the back pressure (BMW service has a special tool, an expensive one, to achieve this through hooking up a pneumatic hose to the installed VANOS and sending electrical signals to the solenoid to move the piston to the fully retarded position, i.e. fully recessed into to the front of the VANOS unit, but it is generally not available to the public);
  • You will therefore be prevented from achieving full retardation position of the camshafts before tightening the hub bolts, and thus you will not have correct timing at TDC for idle.
  • This procedure is peculiar to the Z4 installation because you can only join the two parts of the cam splines/pistons AFTER the VANOS body is first positioned onto the cylinder head, whereas with an M3 E46, the splines are joined and fully recessed into the VANOS body BEFORE positioning it onto the cylinder head and any back pressures can be overcome on the work bench.

STEP 3

Prepare (have them ready) to replace the six Torx bolts holding the two cam covers that come with the rebuilt Beisan VANOS body with old-school HEX bolts from the ORIGINAL body if so equipped (factory spec).

  • Why? Once again, it’s a clearance problem. You will need to tighten the bolts AFTER you have installed the VANOS to the cylinder head AND you likely can’t modify a Torx allen key by cutting it down (Special Tool No. 1 in the ‘Before you Begin’ section above) so that it will fit the bolt because Torx are tapered and won’t seat properly after you modify them. Hex keys are not tapered and work perfectly.
  • If your OLD body has the HEX bolts, just use these to swap out the Torx bolts. If not, go to a BMW dealer and they might have them in stock or two day order. You will need six of them. Have them ready when you’re re-installing the VANOS to the cylinder head.

STEP 4

Prepare the crankshaft TDC position and cam timing.

  • Set your crankshaft to TDC with the crank holding pin inserted. (Make sure to read up on this point in the Beisan M3 E46 Standard Instructions https://beisansystems.com/s54-vanos-rattle-procedure/.)
  • Align your two camshafts correctly using the BMW special cam timing tool (bridge) as pictured GREEN arrow. (Also described in the Beisan M3 E46 Standard Instructions.)
    • If you don’t have this tool, you can’t do this job DIY! Period.

**NOTE: Make sure you read up and watch Youtube videos to understand fully how to use this tool and have it seated correctly for an accurate reading and positioning of the camshafts before you go further. Good Youtube links are provided below.

**ALSO NOTE: there are “two” possible TDC lock positions: know how to determine the TRUE TDC by inspecting the cam LOBE positions at Cylinder 1 facing each other at approximately 45o.

STEP 5

Insert the two gear splines into the cam hubs (RED arrows), as shown in picture below.

ALSO insert the regulating valve (GREEN arrow) into the cylinder head.

MAKE SURE:

  • You read up or watch Youtube videos on how to find and position the SWEET TOOTH (sometimes also MAGIC TOOTH or SMART TOOTH). In the picture, I have placed marks to align my sweet tooth during reassembly. Your marks may be placed differently, but there is only one correct insertion where the spline gears fit into the hubs so that they give the full range of motion/actuation from retardation to advance of the camshaft.
  • NOTE: if you don’t get this right, your engine will start, idle, and seem to accelerate okay, but the rev curve will flatten out at around 5,000 – 5,500 rpm (lose oomph).
  • BEFORE you insert the spline gears, the two hubs (exhaust and intake) are turned all the way CLOCKWISE as far as they will go.
  • Then, as you begin inserting the hubs on their Sweet Tooth positions, the hubs should move freely COUNTERCLOCKWISE as you insert the splines deeper into the camshaft.

STEP 6

Position the VANOS body for re-assembly to cylinder head.

  • First, on the VANOS body, pull the actuator pistons far enough forward so that the spindle nuts are accessible to a wrench;
  • Second, position the VANOS gasket to the cylinder head;
  • Finally, line up and position the VANOS body to the cylinder head using 2 long 10mm bolts from the lower solenoid disassembly in STEP 2 (these will be returned to the solenoid once you finish reassembly);

**NOTE: DON’T FORGET to position the Vanos GASKET at this time while inserting the long bolts to the cylinder head.

STEP 7

Join the splined gears to the piston spindles.

  • Use two small needle nose vise grips to hold the spindle nuts from edging back into the piston housing as you begin tightening by fingers.
  • With fingers, start the mating of the piston spindle nuts to the spline gear threads.
  • NOTE: MATING IS REVERSE THREAD, therefore lefty = tighten.
  • Take your time, it may require some fine finger dexterity and slightly adjusting the tilt of the VANOS body to get the threading started. It may take several attempts.
  • Once started with fingers, you will finish up tightening with wrenches.
  • Tighten snug with wrenches, but no need to overtighten.
  • The spline gears inside the sprocket hubs can be allowed to pull out as required once the tightening is underway (RED arrow), even all the way out (that’s okay because you have marked your Sweet Tooth for reinsertion).

STEP 8

Push the pistons fully back into the VANOS body

  • Once the splines are mated to the pistons and tightened,
  • Push the splines/pistons all the way into the VANOS body’s piston chambers so that with your finger you can feel the piston ends flush with the openings in the front (caps off).
  • This will mean that the spline gears will come all the way out of their sprocket hubs. That’s okay, you have marked the Sweet Tooth for the reassembly in the next step.

STEP 9

Begin mating the VANOS body to the cylinder head

  • Make sure the sprockets are rotated all the way CLOCKWISE again;
  • Slowly start pushing the VANOS body toward the cylinder head;
  • LINE UP THE SWEET TOOTHS again as you keep pushing the VANOS body toward the cylinder head;
  • LINE UP THE EXHAUST SPROCKET TANGS to the correct holes in the OIL PUMP DISC as you push the VANOS body toward the cylinder head;
  • STOP once you reach a 5 mm gap to the cylinder head (spline gears should still be poking out of their hubs 1/4 to 1/2 inch: see picture).

STEP 10

Re-assemble piston caps to VANOS body

  • Put the two piston chamber CAPS back onto the VANOS body;
  • Tighten the six bolts using the modified (shortened) 5mm Allen hex key.
  • TIP: to tighten some of the bolts, you may need to hold your tool through the radiator fan cross brace hole.

STEP 11

Swap out the long 10mm hanger bolts with the correct mounting bolts

  • You can now replace the 10mm long bolts used for hanging the assembly with the proper length for final mating of the VANOS body with the cylinder head.

STEP 12

Pre-tension the hub bolts

STEP 13

Complete the mating of the VANOS body to the cylinder head

  • After you have pre-tensioned the hub bolts and have the exhaust sprocket tangs correctly positioned in the pump disc, slowly complete the mating of the VANOS body onto the cylinder head using a 10mm wrench alternating side to side on the two corner mounting bolts first, 1/4 turn at a time, until snug.
  • Then put in the three lower mounting bolts and tighten snug
  • Complete tightening by using torque wrench
    • Torque to 8 ft-lb (or 10 Nm)
  • When fully mated, the teeth of the spline gears should still be poking out a little on the INTAKE sprocket. See picture GREEN arrow. (The gears on the EXHAUST sprocket will be out of sight because of the staggered design of the two sprockets.)

STEP 14

Re-check timing alignment of camshafts BEFORE final tightening of sprocket bolts

  • Recheck the cam alignment using the BMW camshaft alignment tool to confirm that they have not moved following the mating sequence;
    • if off a little, use a 24mm wrench on the camshaft itself (between Cylinder 1 and 2) to bring it to correct alignment. See video courtesy of Fatboys Garage Youtube Channel here: https://www.youtube.com/watch?v=_nMUCe7TD2o
      • You can start watching at the 8:45 mark
      • **NOTE: Always remove the pin from the alignment tool when adjusting the camshaft, or you might bend the pin and make it useless

STEP 15

Final tightening of sprocket bolts

  • After you have confirmed camshaft alignment with TDC;
  • Using a 10mm CROW’S FOOT on a torque wrench, do a staggered torquing of the sprocket bolts and follow Beisan Instruction here: https://beisansystems.com/s54-vanos-rattle-procedure/ (about 80% of the page down)
    • Torque is 10.5 ft-lb (or 14 Nm)
  • You will need to turn the crankshaft to achieve this;
  • Use masking tape to secure the crow’s foot so that it doesn’t inadvertently come off during tightening and drop into the engine cavity.

  • AFTER TORQUING, check the camshaft alignment again and confirm both are still aligned at TDC (with crankshaft pin inserted);
  • If alignment is off, turn the crankshaft one more time to TDC, put pin in, and re-check (NOTE: there may be just a little bit of play in inserting the crankshaft pin which can be enough to give you a false reading at the cam alignment tool. Play with the crankshaft pin a little to move the crank fractionally, and that may resolve the reading);
  • If still off, loosen the hub bolts to pre-tensioning status and adjust the camshaft with a 24mm wrench as described in STEP 13, and repeat STEP 14.

STEP 16

Reassemble the Solenoid Assembly to the VANOS body

  • Clean the solenoid plenum and sealing plate with brake cleaner just prior to reassembly
  • Position both beneath the VANOS body correctly (follow Beisan instructions link below) and reattach using the five T-25 Torx bolts (three long and two short) that came supplied with the rebuilt Beisan unit: torque evenly in multiple passes
    • Torque is 7 ft-lb (or 10 Nm)

REST OF INSTRUCTIONS ARE SAME AS M3 E46 found here https://beisansystems.com/s54-vanos-procedure-e46-m3/ and on Youtube.

Good luck and happy driving!

Will B.

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