E90 320i N46 Vanos

[morne W]

Hi folks

Need some advice from all you learned fanatics please.

I had the head removed from a N46 to replace valves, due to lack of compression cylinder 1, about a month ago. New head gasket was fitted and everything put back.

I've since sold the car and yesterday she broke down. It would appear the vanos pulley either sheared from the camshaft or the cam has snapped. Covers still need to come off to make sure which happened.

Before I go pick a fight with the mechanic, what are the reasons this would happen? If workmanship, why would this only happened a few weeks later? What are the other reasons this might happen?

Please help!!

 

[zakes27]

i've heard a cam snapping before on an e90 due to lack of oil pressure.
by vanos pulley u mean the vanos gear/unit? if so , the vanos gear could've been worn through (check sump for silver metal sheddings), timing chain could've snapped (rare) and cause the piston to hit the valves.

mechanics has a tool that can remove valve stem seals and fit new ones without removing the head (and still charge you for a complete head removal), so check if the head gasket is new.

if the head was remove, the mechanic should've noticed that oil was been starved to the head or worn out vanos gears/timing chain.

i just replaced timing chain kit, sump clean up, one way valves, both vanos gear, vanos solenoids, bearing ledge clean up ... was not cheap

 

[morne W]

i've heard a cam snapping before on an e90 due to lack of oil pressure.
by vanos pulley u mean the vanos gear/unit? if so , the vanos gear could've been worn through (check sump for silver metal sheddings), timing chain could've snapped (rare) and cause the piston to hit the valves.

mechanics has a tool that can remove valve stem seals and fit new ones without removing the head (and still charge you for a complete head removal), so check if the head gasket is new.

if the head was remove, the mechanic should've noticed that oil was been starved to the head or worn out vanos gears/timing chain.

i just replaced timing chain kit, sump clean up, one way valves, both vanos gear, vanos solenoids, bearing ledge clean up ... was not cheap

So it ended up being the bolt that holds the exhaust vanos gear onto the cam. Cam is ok, rockers are fine too, so it seems the valves aren't bent. Just need to set timing and start, hope the valves aren't bent or anything else.... eish

 

[zakes27]

i've heard a cam snapping before on an e90 due to lack of oil pressure.
by vanos pulley u mean the vanos gear/unit? if so , the vanos gear could've been worn through (check sump for silver metal sheddings), timing chain could've snapped (rare) and cause the piston to hit the valves.

mechanics has a tool that can remove valve stem seals and fit new ones without removing the head (and still charge you for a complete head removal), so check if the head gasket is new.

if the head was remove, the mechanic should've noticed that oil was been starved to the head or worn out vanos gears/timing chain.

i just replaced timing chain kit, sump clean up, one way valves, both vanos gear, vanos solenoids, bearing ledge clean up ... was not cheap

So it ended up being the bolt that holds the exhaust vanos gear onto the cam. Cam is ok, rockers are fine too, so it seems the valves aren't bent. Just need to set timing and start, hope the valves aren't bent or anything else.... eish

eish hectic .. glad nothing is damaged!

 

[Manfred]

the bolts holding the vanos unit on camshaft can only be used once.

 

[Slant]

Yep, when I started reading this thread that bolt was the first thing that popped up, however, I’ve used the bolts more than one but not more than twice. It was possibly over torqued. If you weren’t the first owner then there is no way to tell wether those bolts have been used before.

Best practice, use the bolts only one, the cost and time of repairs is much more than ZAR55