Valve stem seals...becoming a normal thing

[Michael@GermanAutoWerks]

We are on our tenth n54 that is in need of valve stem seal replacment this year. It seems like it's becoming the norm for higher mileage n54s. 70k miles and up. We have been getting quite a few smoking n54s, not all have just been valve stem seals, but upon removal of the turbos we have seen about 80% of the cars needing them that come through our shop.

Heres is what a leaking valve stem seal would like look wit has the turbos removed

Special tool needed to release tension of the valve springs so the cam can be removed, without this you run a risk of cracking or damage.

Shop air is forced into the cylinders to keep the valves in place sof once the keepers are removed it does not fall into the cylinder.

Our special tool needed to be able to replace them in the vehicle, the conventional way is removing the whole head and doing it on a bench or such.

 

[veer90]

if the mileage at which they go bad is 70k as you claim, we would have seen a lot more of these cases by now. everyone seems to forget the N54 was first released late 2006, and has been out 11+ years now.

good post but I'm highly suspect of the mileage.

 

[pysical]

Had my engine rebuilt at 130k. Had the head off and ported. Guy who did the work said my valve seals looks fine.

 

[ATL-IS-N54]

This is news to me... Stem seal viagra

 

[Jeffman]

I’m wondering out loud if the valve stem seals are more prone to degradation by ethanol... if so, yikes! ...and potentially exacerbated by port-injection...double yikes!!

 

[Alex@abrhouston]

no, they are not.

 

[Jeffman]

Ok...phew...(as you could see, I got a little concerned.)

 

[MMP]

Just to add to the discussion, we have rebuilt about 15 heads and all 15 had the exhaust valve guides worn out of spec or on the very limit which required replacement and 2 of the heads had the intake valve guides worn out. We buy custom made valve guide replacements when we need to replace valve guides because BMW doesn’t make them.

 

[veer90]

Just to add to the discussion, we have rebuilt about 15 heads and all 15 had the exhaust valve guides worn out of spec or on the very limit which required replacement and 2 of the heads had the intake valve guides worn out. We buy custom made valve guide replacements when we need to replace valve guides because BMW doesn’t make them.

Out of those 15, were all of those MMP ported heads, oem spec rebuilds only, or a mix?

Wondering how many MMP heads are out there since no one has posted any results afaik.

 

[MMP]

a mix of built engines that have shipped, built engines in process and people that have bought a head only.

 

[carabuser]

Bit of thread necro, but for anyone that has done this valve seal replacement what parts did you use?

I ordered Corteco 12030147 for the exhaust valves and Corteco 12030152 for the inlet valves. The exhaust seal looks identical to the BMW part that came off the engine but the inlet seal looks slightly different, same width etc but shape a bit different and it's green rather than red. Is this normal?

Not sure if I should just buy the BMW part number for the inlet. Don't want to do the job twice!