Bent valve! Causes and long term...

[V8FunNaturally]

Originally Posted by SenorFunkyPants

It goes something like: go over a hump backed bridge fast enough that your wheels leave the ground and with engine at high revs. In a panic and while still airborne, you lift off the throttle , brake and shift down....Gearbox software thinks its safe to shift down but when you hit the ground you overspeed the engine
Like I said its unlikely.

oh but that's a dct scenario, not 6MT I guess you can money shift a MT too.

Originally Posted by dparm

The amount of fuel in the oil is going to be extremely low. These are not direct injection motors. My most recent UOA showed the fuel content as being "under 0.5%", which is effectively 0. Other UOAs posted here show similarly low numbers.

I would worry more about moisture in the oil, but even that will be burned off within a few minutes of the oil passing the 160 F mark.

Wrong, like I said it depends completely on your driving profile but also on the thermometer where you live. If in the winter you drive a lot of short distances highway or not. Then you have high fuel entrainment as the evaporation temperature is mostly only reached briefly. There can be a significant amount of gas in the oil and I mean significant. There's even a note about this from BMW.

[dparm]

Originally Posted by sunsweet

oh but that's a dct scenario, not 6MT I guess you can money shift a MT too.



Wrong, like I said it depends completely on your driving profile but also on the thermometer where you live. If in the winter you drive a lot of short distances highway or not. Then you have high fuel entrainment as the evaporation temperature is mostly only reached briefly. There can be a significant amount of gas in the oil and I mean significant. There's even a note about this from BMW.

I have yet to see a significant amount appear on the UOAs shown in this site. Anyway, a tiny amount of gas in the oil is not the end of the world. The sump is huge and can deal with a bit of fuel dilution.

[SenorFunkyPants]

Originally Posted by sunsweet

oh but that's a dct scenario, not 6MT I guess you can money shift a MT too.

The OP has a DCT and the explanation was how you can over rev a DCT.
Am I missing something?

[V8FunNaturally]

Originally Posted by dparm

I have yet to see a significant amount appear on the UOAs shown in this site. Anyway, a tiny amount of gas in the oil is not the end of the world. The sump is huge and can deal with a bit of fuel dilution.

Well, it also depends on which gas brand you use.

The note from bmw is quite dramatic though :

"[...]. if in the winter you drive a lot for short distances (= high fuel entrainment as the evaporation temperature is mostly only reached briefly) and then a long distance (fuel can then evaporate readily), this journey will
cause a considerable drop in engine oil level. This is not engine oil consumption, but rather a change in engine oil level caused by the fuel content in the engine oil. Customer complaints are often the result of this effect. It canhappen that the engine oil level drops by more than 1 litre after driving just a few hundred kilometres. "

Basically BMW is saying under winter conditions and short drives there can be as much as 1 liter of gas in the oil !

My point was using the car on short commute daily in the winter is not good. Not to mention possible oil foaming from the temperature swing / increased volume of oil.

[paddy335]

Originally Posted by bruce.augenstein@comcast.

If you did do a money shift, they'll know, so be prepared to open your checkbook wide.

Bruce

PS - Did a money shift (3-2 instead of the attempted 3-4) on an E36, and a new long block (installed) cost me $8800. Bummer.

Out of interest, how do you money shift the DCT....I would have thought it would have in-built protection from that?

[scm6079]

Originally Posted by sunsweet

...also on the thermometer where you live. If in the winter you drive a lot of short distances highway or not. Then you have high fuel entrainment as the evaporation temperature...

I'm in Mesa, AZ - so it never gets to freezing out here. Typical winter daytime temp is still warm - in fact it's 82 degrees today, and has been in the 70's most of the winter.

Originally Posted by AWAirFlow

may be broken valve spring. they have to take it apart and check. techs told me it was bent valve before opening it up and realizing it was a broken valve spring.

Originally Posted by s85e90

Most likely the valve spring failed which has happened a number of times on these cars. Yours just got worse luck and collided with the piston to bend the valve

Originally Posted by kerrit

there are a few reports on this forum of bent valves if you search. Theory is a bad batch of valve springs used on our engines.

Originally Posted by M3Captain

Broken spring lock or worn valve guide. If there was no piston contact and you didn't continue driving it you may be ok. Post up when you get a diagnosis from the dealer.

I don't have any explanation yet - but I *did* get some photos from my helpful service rep at the dealer. If you look in the first photo, that looks like a broken valve spring to me. I'm not sure about the other photos.

[Vic311]

So it was a broken spring. Good to hear that the issue is consistent and not due to over rev or timing.

On a side note, you should really consider using techron more frequently. You have some moderate carbon deposit build up.

[V8FunNaturally]

Originally Posted by Vic311

So it was a broken spring. Good to hear that the issue is consistent and not due to over rev or timing.

On a side note, you should really consider using techron more frequently. You have some moderate carbon deposit build up.

what's techron ?

Nice pictures OP by the way, hope you'll be back on the road soon..

[s85e90]

Techron is an additive; made by Chevron to be put into the gas tank every so often. Chevron gas also contains this.

Side note: i was right

[Z K]

Originally Posted by s85e90

Techron is an additive; made by Chevron to be put into the gas tank every so often. Chevron gas also contains this.

Side note: i was right

+1 Took me a min to realize that Chevron gas stations don't exist in 1/2 the USA. We take Chevron gas stations for granted here. But then we also have to live with our "premium" 91 octane gas.

[CurbBender'90]

I would get it checked ASAP n I've gotten 19.9 and it won't go up any higher, I saw what others got(lower) n tried pushing it more. (19.4)

[X5-User]

I see a number of M3 guys with broken spring on this forum. Whats going on ??!! This raises my concern on the quality of M3 V8 engines. How much would this cost to fix if out of warranty?

[M3-S65]

Originally Posted by Palestine

I see a number of M3 guys with broken spring on this forum. Whats going on ??!! This raises my concern on the quality of M3 V8 engines. How much would this cost to fix if out of warranty?

Why would you be concerned? Is it the fact that you paid 50 to 75k for you car and expected reliability at least as good as a POS Dodge?

If that worries you...read the 95 page bearing thread
http://www.m3post.com/forums/showthr...hlight=bearing

Honestly, this is the minority not the majority and we all run a low probability. The forum is a sounding board for problems not praise.
However, don't go off your warranty...although it is probably as reliable as a Dodge, the dodge engine is 10k and ours is 25k.

[X5-User]

Originally Posted by M3-S65

Why would you be concerned? Is it the fact that you paid 50 to 75k for you car and expected reliability at least as good as a POS Dodge?

If that worries you...read the 95 page bearing thread
http://www.m3post.com/forums/showthr...hlight=bearing

Honestly, this is the minority not the majority and we all run a low probability. The forum is a sounding board for problems not praise.
However, don't go off your warranty...although it is probably as reliable as a Dodge, the dodge engine is 10k and ours is 25k.

I think the rod bearing issue is overblown. How many people have this issue you so far? probably 3 or 4? even the poll someone had not long ago many m3 owners misunderstood the question. However, the bent valve thing is appearing more specially from later models.

[aus]

Originally Posted by Palestine

I think the rod bearing issue is overblown. How many people have this issue you so far? probably 3 or 4? even the poll someone had not long ago many m3 owners misunderstood the question. However, the bent valve thing is appearing more specially from later models.

3 or 4??? Really??

http://www.m3post.com/forums/showthr...light=Registry

.

[dparm]

Originally Posted by Z K

+1 Took me a min to realize that Chevron gas stations don't exist in 1/2 the USA. We take Chevron gas stations for granted here. But then we also have to live with our "premium" 91 octane gas.

If you have Texaco it's the same stuff. They even advertise "Texaco with Techron".

Techron is in their gas but at very very small "maintenance" doses. The bottle you buy at the store is highly-concentrated and more of an atom-bomb treatment for neglected systems.

Techron is really just PEA, or polyether-amine. It's a well-regarded cleaner. Gumout Regane, Red Line SI-1, and Amsoil PI all use it in large quantities too. Other gas stations have similar chemicals in their gas, as mandated by law.