Another blown motor, With Pictures

[Phantom]

May 5th, 2002: I was riding shotgun in this 2002 M3 at Firebird Raceway when the motor blew .

6-speed manual tranny. Approx 4500 miles on the odometer.

Exiting the final turn onto the main straight at the main track, the driver, Vinnie, was upshifting from 2nd to 3rd gear short of redline, approximately 7500 RPM. I had been watching his shifting and footwork technique for the past few laps, so I'm confident that my description of the events is accurate.

Vinnie had the clutch depressed and was passing into neutral on the way to 3rd gear. While the clutch was still depressed and the revs were dropping between shifts, the gearshift hesitated to go into 3rd. Distracted by the tranny, Vinnie and I both looked down at the gearshift momentarily. Just as Vinnie intently selected 3rd gear I heard a distinctive "POP!", following which the motor was making a disturbing chugging sound, not making any power. Steaming coolant or smoke billowed from under the hood as I advised Vinnie:

"Shut it off. Pull over to the left, offline."

With the car stopped on the straight, off of the racing line, we would have waited in the vehicle for the marshaller's signal, but steam or smoke continued to billow from under the hood. Not knowing which it was, and fearing the potential for fire, we cleared the track behind us before egressing the car.

Once safely out of the car and on the other side of the safety wall we noticed a mixture of coolant and motor oil pooling on the track under the car.

I am not a trained mechanic, but I'm mechanically inclined with 15 years experience of DIY maintenance on my own cars, motorcycles, and racing karts. I hold a B.S. in Aerospace Engineering from the US Air Force Academy and I have 13 years experience studying aircraft systems as a fighter pilot and airline pilot. Here is my best GUESS at what happened:

Approaching and during the upshift from 2nd to 3rd the motor failed. With the clutch depressed and the failed or failing motor disconnected from the drive wheels the revs were free to fall, perhaps to zero. The large disparity between the very low motor RPM and the driveline RPM impeded selection of 3rd gear due to increased load on the tranny synchros. This required Vinnie to use more than the normal attention and effort to overcome the increased synchro resistance. Once in third gear, the clutch was released and the driveline stress forced the failed motor to increase RPM, leading to more catastrophic failure and the "POP".

I surmise that our attention was drawn to the gearbox and away from the tachometer during the selection of third gear. Thus, we didn't notice any potential abnormally low engine RPM that may have accompanied the initial stages of engine failure.

What do you guys think?

[Stockman]

May 5th, 2002: I was riding shotgun in this 2002 M3 at Firebird Raceway when the motor blew .


Notice Link??

http://www.cecilwalker.com/PhotoSite.../img_20251.htm

[Bob ///M3]

That's a shame!

I expect "if" the rpms were very low when the clutch was finally engaged into 3rd gear, at that ground speed, the rear tires would have locked up somewhat since the engine revs were at such a great difference. Still, it sounds like the engine problem had already begun to occur prior to the gear selection.

I certainly hope BMW will take care of these engine problems soon or they will only hurt their "M" reputation. I look for a major engine design change on the E46 M3 engine before this is over! I just hope BMW corrects the problem for current E46 M3 owners and reimburses them for their losses in time, aggravation and the unnecessary expenses incurred while owning the car...and at time of re-sale.

If there was ever a time not to own the first year or two of a new model car (or performance engine), this one seems to be it!

Listen to the sounds of a "broken" E46 M3 engine!

Bob ///M3

[Phantom]

Originally posted by badbadm
Shouldn't you have been able to hear the revs drop to nil while he was trying to find 3rd gear? Did you? I thought that if the revs went from 7500 to 0 during a 2 - 3 shift, you would know it whether you were looking at the tach or not.
What do you think?

badbadm,
We were just past the apex, accelerating through more than 60mph, with the windows full down, wind noise, road noise, tire noise, (cheering crowd noise??) all while wearing helmets. The whole thing happened in the time it takes to make an expeditious 2-3 upshift under track conditions.

In that time frame under those conditions I doubt I would have noticed any difference between normal RPM decay between upshifts and RPM decay due to a failed or failing engine.

[Kevlar]

This is horrible... as sad as it may sound, the guys at Merc Benz must be laughing everytime they hear this.

[Phantom]

Originally posted by Bob ///M3
That's a shame!

I expect "if" the rpms were very low when the clutch was finally engaged into 3rd gear, at that ground speed, the rear tires would have locked up somewhat since the engine revs were at such a great difference.Bob ///M3

Bob, I wonder if a blown motor would have MORE drag or LESS drag on the driveline when the clutch is released. I also wonder if it depends on what has failed inside the motor. Any ideas?

[Bob ///M3]

Yes, if the failure involved the valves being bent there would be less cylinder compression and the engine would freewheel easier. However, if the failure involved something that created added resistance to the engine's rotatation, it could cause the engine to act as a greater brake than normal. It all depends on what was broken in the engine...

From what I hear the chances are good that # 2 rod bearing failed. This might have caused the rod to be "thrown" and head damage to occur. It seems that BMW has a problem with the rod bearings and/or crankshaft in some fashion. They have increased the bearing clearances from .03mm to .04mm and changed the engine oil to 10W-60 because of this clearance change in hopes of prolonging the life of these engines. My best bet is that this is a band-aid approach until BMW can cut-in necessary changes to once and for all correct this major problem. I look for a semi-major revamping of this engine before long. BMW's "M" reputation is on the line...and they know it!

Bob ///M3

[Phantom]

Originally posted by Bob ///M3

I certainly hope BMW will take care of these engine problems soon or they will only hurt their "M" reputation. I look for a major engine design change on the E46 M3 engine before this is over! I just hope BMW corrects the problem for current E46 M3 owners and reimburses them for their losses in time, aggravation and the unnecessary expenses incurred while owning the car...and at time of re-sale.
Bob ///M3

Later on I forwarded Vinnie links to this forum and the roadfly forum discussing engine failures when he told me his initial dealings with the BMW dealer were a bit difficult. Initially the service rep denied knowledge of E46 M3 engine failure history. Vinnie then returned to the dealer armed with this information and asked for a new motor rather than a rebuild. The dealer was quick to comply.

Thanks go out to all those E46 M3 owners who have shared their blown motor experiences, and to bimmerforums.com and roadfly (adminstrators/moderators/members) for getting the word out!!!