Engine Overspeed

[SliM3]

Welp, nothing really to say other than a big resounding FAAAAAWK!! Doing a little spirited driving, rpm's skyrocketed and before I knew it boom, pulled the rod cap right off.

In the pic you can see how the crank counterweight pushed the #2 rod right out of the side of the block, and also the exposed main oil feed galley.

Not to mention almost lost control of the car once the engine locked-up & oil hit the tires, trying to pull off to the shoulder of the freeway. Pucker factor = 11!

Sooooo, looks like I've got my hands full again this winter.

[Icecream]

ouch man! what did you do? hit 12k on a 3-2 shift?

[repoman89]

Curious if you have any sort of shifter kit. I find I’m much more uncertain about gearing with the soft and loose stock shifter in my E39 M5 than I am with the Autosolutions kit in my M3. Those AS kits are great for nailing any gear change.

[yhp2009]

Ooof! How many miles did it have? Hopefully you can either find a good replacement engine. Or do a full rebuild. Either way that is one metal way to go out

[Martyn]

Sorry to see this Brian, you'd not long ago built this up!

[Tbonem3]

Sorry Brian

[WOLFN8TR]

Sorry to see this Brian, you'd not long ago built this up!

X2...I do believe so a few years ago.
I can’t even imagine. 🙁

[SliM3]

Thanks guys! Yeah this was a rebuild from a few years ago, no shifter kit just SMG. Optimistically speaking, I'm hoping this only means a new block and (hopefully) repaired crankshaft. I have all the stock pistons and rods so most likely those will go back in. Obviously I'll know what I'm dealing with once I get the engine torn apart, but from what I can tell using a cheap borescope the piston didn't appear to make contact with the valves. So for now I'm calling the cylinder head good.

[gabylonfive]

Thanks guys! Yeah this was a rebuild from a few years ago, no shifter kit just SMG. Optimistically speaking, I'm hoping this only means a new block and (hopefully) repaired crankshaft. I have all the stock pistons and rods so most likely those will go back in. Obviously I'll know what I'm dealing with once I get the engine torn apart, but from what I can tell using a cheap borescope the piston didn't appear to make contact with the valves. So for now I'm calling the cylinder head good.

i always assumed the SMG was impervious to overrev - i guess that's not the case? did you initiate a downshift when this happened?

[Icecream]

i always assumed the SMG was impervious to overrev - i guess that's not the case? did you initiate a downshift when this happened?

Stock it is. It will not downshift unless it will stay below 8k.

[yhp2009]

Stock it is. It will not downshift unless it will stay below 8k.

Thats legit scary to have smg that doesnt do this calculation for you. Good luck OP

[jbfrancis3]

Terrible, sorry to see. With whatever setup you have (I'm talking ECU, logging, etc), is there any way to determine what peak rpm was hit?

[SliM3]

Terrible, sorry to see. With whatever setup you have (I'm talking ECU, logging, etc), is there any way to determine what peak rpm was hit?

I was thinking about this after it happened, & I know the computer logs max rpm for service claims but not quite sure where it's located.

i always assumed the SMG was impervious to overrev - i guess that's not the case? did you initiate a downshift when this happened?

I downshifted to third at <60 mph, then full throttle while admittedly paying more attention to AFR instead of tach and that was all she wrote. I heard what must've been the cap initially being sheared off within seconds before I got the shudder, smoke and 0 on the tach.

[r4dr]

Stock it is. It will not downshift unless it will stay below 8k.

What's the logic for removing this?

[mrgizmo04]

Ouch, sorry man.

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