Blown Engine: Part Deux - Teardown

[b4hand]

Well it would make sense that the clogged exhaust caused a backflow which in turn raised the temperature of the cylinder eventually leading to detonation. Poor little S65

[SYT_Shadow]

Originally Posted by b4hand

Well it would make sense that the cloggest exhaust caused a backflow which in turn raised the temperature of the cylinder eventually leading to detonation. Poor little S65

That may have been it. Poor thing looks tortured!

[akkando]

I don't know anything about anything and I'm sure you're correct the main bearing took out the rod bearing but, how do you know it wasn't the other way around, the rod bearing failing then taking out the main?

[SYT_Shadow]

Originally Posted by akkando

I don't know anything about anything and I'm sure you're correct the main bearing took out the rod bearing but, how do you know it wasn't the other way around, the rod bearing failing then taking out the main?

The rod bearing hasn't spun. It had damage on it, but it could be removed easily and the crank was not marred.

The main bearing is welded onto the crank, the bedplate has clear marks of the tang messing the surface up.

[Richbot]

Was it #1 that had all the detonation witness marks? I'm having trouble deciphering which cylinder was which - and curious if closer inspcetion reveals any impact to the rod bearing condition on the cylinders where there was detonation

Originally Posted by SYT_Shadow

The rod bearing hasn't spun. It had damage on it, but it could be removed easily and the crank was not marred.

The main bearing is welded onto the crank, the bedplate has clear marks of the tang messing the surface up.

Yeah, but how do you KNOW

I mean, you can't really KNOW anything without being INSIDE the engine at the time of the failure observing what was happening

*begin 12 page flame war*

[SYT_Shadow]

Originally Posted by Richbot

Was it #1 that had all the detonation witness marks? I'm having trouble deciphering which cylinder was which - and curious if closer inspcetion reveals any impact to the rod bearing condition on the cylinders where there was detonation



Yeah, but how do you KNOW

I mean, you can't really KNOW anything without being INSIDE the engine at the time of the failure observing what was happening

*begin 12 page flame war*

All the rod bearings look great except for #1, which is attached to the main bearing that spun.

Lots of cylinders have detonation, but other than #1 rod bearing they all look fantastic. Suspiciously good if you ask me! If I hadn't removed them myself I'd have a skeptical hippo look.

None of the rod bearings spun whereas main bearing #1 is welded onto the crank and visibly spun

[BPMSport]

That detonation level looks absolutely insane.

Have you had someone read out the misfire/knock data from the dme on each of the cylinders? I think this would be useful information to compare to each cylinder. Also interested in seeing the long term ignition correction degree offset per cylinder.

I can't imagine the DME not pulling ignition timing back like crazy with ignition events of that magnitude. The DME is only allowed to pull so much (this is configurable), as are the settings for when and how much to add back and the steps in between.

I have never see anything like that on the pistons even on heavily tracked and raced cars, including dedicated track cars. The worst I've seen are bearings they look a bit beat up (mainly connecting rod bearings and in much fewer instances main bearings).

Sorry that happened, that looks absolutely awful. Thank you for sharing the tear down pictures. I wish we saw more posts of engines being torn down that show acceptable wear levels.

We had an issue last year with an M2 N55 in which the customer over-reved the engine and after that was severely down on power, making roughly 200HP. We found one of the VANOS gears was out of position from the over rev. We retimed the motor and it would still not pass the VANOS test. We then replaced the VANOS unit and although power was up another 40HP, the car was still drastically underpowered. We then scoped the cat through the pre car oxygen sensor hole and found the cat completely melted and disintegrated.

This was on a bone stock car, never tuned, never tracked. I still can't figure out how a momentary over rev would damage a cat that badly. This car had ZERO faults, sounded completely normally and exhibited no issues whatsoever other than being down on power. Just shows how something can be completely awry and with no faults it's difficult to pinpoint the exact issue. When we encounter a strange issue, we always scope the cat to make sure everything looks proper there.

Good luck on getting this resolved.

[EightBit]

SYT_Shadow how did the other mains look besides one and two? Thanks for sharing... crazy pics!

BPMSport whats your thoughts of the main bearings you’ve seen from tear downs? Sorry to hijack, But good timing for me

Cheers

[BPMSport]

Originally Posted by EightBit

SYT_Shadow how did the other mains look besides one and two? Thanks for sharing... crazy pics!

BPMSport whats your thoughts of the main bearings you've seen from tear downs?

Cheers

The majority of main bearing issues we've seen are from supercharger setups that drive components further off the front end of the crank, which in theory makes the crank a "lever", potentially increasing load in certain places. In these instances we have seen wear in cyl 4 & 8 mains and more rarely the front two. Most of the kits retain the stock style supercharger pulley configuration and do not have this potential issue. I have seen main bearings fail on a couple stock motors, but this Is far and few in-between.

I'm curious if the profile of the cams, in conjunction with the vanos position commanded had anything to do with the more severe detonation events this car experienced. We religiously see higher levels of combustion issues on cylinders 3 and 7 on nearly every M3 we've read this data from, and we've pulled it from hundreds of cars. It's to the point that we've thought about selectively reducing ignition in these two cylinders to combat this. Normally when the logs are pulled, the cylinders that have a higher instance of combustion quality issues coincide with higher bearing wear on those specific cylinders. The frustrating thing is that the DME allows huge differentials between the cylinders, and doesn't trigger a fault or limp mode until the combustion issues are more severe and repeatable in X number of crankshaft revolutions. Have seen instances where a faulty coil has caused 10,000 combustion quality issues in one cylinder, 10x more than the other cylinders recorded, but no faults stored because it didn't occur frequently enough to satisfy fault triggering over an extended period of time. In my opinion this is reducing the life of the bearings in they cylinder slowly, and over this extended period of time. Detonation as shown in the OPs pictures I would think would be extremely audible and noticeable while driving.

In the interest of gathering more information, we'd be happy to read this information from the OPs car on the house. I would also be interested in the flow data from each injector. We spent awhile last year chasing down audible knock on a stock M3. Plugs and coils and some other parts didn't solve the issue. After having the injectors flow tested, some were down as much as 30%. There are a lot of variables in play, and the more data that is known and obtained allows more logical conclusions to be drawn as to what may or may not have been a contributing factor.

[wfdeacon88]

Sorry for a dumb question, but a tune with test pipes and secondaries in place.. what category does that fall into by your definition? Since they are secondaries and far back on the X-pipe, are these ok? Thank you for the post and commentary.

[EightBit]

Wow that’s a huge concern for the OE DME.

Thanks for your detailed reply mate.

Cheers

[SYT_Shadow]

Originally Posted by wfdeacon88

Sorry for a dumb question, but a tune with test pipes and secondaries in place.. what category does that fall into by your definition? Since they are secondaries and far back on the X-pipe, are these ok? Thank you for the post and commentary.

When you see the vids of the red hot headers you can see how the temperature drops as the exhaust continues its path. Secondaries must see much less heat than primaries so you're probably doing fine

[SYT_Shadow]

Originally Posted by EightBit

SYT_Shadow how did the other mains look besides one and two? Thanks for sharing... crazy pics!

BPMSport whats your thoughts of the main bearings you’ve seen from tear downs? Sorry to hijack, But good timing for me

Cheers

there are some pics that show all the main bearings. They were fine. Main bearing #2 shows some extra unhappiness, probably due to the mess that happened in main bearing #1

[SYT_Shadow]

Originally Posted by BPMSport

That detonation level looks absolutely insane.

Have you had someone read out the misfire/knock data from the dme on each of the cylinders? I think this would be useful information to compare to each cylinder. Also interested in seeing the long term ignition correction degree offset per cylinder.

I can't imagine the DME not pulling ignition timing back like crazy with ignition events of that magnitude. The DME is only allowed to pull so much (this is configurable), as are the settings for when and how much to add back and the steps in between.

I have never see anything like that on the pistons even on heavily tracked and raced cars, including dedicated track cars. The worst I've seen are bearings they look a bit beat up (mainly connecting rod bearings and in much fewer instances main bearings).

Sorry that happened, that looks absolutely awful. Thank you for sharing the tear down pictures. I wish we saw more posts of engines being torn down that show acceptable wear levels.

We had an issue last year with an M2 N55 in which the customer over-reved the engine and after that was severely down on power, making roughly 200HP. We found one of the VANOS gears was out of position from the over rev. We retimed the motor and it would still not pass the VANOS test. We then replaced the VANOS unit and although power was up another 40HP, the car was still drastically underpowered. We then scoped the cat through the pre car oxygen sensor hole and found the cat completely melted and disintegrated.

This was on a bone stock car, never tuned, never tracked. I still can't figure out how a momentary over rev would damage a cat that badly. This car had ZERO faults, sounded completely normally and exhibited no issues whatsoever other than being down on power. Just shows how something can be completely awry and with no faults it's difficult to pinpoint the exact issue. When we encounter a strange issue, we always scope the cat to make sure everything looks proper there.

Good luck on getting this resolved.

I've also heard of some instances of F8Xs melting their cats. To track with primaries in place is a risk for sure. I won't be doing that again...

No one read the DME after the failure, but this was two years ago so the ECU lives on with the stroker engine build

[SYT_Shadow]

Originally Posted by BPMSport

In the interest of gathering more information, we'd be happy to read this information from the OPs car on the house. I would also be interested in the flow data from each injector. We spent awhile last year chasing down audible knock on a stock M3. Plugs and coils and some other parts didn't solve the issue. After having the injectors flow tested, some were down as much as 30%. There are a lot of variables in play, and the more data that is known and obtained allows more logical conclusions to be drawn as to what may or may not have been a contributing factor.

Unfortunately the DME has been overritten several times.

It's not a bad idea to replace injectors... I will be replacing the stroker injectors for sure

[Obioban]

Originally Posted by SYT_Shadow

I've also heard of some instances of F8Xs melting their cats. To track with primaries in place is a risk for sure. I won't be doing that again...

No one read the DME after the failure, but this was two years ago so the ECU lives on with the stroker engine build

I was just going through S65 part diagrams-- did BMW get rid of the EGT sensor? Seems like it's a pretty great thing to have, for exactly the reason you mention above (cat overheat protection)...

[SYT_Shadow]

Originally Posted by Obioban

I was just going through S65 part diagrams-- did BMW get rid of the EGT sensor? Seems like it's a pretty great thing to have, for exactly the reason you mention above (cat overheat protection)...

I have no idea... but I asked for the catless tune and then ran it with cats so I would expect the EGT protection to be removed

On the F8X generation the cats are so close to the exhaust ports that it's a wonder they survive at all. I can only imagine the temps they see.

In the S65 the cats are way after the headers in the bottom of the car

[Obioban]

Originally Posted by SYT_Shadow

I have no idea... but I asked for the catless tune and then ran it with cats so I would expect the EGT protection to be removed

On the F8X generation the cats are so close to the exhaust ports that it's a wonder they survive at all. I can only imagine the temps they see.

In the S65 the cats are way after the headers in the bottom of the car

I don't see an EGT on the F8X diagrams, either. Weird.

[BPMSport]

Originally Posted by Obioban

I was just going through S65 part diagrams-- did BMW get rid of the EGT sensor? Seems like it's a pretty great thing to have, for exactly the reason you mention above (cat overheat protection)...

There is no separate EGT sensor (which I agree wouldn't have been a bad idea to carry from the E46). Temp plausibility is monitored by pre-cat o2s (calculated) IIRC.

[BPMSport]

Originally Posted by SYT_Shadow

Unfortunately the DME has been overritten several times.

It's not a bad idea to replace injectors... I will be replacing the stroker injectors for sure

Even if the DME was flashed multiple times a lot of this information may be retained.

We have a couple sets of flow tested stock injectors in case you're interested - but sending yours out to be tested, cleaned and tested again is a less costly route if you can afford some downtime.

[EightBit]

Originally Posted by SYT_Shadow

there are some pics that show all the main bearings. They were fine. Main bearing #2 shows some extra unhappiness, probably due to the mess that happened in main bearing #1

Good to know, thanks mate.

Cheers

[VictorH]

Originally Posted by BPMSport

Even if the DME was flashed multiple times a lot of this information may be retained.

We have a couple sets of flow tested stock injectors in case you're interested - but sending yours out to be tested, cleaned and tested again is a less costly route if you can afford some downtime.

Any company in particular you like for cleaning and flow testing injectors?