Marcus' E46 M3 Blown Motor Diagnosis - THE RESULTS ARE IN

[HPF Chris]

To get everyone up to speed. Marcus has the HPF stage 3 turbo system on his M3. He decided to swap out his fuel system and EMS and go with ProEFI. Marcus had issues with the car and shipped it to us for diagnosis and repair. Here is what we found.

[ame]http://www.youtube.com/watch?v=VuSoCsYj0jY[/ame]

[ame]http://www.youtube.com/watch?v=vQAIiLM0bQg[/ame]

[ame]http://www.youtube.com/watch?v=CYgjAlsdcqU&feature=player_embedded[/ame]

[BadBoostedBmwM3]

Oops... Cracked ring lands. IIRC, he was making more power than a regular stage 3 setup.

I was unaware of Marcus' problems. When did this happen?

[milKt]

So it seems the hardware is free from blame.
Can you guys VIEW the PROEFI tune?

What is their stance on the issue?
and
did Marcus and PROefi make any promises to each other concerning the risks of serious race car pauer?


EDIT: a "too small" ring gap variable is interfering with blame being placed on the PROefi tune. Is it possible that Marcus' engine build was slightly different (accidentally) than the 85 other HPF engine builds and has played a large part in the engine failure?

.

[nondescript]

I wasn't expecting too much from the title, but actually learned some good stuff there. Thanks for posting that video. It's science.

I'd love an explanation about forged aluminum shrinking once it hits a critical temp. That sounds interesting.

[5mall5nail5]

Chris - this is common failure on a motor that is run too hot on a ring gap too tight with a wall clearance too small. I am not sure what the builder is talking about the piston shrinking down - you were right, the reason it rocked in the bore is because of the wear from the expansion. In my unprofessional but avid enthusiast opinion - I would venture to say that this motor was probably pushed hard on the tune especially considering its one of the ProEFI builds on E85. Jason has a product to push and if his numbers are X% higher than AEM numbers, more people will switch, your shop will be sold, and the world will be better. But, he's likely tuning way more on the edge. The truth is that the exhaust temperature really wouldn't have been as hot as your engine guy is saying - the cylinder temp was up, the pressure was up, but the EGT isn't as crazy because the catastrophe is occurring in the cylinder. When the tune is soft you get higher and higher EGT because of the combustion event happening later and later and ultimately making its way nearer the exhaust stroke.

My vote would be if they're going to run 350 kPA on those setups you need to open the ring gap and wall clearance. The motors might smoke a bit when not being pushed (when the pistons aren't expanding) and might have some piston slap. The customer won't be as happy with a motor more prone to smoking but it will be "normal" for the build. That rocking that your tech saw is what takes out spark plugs in other motors with off-center spark plugs. Our heads have a centralized spark plug so the "lever" in the piston/wrist-pin is centered so the only time we see interference is if something reaaaally bad happens. Other motors will see spark plug gaps close down due to piston wear and ring land failure that is an early indicator of potential melt down.

Definitely ProEFI's fault. The motor was not setup to reach those temperatures. They should have had better knock control. They didn't poke holes through the piston so it wasn't catastrophic knock event/failure, but the engine was not setup to be making that much heat. Could have been prevented but I feel like ProEFI is/was probably out to "prove" something with these early setups.

</amateur opinion>

I'd love an explanation about forged aluminum shrinking once it hits a critical temp. That sounds interesting.

I've talked to a few builders and engineers in my time with doing these builds and have never heard of a piston shrinking at high temp. Shrinking in the cold and slapping, sure. But when they get hot, things expand. The piston "shrunk" because it left measurable material deposited to the cylinder wall!

This builder does not instill a great feeling of confidence in my opinion!

[bawareca]

.............

+1
More or less what most FI motors are hurt/killed.
Just want to add that the preignition kills the engines in a matter of a few strokes.It is like hammering the top of the piston with a 10 lb mallet-it can only take as much before it xplodes and the conrod bents.

[wazzu70]

Chris, thanks for sharing the informative videos lately. They are pretty cool and help educate the community. Props on that!

You can heat shrink aluminum, although I haven't heard of it in a piston, it does not mean its impossible. The material will expand to a certain point, but at elevated temperatures the material becomes malleable enough to be reformed. Aluminum also has a much higher chance of this due to the lower melting point. If you look around you can see shrinking hammers and slapping files used in body work to shrink the metal and "pull in" dents.

I'm not a materials expert, but it seems plausible that with spiking cylinder temps the piston could slightly deform and become smaller than it was before after it cooled. Keep in mind the cylinder tolerances and how much the piston would have to deform to start causing issues and a downward cyclical spiral....especially with a bad tune.

[5mall5nail5]

In order to reduce aluminum in size you need to work it. For it to be soft enough to be worked as a whole, that bore would be coated with aluminum. They're already forged pistons so they've been compressed in their molten state previously. I don't buy the "shrunk" piston thing at all.

[ZooyorQ]

There is a tremendous amount of history behind this motor that is clearly not discussed in the video.

Source: I own the car.

[GT35Rm3]

go on.....

[ZooyorQ]

The forced induction thread on E46F has a seriously long and intense debate going on regarding it. I'm trying to stay neutral.. but if you're interested you can find more info there.

[SiGmA]

Appears to be ring gap and wall clearance related... I'd love to have Don or one of the other builders chime in.

Chris, how would you feel about having some shop like Bearing Service take a look at the motor and give their opinion? I bet they would do it for free. Good people.

[GG///M3]

Appears to be ring gap and wall clearance related... I'd love to have Don or one of the other builders chime in.

Chris, how would you feel about having some shop like Bearing Service take a look at the motor and give their opinion? I bet they would do it for free. Good people.

This.

[BadBoostedBmwM3]

It seems like we all can safely agree the tune was not "safe."

I'm not an expert... The only think I saw was that head lifting was lifting. (obviously, I saw the cylinder destruction.)

I don't know if the shrinkage is plausible or not, but I can see it happening.

[rukman]

[ame]http://www.youtube.com/watch?v=_VrFV5r8cs0&feature=youtube_gdata_player[/ame]

[good & tight]

If the bore was too small there would piston skirt scuffing. Evidence of the ring gaps touching would be on the ends themselves (shiny finish)
When ring gaps touch the ring starts to fold in half making marks on the top of the cylinder bore called eyebrows.

[GG///M3]

The forced induction thread on E46F has a seriously long and intense debate going on regarding it. I'm trying to stay neutral.. but if you're interested you can find more info there.

It would be best to post the useful info here. Sucks that this has happened dude.

[MTrace]

It is a very good read.

http://forum.e46fanatics.com/showthread.php?t=908439

[wazzu70]

In order to reduce aluminum in size you need to work it. For it to be soft enough to be worked as a whole, that bore would be coated with aluminum. They're already forged pistons so they've been compressed in their molten state previously. I don't buy the "shrunk" piston thing at all.

As I said, I'm not a materials expert and this topic is something out of my league. All I know is that it is possible to heat shrink aluminum even though it is counter intuitive to think so. Whether or not heat shrinking can happen in this scenario is beyond me.

The e46F link was interesting. I think the bottom line is the engine obviously needs to be built to the target power. You can't build an engine for a certain power level and then just decide to increase power say 50% more. The tolerances on everything need to be chosen to meet the desired target.

As someone mentioned in the other thread, the engine could have been just fine at the power level it was designed for and trying to squeeze more out of it might have put things over the top. I don't have enough experience to eyeball the the pistons and know if the piston rock was too much piston to wall clearance, or if that much clearance is necessary for those power levels.

For HPF it would be wise to record what the ring gaps and piston to wall clearances are on the motors so if the car is tuned by someone else they will have that information and should choose an appropriate power target given the setup.

Nothing is worse than just assuming a "built" engine is bullet proof. There is so many factors that come into play.

FWIW Accurate Engines in Lynwood, WA is where most of the BMW race cars in the area go to have their work done. Might be worth reviewing the engine with Mike there. I have nothing to gain from this, I have just found the shop useful in the past and plenty of friends have had similar experiences on their race engines.

[BadBoostedBmwM3]

The e46F link is very interesting...

[Brody @ Miller]

It's hilarious. As usual.

[5mall5nail5]

For HPF it would be wise to record what the ring gaps and piston to wall clearances are on the motors so if the car is tuned by someone else they will have that information and should choose an appropriate power target given the setup.

That's usually what "blue printing" involves.

Sent from my DROIDX using BF.com

[GG///M3]

I think I'm going to have to agree with the ProEFI guy, and some of the other guys over there. This guy hammered it here http://forum.e46fanatics.com/showpos...1&postcount=74

[wazzu70]

That's usually what "blue printing" involves.

Well, mostly yes. Still, its clear they do not release this information to the customers. I'm not even sure if they keep the info themselves or if they just trust the builder.

At least from the thread it seems like they don't keep this info or give it to the customers. Maybe that's not the case.

[hobbit382]

The motor was not built for it? It's 1 of 3 sleeved blocks from hpf. It's the strongest one they make but you guys think it's the tuners at fault for overpowering it?

The engine had problems since it was delivered. Major oil consumption and fouling of the #5 plug over and over. I garuntee it had a broken ring right from the start. It has a .040 underbore motor and I bet they used a less than ideal ring compressor.