V6 piston failure

[Camber74]

Hello, 

my Evora S, with only 6000km...fail with engin rattles...diagnosis...most probably piston failure in the rear bank of V6. Disaster....

Lotus first answer is that V6 is over-reliable...you were very unlucky, but I don't trust it, and I was able to understand at least 10 cases in Italy only....You can understand the level of disappointment. I would ask if someone else experienced the same big issue, and how manage it.

thank you in advance!

Edited May 6, 2017 by Camber74

[JayEmm]

To my knowledge V6 engine failures are very rare.. what age is your car?

[Camber74]

2011

 

[The Pits]

Sorry that you've had this. I've never heard of a V6 engine failure in a Lotus, let alone at such a low mileage. It will be interesting to see who else comes forward but I believe this is very rare. The Toyota V6 is very tough. I hope you have some form of warranty. If not you would hope there might be some goodwill gesture if you bought it from a dealer. Fingers crossed that it's something else less expensive.

[DanR]

If there are 10 engine failures in Italy I would be suspicious of the fuel. Maybe it's not the octane it's supposed to be sold as?

[ramjet]

Dan might be onto something. I have never heard of a Toyota V6 failing like this. Best of luck proving it is fuel though.

[Alfa2Evora]

I'm driving down to Sicily and back later this year - I hope it's not catching.

[JayEmm]

I doubt it is fuel. I suspect one of the reasons the engines are not very stressed is that if someone in the USA fills the car with 87 octane (equivalent to our 91 I believe) the car still has to work...

I believe putting Super only stickers on the car doesn't get Lotus out of trouble if an engine goes pop.

[NedaSay]

Except that 87 is way worse than 91...  In order to cope with our bad fuel, Lotus and other manufacturers do have to remap the ECU so that the engine keeps delivering performance,  If some do wonder why the Sport 410 does not deliver the same torque figures over here look no further than that.  

Now considering that the 2-GR is built to be bulletproof, a bad mix of bad oil and bad fuel could still kill the car's engine. It would take a lot though, especially considering that Toyota QA process is "very thorough" and Lotus doesn't touch the block, it can still happen. Although if 10 cars in Italy have been subject to that while we haven't heard of such troubles anywhere else I think is extremely weird.  Now the car in question is 6 years old and only has 6000km, so the engine is "barely" out of its running period... Could have the engine been abused in the first 1500km before you acquired it?    

[PaulCP]

4 minutes ago, NedaSay said:

Although if 10 cars in Italy have been subject to that while we haven't heard of such troubles anywhere else I think is extremely weird.   

Unless the "10 cars" is just an exaggeration. As you say, strange that no such problems are known elsewhere

[Vulcan Grey]

I read of one in Vienna (posted on LT) that had broken pistons.  But it was highly modified (Komotec I believe)

[Camber74]

It's not an exageration, or at least I'm already in contact with 4 persons, I still need to find the others, I only ear of them from some service shops. Anyway, I agree with you that it's hard to believe that in the world this is not diffuse. Really hard to believe. I'll take you in touch of next steps.

[NedaSay]

I expect the dealers would escalate this to the factory, 4 engines suffering from piston failures from Toyota blocks in the same country, if yes this cannot be random and there's probably an external condition to explain it I think.

[#84]

Alessandro,

 I am really sorry to hear about your engine failure. Worse is that it is not the only Evora S who had this issue. It has happend twice to me. The postive part of it was that it was fully covered by the insurance company due to mileage (32410 km) and age (2011 -> Aug 2015). The sad part was that it took them 1 year to fix the engine, partly due to the fact that they missed the melted main catalyst the first time and had to re-do it once more. It ended with a new short block (block + crankshaft + con rods + pistons).

 It cannot be fully proven what happened first and why, but piston no 5 "ring land" collapsed and pre-cat on that cylinder bank melted followed by melting main catalyst. When you have such a piston collapse, you loose most compresison on that cylinder and it will maybe not ignite. If it ignites, it leaves a lot of unburnt fuel to burn in the catalyst/s.

 When this was clear and they had to do the second engine repair, swapping block, I decided to get rid of the original exhaust system and called Jim Valentine (Mr. "2bular"). We had an interesting discussion and he claimed such failures had happend before with his conclusion that the lambda sensor fitted to the exhaust manifold had got too hot, giving false signal, resulting in too rich mixture which finally caused burning fuel and meltdown of the pre-cat. Shortly after this, Jim added the kit to his webpage and called it "Engine Protection kit", which I would say is a fair description. http://www.2bular.co.uk/evora-s/engine-protection-kit

If I understand it correctly, the Ferrari F430's has suffered from exactely the same problem.

 I had quite a tough time with the insurance company who came up with a lot of stupid explanations leading to the conclusion that there was something wrong with the car when I bought it, since I only had it registered for 6 weeks when the breakdown occured. I searched all forums, but found nothing. Lotus supported with a neutral opinion about what could / could not have happened, but did not comment wether it happened before, or not. The authorized dealer/workshop as well as the large German dealer I bought the car from (and sold the car as new) claimed they had never heard of anything similar. Anyhow, it took me three months, a legal process and full use of my solid background within engine development to win the case.

And today I am happy with a lovely sounding and well performing sports car, well the very same Evora S to be clear.

 

[#84]

I believe I forgot one of the more essential parts of the explanation, how the piston breaks.

With melting catalyst the back pressure increases which increases cylinder pressure and temperature, which in turn leads to knocking (pre-ignition). You hear it clearly as a pingin noise, almost like a small cow bell ringing very rapidly. At low engine speed it damages the piston top; it looks like a woodpecker has attacked the piston. At high engine speed the cylinder pressure can get so high so that the piston collapses. This is obviously what happens to the Evora S.

Higher ambient temperatures and lower octane number lowers the safety margin considerably.

[Camber74]

Andreas thank you so much.

I'm partially confuse from your explaination...let's confirm if I have understood the dynamic in your analysis:

- hot lambda get wrong mixture that broke pre-cat.

- melted cat increased back pressure that with knocking broke pistons.

could you confirm it?

I still didn't see the pictures of my 2 pistons broken, but if the damage will be exactly the same I'll be very interested to contact you also privately.

still waiting Lotus formal answer about warranty, already lost one month...and lost Millemiglia that will happens next week.

alessandro

 

[#84]

Confirmed. You understood it correctly.

Maybe the pre-cat can break also without faulty air/fuel mixture, but I assume Lotus have done their best to evaluate the concept so that should not happen on road or on a normal track day.

You are welcome to contact me anytime.

[JayEmm]

As I understood it, the issue the Ferrari 430 had was the cats were above the engine, and they could come apart and effectively get sucked into the engine. Which is not good

[Bibs]

1 hour ago, JayEmm said:

effectively get sucked into the engine

I can't see how that would be possible? Hell of a design flaw if it is! 

[Trevsked]

With the 430 it was the manifolds that crack and small parts do indeed return upstream into the engine. DOn't think this is exclusively a Ferrari thing but any engine with a degree of overlay on the cam timing.

 

Trevor.

[Camber74]

Attached picture of the 2 pistons broken, failure looks similar to your, and exactly the same on both.

After 2 weeks, still any answer from the Lotus on warranty,really embarassing to still believe a serious company.

Next monday I'll be for business on Sweden...but in Stockolm and I see it's far from you to meet face to face.

keep forum posted on next steps.

Alessandro

 

 

[CaptainSlow]

Regarding fuel I noticed the following page at Lotus Cars; Fuel compatibility

[Julian73]

On 5/8/2017 at 13:19, NedaSay said:

Except that 87 is way worse than 91...  In order to cope with our bad fuel, Lotus and other manufacturers do have to remap the ECU so that the engine keeps delivering performance,  If some do wonder why the Sport 410 does not deliver the same torque figures over here look no further than that.  

 

Octane is stated per RON, MON tests where RON is typically about 8 or 10 points higher than MON.  The US uses the average of RON+MON while Europe uses RON thus 87 on a US pump is about same as 91 on a European pump.  The 410 is detuned in the US to the 400 numbers not because of fuel but so to maintain EPA homologation, too few 410's will be sold to justify recertification costs; same will probably happen on the 430.  Besides we are already running our S1's at 430.

[Breeze]

I would think the problem is caused by using low octane fuel. i.e. Senza Piombio Normal. It's a supercharged engine, and with the higher ambient temperatures and low octane fuel, you will get knocking under load. I always run my Evora S on 100 Octane, though it should be fine on 98 octane as well.  The owners handbook clearly states 95 Octane minimum, running on anything less is clearly asking for trouble.

I had my car over at English Car in Firenze for a service. There was a white Evora in bits that had trashed it's engine. I was told that the car had been driven for several thousand kilometres after the engine warning light had come on. To the owners surprise, the engine had detonated. Obviously, and correctly, Lotus would not pay. it was the owners fault.

[Camber74]

It's possible.

my humbles considerations are:

1) i always used at least 95 ron gas, or more.like specified. 

2) humans except Lotus designers controls detonation since 100 years...a Smart engine have more specific power than an Evora S engine and controls detonation w/o any issue. Despite all the car costs like a small block.

3) No light pop up, also after braking one cat and 2 pistons. And this has ben verified from 2 official dealers.

4) the white Evora you saw..broke 2 (two! ) engines in one year. 

Then Lotus, first should  learn how to design engines (better say adapt engines), then could allowed to say to the customers that it's their fault, no warranty...and other stories like that to save his back.

 

alessandro,

 

 

Edited September 25, 2017 by Camber74