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Flammable Lambo?


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#1 BRG

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Posted 28 November 2014 - 22:14

At the risk of exposing my ignorance even more than usual, is it actually feasible that using the wrong spark plugs can set your car on fire?

 

"Property tycoon Jon Hunt claims the wrong type of spark plugs was fitted to his Lamborghini Miura SV by the garage that serviced it last year."

 

A pity to see a Miura burnt out, but this story seems odd to me.  

 



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#2 imaginesix

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Posted 28 November 2014 - 22:52

Insurance had to get their money from someone.



#3 Lee Nicolle

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Posted 28 November 2014 - 23:19

A near impossibility. The car may have caught fire due to many reasons from the service. Though unlikely. 

But wrong spark plugs? Sorry, unless the engine expired taking a fuel line in its wake.

Wrong plugs can obviously cause rough running , detonation and even real engine damage. Though you would think a so called expert would have the right plugs to fit. Unless the junior fitted the wrong ones.

Rich blokes and their numpty lawyers, who may have been believed. Never let the facts get in the way of a lawyer!



#4 Wuzak

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Posted 28 November 2014 - 23:56

In 1945 the Royal Aircraft Establishment were testing captured German aircraft. Among them was the push-pull Dornier Do 335. One test pilot died (I will have to look up his name) when the rear engine caught fire causing the plane to crash.

 

The cause of the fire has often been attributed to insufficient cooling, but the likely reason is that a faulty spark plug failed and was ejected from the head, with the fuel/air mix exiting the engine and igniting. 



#5 Canuck

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Posted 29 November 2014 - 03:54

That sounds very much like the recentish...okay decade-old Ford sparkplug problem.

#6 Kelpiecross

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Posted 29 November 2014 - 04:20

In 1945 the Royal Aircraft Establishment were testing captured German aircraft. Among them was the push-pull Dornier Do 335. One test pilot died (I will have to look up his name) when the rear engine caught fire causing the plane to crash.
 
The cause of the fire has often been attributed to insufficient cooling, but the likely reason is that a faulty spark plug failed and was ejected from the head, with the fuel/air mix exiting the engine and igniting.


Woozy - I personally doubt the "fuel/air" explanation - but you never know. I doubt it because years ago I attempted to make a cheap heating torch by putting a carby on the inlet of an old compressor and a hose and a nozzle on the outlet. The resulting fuel/air mixture totally refused to ignite no matter what I tried. When I directed the mixture on to a small pile of burning cardboard it very effectively put it out.

I assume that to make petrol vapour (of the particular F/A ratio used by an engine) ignite it has to be compressed and heated to the point where it is about to self-ignite anyhow.

Edited by Kelpiecross, 29 November 2014 - 04:24.


#7 gruntguru

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Posted 29 November 2014 - 07:13

Woozy - I personally doubt the "fuel/air" explanation - but you never know. I doubt it because years ago I attempted to make a cheap heating torch by putting a carby on the inlet of an old compressor and a hose and a nozzle on the outlet. The resulting fuel/air mixture totally refused to ignite no matter what I tried. When I directed the mixture on to a small pile of burning cardboard it very effectively put it out.

I assume that to make petrol vapour (of the particular F/A ratio used by an engine) ignite it has to be compressed and heated to the point where it is about to self-ignite anyhow.

So you have never tried welding an empty fuel tank?

 

I think you were running a bit lean. Even if you had enough airflow through the carb to pull a correct AFR, the heavier fractions of the petrol condensed on the bottom of you compressor tank. Try gas next time you want to make a bomb.



#8 Catalina Park

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Posted 29 November 2014 - 07:42

It might have been something silly like fouled plugs and the muffler slowly filling with petrol from the non firing cylinders.

#9 Kelpiecross

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Posted 29 November 2014 - 09:14

So you have never tried welding an empty fuel tank?
 
I think you were running a bit lean. Even if you had enough airflow through the carb to pull a correct AFR, the heavier fractions of the petrol condensed on the bottom of you compressor tank. Try gas next time you want to make a bomb.


Welding a petrol tank: - if there was even a tiny amount of liquid petrol left in the tank I would imagine the air would be saturated and thus very rich - and ready to burn explosively.

Enough airflow?: The petrol was disappearing from the tank at quite a reasonable rate.

No compressor tank - even I am not that silly. This was about thirty years ago - I was using the compressor cylinder alone and I think it was ex-commercial refrigerator (as was often the case with home compressors years ago).

I really am just reporting what happened - I am not really making any definite judgement as to why it happened. But I always took this observation to explain why cars can be so hard to start etc. unless everything is just right - because the actual mixture is not all that readily flammable. ( I would like to use the correct word "inflammable" - but these days I think it has the opposite meaning for most people).

But - try it for yourself (I never have) - take a plug out of a cylinder - start the engine and see if the gas flow coming out of the plug hole can be ignited.

Actually - it just occurred to me that trying to light the fuel/air mixture from a plug hole might be a good test to see if it could be the cause of the Do335 crash.

Edited by Kelpiecross, 29 November 2014 - 09:29.


#10 Wuzak

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Posted 29 November 2014 - 09:56

Kelpie, the DB 603 in the Do 335 was direct injected, so the fuel was under some pressure into the cylinder. 

 

The location of the spark plugs was just over the exhausts as wel, so that may have been part of the problem.

 

DB603_schema.jpg



#11 Dipster

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Posted 29 November 2014 - 10:57

Welding a petrol tank: - if there was even a tiny amount of liquid petrol left in the tank I would imagine the air would be saturated and thus very rich - and ready to burn explosively.

Enough airflow?: The petrol was disappearing from the tank at quite a reasonable rate.

No compressor tank - even I am not that silly. This was about thirty years ago - I was using the compressor cylinder alone and I think it was ex-commercial refrigerator (as was often the case with home compressors years ago).

I really am just reporting what happened - I am not really making any definite judgement as to why it happened. But I always took this observation to explain why cars can be so hard to start etc. unless everything is just right - because the actual mixture is not all that readily flammable. ( I would like to use the correct word "inflammable" - but these days I think it has the opposite meaning for most people).

But - try it for yourself (I never have) - take a plug out of a cylinder - start the engine and see if the gas flow coming out of the plug hole can be ignited.

Actually - it just occurred to me that trying to light the fuel/air mixture from a plug hole might be a good test to see if it could be the cause of the Do335 crash.

My dear old Dad taught me how to (gas weld) a tank by simply emptying the fuel and replacing it with water. It worked



#12 Magoo

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Posted 29 November 2014 - 13:54

Kelpie, the DB 603 in the Do 335 was direct injected, so the fuel was under some pressure into the cylinder. 

 

The location of the spark plugs was just over the exhausts as wel, so that may have been part of the problem.

 

DB603_schema.jpg

 

 

 

On inverted engines such as these, it pays to know your kurbelgehäusedeckel from your zylinderkopfdeckel. 


Edited by Magoo, 29 November 2014 - 14:00.


#13 fredeuce

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Posted 30 November 2014 - 06:52

Rich blokes and their numpty lawyers, who may have been believed. Never let the facts get in the way of a lawyer!

Wonderful stereotype you paint there Lee . Too many legal TV dramas in your diet?

Fact is if you read the rest of the story you would see that there are various other claims being made about the cause. Further this is simply the statement of claim of the aggrieved Mr. Hunt.

No doubt the defendant will have his own legal team bring in its own experts to examine the smouldering ruin to make their own assessment of the cause.

All that can be said at this stage is that the first salvo has been fired. The next will be the defence , then the trial if it gets that far.

The court won't be deciding this one with out the aid of experts in the relevant field.

#14 Kelpiecross

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Posted 30 November 2014 - 07:00

On inverted engines such as these, it pays to know your kurbelgehäusedeckel from your zylinderkopfdeckel.


How very true.

#15 Magoo

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Posted 30 November 2014 - 12:23

I wouldn't judge based solely on a short and awkwardly worded news story. There are countless ways a simple spark plug replacement could eventuate in a crispy Miura. Could be the news story simply failed to relate what happened in a clear way. 



#16 Canuck

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Posted 30 November 2014 - 15:08

Any time I have read news coverage of an event that I have involvement or inside knowledge of,I'm left wondering what event they're talking about. The difference between the "news" media and reality is often substantial. But then I suppose there's your side, my side and the truth.

#17 Magoo

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Posted 30 November 2014 - 16:54

Any time I have read news coverage of an event that I have involvement or inside knowledge of,I'm left wondering what event they're talking about. The difference between the "news" media and reality is often substantial. But then I suppose there's your side, my side and the truth.

 

Since the internet is essentially destroying news for profit, it's going to get a lot worse before it gets better. 



#18 Ross Stonefeld

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Posted 30 November 2014 - 17:39

I was amused at the paragraph in a major international paper that described the new Star Wars trailer as 'leaked on twitter'. Rather than hyped and shown in theatres.



#19 BRG

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Posted 30 November 2014 - 19:31

Any time I have read news coverage of an event that I have involvement or inside knowledge of,I'm left wondering what event they're talking about.

How true this is - I have had 100% the same experience.  It makes you wonder if anything you read is true.



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#20 munks

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Posted 30 November 2014 - 23:07

On inverted engines such as these, it pays to know your kurbelgehäusedeckel from your zylinderkopfdeckel. 

 

Rarely do I literally LOL.



#21 Magoo

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Posted 01 December 2014 - 20:57

I was amused at the paragraph in a major international paper that described the new Star Wars trailer as 'leaked on twitter'. Rather than hyped and shown in theatres.

 

I have noticed a really appalling trend recently in which the media outlet knows full well that the story is baloney and will be completely debunked in a few hours. But they don't care -- they just make up stuff that people will click on. There are a number of news sites that call themselves "parody sites" but there is nothing funny about the stories -- they're simply fake. 


Edited by Magoo, 01 December 2014 - 20:58.


#22 Ross Stonefeld

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Posted 01 December 2014 - 23:28

Hip hip...

 

 

The Onion’s Clickhole associate editor Daniel Kibblesmith will join BuzzFeed as a staff writer for its Buzz vertical, the publication told staffers Monday … BuzzFeed was among the sites Clickhole was founded to lampoon.

“I’m extremely excited to join the BuzzFeed team,” Kibblesmith told Poynter. “I’ve never felt closer to my ultimate goal of living directly inside of the internet.”



#23 Lee Nicolle

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Posted 02 December 2014 - 06:37

Welding a petrol tank: - if there was even a tiny amount of liquid petrol left in the tank I would imagine the air would be saturated and thus very rich - and ready to burn explosively.

Enough airflow?: The petrol was disappearing from the tank at quite a reasonable rate.

No compressor tank - even I am not that silly. This was about thirty years ago - I was using the compressor cylinder alone and I think it was ex-commercial refrigerator (as was often the case with home compressors years ago).

I really am just reporting what happened - I am not really making any definite judgement as to why it happened. But I always took this observation to explain why cars can be so hard to start etc. unless everything is just right - because the actual mixture is not all that readily flammable. ( I would like to use the correct word "inflammable" - but these days I think it has the opposite meaning for most people).

But - try it for yourself (I never have) - take a plug out of a cylinder - start the engine and see if the gas flow coming out of the plug hole can be ignited.

Actually - it just occurred to me that trying to light the fuel/air mixture from a plug hole might be a good test to see if it could be the cause of the Do335 crash.

I had a crook batch of plugs once. Over the course of a race weekend I blew out two. Luckily both near the end of the race so I finished sounding like a chaff cutter. But no fires, no damage [though that could of happened] Subsequently  I pulled the rest out and 3 more were cracked on the porcelain. The rep gave me a couple more sets and I never had a problem after. This on a 12-1 Chev operating around 7000 rpm.

Over the last 45 years I have seen quite a few broken plugs, some caused by poor fitting, some by faulty manufacture. None of the cars have caught fire!!



#24 Lee Nicolle

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Posted 02 December 2014 - 06:45

My dear old Dad taught me how to (gas weld) a tank by simply emptying the fuel and replacing it with water. It worked

That is safer, but I have still seen them go boom,, just a smaller bang.

No way I would ever put a welding flame on a tank. 

Usually you can solder small leaks,, with a soldering iron, not a flame.

Personally I just use epoxy, araldite or devcon. You stlill have to get the fuel out of the tank though unless it is the top of the tank. Or in my case last weekend the breather pipe pulled out. So I araldited it back in.

I have Devconed suspect areas in engine pans [before the oil gets there] as well as an oops porting an intake runner. Those heads are still being used such 20 years later.



#25 Hank the Deuce

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Posted 02 December 2014 - 09:29

I was under the impression that Miuras were quite flammable in their natural state in any case, and any alleged assistance on the part of the wrong trousers spark plugs would be less than necessary...



#26 BRG

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Posted 02 December 2014 - 11:29

Is that in fact the case?  I did wonder about that given the level of reliability of Italian supercars of that era.  Not to mention the current Ferrari 458's early record of self immolation.



#27 Hank the Deuce

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Posted 02 December 2014 - 17:49

I've read plenty of anecdotes touching on their propensity to burst into flame... over-fuelling the Webers on part throttle was mentioned as a routine Muira drama, at least with the early ones, but I've never even seen one in the flesh, let alone been in a position to verify the legend...



#28 Peter Morley

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Posted 02 December 2014 - 18:59

Looks like they are claiming the heat range of the plugs was wrong and cause the fire, shouldn't be too hard for the garage to find someone who can prove that is ridiculous.

If they only pursue that route it should get thrown out of court.

 

It would be interesting to see some of Foxton's customers applying such tactics in reverse, no idea what their reputation used to be (before he sold the company) but they don't seem to be very popular these days!



#29 gruntguru

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Posted 03 December 2014 - 23:41

I can imagine a scenario where a plug several steps too hot would cause pre-ignition leading to failure of a head or piston and ultimately a fire. You would need to be driving hard and "not notice" the misfire although that can happen on a 12 cyl.



#30 Lee Nicolle

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Posted 04 December 2014 - 09:05

Looks like they are claiming the heat range of the plugs was wrong and cause the fire, shouldn't be too hard for the garage to find someone who can prove that is ridiculous.

If they only pursue that route it should get thrown out of court.

 

It would be interesting to see some of Foxton's customers applying such tactics in reverse, no idea what their reputation used to be (before he sold the company) but they don't seem to be very popular these days!

Generally a hotter plug has a more projected nose [the electrode sticks out further]. That is a possibility too hit a piston and cause engine damage. Though generally that would never cause a fire. Poorly maitained Webers may, if the float sinks they get horribly rich. Though a factory airfilter should reduce any potential spread of fire.

Though a dud fuel line is the most probable culprit. Wether it was dislodged by the repairer, a fitting broke or similar. A engine sneeze with a rich carby may cause an air box fire but that is it 



#31 fredeuce

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Posted 04 December 2014 - 21:44

Lee , hotter or cooler spark plugs are a function of the degree of contact between the insulator and the metal casing of a spark plug. Length of the electrodes is the reach. Given any style of plug with the same reach there is always a range of hotter or cooler options. Hotter or cooler plugs is not determined by reach.



#32 Ross Stonefeld

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Posted 04 December 2014 - 22:06

Well, let's take the discussion in a different direction briefly. Let's say it's 100% now spark plug related. Is there another logical explanation for these thing going up in flames :p



#33 BRG

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Posted 04 December 2014 - 23:51

It's a 50 year old Italian supercar, with all the problems, faults and so on that implies?  Unless HR Owen did a complete restoration with all new parts, then all sorts of electrical and fuel system issues could be the cause.  



#34 fredeuce

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Posted 05 December 2014 - 00:39

It appears that these cars have a reputation for self combustion.

 

Have a look at this link . Scroll about 3/4 of the way down the page . Interesting .

 

http://www.netcarsho...miura_roadster/

 

I would add that if what is described is correct then this raw fuel is building up because the needles and seats in the float chambers can't hold back the fuel being delivered at idle. If so, then when a float chamber over fills , yes fuel can exit discharge nozzles but is not confined to that means of exit only . The fuel will escape from any place it can such as vents in float chambers , along throttle shafts and exiting throttle bodies all of which will result in raw fuel onto the top of the engine. Engine heat will cause it to vapourise and this situation combined with the distributors off the left hand of the cam-boxes wouldn't take to much to ignite the vapours .


Edited by fredeuce, 05 December 2014 - 01:17.


#35 Lee Nicolle

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Posted 05 December 2014 - 02:37

Lee , hotter or cooler spark plugs are a function of the degree of contact between the insulator and the metal casing of a spark plug. Length of the electrodes is the reach. Given any style of plug with the same reach there is always a range of hotter or cooler options. Hotter or cooler plugs is not determined by reach.

I have never seen a projected nose cold plug. Nor a shrouded nose hot one. In the same basic range of plugs, eg Champion N series, J series, L series or eqivilants in NGK. Surprisingly the only plugs I have ever used and even then the NGKs were because Champion did not make one to suit.

And I have aquired a LOT of cold plugs over 40 years. And on occasion fitted hotter ones too



#36 Lee Nicolle

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Posted 05 December 2014 - 03:11

It appears that these cars have a reputation for self combustion.

 

Have a look at this link . Scroll about 3/4 of the way down the page . Interesting .

 

http://www.netcarsho...miura_roadster/

 

I would add that if what is described is correct then this raw fuel is building up because the needles and seats in the float chambers can't hold back the fuel being delivered at idle. If so, then when a float chamber over fills , yes fuel can exit discharge nozzles but is not confined to that means of exit only . The fuel will escape from any place it can such as vents in float chambers , along throttle shafts and exiting throttle bodies all of which will result in raw fuel onto the top of the engine. Engine heat will cause it to vapourise and this situation combined with the distributors off the left hand of the cam-boxes wouldn't take to much to ignite the vapours .

I agree, hence the car catching fire presuming this car did not have the modified fuel returns.

Though fuel returns to me are a patch on a fuel system for a carby engine.Though can be effective. But  can also cause hi performance problems as distinct from low speed problems.  IF the pump pumps the correct pressure, eg Weber usually about 4 lb the needles should always hold the pressure. IF the pump is pumping more pressure than required the carbs will be rich anyway. Most carbs will get richer with more fuel pressure and go lean [and not function properly] with too little. EFI engines are the same though do need fuel returns because of the pressures invoved. A fuel pressure guage in the dash is always a good tuning tool, often resolves a whole pile of dramas. And many pumps should but do not pump enough volume, hence the pressure goes away at full throttle, the engine leans out and breaks, or just goes slow.

Multiple carb set ups are generally never very good for low speed street driving. Too much air  and not enough air speed. But the ultimate for top end power, often exceeding efi set ups [even multi throttle styles] though very seldom in driveability or fuel consumption. A Weber is still very hard to beat for motorsport sprint use.

On the Lambo I suspect a single 4bbl  [or 6bbl] may have been far more effective for road use. But not nearly as exotic!



#37 gruntguru

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Posted 06 December 2014 - 04:36

I have never seen a projected nose cold plug. Nor a shrouded nose hot one. In the same basic range of plugs, eg Champion N series, J series, L series or eqivilants in NGK. Surprisingly the only plugs I have ever used and even then the NGKs were because Champion did not make one to suit.

And I have aquired a LOT of cold plugs over 40 years. And on occasion fitted hotter ones too

Projected nose plugs are usually intended to protrude into the mixture streaming past the intake valve seat, cooling the tip of the plug in proportion to increased load or rpm. The projected nose plug therefore typically needs to be a "hotter" plug. That doesn't change the fact that all plugs in a particular series, whether projected or shrouded nose, will be the same length regardless of heat range i.e. projected nose plugs come in a variety of heat ranges and so do shrouded.


Edited by gruntguru, 06 December 2014 - 04:37.


#38 Lee Nicolle

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Posted 06 December 2014 - 06:07

Projected nose plugs are usually intended to protrude into the mixture streaming past the intake valve seat, cooling the tip of the plug in proportion to increased load or rpm. The projected nose plug therefore typically needs to be a "hotter" plug. That doesn't change the fact that all plugs in a particular series, whether projected or shrouded nose, will be the same length regardless of heat range i.e. projected nose plugs come in a variety of heat ranges and so do shrouded.

Again,, as I said the cooler plug per style is more shrouded. I have used about 10 styles of plugs over the decades, the hotter ones are always more projected. No ifs buts or maybes.


Edited by Lee Nicolle, 06 December 2014 - 06:22.


#39 gruntguru

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Posted 06 December 2014 - 08:44

Generally a hotter plug has a more projected nose [the electrode sticks out further]. That is a possibility too hit a piston and cause engine damage. 

 

 

Again,, as I said the cooler plug per style is more shrouded. I have used about 10 styles of plugs over the decades, the hotter ones are always more projected. No ifs buts or maybes.

 

Yeah but nobody is suggesting the wrong "style" of plugs were fitted - just the wrong heat range. A hotter plug of the correct style is not going to "hit a piston"