Car caught fire....again!

[dantheman]

2 years ago I was doing a trackday and my car caught fire:
http://www.imoc.co.uk/forums/viewtopic.php?t=159204

Since then I have added a flat floor and fans in the engine lid:
http://www.imoc.co.uk/forums/viewtopic.php?t=165171

I was doing a trackday at Snetterton on Thursday and after about 7 laps there is smoke in the cabin. I pull over by a marshal post and realise I have forgotten to turn the fans on....oops. I open the engine lid and see fire licking up the centre of the firewall, in that indented well area. Coolant is p1$$ing all over the floor (not sure what was cause and effect).

Thats all to be investigated. My question is, has anyone else had a fire in their engine bay whilst on track? I know the turbo gets very hot and that area is fairly tightly packed, so maybe things are spontaneously combusting? I've suffered 2 fires now and I can't blame the 2nd one on grass. Does this happen to anyone else or do I have a problem specific to my car that needs diagnosing?

[ashley]

A fire around the fuel tank vent anti spill tube?




Maybe a leaky fuel vent pipe? Have you removed your charcoal canister by any chance? Maybe your vent system is blocked, and as the tank gets hot on track the vent system is pressurising and releasing fumes through a leak in the area?

Lucky the tank didn't go up with a fire in that area

[al/c]

check the live wire to the starter motor as i had this happen a couple of years ago,the insulation had worn through in that area and earthed out setting fire to the fuel pipes.

[dantheman]

Just got the footage from the car. Here's the moment it happened.

http://youtu.be/x-cRudOxvqE

Still trying to work out why the car snapped coming out of that corner, which it hadn't done all day. Don't know if i noticed the smoke and got distracted, whether it dropped a load of coolant in front of my rear tyres or whether it was something completely other.

[Danbob]

Watched the video, looks like a lot of smoke! Certainly enough to cause a driver distraction!

How was the smoke getting into the cabin? Is your interior stripped? Could you pin point it?

Sorry I can't answer your actual question, I've never yet had a fire on track (touch wood)

Do you have any exhaust gas temp logging pre or post turbine? Might be interesting to look at the temps leading up to the fire....

[dantheman]

Yeah the interior is stripped, so it came in through the hole where the gear cables go. When I opened the engine bay the fire was against the firewall, in the centre. Thats about as specific as I can be.

No exhaust gas logging.

[dantheman]

So I've had a look at the car. There isn't anything obvious as to what caused the fire. The ventilation piping posted above all looks intact, no cracks or any untoward signs. I worked of the principle that the fire would spread upwards.

I traced the burnt wiring down as far as I could to find the source and they are only singed from the cabin hole upwards. Clearly the chassis metal didnt set them on fire...or did it? I noticed something on the rubber pipe that connects to the bottom of the fuel ventilation piping. Its a dark patch, looks like a singe mark. I've taken a couple of pictures. Problem is I cant really see it in detail. I've just managed to get a finger on it and there is no large hole or split. However if this pipe carries fuel vapour then I can't tell if it is still gas tight. Its impossible to see or reach properly. Don't know whether it is cause, effect or irrelevant?






My worst fear has been confirmed with the coolant leak. Its coming from the hose from hell, the 3 inch piece of tubing under the turbo. I only changed that 2 years ago and the car has hardly done any milage since then. If anyone has any tips on how to change it easily I would appeciate it.

[Rogue]

I'm pretty sure I can answer your question here. It was your coolant that was on fire! The flash point of ethylene glycol is ~250 degrees c and it will be pretty well atomised by the pressure in the failed hose. It will then spray directly onto the hottest part of the engine. You should also have noticed a blue / green tinge to the flame.

Same thing happened to me once on my mk2 turbo race car!

[mrturbotom]

Silicone lubricant for hose assembly really helps fitting the hfh

[SonicSW20]

I'm pretty sure I can answer your question here. It was your coolant that was on fire! The flash point of ethylene glycol is ~250 degrees c and it will be pretty well atomised by the pressure in the failed hose. It will then spray directly onto the hottest part of the engine. You should also have noticed a blue / green tinge to the flame.

Same thing happened to me once on my mk2 turbo race car!

Coolant can set on fire? Wow

[dantheman]

You may be right Rogue, I hadn't considered that.

I've replaced the damaged wiring, the fuel hoses (boy they are a real pain to get in place, all kinds of arm contortion) and replaced the HTH. When i filled up the cooling system to check for any leaks, drops were coming from the centre of the turbo. the part where the 2 metal coolant pipes go in has what I can only describe as a collar, bolted top and bottom. Coolant is dripping from this collar, round the bottom bolt. I attempted to undo the bolt but just rounded it off. Only thing I can think of doing is removing the turbo to inspect properly, which is annoying because the fuel pipes and HFH would have been so much easier if I had known this in the first place!

GRRRR.

[bobhatton]

You do have all the heat shielding still in place?

[dantheman]

Its so modified in there I don't remember what is there as standard! The turbo heat shield is there. I removed everything from the firewall.

[aussieGT]

I removed everything from the firewall.

'and my car caught fire again'


Think i'll leave mine in place!!

[bobhatton]

I removed everything from the firewall.

'and my car caught fire again'


Think i'll leave mine in place!!

There is a chap down here that removed the heat shielding from the bulkhead to make it easier to change his turbo, did not put it back, his car is no more it went up in a big ball of flames.

[wilkie senior]

So I've had a look at the car. There isn't anything obvious as to what caused the fire. The ventilation piping posted above all looks intact, no cracks or any untoward signs. I worked of the principle that the fire would spread upwards.

I traced the burnt wiring down as far as I could to find the source and they are only singed from the cabin hole upwards. Clearly the chassis metal didnt set them on fire...or did it? I noticed something on the rubber pipe that connects to the bottom of the fuel ventilation piping. Its a dark patch, looks like a singe mark. I've taken a couple of pictures. Problem is I cant really see it in detail. I've just managed to get a finger on it and there is no large hole or split. However if this pipe carries fuel vapour then I can't tell if it is still gas tight. Its impossible to see or reach properly. Don't know whether it is cause, effect or irrelevant?






My worst fear has been confirmed with the coolant leak. Its coming from the hose from hell, the 3 inch piece of tubing under the turbo. I only changed that 2 years ago and the car has hardly done any milage since then. If anyone has any tips on how to change it easily I would appeciate it.

forgive me if you moved it but shouldnt you have a rubber gromit to protect the cables on the metal?

[dantheman]

There is a chap down here that removed the heat shielding from the bulkhead to make it easier to change his turbo, did not put it back, his car is no more it went up in a big ball of flames.

Ok so what is supposed to be on the firewall other than sound deadening?

forgive me if you moved it but shouldnt you have a rubber gromit to protect the cables on the metal?

Maybe? If there is normally a gromit there I probably removed it because I have so many wires going through that hole there was no space for the gromit. I don't see a problem with that though, the wires are all insulated and not under tension. I will wrap them in tape to be sure though.

[ashley]

You do need some form of heat shield on the bulkhead itself imo

WRT the rubber grommits- I would refit them simply to seal the cabin from the engine bay, last thing you want is to gas yourself in the event of a small exhaust leak

[aussieGT]

forgive me if you moved it but shouldnt you have a rubber gromit to protect the cables on the metal?

I don't see a problem with that though, the wires are all insulated and not under tension. I will wrap them in tape to be sure though.

imo they don't need to be under tension to give you problems. As long as its making contact - vibration and jolts would probably be enough within time to give you a short.

It's like trying to cut a steak with a butter knife, it won't happen quickly and is messy but it'll happen.

Rubber is the best for wires ducking through metal holes, guess thats why they made rubber grommets. Tape may do for a while, but it can slip through the hole when the wire moves, a grommet insulates the hole, not the wire.