Big Bang Theory ?

[Stirlingmoz]

Hi..I started my van yesterday after a two week rest.

Was running perfectly when parked.

Usual starting procedure adopted - one depression of accelerator pedal and crank him over.

Then....V loud bang.

Engine started but rang like s@*t.

Pop open the rear and there is a hole in the Pict 3 34 carburettor that wasnt there before !.

Some kind of round blanking plug about 1cm diameter had blown out of the carb.

I put my thumb over the hole and normal running resumed. Tricky to drive like this though !.

Torch out and a hunt round the engine bay and there was the blanking disc sitting all innocent like on top of the battery.

I popped it back in the hole but it's not a very tight fit.

Should I superglue this is in place or is it some kind of safety feature in the event of backfires ?.

The flying blanking disc has put a dent in the back of the engine lid too. It was a big bang.

Vans now runs as sweetly as ever. Weird huh

 

[aogrady]

Blimey!

I have heard of these discs popping out, or being loose, but yours went with style!
Guess, some 2 part epoxy resin like araldite would fix it in well?
Result that you found the bung, could have fallen anywhere!
Also heard of the brass pipe fixed in the carb where the fuel pipe is fitted - these come loose to0, spray fuel everywhere, so have a mooch at that too!

Cheers!

Alistair

 

[Justin & Muttley]

Also heard of the brass pipe fixed in the carb where the fuel pipe is fitted - these come loose to0, spray fuel everywhere, so have a mooch at that too!

You are correct - this happened on my wife's beetle two weeks ago and the resulting fire was a bit scary - fixed it by deforming the pipe slightly and hammering it home, then secured it with wire to the other side of the carb.

 

[Bookwus]

Hiya Stirling,

That plug that blew out is known as the (no big surprise here) blow-out plug. Solex designed this pressure relief device into the wall of the carb in order to prevent possible damage to other components in a backfire situation. Your backfire popped it out just as it was designed.

Many will advise you to seal the plug in place with some sort of adhesive. While that will work to hold the plug in place it does defeat the plug's intended function. It's better to peen the plug in place and call it good. If you look at the plug surround closely you'll notice that was the way the plug was originally installed.

 

[noddy]

Just a point check that the adhesive is solvent resistant, blue hylomar would be my choice.

 

[Stirlingmoz]

Thanks for the replies guys.

What do you reckon on a spot of thread lock to fix it back in ?.

Would it be too strong ?

PS..Just been back out to my van and some low life has pulled the VW badge off the front, breaking the clips and denting the front panel.

It was only out there unattended a matter of hours.

I'm gutted. Ive lived here 17 years and it's the 1st time my neighbours have heard me swear.

My Sunday is now officialy spoilt.

Stirlingmoz

 

[AxlFoley]

Dude, thats just shit! I hate it when sometihng like that happens, keep your eye out for some scrote with a VW sigh on the front of their BMX

As for the plug, could it be that it deformed slightly when it blew out? can you buy them new? it may be that a new one would be a nice snug fit.

Mark

 

[Stirlingmoz]

Just ordered a new front badge and clips for my van.

I'll attempt to pull the (fortunately shallow) dent out of the front panel later with a plunger.


I can't find anyone who sell the blanking plug as a spare.

I'm going to go with thread lock and see how I go.

At least I found it or I would be looking for a scrap carb to rob for spares.

Stirlingmoz

 

[easy]

I had exactly this happen on my van and was stuck in Woolacombe at night whilst trying to sort out something to do. In the end i got a cork from the Red Barn and cut it to fit into the hole and it got me 10miles back to the campsite! In the morning got up opened the engine lid and found the plug just under the bottom pulley! :roll: put it back in with some loctite and never came out again 8)

 

[giraffeinbath]

This happened ours mine a little while ago, intended to try to find another blanking plug but I've not got around to it yet, currently there's a 5p covering the hole held in place with a big lump of blue tack......dosn't sound ideal but it just got us Croyde and back this weekend 8) :mrgreen: