Club G40 Forum

Technical => Engine and Transmission => Topic started by: Karlos the jackyl on August 14, 2012, 12:37:56 PM

Title: Polo G40 Sodium filled exhaust valves --- Myth ?
Post by: Karlos the jackyl on August 14, 2012, 12:37:56 PM
I've always wondered if it was true so ....

On a mass clearing mission I stumbled accros some old G40 exhaust valves and cut one in half using a grinder.

It was obvious these were hollow stems , but tipping them upside down revealed no traces of sodium.

I abandoned the valves and left them on the pavement about 30 mins later I could hear spitting noticed the valves were bubbling over

I can only assume the heat from the sun caused the sodium to react in such a way



(http://farm9.staticflickr.com/8304/7780519448_ea7b25d7da.jpg)


Title: Re: Polo G40 Sodium filled exhaust valves --- Myth ?
Post by: Yoof on August 14, 2012, 12:49:51 PM
Quote from: Karlos the jackyl on August 14, 2012, 12:37:56 PM

I've always wondered if it was true so ....

On a mass clearing mission I stumbled accros some old G40 exhaust valves and cut one in half using a grinder.

It was obvious these were hollow stems , but tipping them upside down revealed no traces of sodium.

I abandoned the valves and left them on the pavement about 30 mins later I could hear spitting noticed the valves were bubbling over

I can only assume the heat from the sun caused the sodium to react in such a way


Myth Busted!



It's solid at room temp- so would be one large lump at the bottom of the valve... hence not coming out.

I'm no chemist, but I'd guess it's reaction with water vapour in the air produces gas (sodium hydroxide) and gas (hydrogen)
Title: Re: Polo G40 Sodium filled exhaust valves --- Myth ?
Post by: Karlos the jackyl on August 14, 2012, 01:01:39 PM
I agree , a quick google confirms water in the air causes the reaction.

Title: Re: Polo G40 Sodium filled exhaust valves --- Myth ?
Post by: Andy on August 14, 2012, 01:06:52 PM
Cut another one open and drop it in a bucket of water.  ;D
Title: Re: Polo G40 Sodium filled exhaust valves --- Myth ?
Post by: Nick_S on August 15, 2012, 11:46:06 PM
Quote from: Andy on August 14, 2012, 01:06:52 PM
Cut another one open and drop it in a bucket of water.  ;D


Haha auto ignition of hydrogen on the grand scale :D If you hear it fizzle just from water vapor, get out your ear plugs and schrappnel screen for the bucket test!
Title: Re: Polo G40 Sodium filled exhaust valves --- Myth ?
Post by: ereeiz on August 16, 2012, 04:25:38 PM
I remember seeing that in physics many moons ago. The teacher then stuck another two elements in from around the same place on the periodic table. Fun stuff 8)
Title: Re: Polo G40 Sodium filled exhaust valves --- Myth ?
Post by: youngprodigys on August 16, 2012, 04:39:47 PM
Quote from: Andy on August 14, 2012, 01:06:52 PM
Cut another one open and drop it in a bucket of water.  ;D

bloody hell! it will bloody kill him! dont do that.

only kidding, i watched a lad at school chuck a lump of potassium in the sink in a chemistry class, the resulting reaction was so big the sink smashed to pieces and came off the wall with a very large purple flash
Title: Re: Polo G40 Sodium filled exhaust valves --- Myth ?
Post by: gofasterpinch on August 17, 2012, 09:24:19 AM
Quote from: ereeiz on August 16, 2012, 04:25:38 PMin physics

surely it was chemistry?  ;D
Title: Re: Polo G40 Sodium filled exhaust valves --- Myth ?
Post by: ereeiz on August 17, 2012, 10:04:23 AM
Quote from: gofasterpinch on August 17, 2012, 09:24:19 AM
Quote from: ereeiz on August 16, 2012, 04:25:38 PMin physics

surely it was chemistry?  ;D
We hadn't started "chemistry" at that point as a lesson, it was all done under physics. Didn't start it as a proper lesson 'til yr 10