How does that go - "True dat, yo".  

VW's service manuals are very conservative b/c, just like today's public 
schools, they must account for the lowest common denominator.  Just think about 
all those "one time use ONLY" bolts that you've re-used that haven't gone 
ballistic.  


When the 16v GTi was introduced, it had specs that were generally unheard of at 
that time - 10.5:1 compression ratio and sodium-filled valves for extra cooling 
effects.  Since that time, the automotive world has rushed past VW's 
innovations.  Sodium-filled valves are still around and fairly commonplace 
although I'm seeing that stainless steel is becoming a popular replacement.  


Matthew




>________________________________
>From: Steven Arguello <[email protected]>
>To: Volkswagen a2 16v discussion list <[email protected]>
>Cc: Matthew Yip <[email protected]>; Volkswagen a2 16v discussion list 
><[email protected]>
>Sent: Friday, June 24, 2011 9:42 AM
>Subject: Re: [a2-16v-list] valve refacing
>
>When I mentioned it, the guy said "not worry". I'm sure there are lots of 
>sodium valves out there and he's done millions.  You're also not supposed to 
>straighten alloy wheels or chrome steel ones or use a cell phone while filling 
>the tank. 
>
>
>
>On Jun 24, 2011, at 9:30 AM, Chad Rebuck <[email protected]> wrote:
>
>> So if my valves didn't explode in the face of the machine shop guy
>> then I shouldn't worry about them exploding or falling apart in the
>> engine?
>> 
>> If sodium filled valves are common there has to be some information
>> available to the machinist on valve composition and warnings specific
>> to each engine, but I'll ask firsthand so I can see his reaction.  If
>> I ask the lady at the desk over the phone he'll have too much time to
>> think of a nice sounding answer :)
>> 
>> On Fri, Jun 24, 2011 at 9:23 AM, Matthew Yip <[email protected]> wrote:
>>> Sodium metal - fun stuff.  The special disposal method is to cut the stem 
>>> open and put it in water.  The chemical reaction releases heat and hydrogen 
>>> - can you say "boom".
>>> 
>>> 
>>> When I was in HS, our chemistry teach talked about sodium metal and 
>>> lamented that he couldn't get sodium metal to demonstrate it's reactive 
>>> powers.  Having a father who was a chemist (and a senior scientist) came in 
>>> handy.  Went home and said "Dad, could you perhaps get me some sodium metal 
>>> for school?"  The next day, my Dad handed me a little vial filled with oil 
>>> and several lumps of silvery metal and a warning to  "Be careful with that 
>>> - don't let it dry out or come in contact with water".
>>> 
>>> 
>>> Let's just say that the next chemistry class held quite a bit of 
>>> amusement...
>>> 
>>> Matthew
>>> 
>>> 
>>> 
>>> 
>>>> ________________________________
>>>> From: Steven Arguello <[email protected]>
>>>> To: Volkswagen a2 16v discussion list <[email protected]>
>>>> Cc: a2-16v <[email protected]>
>>>> Sent: Friday, June 24, 2011 9:05 AM
>>>> Subject: Re: [a2-16v-list] valve refacing
>>>> 
>>>> They're sodium filled and can explode or something. My guy (eastern 
>>>> European) said it wasn't a problem. But I told him take off as little as 
>>>> possible, I think it's only the exhaust. You're not supposed to throw them 
>>>> in the recycling or trash, you cut the stem off and throw them in water 
>>>> first they boil or something.
>>>> 
>>>> 
>>>> 
>>>> On Jun 24, 2011, at 8:53 AM, Chad Rebuck <[email protected]> wrote:
>>>> 
>>>>> I think I may be picking up my engine from the machine shop today.  I
>>>>> was reading in the Bentley:
>>>>> 
>>>>> "The valves must not be refaced.  They must be hand lapped only."
>>>>> 
>>>>> Why is this and what is the problem with having them machined as I
>>>>> expect mine were?
>>>>> _______________________________________________
>>>>> a2-16v-list mailing list
>>>>> [email protected]
>>>>> http://mail.a2-16v.com/mailman/listinfo/a2-16v-list
>>>>> For list archives, see listinfo link above.
>>>> 
>>>> _______________________________________________
>>>> a2-16v-list mailing list
>>>> [email protected]
>>>> http://mail.a2-16v.com/mailman/listinfo/a2-16v-list
>>>> For list archives, see listinfo link above.
>>>> 
>>>> 
>>>> 
>>> _______________________________________________
>>> a2-16v-list mailing list
>>> [email protected]
>>> http://mail.a2-16v.com/mailman/listinfo/a2-16v-list
>>> For list archives, see listinfo link above.
>>> 
>> 
>> _______________________________________________
>> a2-16v-list mailing list
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