[T3] Bad day at the (FI) office

[Jim Adney]

On 3 Apr 2016 at 20:01, Daniel Nohejl wrote:

> I´m thinking of this interior image of a stock muffler from Russ Wolfe when I think that my sensor location must at least be decent 
> 
> DSCF0086.jpg <http://classicvw.org/gallery2/d/3253-5/DSCF0086.jpg>

That's a photo of one of the "good" mufflers. Note that the pipes 
from the rear cylinders are long inside, while the connections from 
the front cylinders are short. That makes the total length from the 
heads about the same, since the front cylinders have the extra length 
of the lower heat exchangers to pass thru. This makes for approx. 
equal length pipes, which is desirable. Genuine VW and Leiztritz 
mufflers look like this, and you pay extra for it.

> I stopped using anti-seize after reading this a few years ago, but perhaps oil winds up doing the same thing?
> 
> http://www.jagrepair.com/images/AutoRepairPhotos/NGK_TB-0630111antisieze.pdf

I use a lubricant made with MoS2 rather than any metal base. The 
metal based anti-seizes will leave traces on the face of the head, 
where the plug can rub as you're installing it. If you're unlucky, 
some of that metal can get on the insulator and eventually short out 
the spark. MoS2 is non-conductive, so there's no danger of that 
happening. 

If I read between the lines of the NGK pdf, I get the impression that 
they never expect you to reinstall a plug once it's been in service 
and then removed. They say that the plating stays behind when you 
remove the plug, so I get the impression that on a second 
installation you're unprotected.

I have a few tubes of the MoS2 lube available. One tube would be a 
lifetime supply, because it only takes a dab to do a plug. I use it 
each time, but that's probably not necessary once the threads in the 
head have seen it a few times.
-- 
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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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