exhaust insulators

[Jeremy Edmondson]

FreshMar at aol.com wrote:
> 
>   I am working on a VW type four engine, working ground up on a fi
> system. I don't see too many postings for these vehicles, but I assume
> you all know they are air cooled, it's own little adventure. I wonder if
> anyone has tried fiberglass or some othe kind of insulator aroun exhaust
> pipes. I have heard they tend to trap moisture and speed up rust. The
> other option is to construct some kind of sleeve around the pipe out of
> sheet metal and seal it at the top and bottom.


You can buy a ceramic wool blanket which will withstand high temps and has good insulating 
properties.  The stuff I used was around 3/4" thick.  Just wrap it around and wire it on, then 
tape over it with aluminum tape.  It wored very well on my MG which did not have a cross flow 
head, by the time I put big carbs and headers on it there was no room for a heat shield.  You will 
also make more hp with lagged exhaust, not much more though.  It does keep the under hood temps 
down.  The down side to this is that with steel headers high temp oxidation takes place and large 
amounts of scale form very quickly on the pipe under the lagging.  I also had a big problem with 
the headers cracking all of the time.  You will really need stainless steel or inconel headers if 
you want to do this properly.

Jeremy Edmondson