Re: [Amc-list] Big motor small heads,,,

[Frank Swygert <farna@xxxxxxx>]

It's easy to keep the factory "header" from cracking, or at least easy to greatly reduce the potential to crack. The tubular exhaust manifolds move a lot more than cast iron ones, and can't support as much weight. All that's needed is an exhaust hanger near the firewall so that the manifold isn't supporting the weight of the exhaust system. That was okay for a heavy iron manifold, stresses the joints on the tubular ones too much. Or a metal brace attached to say a bell housing bolt and the exhaust system, sort of like the old L-head exhaust brace, which is just a piece of 1" wide x 1/8" thick flat bar drilled to attach to a bell housing bolt and the other end drilled so a u-bolt goes around the exhaust pipe and through the brace -- both ends through the brace). 

I always weld the cracks the add a few gussets, and a strap or bar between the last three on the Renix exhaust manifold. I have a 91-95 exhaust manifold that shows signs of cracking at a joint or two but no signs of exhaust leaking. I'll weld them anyway and see how best to gusset/brace it to prevent future cracks. 

---------------
Date: Sat, 18 Oct 2008 09:50:23 -0700
From: Jim Blair <carnuck@xxxxxxxxxxx>

As long as they can convince people they won't break like the factory ones they will do all right. (referring to factory Jeep "headers" cracking)

-- 
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
http://farna.home.att.net/AMC.html
(free download available!)

_______________________________________________
Amc-list mailing list
Amc-list@xxxxxxxxxxxx
http://splatter.wps.com/cgi-bin/mailman/listinfo/amc-list