I still say braze it in there! I've seen ground through holes in exhaust ports brazed over and polished and it worked fine. If it'll stand that it'll hold that plate. Sent from my BlackBerry® wireless device from U.S. Cellular -----Original Message----- From: Frank Swygert <farna@xxxxxxx> Date: Mon, 08 Feb 2010 10:57:44 To: <amc-list@xxxxxxxxxxxx> Subject: Re: [AMC-list] exhaust ports... Yeah, that's a good concern! Temps will be in excess of 600° coming out the port. Could you go to 1/4" for the top? I don't think you'll eat through or melt the plate, but warpage will be a concern that I didn't consider when I replied. You've put a lot more thought into it, more than the 10 minutes I did before replying! --------- Date: Sun, 7 Feb 2010 20:52:34 -0800 From: tom jennings <tomj@xxxxxxx> On Sun, Feb 7, 2010 at 08:41, Frank Swygert <farna@xxxxxxx> wrote: > Just the opposite -- sounds well within reason. I don't think I'd worry > about the furnace cement though. Since the insert will stay in place by > shape, don't worry about a little exhaust gas or heat rising into that well. > You main concern is flow, right? At anything above idle exhaust gas velocity > will be increased to a point that a small "crack" along the leading edges of > the insert won't matter. > Actually I was more concerned with heat, eating the relatively thin (3/16") steel roof filler plate. I figured with hot gases on only one side the metal wouldn't cook. Cast iron has poor heat transfer and is much larger mass and has a water jacket under it. My steel roof will be thn and right in the exhaust. I also figured if it warped from heat then it could lift up and get hotter/warped-er... because I'd like this to be a one-shot deal and not do some long term development I prefer gross overkill. But I might just weld the three pieces in-place and be done. Tabs welded to the plug and a ver small milled notch on the head would let the manifold retain it and only reduce the gasket area 1/8" on two small spots. -- 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://list.amc-list.com/listinfo.cgi/amc-list-amc-list.com _______________________________________________ AMC-list mailing list AMC-list@xxxxxxxxxxxx http://list.amc-list.com/listinfo.cgi/amc-list-amc-list.com