muller@market.alliant.com (Jim Muller) (02/27/90)
With all the talk about engine fires, here is a thoguht to consider. The catalyst is intended to continue oxidation of fuel that went unburned in the cylinders. As such, the richer the engine runs, and the poorer your combustion is, then the hotter your catylitic converter will run. I have no idea why Aran Guy hd such problems with his Spitfire (mine has hd no such troubles [knock on dashboard *! *!]) but it suggests there was some problem from day one (though I would've figured he would have fixed it). Anyway, one moral of the story is to keep that engine well-tuned. Keep the spark nice and hot, and keep the carb in good shape. Jim
guy@bevsun.bev.lbl.gov (Aran Guy) (02/27/90)
Jim says: As such, the richer the engine runs, and the poorer your combustion is, then the hotter your catylitic converter will run. I have no idea why Aran Guy hd such problems with his Spitfire (mine has hd no such troubles [knock on dashboard *! *!]) but it suggests there was some problem from day one (though I would've figured he would have fixed it). And I say: Jim's right; I finally figured out what happened, with the help of a smog tech. I didn't say what it was, so as not to detract from the discussion. The EGR valve was intermittantly hanging open and leaning out the mixture at speed. This caused a mild high speed misfire due to LEAN mixture, and the catalyst got the gas it needed to cause all that trouble. The point is ANY component of the smog system can in one way or another adversely affect the operation of the converter, and with said converter mounted in such a lousy place there isn't much room for error. By the way, the replacement EGR valve was $134, because of exhaust erosion of seat, it wasn't possible to clean it like the manuals say. Aran Guy guy@bevsun.bev.lbl.gov