hot exhaust issue

Joined
Oct 11, 2006
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204
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Las Vegas, Nevada
My 60 has a very high exhaust temp., I've tinkered on this thing for a few years now and have been slowly changing and rebuilding it a part at a time, yet, it always has this hot exhaust temp. that , if you hold a rag over the tail pipe , the rag will actualy ignite into flames-what on earth would cause such a thing?. Sure it's not supposed to blow cold air out the tailpipe, but this is over the top...Cataletic converter issue maybe?
Any thoughts would be most appriciated.
 
Joined
Oct 30, 2006
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Heber City, UT
I believe the exhaust is supposed to be 200 degrees cooler out the back of the catalytic converter. When was the last time it was replaced?
 
Joined
Oct 11, 2006
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I don't know, the PO may have but I really don't know for sure, I read somewhere that the exhaust gases are around 1200 deg. rite out of the head, seems things should be a lot cooler comming out of the back. 200 deg. is a considerable amount, but still this is all too strange for me, Does anyone have any idea how many degrees should be comming out the tailpipe?
 
Joined
Feb 12, 2005
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bay area
rhon,

the temp. at the outlet of the cat can reach temps up to 1450 degrees F; even higher if your cat temp sensor and/or air injection system isn't working properly. above about 1450 degrees, the air injection system should shut down to prevent overheating the converter.

i really have no idea how hot the exhaust should be at the tailpipe but being able to set something on fire doesn't sound good.

other things that can cause high combustion temps are a lean mixture or an inop EGR system.

if you really want to get to the bottom of this, i'd suggest getting the factory emissions manual. the air injection system alone is enough to make even the most seasoned mechanic's eyes glaze over.

just out of curiosity, tomorrow i'll see how hot my exhaust is at the tailpipe and report back.
 

60wag

SILVER Star
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Jun 25, 2003
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Boulder, CO
Usually a lean running condition will elevate the exhaust temp in the engine but your problem may be a rich condition where the excess fuel/hydrocarbons are being burnt in the cat leading to the high exhaust temp. Is the temp sensor still attached to the cat? Is the shell of the cat discolored from high heat? I'd vote for either an emissions hardware issue or a problem in the carb. You might find a shop with an exhaust analyzer to help track down the problem.
 
Joined
Dec 14, 2006
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Tahlequah OK
That is crazy! You need to videotape it. I hold my hand in front of my exhaust to feel how the engine is firing, and it is warm but not to the point where it would ever burn me.
 
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bay area
245 degrees F at the outlet of the tailpipe, fully warmed up after a hard run on the freeway. fully functioning cat temp sensor, speed sensor, and AIR system.
 
Joined
Oct 11, 2006
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Crazy bussiness here for sure, I don't see ant discolorization on the Cat and the sensor seems to be in tact also, the EGR valve is disconnected, I did a recent lean drop on the carb. I'm pretty sure it's adjusted correctly- maybe a little rich as I ended up with about 3 1/2 turns on the idle mixture screw as apposed to the 2 turns factory setting- but this is where it ran best. Sure do like the sound of 245. deg. but am far away from that, Does the EGR system actualy allow gases to recirculate at idle speeds? As far as showing the magic burning rag, let me play with the digital camara and see if I can figure out how to attach it here.
 
Joined
Feb 12, 2005
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bay area
rhon,

crazy business for sure. perhaps you'll want to get one of those little handheld infrared thermometers and see exactly what temperature you're running both at the tailpipe and at the outlet of the cat.

http://www.thetoolwarehouse.net/shop/TTW428.html#953

those are just some examples of the many types of thermometers out there but you can get them at sears and i believe most of your local parts stores. good to have around the garage for checking coolant flow, AC duct temperature, etc.

EGR should not flow at idle.

PS40-2, the absence of a cat plus headers should make your exhaust cooler. the cat is the one thing that will heat up your exhaust for in order for the cat to work effectively, it needs to be hot...really hot.

hey rhon...maybe you could get a job at the circus as a sideshow; "Rhon and his amazing self igniting rag!" ;)
 
Joined
Oct 11, 2006
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Las Vegas, Nevada
Thanks for all the input, let me see if I can find a pyrometer somewhere , that should give some more insite on all this, went out last nite and gave the ABV a checkover per the manual all seems to be functioning per specs. ( replaced it last year at smog time),.

Ah , the problems that always seem to pop up, especialy when there are plans to spend money on other things.
 

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