Is the goal to streamline the approach to the lump in the way of the exhaust gas stream?
I agree that JB Weld won't hang in the heat of That kitchen.
I have some high temperature epoxy that cost considerably more. But, exhaust gas temperature is way too high, even for it.
Excerpt
Ooopsies,,, looks like I got the whole thing...
Mmmkay , this is a hot rod engine, so, probably higher compression and generally hotter, but I don't see how a resin mix is gonna survive in a stream of hot gas. Might get soft and shoot it like a gooey spitwad into your exhaust... the result of which would probably be a pretty quick and noticeable decrease in exhaust gas flow,, if ya get my drift.
I'm not seeing better than six hundred degree stuff.
http://www.hotrod.com/how-to/additional-how-to/1504-when-do-gas-exhaust-tempe...When Do Exhaust Gas Temperatures Become A Cause For Concern?When Do Exhaust Gas Temperatures Become A Cause For Concern?The All Wheel Drive 2.7L Ecoboost 2017 Ford Fusion Is Packing 325HP & 380 Lb-Ft!Vintage Inlines Launches to Continue Helping Inline-Six EnthusiastsMore Cars and Pics From Lambrecht Chevrolet - Hot Rod Magazine Blog
Hot Rod » Additional How To
When Do Exhaust Gas Temperatures Become A Cause For Concern?
Written by Marlan Davis on March 5, 2015
Contributors: Holley/Weiand
When Do Exhaust Gas Temperatures Become A Cause For Concern? View All 3 Photos
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Q:
I have a 1940 Ford four-door pickup street rod with a 1974 Corvette four-bolt-main 350 and a 700-R4 transmission. I had the engine bored 0.030-over and totally rebuilt. It has a mild Edelbrock cam, hydraulic lifters, and a geardrive. It has ceramic-coated headers. I am concerned some cylinders are running hot. When the engine has warmed up, using my infrared thermometer I get these readings on the header tubes at idle:
Cylinder No. 1 300 degrees F.
Cylinder No. 2 300 degrees F.
Cylinder No. 3 530 degrees F.
Cylinder No. 4 450 degrees F.
Cylinder No. 5 360 degrees F.
Cylinder No. 6 470 degrees F.
Cylinder No. 7 350 degrees F.
Cylinder No. 8 390 degrees F.
I have three cylinders running hotter than the others. I have asked several mechanics and one engine builder what could cause this, but none has an answer. Maybe this is nothing to be concerned about?
Hal Bennett
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You’re right, it’s nothing to be concerned about. At-idle exhaust gas temperature (EGT) readings on a gasoline-fueled motor just aren’t accurate. “No-load EGT temperature readings are meaningless,” proclaims engine builder Ken Duttweiler. That’s because fuel metering is still controlled by the idle system, so the fuel dispersal pattern and distribution isn’t at all uniform, and thus not indicative of what the engine sees under running conditions. “There needs to be air/fuel movement, so you can’t expect equal EGTs at idle,” explains Westech Performance’s Steve Brulé. “At that point, the fuel is just dribbling in through the carb’s idle transfer slot; there’s no real atomization.” In other words, temp readings need to be taken under load—at least at a steady-state, light-throttle, 3,000 rpm for no less than 30 seconds; even better would be at wide-open-throttle (WOT). Either way, realistically, that requires an engine or chassis dyno.
But even under load, gross EGT readings are affected by so many different factors that they should not be considered a primary reliable tuning aid. First, the ceramic coating on the headers throws off the reading; you really want actual in-tube gas temperatures, which means thermocouples on every tube. Second, the readings need to be taken at the same distance on each tube relative to the exhaust flange. Third, even if the measurements are taken at the same distance from the flange, bends in the tubes will change the readings: The tighter the bend, the higher the observed temperature. Fourth, the observed temperatures can vary due to many factors, including intake manifold design, carburetor tuning, and ignition timing. For example, adding more ignition advance reduces EGT, because the mixture is burning earlier. Leaning out the carburetor raises EGT. And intake manifold runners on a single four-barrel intake are not all the same length. To a large extent, when reading actual temperatures, you need to have prior experience of what was previously considered “normal” for the particular combination. On that basis, EGT deviations from the known, good baseline would indicate a need for further investigation.
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Having said that, according to Brulé, the “correct” EGT is the temperature at which your engine is making its best power over the duration of time and rpm it will be running at. Every engine combo’s slightly different, so engine builders are often reluctant to quote exact numbers. If you pin him down, Duttweiler will quote, 900–1,000 degrees on the outside of the tube at 3,000 rpm after 30 seconds under load. “Coated headers may be 200–300 degrees cooler, so figure about 700 degrees with them. As for WOT readings, on a gasoline, normally aspirated engine, I consider 1,200–1,300 degrees normal; add another 300–400 degrees on a boosted engine. If I see a 400-degree disparity between the range of cylinders, it would be a concern.” Brulé adds, “If you see 800 degrees or 1,700 degrees on a naturally aspirated engine at WOT, obviously, that’s out of the ballpark. Remember, wide open is where these things become critical.”
WOW!!!!! You found a serious product...
Manley Miracle Seal Epoxy
This two part adhesive is best for repairing exhaust ports and any other parts that are subject to high temperatures up to 1350 degrees. Can be sanded after curing. Mixing sticks included.
That just might work out. Have you considered building a framework, like rebar, or using a mesh, like a stainless steel scrubbie to help it stay together?
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