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really hot headers

1K views 8 replies 8 participants last post by  MartinM 
#1 ·
I've got a 351 windsor in a cobra cit car. When i start the engine(has never run before), the temp gauge reads a good running temp and oil pressure is fine, but the headers turned bright red they were so hot. Any suggestions?
 
#3 ·
most cases, it`s due to there is no air to flow around them, and break in time is the only real time you run the engine at 2000 rpm not moving for any lenth of time. make sure your not overly rich, or lean, and another thing you can do is use the carb accelerator pump, do not move the throttle, when the headers are glowing, and you pump more fuel to it, if the glow gets worse it`s too rich, if it gets better, too lean. but this is a common occurance during cam break in.
 
#4 ·
I had that problem once and it turned out to be a vacuum leak at the manifold. Check and see which tubes are glowing, then follow the run back up the intake and see if you might have a fitting loose. Be careful as the temp can cause piston failure, even a meltdown if they are aluminum or hyper's. To see if a fitting of hose is leaking vacuum, get the motor running, and use an aerosol spray to spray on the fitting or whatever and see if it effects the way the engine is running. If so, I would bet that might be your leaking spot. Do that for each header tube that glows or turns red.
 
#5 ·
Hot exhaust manifolds indicate an overly lean condition. Check for vacuum leaks as suggested in previous post. Also the carburetor may be jetted wrong, but my guess is a vacuum leak. Too rich condition will make the headers run cool, in fact guys with chrome headers will often richen the mixture to keep the tubes from turning blue. It works. WShatever the case, fix the problem immdeiately, otherwise you WILL melt a piston or wipe out the exhaust valves.
 
#9 ·
Thank you for all the help on this.
I believe the problem was caused by one or more contributing issues:

1. The car had been sitting for 6 months and the gas may have gone bad. I added premium gas to the tank on the theory that it would "dilute" the bad gas.

2. At one point, I had the rockers improperly tightened. Loose rockers will, I believe, contribute to the overheating problem in the headers.

3. I think I had the carburetor set too rich. (at the idle adjustment screws)

4. I believe I had the timing set correctly. The comment that retarded timing will cause the overheating is correct. The gas in the cylinder is ignited too late to fully burn, and it is therefore partly burning in the exhaust headers.

5. The break-in procedure for the new camshaft (running the engine at 2200 rpm for an extended period with the car stationary) may cause an unusual build-up in heat in the headers. Normal operation, with air moving around in the header area, may not cause this much heating.

6. I had plugged the vacuum connections on the carburetor, and I don’t use any vacuum attachments. So I don’t think that a vacuum leak was a contributor.

Any way. The problem is now solved, and some or all of the above changes may have fixed it. Thanks again.

M>
 
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