header temps?
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Instructor
Joined: Mar 2008
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From: Hopkinton Ma
header temps?
I picked up an infrared temp gun to check engine temp and was checking everything else under the hood and found that four out of eight header temps where alot higher. I can't remember the exact temps now, but I do remember that the two center exhaust ports on the passenger side where twice the temp of the others. Does this suggest valves are out of adjustment and It's getting blow by? And if that's the case what are the settings suppose to be for valve lash. The motor is down now(fuel problem)But this is something I would like to check out while it's apart. Thanks, Vinny
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It can depend greatly on the header material and coating....even if they are painted. General numbers Ive seen on many engines, using the same method.
A. spot heat reading on gun, keep the gun at the same distance and ANGLE to the tube. I check at about 1 inch from the port on the top of teh tube. Sometimes 1.5-2 inches, and ussually look for the highest sustained number.
450-550 degrees at idle.....ussually when compared with a wideband o2 sensor has indicated that they were idling rich, ussually around 12.5-13.0 to 1. Efi engines I ve checked often idle at 650-750 degrees and when checked on a wide band o2 check at 14.4-15.5 to 1.
Typically I ve seen 150 degrees at the most on the center two cylinders of sbc's that are in a good state of tune.
A. spot heat reading on gun, keep the gun at the same distance and ANGLE to the tube. I check at about 1 inch from the port on the top of teh tube. Sometimes 1.5-2 inches, and ussually look for the highest sustained number.
450-550 degrees at idle.....ussually when compared with a wideband o2 sensor has indicated that they were idling rich, ussually around 12.5-13.0 to 1. Efi engines I ve checked often idle at 650-750 degrees and when checked on a wide band o2 check at 14.4-15.5 to 1.
Typically I ve seen 150 degrees at the most on the center two cylinders of sbc's that are in a good state of tune.
Thread Starter
Instructor
Joined: Mar 2008
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From: Hopkinton Ma
I'm going to pull the valve covers tomorrow to see what heads are on the car and check to see if I can find out where the ticking is coming from. That's one of the reasons I was asking about settings. I have to get a pressure gauge to be able to see what the fuel pump is doing and rebuild the carb. Hopefully I can find the problem with out breaking the bank. I'm starting to remember why I've been buying new cars for the last 25 years.
Le Mans Master
Joined: Feb 2001
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From: Northern CA
I have ceramic coated, center dump headers with 3/8 flanges. Temps range from 295 to about 350 degrees after a long drive. Each of the tubes is a little different.
2-1/2 inch dual exhaust and a Performer intake. Seems fine.
2-1/2 inch dual exhaust and a Performer intake. Seems fine.
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From: Camp Verde AZ
C1 of Year Finalist (performance mods) 2019
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I have ceramic coated, center dump headers with 3/8 flanges. Temps range from 295 to about 350 degrees after a long drive. Each of the tubes is a little different.
Most IR guns that cost less than $300 are calibrated for a flat black surface with high emissivity. Silver ceramic headers will register much lower on a fixed Em IR gun even though temps may be the same on a rusty steel header.
That is also why you measure the temp of the black upper radiator hose rather than the chrome T-stat housing or aluminum intake manifold.
Doug
