Cylinder Head Temp
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Nordschleife Master
Joined: Feb 2011
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Cylinder Head Temp
My guage never goes above the top white line, but the engine clatters like it's hot. The water bridge reads 190 but the heads read 210 on an IR meter.
What's normal for the head temp?
What's normal for the head temp?
Chronic Tool Dropper
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Joined: Oct 2001
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From: Bend, Oregon
External head temps vary a lot based on ambient air temp, load on the engine, and perhaps most importantly where you are measuring. The exhaust side of the head tends to be hotter than the intake side, amazingly. If you are shooting temps of the cam cover rather than the head itself, you get some conducted heat from the head underneath, plus a bit of attemperation from the oil spray inside.
IR guns are handy tools for lots of things, so long as you recognize a few limitations. The actual temp reading area is a cone, so the effective sensing area gets bigger as you move away from your target. The most accurate readings are from an inch or two away. The laser is a targting device only, and roughly indicates the middle of the end of that cone. The laser itself plays no part in the temperature measurement. The measurement depends on having a solid target, so no good direct air temps are available. Similarly, reading the surface temp of a liquid is iffy at best. For those things a direct-reading thermometer is the weapon of choice. External skin surfaces are not a good indication of internal body temp, so don't shoot yourself in the head trying to determine if you really do have a fever. You can try a shot at the bottom of your tongue similar to where you'd stick an oral thermometer, but you have to take that reading with your mouth closed so there's no evaporative cooling effect to correct out. Might work shooting into the interior of your ear, but that's a tough shot-- to get the end of the cone small enough to only read inside, the sensor needs to be right against your ear; tough to aim yourself when you can't see.
Last but not least... Do Not Look Into Laser With Remaining Eye.
IR guns are handy tools for lots of things, so long as you recognize a few limitations. The actual temp reading area is a cone, so the effective sensing area gets bigger as you move away from your target. The most accurate readings are from an inch or two away. The laser is a targting device only, and roughly indicates the middle of the end of that cone. The laser itself plays no part in the temperature measurement. The measurement depends on having a solid target, so no good direct air temps are available. Similarly, reading the surface temp of a liquid is iffy at best. For those things a direct-reading thermometer is the weapon of choice. External skin surfaces are not a good indication of internal body temp, so don't shoot yourself in the head trying to determine if you really do have a fever. You can try a shot at the bottom of your tongue similar to where you'd stick an oral thermometer, but you have to take that reading with your mouth closed so there's no evaporative cooling effect to correct out. Might work shooting into the interior of your ear, but that's a tough shot-- to get the end of the cone small enough to only read inside, the sensor needs to be right against your ear; tough to aim yourself when you can't see.
Last but not least... Do Not Look Into Laser With Remaining Eye.
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Nordschleife Master
Joined: Feb 2011
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Thanks Doc, I already know all that. I'm shooting as close as I can get to the front middle of each head with nothing in the way. That's about 2 inches.
So what's normal with the engine fully warmed up?
So what's normal with the engine fully warmed up?
Captain Obvious
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