What is normal header temperature?

[wachuko]

Folks,

Just curious. I was warming up the car and decided to measure engine temp... open the hood and I see the headers glowing






Measured header temp in the 960F. Is that normal? No wonder the air box, and coolant bottle deteriorate so much... I could not touch the hose from the intake to the air flow meter because of how hot it was!

[So Cal Mark]

960 should only occur under a pretty heavy load. If that was at idle I'd look at the fuel mixture and timing very closely. Both of those items will have an effect on exhaust temps. If the car is running a cat. I'd check the temp at the inlet and outlet and see if it's restricted. When you get over 1000F, mild steel won't hold up very well depending on the gauge of course

[wachuko]

960 should only occur under a pretty heavy load. If that was at idle I'd look at the fuel mixture and timing very closely. Both of those items will have an effect on exhaust temps. If the car is running a cat. I'd check the temp at the inlet and outlet and see if it's restricted. When you get over 1000F, mild steel won't hold up very well depending on the gauge of course

Mark, thank you. That was measured not at idle but at high revs. I will measure, just for fun, temps around the cat and post them here.

The whole system will be replaced by your system (trying to sneak out the credit card without my wife knowing ). Which reminds me that I have to add a wish list in my other thread.

Also, at your suggestion, I will get rid of the air box. The one in this car was deformed, I am thinking because of the extreme heat...

I don't want to hide the new headers under a mess of heatshields... there has to be some better way to protect these parts and still have complete visibility of the headers...

[mdrburchette]

I measured the temp on my stock manifold and it was around 1300 degrees. I didn't think that was unusual.

[Snoopy]

Problem: No heatshield...

[ventura ace]

I measured the temp on my stock manifold and it was around 1300 degrees. I didn't think that was unusual.

1300°F ????

Hal and I did some extensive testing to compare the intermal and external thermostat systems, and one of the parameters that we monitored was the exhaust manifold temperature. This is the 1608 cc engine stock 4:2 cast iron manifold. After idling for 25 minutes (starting from ambient 70°F), it settled in at about 600°F. After driving at normal freeway speeds, it peaked out at about 670°F, but seemed to settle in at around 610°F or so. Total engine run time was 75 minutes, so it had plenty of time to reach equilibrium temperature for a normal drive with combination of Freeway and city stop and go traffic.

Are you sure about that 1300°F Denise?

Alvon

[mdrburchette]

I used an infared thermometer. Unless it malfunctioned, I don't have a reason to think it was wrong.

[ventura ace]

We used the same type of optical temperature measurement device. Actually 2 of them, one was Hal's and one that I borrowed from work. All the other temperatures that we measured around the head and water passages were in the expected 180° - 210° range, so I believe that the exhaust manifold temperature was probably a good number, too.

At 1300°F, it would glow a dark red that would be visible even in bright sunlight.

A

[So Cal Mark]

if your manifold is 1300f, I'd say you have completely missed the settings on jetting and timing. Ceramic coating turns dull at 1100, and it's instantaneous. I've watched it happen. I've used both thermocouples and infrared thermometers for testing and the thermocouple is much more accurate, but the infrared is at least in the ball park.
I would expect your stock manifold to crystalize soon and begin cracking

[kilrwail]

At those temperatures I'd be really concerned about annealed pistons and broken rings. Ask me how I know.

[manoa matt]

Mark, how close are your headers going to be in relation to the rubber FI air tube?

[So Cal Mark]

the top of the tube is a few inches from the air intake duct. I recommend either a heat shield or wrapping the intake tube. Even the stock manifold cooks those intake ducts.