Red hot manifold
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Jeff I
Topic author - Posts: 2
- Joined: Sun Jan 13, 2019 9:49 am
- First Name: Jeffrey
- Last Name: Instness
- Location: Oregon
Red hot manifold
While putting the T away tonight I had the hood open and noticed the manifold was glowing red. Note; it seemed like it was only the last 3 cylinders also. I didn't have the car running very long either, I was just putting it away so I only went around the block. It did choke on itself a few times from a rolling start but it is still cold where I'm at and I didn't warm her up like I normally do. My guess is timing but thought I'd throw it out there in case there are a few educated guesses I can add to my investigation tomorrow.
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Steve Jelf
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Re: Red hot manifold
I think you're on the right track. The usual suspect is running too retarded.
The inevitable often happens.
1915 Runabout
1923 Touring
1915 Runabout
1923 Touring
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Mark Gregush
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Re: Red hot manifold
Or running too lean.
I know the voices aren't real but damn they have some good ideas! 
1925 Cut down pickup
1920 Dodge touring
1948 Ford F2 pickup
1925 Cut down pickup
1920 Dodge touring
1948 Ford F2 pickup
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Peter, Memphis TN
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Re: Red hot manifold
Steve's right - that generally means you're running too retarded on the spark.
Here's the reason, as I understand it: If the spark ignites the fuel late, it's still in the process of exploding when the exhaust valve opens, and the explosion continues in the exhaust manifold - thus heating it red hot.
The biggest danger here, is that it will excessively burn the exhaust valve and seat.
This is a good reason to do a night-time run with the hood off. Experiment with different settings of the timing, and your passenger can see the manifold and tell you what's happening.
There's also the possibility of the mixture being too lean. I can't explain why that heats the manifold, without more space than I have here. It's counter-intuitive. You'd think that too much fuel would cause a hotter burn, but take the word of experience on this. While you're doing your night-time drive-around, you could fiddle with the mixture as well.
Here's the reason, as I understand it: If the spark ignites the fuel late, it's still in the process of exploding when the exhaust valve opens, and the explosion continues in the exhaust manifold - thus heating it red hot.
The biggest danger here, is that it will excessively burn the exhaust valve and seat.
This is a good reason to do a night-time run with the hood off. Experiment with different settings of the timing, and your passenger can see the manifold and tell you what's happening.
There's also the possibility of the mixture being too lean. I can't explain why that heats the manifold, without more space than I have here. It's counter-intuitive. You'd think that too much fuel would cause a hotter burn, but take the word of experience on this. While you're doing your night-time drive-around, you could fiddle with the mixture as well.
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Mark Gregush
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Re: Red hot manifold
Running too lean; just heat/flame is coming out the valve no unburnt fuel to help cool the valve. Running a little richer, the unburnt fuel does help cool the valves as it passed into the manifold and helps from burning your valves.
But it could be ether or...
But it could be ether or...
I know the voices aren't real but damn they have some good ideas!
1925 Cut down pickup
1920 Dodge touring
1948 Ford F2 pickup
1925 Cut down pickup
1920 Dodge touring
1948 Ford F2 pickup
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Tom K
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Re: Red hot manifold
Just curious Jeff, carburetor or vaporizer?
A vacuum leak will cause it to run lean. Couldn’t hurt to check the nuts on the manifold and see if they are snug.
A vacuum leak will cause it to run lean. Couldn’t hurt to check the nuts on the manifold and see if they are snug.