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Glowing headers?

Joined
Oct 30, 2001
Messages
2,273
Location
Glen Burnie, MD, USA
Corvette
1986 Bright Red Coupe
Been a while since I've been here; busy with other things :(

Anyway, I'm still working on final tuning of the prom in my 86 and was playing around with it yesterday in the somewhat-dark garage setting timing and such. I noticed that the center two pipes on each header (cyls 3/5 and 4/6) were faintly glowing red. Is this something to worry about, or is that normal and would be covered by the heat shields on a regular set of exhaust manifolds?

Thanks.
[RICHR]
 

OldCorvetteFan

Well-known member
Joined
Jul 3, 2005
Messages
117
Location
Northwest Illinois
Corvette
Black 95 6 spd Coupe (Sold); 2011 GS
I wouldn't expect it to be a normal condition at idle.

Sounds like a lean condition in those cylinders, causing significantly higher exhaust gas temps.

Steven
 

SK.LT1

New member
Joined
Apr 30, 2006
Messages
2
Location
Bedford,Ma.
Corvette
1996Polo Green Coupe
I would check the egnition timing.It sounds like it should be advanced more.
 

c4cruiser

Well-known member
Joined
Feb 22, 2002
Messages
971
Location
Lacey, WA USA
Corvette
87 Gold Z52 Coupe 02 EB Z51 Supercharged Coupe
If it was on one side only, I would think that an injector or two may be dumping fuel at idle and creating an over-rich condition but with the same thing on both sides, that is probably not the case.

Is the engine running rough? What about driving the car for some distance and checking for any glow at the same location. It may also be an indication of plugged pre-cats. Are any codes present??
 

motorman

Well-known member
Joined
Mar 7, 2002
Messages
849
Location
pa
Corvette
2008 Crystal Red Tint Coat
Been a while since I've been here; busy with other things :(

Anyway, I'm still working on final tuning of the prom in my 86 and was playing around with it yesterday in the somewhat-dark garage setting timing and such. I noticed that the center two pipes on each header (cyls 3/5 and 4/6) were faintly glowing red. Is this something to worry about, or is that normal and would be covered by the heat shields on a regular set of exhaust manifolds?

Thanks.
[RICHR]
if this was at idle you may have rich cylinders that cause fuel to be burning in the exhaust port. headers will glow if the car is not moving air past them. even cast iron manifolds get cherry red but under full throttle pulling a load. take a 454 motorhome for a ride after dark with the engine dog house off and the manifolds get so hot they are transparent and you can see the darker area where the opening is in the manifold where it meets the head
 
Joined
Oct 30, 2001
Messages
2,273
Location
Glen Burnie, MD, USA
Corvette
1986 Bright Red Coupe
Ok. Responses to the various posts:

1. Timing is 6* which is what my new memcal calls for. That's what I was checking when I noticed the headers glowing.
2. Engine is idling fine after it warms up but there may be a rich condition during open-loop. This is something I'm going to do a data capture on for the chip guy. There are no pre-cats and the main cat is almost new (less than 2k miles).
3. It's possible that the car is running rich at idle even after warmup since there's a fuel smell during open-loop and very rough idling.

I cannot imagine (but would love to see!) manifolds hot enough to be almost transparent. That sounds both neat and scary at the same time...

So could be lean OR could be rich. Either way, it's probably not normal. I'll capture some data hopefully this afternoon and send it off for analysis.

Thanks again.
[RICHR]
 

jsinga

Well-known member
Joined
Nov 23, 2001
Messages
280
Location
Savannah, GA, USA
Corvette
87 Silver Coupe Way over 200k miles
At curb idle I won't say anything about the red glow. I know for a fact if you raise it to about 1500rpm and get a solid red glow you have a plugged up cat.
If seem to be down on power an exhaust restriction might not be a reach.

JS
 

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