Home » Public Forums » GMCnet » [GMCnet] Glowing Headers
| [GMCnet] Glowing Headers [message #289323] |
Sat, 24 October 2015 17:39  |
Dolph Santorine
Messages: 1236
Registered: April 2011
Location: Wheeling, WV
Karma: -41
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Had the opportunity to open the engine hatch at 65-70mph. 3150 rpm
The headers were mildly glowing.
Is that appropriate? I've never had the opportunity to observe a big block at cruise.
All temps were in the green, and I'm happy with the way it sounds.
I appreciate the input.
Dolph Santorine
DE N8JPC
Wheeling, West Virginia
1977 ex-Palm Beach TZE167V100820
1-ton, Sullybuilt Bags, Reaction Arms, 3.70 LSD, Manny Transmission, EV-6010,
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| Re: [GMCnet] Glowing Headers [message #289325 is a reply to message #289323] |
Sat, 24 October 2015 18:18  |
Chris Tyler
Messages: 458
Registered: September 2013
Location: Odessa FL
Karma: 7
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I havent done this with the GMC or under cruise conditions with any vehicle for that matter. However I can tell you from dyno experiance that most will glow under load under low light. However when they glow at low RPM/load that usually means a lean mixture.
With most engines, adding headers leans the mixture. I have found the driveability was worse after putting on headers unless the mixture was already rich or has been compensated
Was this on steady cruise or on hills?
76 Glenbrook
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| Re: [GMCnet] Glowing Headers [message #289326 is a reply to message #289323] |
Sat, 24 October 2015 18:13 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Dolph,
I'm guessing but at 65-70 mph / 3150 rpm I'd say the EGT was around 1100° F.
From Wikipedia:
Iron or steel, when heated to above 900 °F (480 °C), glows with a red color. The color of any heated object changes predictably (due
to black body radiation) from dull red through orange and yellow to white, and can be a useful indicator of its temperature.
You could buy one of these:
http://www.harborfreight.com/non-contact-infrared-thermometer-with-laser-targeting-69465.html
and verify the temp of the headers.
Regards,
Rob M.
The Pedantic Mechanic
-----Original Message-----
From: Adolph Santorine
Had the opportunity to open the engine hatch at 65-70mph. 3150 rpm
The headers were mildly glowing.
Is that appropriate? I've never had the opportunity to observe a big block at cruise.
All temps were in the green, and I'm happy with the way it sounds.
I appreciate the input.
Dolph
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] Glowing Headers [message #289327 is a reply to message #289326] |
Sat, 24 October 2015 18:16 |
Dolph Santorine
Messages: 1236
Registered: April 2011
Location: Wheeling, WV
Karma: -41
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Thanks. I have one, and will check it next time out.
Dolph Santorine
DE N8JPC
Wheeling, West Virginia
1977 ex-Palm Beach TZE167V100820
1-ton, Sullybuilt Bags, Reaction Arms, 3.70 LSD, Manny Transmission, EV-6010,
> On Oct 24, 2015, at 7:13 PM, Robert Mueller wrote:
>
> Dolph,
>
> I'm guessing but at 65-70 mph / 3150 rpm I'd say the EGT was around 1100° F.
>
> From Wikipedia:
>
> Iron or steel, when heated to above 900 °F (480 °C), glows with a red color. The color of any heated object changes predictably (due
> to black body radiation) from dull red through orange and yellow to white, and can be a useful indicator of its temperature.
>
> You could buy one of these:
>
> http://www.harborfreight.com/non-contact-infrared-thermometer-with-laser-targeting-69465.html
>
> and verify the temp of the headers.
>
> Regards,
> Rob M.
> The Pedantic Mechanic
>
> -----Original Message-----
> From: Adolph Santorine
>
> Had the opportunity to open the engine hatch at 65-70mph. 3150 rpm
>
> The headers were mildly glowing.
>
> Is that appropriate? I've never had the opportunity to observe a big block at cruise.
>
> All temps were in the green, and I'm happy with the way it sounds.
>
> I appreciate the input.
>
> Dolph
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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| Re: [GMCnet] Glowing Headers [message #289328 is a reply to message #289325] |
Sat, 24 October 2015 18:28 |
Dolph Santorine
Messages: 1236
Registered: April 2011
Location: Wheeling, WV
Karma: -41
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I wish I had added a wideband to look at that.
Slight grade, so a load, and it was dusk.
Dolph Santorine
DE N8JPC
Wheeling, West Virginia
1977 ex-Palm Beach TZE167V100820
1-ton, Sullybuilt Bags, Reaction Arms, 3.70 LSD, Manny Transmission, EV-6010,
> On Oct 24, 2015, at 7:18 PM, Chris Tyler wrote:
>
> I havent done this with the GMC or under cruise conditions with any vehicle for that matter. However I can tell you from dyno experiance that most
> will glow under load under low light. However when they glow at low RPM/load that usually means a lean mixture.
>
> With most engines, adding headers leans the mixture. I have found the driveability was worse after putting on headers unless the mixture was already
> rich or has been compensated
>
> Was this on steady cruise or on hills?
> --
> 76 Glenbrook
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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| Re: [GMCnet] Glowing Headers [message #289330 is a reply to message #289329] |
Sat, 24 October 2015 18:54 |
Dolph Santorine
Messages: 1236
Registered: April 2011
Location: Wheeling, WV
Karma: -41
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Senior Member |
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Pun intended?
Dolph Santorine
DE N8JPC
Wheeling, West Virginia
1977 ex-Palm Beach TZE167V100820
1-ton, Sullybuilt Bags, Reaction Arms, 3.70 LSD, Manny Transmission, EV-6010,
> On Oct 24, 2015, at 7:47 PM, Robert Mueller wrote:
>
> Dolph,
>
> With headers you can shoot each cylinder separately; I'd guess that the temps should all be reasonably close; if there is a large
> difference then something is amiss?!
>
> Regards,
> Rob M.
> The Pedantic Mechanic
>
> -----Original Message-----
> From: Adolph Santorine
>
> Thanks. I have one, and will check it next time out.
>
> Dolph
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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| Re: [GMCnet] Glowing Headers [message #289346 is a reply to message #289323] |
Sun, 25 October 2015 00:41 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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Senior Member |
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Dolph Santorine wrote on Sat, 24 October 2015 15:39Had the opportunity to open the engine hatch at 65-70mph. 3150 rpm
The headers were mildly glowing.
Is that appropriate? I've never had the opportunity to observe a big block at cruise.
All temps were in the green, and I'm happy with the way it sounds.
I appreciate the input.
Dolph Santorine
DE N8JPC
Wheeling, West Virginia
Dolph,
I have EGT gauges and at 3100 and a slight grade I see 1100-1200 at the stub pipe after the collector on the headers. At that RPM lots of fire has to get out of the cylinders.
That being said, you really want to be sure that the mixture is starting to get richer. (Power valve beginning to open). You mentioned a Wide Band O2. It is too bad they are as pricy as they are because I believe they can save us a set of valves or even larger expense. Also make sure the weights are advancing the spark in the distributor.and vacuum advance is working as well/
I think for the meantime a check with the laser heat gun will let you know what you need to know.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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