Help! Red Hot Shorty Headers

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Nov 7, 2004 | 07:44 PM

GRX

Thread Starter

Le Mans Master

Joined: Jul 2001

Posts: 6,252

Likes: 2

From: Silicon Valley Kalifornia

Help! Red Hot Shorty Headers

When reving at about 2000-2300rpm for about 1 minute my headers (1985 shorty fac headers) will glow medium red. The engine is stock except for AFR 190 heads, TRW 8.7:1 comp. ratio forged pistons and a mild Crower cam: Specs at .050” tappet lift:
Intake: Duration: 209*
Exhaust: Duration: 217*

Intake:
Opens at: -5.5 ATDC
Closes at: 34.5 ABDC
Exhaust:
Opens at: 46.5 BBDC
Closes at: -9.5 BTDC

Lobe Lift:
Intake: .330” x 1.5 rocker= .495”
Exhaust: .343” x 1.5 rocker= .515”

Lobe separation: 114*

My AFR during this is about 14.7:1.

Any ideas?

Last edited by GRX; Nov 8, 2004 at 10:55 AM.

Nov 7, 2004 | 07:47 PM

PMARTINEZ92126

Racer

Joined: Sep 2002

Posts: 420

Likes: 1

From: SAN DIEGO CA

glowing

when my headers started to glow I had a timing problem. Fixed the timing and the glow went away. Hope this helps.

Nov 7, 2004 | 08:12 PM

GRX

Thread Starter

Le Mans Master

Joined: Jul 2001

Posts: 6,252

Likes: 2

From: Silicon Valley Kalifornia

Forgot to mention that timing adjusted stock.

Nov 7, 2004 | 08:25 PM

James94LT1

Burning Brakes

Joined: Apr 2002

Posts: 934

Likes: 0

From: MO

I had glowing headers when my cam was a tooth off.

Nov 7, 2004 | 08:33 PM

GRX

Thread Starter

Le Mans Master

Joined: Jul 2001

Posts: 6,252

Likes: 2

From: Silicon Valley Kalifornia

Cam is on right. I've checked that before. I was thinking that maybe my custom cam has a bit too much lift on the exhaust valve (.515"). Exhaust valve is large too at 1.65" dia. There is no valve overlap this cam is mild except for the lift.

Last edited by GRX; Nov 8, 2004 at 08:52 AM.

Nov 7, 2004 | 08:37 PM

GRX

Thread Starter

Le Mans Master

Joined: Jul 2001

Posts: 6,252

Likes: 2

From: Silicon Valley Kalifornia

...Engine has about 2 hours on it...garage time.

Nov 7, 2004 | 09:26 PM

Jloshotz

Burning Brakes

Joined: Feb 2004

Posts: 1,024

Likes: 0

From: Long Island New York

Do you have cats? Just a thought...

Nov 8, 2004 | 12:16 AM

redbullapril23

Drifting

Joined: Aug 2004

Posts: 1,830

Likes: 1

From: atlanta Georgia

afr is off. if you havent gotten custom tune. and u have heads and a big ol cam

. get it!
you7r friend
Sean

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Nov 8, 2004 | 07:38 AM

runner140*

Le Mans Master

Joined: Mar 2004

Posts: 8,700

Likes: 298

From: Ft. Lauderdale Fl

Usually when the headers get red...

Thats usually a symptom of a clogged header, could it be that simple.

Nov 8, 2004 | 08:50 AM

#10

GRX

Thread Starter

Le Mans Master

Joined: Jul 2001

Posts: 6,252

Likes: 2

From: Silicon Valley Kalifornia

Cat is not clogged- I've checked. Headers are not clogged- happens on BOTH sides of motor in every pipe.

Last edited by GRX; Nov 8, 2004 at 08:53 AM.

Nov 8, 2004 | 08:55 AM

#11

GRX

Thread Starter

Le Mans Master

Joined: Jul 2001

Posts: 6,252

Likes: 2

From: Silicon Valley Kalifornia

Quote:

Originally Posted by redbullapril23

afr is off. if you havent gotten custom tune. and u have heads and a big ol cam

. get it!
you7r friend
Sean

I do my own tuning. AFR is 14.7 (+/-.3) to 1 during this.

Nov 8, 2004 | 01:36 PM

#12

C4DC

Le Mans Master

Joined: Aug 2002

Posts: 6,079

Likes: 3

From: Clearwater FL

St. Jude Donor '06

Seems like you have covered the bases. I'd try running it without the cats on and see if it does the same thing... Just to be sure it is not the cats.

Nov 8, 2004 | 02:05 PM

#13

CFI-EFI

Race Director

Joined: Sep 2000

Posts: 17,298

Likes: 33

From: The Top of Utah

Quote:

Originally Posted by GRX

When reving at about 2000-2300rpm for about 1 minute my headers (1985 shorty fac headers) will glow medium red.

I had seen this post before but hadn't stopped to read it. I was prompted by your plea in the Engine section. I decided to reply here to keeping it from getting spread over two forums. Glowing headers are caused by air fuel mixture burning after the exhaust valve opening. Often a rich mixture that wasn't fully consumed in the cylinder is one cause. A lean mixture, because it burns hotter than normal, CAN cause it too. Either mixture condition, and even a correct mixture can cause this if the timing is retarded. Retarded timing lights the mixture late and it finishes late, in the headers/manifolds. You have checked the cam timing, the ignition timing, and the A/F ratio. Something you checked is off. Without tearing it back down to verify the cam timing, the simplest thing to check for is the ring on your damper having moved to give you false readings. It HAS to be one of the items you've verified. Your cam is waaaaay mild, as is the compression ratio. No problems, there.

RACE ON!!!

Nov 8, 2004 | 08:46 PM

#14

GRX

Thread Starter

Le Mans Master

Joined: Jul 2001

Posts: 6,252

Likes: 2

From: Silicon Valley Kalifornia

Thanks for your help!

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