Red Hot #6,8

[harshman]

I was breaking in my cam last night and noticed that #6 and #8 were glowing on my headers. It sat still for 25 minutes at 2,000 rpm – I know that this will not be the typical situation for my car and all, I’m just concerned. It got so hot that my carpet started smoking – and I have coated headers. What do you guys think? I’m not sure if the manifold has anything to do with it – I’ve got the old style Torker II on my big block.

[derekf]

If I had to guess, I'd say 6 and 8 are running pretty lean - you might want to check the other signs of that (read the plugs) and maybe fatten up the mixture for those runners.

[harshman]

The plugs look great. Keith (Zefhix) thought I was the distribution through the manifold that was the cause. The carburetor sits at an angle.

[Camaro Zach]

Adjust the valves again, Same thing happend to my 4.3 when i was breaking in the cam. Good luck

[Zefhix]

My only thought is that with the Holley, they have power valves that open with vacumn to richen the cruising circuits. Since the car was breaking-in, running at 2000K, then the car wasn't getting the benifit of the richer mix that would come with the car under load instead of sitting static in the garage. Also, because the carb and manifold are situated diagonally on the block. The number 6 & 8 are seemingly the longest runners (and they're on the secondary side of the sigle plane). The car sounded beautifully smooth & the last time we broke the other cam in the same number 6 & 8 tubes were glowing with different rocker adjustments. That's why I think fuel distribution is the culprit and that the car shoulb be fine when running under load.

What do you guys think?

[David Pozzi]

I think it's unburned fuel burning late in the cycle. You might try adjusting the idle mixture screws when running to see if if influences the header heat, that can point you in the right direction. Idle mixture will still have an effect at 2000. check the air bleeds very carefully, if they plug, fuel will enter the engine in large droplets not in a spray, the droplets will not all burn in the cylinder but can finally burn late in the cycle when the exhaust valve is open, and burn in the headers. The amount of heat radiated can fry hoses at a foot away, it's like a furnace!

[shmoov69]

I have never personally used that intake, but have had friends that have. It is not good with a couple cyl's, I would guess it to be # 6 & 8!
I have always been told to never use a plate setup on that intake because you will pop a couple pistons!

[chicane67]

I'll second David. I think its fuel distribution and depending on what carb you have on the ole rod now, will depend on whats required to fix the problem.

Four corner idle, staggered jetting and a possible secondary power valve....... I would start with the four corner idle myself.

[Zefhix]

Well, maybe Andy (cough, cough) can get and 02 bung welded in and we can wideband the car. When he puts the second set of springs back in the heads, we can tune it and I think the secondary power valve might be a great idea....I'll reset the idle screws at a turn and a half each for a base-line and then jerk with them from there on the wideband if he (cough, cough) gets one. :D

You're in Vegas chicane, why not come over and make it a party? :)

[harshman]

Keith – it sounds like you were at the doctor’s office with your last response. :moon: I’d love to get a wide band but I think spending money on a new manifold would be a better option for now. My carb doesn’t have a secondary power valve. It is a 750 dbl pumper – Holly.

[chicane67]

I'm in.

Anything for a party.............

[harshman]

Tonight at 7:30. I've already broken in the cam and installed the inner springs and changed the oil. Now I just need to finish tuning it and run.

[Zefhix]

Tonight at 7:30. I've already broken in the cam and installed the inner springs and changed the oil. Now I just need to finish tuning it and run.

Andy, I'm stuck at work tonight and tommorow until 9pm and I have wed/thurs. off. I can stop by after work tonight but I won't be there until about 9:30...okay with you?

[harshman]

changed to wed. 7 pm