dirt track racer 81

iTrader: (45)

they reburn in the headers

onebadrubi

So your saying if I purposely stick the wrong jet in my atv, creating a lean situation, it WILL NOT glow red? Maybe you should try this? Im not saying what you are saying is wrong. But I can attest to the incorrect jetting, lean, in a carbed atv will make your header glow red. Never messed with this to the extense of glowing headers on a Fuel injected atv or vehicle. Have seen a well af/r 408 glow uncoated headers also.
Is an atv carb combustion engine any different then this motor we are talking about? Not to my knowledge. But im no where near the intelligent as many on this forum.

budhayes3

iTrader: (19)

If this helps re-enforce the issue, rich=glowing headers/exhaust manifolds, as well as misfire from weak/no spark. I remember burning a spark plug wire on one of my old camaro's and opeining the hood at night as the exhaust primary for the dead cylinder was glowing red.

ScojoDak

Lean mixture? WRONG! From racingarticles.com

Glowing headers mean the engine is lean: This wives’ tale is starting to lose steam, but still believed more often than not. Headers glow red for only one reason, there’s fuel burning inside. The two main reasons are a rich mixture and late ignition timing - which doesn’t give the fuel enough time to burn inside the combustion chamber. Test it for yourself, let your engine idle and crank the ignition timing back to the point where it barely runs, then get out the marshmallows.

dirt track racer 81

iTrader: (45)

im not saying running lean will not cause the header to glow, lean means is getting hotter, but also unburnt fuel that is reburning in the primary gets hotter than normmal also..as i have 5 witnesses that seen a 9.5:1 af ratio with 36 degrees timing made the headers glow on the dyno..pulled the af to mid 12's did not glow at all..the guy ran an aspault supertruck and his crew noticed the headers glow on the track, the driver even said the truck has no power..the guys thought the motor was too lean and kept on adding fuel and got worse so they brought it to us on the dyno and it was running in the low to mid 9' on the af..ive also seen a misfire cause its primary to glow

onebadrubi

Im not saying rich is not the reason. But lean does make a motor run hotter and can cause header glow.

treyZ28

Come up here. We will take my 17.2:1 AFR vehicle for a ride around a trail and examine the primaries.

Dude, common sense. COASTING at 45mph is virtually NO load. How could it be making that much heat at 10% load? The pistons would be GONE long before the headers glowed red. If the STEEL, which is thin and in ambient air is about 1000 degrees, think of what the piston is doing! Combustion temps in an OEM stock engine are above the melting point of aluminum. Think of what would happen if, at part throttle, it was burning so hot that these headers were glowing!

Lean just isn't going to make headers glow if the timing is right. You are going to burn it ALL in the engine. I know several people running very lean AFR on the street that drive hundreds of miles at a time. No problems. There just isn't enough load to make it hot.

onebadrubi

I have not yet said you are wrong trey. And im not going to. Like I said i can go make an atv purposely lean and make the header glow and run extremely hot.

treyZ28

fix the timing and i bet it wont, not without heavy load anyway

redwagon

If you run so lean, that the extreme heat from the combustion process glows the headers red, get ready to park your truck for a while. Because you'll be busy for a while getting all the melted pieces of the piston out of the oil pan.