glowing red headers, how do i fix my tuning issue

been trying to dial in the motor in my f100 for the jalopydrags and cant quite get it right. its a 460 ford and the timing at about 10 degrees advanced. i have a holley 4 barrell carb with #74 jets in the front bowl. when you hold it at about 2500 rpm they start to glow and i have played with the timing and changed the jets last night from 72s to 74s. i am at a loss as to what my problem is, mainly because im not sure what causes the headers to glow. is it a too rich condition and fuel is being burnt in the headers, or a too lean condition and there getting to hot from that. i have played with the timing as well and everything i seem to do there has the same effect. im pretty sure its in my carb but dont know which way to attack the situation. someone please point me in the right direction.

 

my experiance with this is from harley davidson shovel head motors ..so take it for what its worh..I had the same issue with a built S&S shovel head motor i built and it ended up being a combination of too lean and to early on the timing..i fixed that and the problem went away.

 

oops to late in timing not early my bad..not enough coffee this morning yet

 

so by to late you mean retarded? just want to make sure im on the same page.

 

damn, is there a temp gauge on that thing? she's running pretty damn lean.....

 

Yeah, retarded...you maybe have advance springs that are too stiff or stuck parts in there so advance doesn't start early enough. Essentially, the mix is still burning when it reaches the exit. Fix that, maybe normal Ford curve kit from speed shop, and once happier try testing vac advance on both manifold and ported vac to see which the engine likes better.

 

You may not have a tuning issue.

It's fairly common for headers to glow a dull red during the 2000 rpm cam break-in and I'm guessing you may be seeing the same thing.

Do a search for a Holley tuning site and if the jetting is on and timing is reasonable you probably don't have a problem.

 

yep retarded so that some ignition may be taking place in the exhaust manifolds or headers..but a lean condition can do the same thing as i experianced with the H.D. engines after pumping them up to greater cams and displacement..it is a 4 stroke engine so i would think it applys with any 4 stroke..maybe the H.D. engine has a different ignition pattern also it sparks in both cly. at the same time reguardless if it is the compression stroke of that cly..(if that makes sence to you) they dont have a distributor on them (at least the old shovels didnt have the technology at that time to individually ignight each cly. at its compression stroke) so the late ignition on the opposite cly. could be late enough if the timing was off a bit to turn that pipe a bit red at a higher rpm than idle.

 

im leaning toward a lean condition..no pun intended

 

well i dont think that the weights are off in the distributor because before i put the new cam in the headers didnt glow. i was leaning toward the fact that the motor was running to lean. so i guess its safe to say i should start by adding more timing and maybe a little more fuel? thanks for the input

 

oh ok now more info..the cam!
how is the cam set?

 

its a one up from stock edelbrock performer cam. its set at 0 degrees as far as the marks on the timing chain are concerned

 

hotter cam oft needs richer off idle-transition gas

 

put more timing in it it will stop glowing

 

timing chain? you ment gears right? tell me you ment gears...the chain can be moved to any possition..it is the relation of the cam to the crank that is the important issue

 

yea the gears the marks on the gears are set at 0

 

ok ..im calm now..i would say you may be too lean..see if ya cant bost that first..always take it one thing at a time so you know what changed what..try not to shot gun it cause than you will not have a clue as to what changed your issue..and also its easier to change back one thing than trying to remember a shit load of changes..

 

was this durring the cam break in?

 

I don't think you're going to get the tuning info you need by running the engine in neutral at 2500 rpm.

Set the engine up close to stock, carb jetted like they come from Holley, all in timing about 34 degrees or so.
A drag racing curve won't hurt.

It's the total timing you're interested in.
Check a manual for that figure and start there.

Fresh plugs, run the quarter mile with it and check the plug coloration.

Note that with today's 'gasoline' the plugs won't color up all the way in the short amount of time involved with run down the strip.
You'll need some sunshine or a flashlight and a good magnifying glass to check color down deep in the plug.

If the engine is moderatly lean, the horsepower levels you're running won't hurt anything for one quarter mile run.

You can get an idea if your all-in (or total) timing is on the money by looking at the center electrode of the plug.
You'll see a color change that extends down the side of the electrode proper - and not on the ceramic.
The color will match the flat top of the electrode.
Proper timing will show the color change going down 1mm.

No color change on the electrode side shows retarded timing.

More than 1mm down shows timing too far advanced.

Best to check first with a light, but the electrode color change can be enlightening.

I'll bet you ran the car at dusk or after dark.
That's where I first noticed the dull red glow on headers during the cam break-in of a Ford GT390 engine.

 

it was during cam break in when they were glowing but a day later when i was doing final tuning the headers are still glowing. at idle the headers are at about 700 degrees. i know this is to hot. i have an 850 holly on my 454 i may pull it off and try it on this motor

 

oh i forgot to add this to the mix....a vacuume leak..chck to see if you have one.

 

did you have the intake off when you did the cam change? i bet you did..i bet its leaking!..it is a possibility..had this issue before..same outcome..before you go changin the carb..check your intake fit..

 

oh and maybe your exhaust valves are running to tight..so that they are not closing all the way..alot of things to check

 

does it miss and spit at 2500? I had put the cam in 180 degrees off on a SBC. It would idle fine, off idle it spit out the exhaust, and turned the exhaust manifolds cherry red. Flipped the cam 180, and it purred like a kitten. Eldebrock cam, crane timing chain had conflicting information.

 

I ran 74 jets in a roller cammed 350 with an 800 Holley. I ran 82 and 84 in a flat tappet 454 with an 850 Holley.

 

did you verify TDC at #1 on compression stroke before you fired it up for break in? did you verify timing gear marks with a straight edge? i highly doubt the cam was off or the chain would be an issue out of the box.
i would start with the TDC at #1 cylinder and verify the rotor position. that should get you in ball park for timing with the light.

 

yes i had the intake off to do the cam. it is the fourth time its been off for an oil leak and i really made sure it was sealed up when i put it on this last time. i will double check it anyway but i dont think its an intake leak. the exhaust valves are fine the only way to tighten the rockers is down till there tight there not lashed like a chevy. i am positive that the cam is not 180 out and the rotor is on number 1 compression stroke and the pointers all line up. i talked to someone on the phone that said the new timing chain set may be retarded right off the bat being its a pollution motor. the timing chain set is out of an 83 and i should have used a set out of a 1960s vehicle.

 

Always, and I do mean Always make sure the ignition is right before you go jackin' with the carb. Anytime you go with more cam you should recurve the dizzy to a more agressive curve. The advance should start coming in a lot sooner and be all the way in by 3000 rpm. The vacumn advance should be plugged till you get it running right, then fiddle with it, as it is just a mileage device.

 

I'm no Holley-expert, but I would put in some #80 jets and go up from there, especially on a 460ci which needs lots of fuel to burn anyway.
Have someone look at the exhaust-fumes from a distance to see if they're black or not. Black fumes = rich setting.

Here's a list of Holley-carbs and their stock jet-sizes to compare;
http://www.mortec.com/carbs.htm

 

Had that happen before, and the problem turned out to be the timing was way too retarded. The headers glowed red and roasted the paint off of them. It was during the initial break-in, so I didn't want to kill the engine and kept revving it up around 2300 2500 rpm for a while. After getting the timing right, I didn't have that problem anymore.

On a hot rod with a hot cam, the factory specs for timing are kind of out the window. The factory specs are set to run pretty lean without much advance or sometimes with no advance at all in an effort to cut down on "oxides of nitrogen" in the exhaust. But on a hot rod that's smog exempt, it'll usually run a lot better with more initial timing.

Set the timing to about 34 degrees with the engine revved up to where the centrifical advance maxes out (might be around 2500 to 3000 rpm depending on your distributor) and the vacuum advance disconnected and the vacuum line plugged up. Put in some lighter centrifical advance springs to "recurve" the distributor and it'll run better too. You want the advance to come in earlier than stock. In a hot rod with a hotter than stock cam, the centrifical advance should be all the way kicked in by about 2500 - 2800 rpm or so. It doesn't seem to really matter what the initial advance is at idle -- what's more important is what the maximum advance is when it's revved up.

Also, remember to disconnect and plug up the vacuum advance line when you're setting the timing.