New 440 diagnostic help?

[pgaylord]

Howdy, I have a newly-built 440 that isn't running right. Difficult to start, lousy idle. It's got a mild cam on it, and the carb is a QuickFuel 750 SS, new out of the box. I think it's running really rich, not sure why. I've adjusted the idle mixture screws to lean the idle mixture out which has helped a bit. But tonight as I was trying to set the electric choke and it was on fast idle I noticed the headers glowing (see pics) which I thought was a bit odd... is it? Plus, if you notice, not all of the headers are glowing, some more than others. I've also taken a short video of it running at warm idle, there's a slight "tick" noise.... lifters or exhaust?

https://www.dropbox.com/s/uqmhljoln7fj606/Video.MOV?dl=0

Suggestions as to what might be going on here?

 

[NOSTRT980]

https://www.google.com/search?q=glowing red headers&safe=active&gws_rd=ssl

 

[pgaylord]

Yeah, did some more research, and half the material says it's running too lean, other half says too rich. Spark plug says the latter, as I suspected.

And RE the differences in header temps, seems that at off-idle the fuel mixture is too irregular and there are too many other variables to warrant much attention.

 

[Wietse]

I would say, check the ignition timing first.
After check fuel bowl level height is correct.
Then play with the adjustment of the idle mixture screws, a rule of thumb which is close enough most of the times to make a start is, screw them all the way in, and then open 1-1/2 turn.
Use a vacuum gauge and slowly adjust them till you get the best vacuum.

Random glowing might be caused by a dual plane intake if one side of the carb is giving more fuel maybe?

 

[texas69bee]

All good info above. In the past 3 wks I installed the Quickfuel 680 SS. I fouled a set of plugs right away cause it was burning to rich. I ended up with screws at 3/4 of a turn vs the 1 1/4 turns. Get that choke adjusted ASAP after start up to avoid the lean condition. It's openning to soon. I started with my initial timing at 12 and have been able to slowly adjust to 15. An o2 sensor will really help. Change out plugs if you have doubts.

 

[Zeppelin264]

Timing is too retarded. That would be the first thing I'd check.

And glowing headers at high idle isnt really an issue.

 

[Garys1969RR]

I'll bet those look really cool at night! I have heard of this before. The reason they glow is because the fuel/air mixture is completing it's combustion cycle in the headers. If you were to remove the headers and run it, you would see long flames coming out of the ex ports! Like a fountain on the 4th of July! LOL. Most of the combustion cycle should be completed before the ex valve opens, but sometimes not all of it does, as in your case. You have to ask yourself why it's burning so slowly, or late. Could be late (retarded) ignition timing, ex valve opening too early (wrong cam timing/installation), or too lean a mixture. Or a combination of the above. Start with ignition timing set to 20 degrees advanced at idle and see what happens. Then I would look at cam timing. Most cams I've used run best with 4 degrees of advance.

 

[beanhead]

Yes more initial timing. How much depends on your cam and compression... unless you know that your compression is pretty high I would start it close to 20 as Gary recommended and go from there, you just don't want your total timing to be more than 36 or 38 degrees. When I was getting my 440 sorted out my exhaust temps would get really hot really fast because I didn't have enough timing in at idle

 

[pgaylord]

Thanks all!

I cracked open the choke a bit when cold, and turned down the idle mix screws to about 1 turn out, good vacuum and it is starting and idling pretty good now. Still pretty stinky on startup and a bit of black smoke, but overall OK.

Will put the timing gun on it tonight. Car is I think also running really rich on the road... pulled a plug and it was powdery black. I have some jets coming in the mail. Stock jetting on this carb is 74/80. After checking timing, I will change the jets, and start with 72/78 and see how that goes for a while. Anything else I should be thinking?

Appreciate the advice.

 

[beanhead]

As far as the ticking...start by checking your exhaust connection points and look for signs of soot around gaskets (or even feel for air leaking out while running)...a lot of times that stuff needs a re-snug after it's been heated up and cooled off. Rule out the easy stuff first...

 

[coloradodave]

Agree that retarded timing will cause the glowing. Check float levels first for rich condition and sooty plugs.

 

[pgaylord]

Thanks all. Things running a fair bit better after I cracked-open the choke when cold, turned down idle mix, and backed off the idle screw. Float levels look spot on. Timing is at about 19 btdc, which sounds about right. Also re-tightened the header bolts. After a drive last night the plugs are looking pretty good. Still some soot out back on start and more fragrant than I'd prefer, so I ordered some smaller jets. (currently 74/80, going to try 72/78).

 

[texas69bee]

Thanks all. Things running a fair bit better after I cracked-open the choke when cold, turned down idle mix, and backed off the idle screw. Float levels look spot on. Timing is at about 19 btdc, which sounds about right. Also re-tightened the header bolts. After a drive last night the plugs are looking pretty good. Still some soot out back on start and more fragrant than I'd prefer, so I ordered some smaller jets. (currently 74/80, going to try 72/78).

I think your going the wrong way with the choke. Closed when cold, open when hot.
https://holley.com/blog/post/how_to_adjust_a_carburetor_automatic_choke/

 

[pgaylord]

I think your going the wrong way with the choke. Closed when cold, open when hot.
https://holley.com/blog/post/how_to_adjust_a_carburetor_automatic_choke/

Sorry I wasn't clear.... it was previously fully shut when cold. I adjusted it so it was open about a quarter inch when cold to give it a bit more air as previously it was so rich it wouldn't start cold at all.

 

[texas69bee]

Sorry I wasn't clear.... it was previously fully shut when cold. I adjusted it so it was open about a quarter inch when cold to give it a bit more air as previously it was so rich it wouldn't start cold at all.