67 Fury 440 Engine Problems

[SportFury70]

Hi All,

I'm wondering if anyone has any tips/advice for my stepdad for his 67 Fury II with a 440 Super Commando. It's no regular 440 either. That's for another time. Anyway, the car now has a Demon Carb, and TTI headers that came with the exhaust "kit". When the car is cold, it runs like a bat out of hell. It can do burnouts and runs pretty good. But when it gets hot, it does not want to run, and when it's at a stoplight it stalls. My stepdad mostly uses Edelbrock. So the intake got changed from a performer to a regular rpm. Mind you he put an aluminum radiator and electric fans in it too. He did a compression test and checked parts of the engine, and he thought everything looks fine. Since he got so disgusted with it, he just stopped working on it. Now it just sits and collects dust. Since he did a resto, he drove it a little over 200 miles. What could it be, gas tank?

Any help would be appreciated.
Thanks.

 

[detmatt]

Is it hard to start when hot and after it stalls

 

[rkrochen]

First thing I would want to check is to see if it is running lean. Once it’s warmed up you can choke off the carb a bit and see what happens. If it picks up speed you are running too lean. Certain sprays work for this as well.

 

[SportFury70]

detmatt. I can't really explain it. Once it stalls, it starts back up, but takes a minute. It doesn't start up right away.

 

[Newport 66]

Sounds like it too lean.....

 

[1978 NYB]

Vapor lock.

Several things you can do.

Wrap the fuel line with heat barrier wrap.

Carb insulator kit.

External electric fuel pump.

The coil could be bad.... swap it with another one to eliminate that possibility.

I do think the fuel is boiling and changing from a liquid to a gas and causing your problem.

 

[65Fury440]

Figure out if it's a spark or fuel problem.
When it stalls, see if gas squirts out the carb before you crank it anymore. If there is gas, check for spark.
A cheap fuel pressure gauge you can tee in and tape to the windshield would be my personal choice. but. not required.
If there is fuel in the carb when it stalls, yank the coil wire and have someone crank the engine, see if it will jump spark into the cap terminal.
Sounds like the car is almost there, don't quit now.

 

[Davea Lux]

The latest generation of Demon after market carbs tend to be calibrated on the lean side. Does the car run like crap at all throttle ranges after it has warmed up, or just at idle? Try blocking the choke in the half closed position, does the car now idle? If so the idle metering screws are set too lean, try turning them out about one half turn. If the car will now idle without quitting you are on your way to solving that problem part of the problem. The old school way to adjust the idle circuit is to back the idle screws out 3 to 4 turns from the fully closed position. Find a responsible helper and have them start the car, set the park brake and keep one foot on the brakes. Next have them put the car in drive. Now start turning the primary metering screw on one side or the other of the carb inward until the engine just starts to miss fire and then back off that screw 1/4 turn and do the same thing to the other side.

The car should now idle smoothly, if necessary, you might need to adjust the throttle position screw to get to the proper idle rpm range (do this in neutral). You are now ready to test drive the car. If it runs smoothly, you are ready to go.

The primary metering rods on the Demon are often set too lean. If the car idles smoothly, but then starts to run poorly as the throttle is applied to about 1/3 of the way open, you will need to adjust the primary metering rods. This is done by buying a metering rod spring kit. The metering rods are held in constant tension by a small spring, different springs are used to make a richer mixture, it usually works best to change the spring tension by one spring rate at a time. The literature that came with this carb should explain how to install the mixture springs to alter the rate of fuel flow Most places that sell these carbs also have the spring kits.

You should also check to see which Demon is installed, a modified 440 high performance engine should have at least a 750cfm carb. It will still run with a 650 cfm but it will usually run better with the bigger carb, especially at full throttle. FYI, it is a very bad idea to do burnouts with a cold engine, let it warm up so everything is getting properly lubricated.

Before messing with the carb, be sure the car has clean fuel and a clean fuel filter and adequate spark.

You also need to know if a single plane or dual plane intake is installed as the idle circuit adjustment I gave is for a dual plane manifold, as these are more common today.

Dave

 

[CBODY67]

My first thought was a clogged idle system, which MIGHT flow, but not enough, for some reason. Might be a too-lean setting as mentioned, which could be somewhat addressed by the idle screw adjustment, but if the idle tubes in the carb are "restricted", then they'll have to be cleaned out manually with some "twist drill" action. I went through something similar with my '80 Newport 360 2bbl. When I got it, as long as the fast idle cam was engaged, it ran well and had no issues with highway driving. But when warmed up enough to be on base idle, it would die. Even if I just backed-out of the throttle while slowing down for an off-ramp on the freeway.

In the base of the solid brass idle tube, on the bottom of the venture cluster, was a drilled orifice which feeds the idle circuit. I got some small twist drills and went just large enough in drill diameter to "just get brass". Used some carb cleaner to spray it out from the backside, reinstalled, end of problem. BUT it took me a month or so of research to find where the "low speed jet" was in the carb.

Which Demon carb is on the engine?

I can understand the learner calibrations which have been mentioned, but not lean enough to cause stalling per se, IF the idle circuits are adjusted well. IF the carb idle needles have very little sensitivity in their adjustment, it's probably their internal feed circuit that has the problem.

The old "standard" base idle needle adjustment used to be 1-1.5 turns out from lightly-seated. But the threads on the idle screws were coarser back then. Aim for max rpm with those adjustments, without touching the speed screw (noting what the base hot idle speed is, when it'll stay running BEFORE changing anything). As the idle speed might increase from the idle screw adjustment, lower the speed screw rpm. If the engine is modified, it might need a 750-800rpm hot base idle speed to idle decently well in gear. A good timing light and dwell tach are usually all you'll need.

So, check and adjust the ignition timing first, then the idle speed, then the idle mixture. In that order. Do check the carb base gasket for leaks, too! Or any other vacuum leaks, too.

Keep us posted,
CBODY67

 

[SportFury70]

Thanks for the advice everyone. I will pass it along to him and see what he says/thinks, etc. However as far as I know, he has replaced the coil and put an electric fuel pump on already. Yet still runs like crap.

 

[1970cat]

do you have any pictures of the engine compartment so we can get an idea of what we are looking at (for)?

 

[SportFury70]

Sure. I can get some for you. Forgot to mention, the car went through 3 carburetors, and about 3 ignition modules too.

 

[detmatt]

It would be worth checking the fuel pump pushrod.

 

[rags]

looking at the plug wire routing reminds me why i'll never run headers again. after three modules, ever consider trying a point triggered distributor? maybe some ported vacuum to the advance (doesn't appear connected in pictures)?

 

[1970cat]

a little hard to tell from the picture but your fuel line looks pretty close to the front header tube. do you have a fuel filter? you may want to put a clear fuel filter somewhere near the carb. next time you have trouble check to see if there is fuel in it or has it boiled out.

 

[Yeahrightgreer]

Vapor lock.

You beat me to it. I read the first few lines and immediately came to my head. That’s what I’m betting my donuts on.

 

[detmatt]

Which can be a symptom of a short fuel pump pushrod.

 

[rkrochen]

Maybe I am wrong but usually a pump problem shows up on heavy acceleration vs idle. This is due to the fact that the fuel supply is sufficient during idle but can’t handle the requirements of full throttle. This would the the case of a short or worn fuel pushrod. Still think it’s a case of being too lean at idle which is easy to diagnose.

 

[detmatt]

Maybe I am wrong but usually a pump problem shows up on heavy acceleration vs idle. This is due to the fact that the fuel supply is sufficient during idle but can’t handle the requirements of full throttle. This would the the case of a short or worn fuel pushrod. Still think it’s a case of being too lean at idle which is easy to diagnose.

I found the exact opposite when I was having pump rod issues. At low RPM the short throw because of the shortened push rod resulted in poor fuel delivery at lower rpm which would be exacerbated when under hood temps are evaporating fuel At an even higher rate than if there is more air circulating at speed.

 

[rkrochen]

Interesting I can see what you are saying. In any event I do believe this is a simple cure and hope that with the information provided they get this problem sorted out in a timely manner so they can enjoy the car.