Still running rich

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twayne24365

twayne24365

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Still tunning on the 440, ive got the jets down to 80's front and rear, and it still is running rich, exhaust has a strong fuel smell. With the combo i cant see how the jets are still too big.
.030 over 440
10.5:1
Cnc stealth heads
.620/.626. 260/[email protected] solid
Victor intake
850 holley double pumper.
Could ther be another problem or is it just too much jet?
 
What primary power valve? Vacuum reading at idle? What initial timing...if applicable considering what your idle speed may be?
 
Info on the ignition system you are running might help also, as it may be a weak spark problem and not just carburetion.
 
What do the jets have to do with idle mixture?
 
My bet is an incorrect power valve. What's your vacuum reading at idle in drive?
 
I am assuming you are talking about it being rich at idle because I doubt you would notice fuel smell in the exhaust at wide open throttle, I would go back to the jets that were in it so you don't lean out at wide open throttle, main jet's will have no affect on idle quality, check the power valve, float level a little under half way up the hole, then tune on your 4 corner idle screws, turn them all the way in one at a time, can you kill the car with the third one or can you turn them all in and the car still runs? do you have adjustable air bleeds on top of the carb, these would be the holes on the outside, the inside ones are high speed air bleeds
 
I just put some custom bushings in MSD and increased the initial timing. Much better burn at idle if you get initial up
 
Ok, ignition is a pro billit distributor with blaster coil and msd6al. About 19 initial 36 advanced. The jets are stock, 80's front and rear. It has a 6.5 powervalve. I do not know the vacume, havent checked that yet. But idles 1100 in park and 900-1000 in drive
 
Also found that te primaries were pouring fuel from the boosters, replaced the needle and seat which took care of that problem
 
Get a bushing and bump initial to the 26 range. Huge cam, avg compression likely needs a bunch more timing. simple test, twist the distributor a little clockwise at idle. If it picks up rpm, the engine wants the timing. Find the point it kicks back on the starter.

IMO, you could likely run that set up locked out.
 
I had a 440 very similar to what you now have. I ran a 750cfm AED carb on it.

Drove it and bracket raced with it. some may say this setup would be lean. However, the car ran mid 7's in the eight mile at 3550 pounds, and the EGT readings were always around 1350 to 1370 degrees. It ran great on the engine set up as follows:

jet -- 78's front, 80's rear
Power valve front -- plugged
Power valve rear -- plugged

The float levels were set to be at or just above the half way point in the sight glass.
If your carb has plugs and no sight glass, set the float level with the engine running and the plugs out. raise the floats until fuel just BARELY starts to seep out.

Idle screw settings may vary, but if you have to turn them out over 1 turn, then something is wrong. remember that the further out the 4 corner idle screws are, the more fuel that is being pulled. Mine was perfect at about 3/4 of a turn out from seated.

Fuel pressure has been mentioned. around 7 to 7.5 lbs is about the limit in MOST applications. not saying a car won't run more, because I know some who run around 8 to 8.5. just saying you don't want 10 freaking pounds blowing past the needle and seat.

I would start by doing these adjustments one at a time, and sneaking up on the carb tune. Don't make to big of an adjustment at once.

After that, if you are still rich, I would then move on to the suggestions that everyone has given. Lot of smart guys here on the forum. My advice is to take one suggestion and try it before moving on to someone else's suggestion. that way you know what worked and what didn't without getting way out there with so many changes.

good luck.
 
I just read back over the thread and seen where you said your total timing was at 36 degrees. Most of the 440's I've had ran best with around 38 degrees, but that doesn't mean that yours will. I also agree with Crackedback in the fact that your application could probably run locked out on the distributor.
 
The fuel pressure is about 6.5, and floats set to just a trickle running out, once this rain clears up ill take a vaccume reading and mess with the timing a little, like crackedback said, the idle screws are at 1.5 turns out as well. And if it helps the car weighs 3500 with me, 8" 5000 converter, 4.56 gears, and 29.5x9 slicks
 
twayne24365 said:
The fuel pressure is about 6.5, and floats set to just a trickle running out, once this rain clears up ill take a vaccume reading and mess with the timing a little, like crackedback said, the idle screws are at 1.5 turns out as well. And if it helps the car weighs 3500 with me, 8" 5000 converter, 4.56 gears, and 29.5x9 slicks
Click to expand...

Twayne, does the carb have a power valve in it, or are both metering blocks plugged?

1.5 turns out on the idle screws is a ton. that in its self is pulling a lot of fuel.
 
It's pulling fuel because the power valve is open at idle in gear. That 6.5 is not low enough I bet for that huge cam. No sense in going any further at all with diagnosis without a vacuum reading. That needed to be the first thing you did. It would saved you some trouble.

You can throw the jets on the ground when talking about idle mixture. They are not in the idle circuit. Trying to tune idle mixture with jets will have no effect at all. I guess you found that out.
 
RustyRatRod said:
It's pulling fuel because the power valve is open at idle in gear. That 6.5 is not low enough I bet for that huge cam. No sense in going any further at all with diagnosis without a vacuum reading. That needed to be the first thing you did. It would saved you some trouble. You can throw the jets on the ground when talking about idle mixture. They are not in the idle circuit. Trying to tune idle mixture with jets will have no effect at all. I guess you found that out.
Click to expand...

Agreed
 
RustyRatRod said:
It's pulling fuel because the power valve is open at idle in gear. That 6.5 is not low enough I bet for that huge cam. No sense in going any further at all with diagnosis without a vacuum reading. That needed to be the first thing you did. It would saved you some trouble.

You can throw the jets on the ground when talking about idle mixture. They are not in the idle circuit. Trying to tune idle mixture with jets will have no effect at all. I guess you found that out.
Click to expand...

Completely right, this is my fathers car and hes pretty hard headed, ive been telling him this the entire time, ill take a vacume reading today...... So looks like i gotta get a power galve plug. Ill do this first but ill still play with the timing and such
 
RustyRatRod said:
It's pulling fuel because the power valve is open at idle in gear. That 6.5 is not low enough I bet for that huge cam. No sense in going any further at all with diagnosis without a vacuum reading. That needed to be the first thing you did. It would saved you some trouble.

You can throw the jets on the ground when talking about idle mixture. They are not in the idle circuit. Trying to tune idle mixture with jets will have no effect at all. I guess you found that out.
Click to expand...

this ^^^^^ if the cam is as big as i think a 6.5 pv is more than likely a problem but without a vacuum number we can only guess .
 
Ok guys, started the car and let it warm up, then i set all the idle screws to 1 1/8 turns out, the idle slightly increased and seemed to run a little smoother, found my "old" vacume gauge and its pulling around 8 pounds.
 
Higher idle speed will almost always result in higher vacuum reading. Reset it to your base idle setting and see what you have for vacuum. You need apples to apples comparison.

You need to cure the fuel dripping from the boosters. If it's dripping, you'll NEVER get a decent idle tune on it.

For what you have, I recommend putting a PV plug in both ends and get the idle tune up correct. Once you have it correct, remove the carb and look at the transfer slots to make sure there isn't too much exposed. If they are, you need to rethink.

A PV activated or affecting idle quality means the throttle blades are open too far.

Turn more initial into it and quit screwing around. :)
 
Well the fuel dripping from the booster is fixed, i did reset the idle before i took the vacume reading. I will put some more timing into it tho, ill get my uncles timing light monday to see where things are at and tune from there
 
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