Rich 1000 CFM Demon

I switched from an 850 Demon to a 1000 CFM race Demon and have had rich issues since.

We have a pretty well built 460 and have had good luck running
a 1000 cfm carbs on similar sized motors before, so I'm figuring this is just a tuning issue.

I put an off road kit in this demon and cleaned it out because it had sucked in some mud in a previous life.

Floats set 3 times, jets backed off to 87's and 86's.

We took it to the 1/4 mile drag strip and it used almost 2 gallons a pass which I thought might be excessive, but I'm not sure.

When it's brought up to temperature it still blows a ton of black smoke out when revved up and especially the first pass. It will always miss sputter a little (please see video) and you can even see a little fire out of the headers but second pass on, it never misses a lick. Still blows some black smoke but not as much as the initial pass.

I've changed plugs with no help. When doing a plug check after WOT they appear to be burning about right.

Please take a look at the video to see exactly what I'm talking about.

http://www.youtube.com/watch?v=sDAW2ym863E

The cam pulls 17” of vacuum at an idle. The power valve is good but is stock whatever a 1000 CFM Race Demon comes with.

Any suggestions would be greatly appreciated!

Thanks,

McQ

I switched from an 850 Demon to a 1000 CFM race Demon and have had rich issues since.

We have a pretty well built 460 and have had good luck running
a 1000 cfm carbs on similar sized motors before, so I'm figuring this is just a tuning issue.

I put an off road kit in this demon and cleaned it out because it had sucked in some mud in a previous life.

Floats set 3 times, jets backed off to 87's and 86's.

We took it to the 1/4 mile drag strip and it used almost 2 gallons a pass which I thought might be excessive, but I'm not sure.

When it's brought up to temperature it still blows a ton of black smoke out when revved up and especially the first pass. It will always miss sputter a little (please see video) and you can even see a little fire out of the headers but second pass on, it never misses a lick. Still blows some black smoke but not as much as the initial pass.

I've changed plugs with no help. When doing a plug check after WOT they appear to be burning about right.

Please take a look at the video to see exactly what I'm talking about.

http://www.youtube.com/watch?v=sDAW2ym863E

The cam pulls 17” of vacuum at an idle. The power valve is good but is stock whatever a 1000 CFM Race Demon comes with.

Any suggestions would be greatly appreciated!

Thanks,

McQ

How much timing does the motor have in it at idle? What kind of rpm does it idle at and how far open are the primary butterflies versus the secondaries? Are you sure it is black fuel smoke? I ask because watching the video it look more like it is grey/oil then fuel but it was taken at a distance.

Thanks for the reply.The engine has a pinned distributor at 34 degrees. It idles at 1000. and just checking the butterflies at idle, the front appears to be the same as the back possibly a hair opened more than the rears,,, but maybe not.Both butterflies are barily cracked open at an idle. If closed is zero degrees and 100% open is 90 degrees they appear to be about 10 degrees open at an idle.

I'm not sure that its fuel, but from the fuel vs oil I've seen in the past, I and other racers believe it's fuel. The BG 850 vacuum 2nd I had on it produced smokeless hole shots. As soon as I put this 1000 on the smoke started rolling at an idle, when trying to clean it out5 and during most hole shots.

Thanks again for your help. I'll post some of our highlights in this catagory (under 4x4) in a few minutes and you can maybe talk a better look at it. The only 850 pass you'll see is when the truck"the Bomb" isn't painted. everything when the truck is painted yellow has the 1000 Demon on it.



PS it does have crank case evac tubes on it ond one of them is on the firewall side of the valve cover but I would think it should be sucking oil woth the 850 also if it was in fact doing that, wouldn't it. Also please don't forget about the misfiring on the first pass only?

Thanks again!

McQ

Thanks for the reply.The engine has a pinned distributor at 34 degrees. It idles at 1000. and just checking the butterflies at idle, the front appears to be the same as the back possibly a hair opened more than the rears,,, but maybe not.Both butterflies are barily cracked open at an idle. If closed is zero degrees and 100% open is 90 degrees they appear to be about 10 degrees open at an idle.

I'm not sure that its fuel, but from the fuel vs oil I've seen in the past, I and other racers believe it's fuel. The BG 850 vacuum 2nd I had on it produced smokeless hole shots. As soon as I put this 1000 on the smoke started rolling at an idle, when trying to clean it out5 and during most hole shots.

Thanks again for your help. I'll post some of our highlights in this catagory (under 4x4) in a few minutes and you can maybe talk a better look at it. The only 850 pass you'll see is when the truck"the Bomb" isn't painted. everything when the truck is painted yellow has the 1000 Demon on it.



PS it does have crank case evac tubes on it ond one of them is on the firewall side of the valve cover but I would think it should be sucking oil woth the 850 also if it was in fact doing that, wouldn't it. Also please don't forget about the misfiring on the first pass only?

Thanks again!

McQ Does the smoke kinda linger in the air just a little after seeing it or is it gone almost immed? Also on the first start up is is possible that the fuel is leaking into the plenum between uses and you then are trying to fire the raw fuel? Next time before starting it for the first time look at the float levels and see if you see any fuel inthe bowl.

I posted the video up on the 4x4 portion of the board. After looking at the video it does seem to appear to be smoking going down the track to some degree also. If you watch several passes from Miles Iowa when the rear of the truck is videoed, you can really see the black smoke roll. But nothing close to when first pass or the attempted clean out beffore the first pass. If it was oil I'd think the plugs would have to show it! They are perfect tan.


The fuel is still visible in the sight glass of both bowls. The smoke does seem to linger in the air for a little while.

Thanks