Author Topic: 440 Issues  (Read 12580 times)

Offline moper

  • Resident
  • *****
  • Posts: 2368
Re: 440 Issues
« Reply #45 on: September 19, 2006 - 01:08:00 PM »
What CP said, now and earlier. Demons have a demon inside..It's called machining flash. That and in some instances, the shavings never get totally cleaned out of the metering plate after drilling. I'd pull the blocks, take out the emulsion bleeds ( the little jet looking things at the top of the float dowl side of the plates), and blow it all out. Inspect very carefully for pcs of aluminum that are still clinging to the inside of drilled holes or passages. Remove any you can find. Then, I'd install small air bleeds for the main jets, and try some more tunig. You cant get it any richer because the air bleeds are too large. Jetting wont help until the bleeds are reduced, then they will be effective. Or run a Holley HP or plain od 4150. I like the 800 cfm for a street car with a 440.




Offline 440Charger

  • Jr. Member
  • **
  • Posts: 104
Re: 440 Issues
« Reply #46 on: September 26, 2006 - 02:51:48 AM »
Ok so are Demons crap or what?  I thought they were high end carbs when I bought it.  From what you guys are saying, they're not.

If you had my engine (specs are on page 1), which carb would you use? (size and brand)

Thanks,

- Doug

I love my 440...but it's not loving me back...yet

Offline MEK-Dangerfield

  • C-C.com Expert
  • ********
  • Posts: 20946
  • I don't get NO respect! Member since 1/25/2002
Re: 440 Issues
« Reply #47 on: September 26, 2006 - 03:30:53 AM »
I'll bite first.  :naughty:

I only know about Holley's, so I would say a Holley double-pumper. Either 800, or 850 CFM. It sounds like your car is built more for top end performance anyway. The double-pumpers are very responsive.

  Mike

Mike

1970 Challenger - SOLD
2016 SXT+.  1 of 524 SXT+'s in Plumb-crazy for 2016.

Offline moper

  • Resident
  • *****
  • Posts: 2368
Re: 440 Issues
« Reply #48 on: September 26, 2006 - 06:03:48 AM »
Doug, have you now eliminated the pinging? The intake/carb is all sealed up right, correct? In tuning, one always sets the timing curve first. Then you adjust the carb. I didnt re-read the whole post,. but I think you got that fixed. The Demon carbs are not junk. They can be very good at what they do. Like anything else, you need to understand how they work, and what might cause issues, to get them perfect. In many cases, out of the box they work better than what they replaced. That doesnt mean they are tuned, just better than before, and that's enough for a lot of buyers. If you're sensitive enough to see it's got an issue, then you can addres it by fixing the Demon, or finding someone who can for you, or replacing it with something else, and tuning that. I dont think you'll find any carb perfect out of the box. I never can. With your gearing and engine, I would run as first choice a Holley Street Avenger p/n 80770, it's a vaccum sec 770cfm (wet flowed) with electric choke. As a second choice, I dont think you can go wrong with a 4150 series 800CFM (dry flowed) double pumper. But the 800 will need tuning, as will the Avenger to get them dialed in.

Offline 440Charger

  • Jr. Member
  • **
  • Posts: 104
Re: 440 Issues
« Reply #49 on: September 26, 2006 - 12:21:39 PM »
Yep, got the vaccum leak fixed by installing the proper gasket set.  We still can't eliminate the pinging, and we know we're still running lean by checking the plugs after each run with bigger jets.  I'm going to call Barry Grant today and see what they say.

Lots of Holley fans here  ;)

When you say set the timing first, then adjust the carb, do you mean set it to where it should be (36 to 38) then jet the carb until it runs without ping?  Sry I'm not a carb expert so when I think "tuning the carb" I think of setting the idle mixture, speed, and jets.  I'm sure there is more to it than that  :clueless:

** Just called Barry Grant and the techie suspected the fuel lines are too small.  Also offered to flow test it if I send it in.
« Last Edit: September 26, 2006 - 12:40:58 PM by 440Charger »
I love my 440...but it's not loving me back...yet

Offline MEK-Dangerfield

  • C-C.com Expert
  • ********
  • Posts: 20946
  • I don't get NO respect! Member since 1/25/2002
Re: 440 Issues
« Reply #50 on: September 26, 2006 - 04:16:30 PM »
I'm not sure about the fuel line thing. My Challenger still has the original 5/16 inch fuel line, which is supposidly too small for a 440. They should have 3/8 inch. I do have a hi-volume fuel pump though. I have no trouble, but then again, I don't race my car down the strip either. I have an interior fuel gauge, so I know if my pressure is up to snuff or not. I know Rev and Redline had trouble with their Demon running incredibly lean. They switched to a Holley.  :lol:


  Mike

Mike

1970 Challenger - SOLD
2016 SXT+.  1 of 524 SXT+'s in Plumb-crazy for 2016.

Offline 440Charger

  • Jr. Member
  • **
  • Posts: 104
Re: 440 Issues
« Reply #51 on: September 26, 2006 - 07:46:40 PM »
Yeah we decided to go with a 3/8'' line and a high volume pump based on what you all have posted and other sources.  Not sure if I should go mechanical or electric yet...I assume there are hi volume mechanical pumps out there. 

I think we're going to stick with the Demon for now.  The more I work with it the more I like it  :thumbsup:.  I'm betting the new fuel system will flood the system with huge jets we have in now and we'll probably have to go down a few sizes.

- Doug
I love my 440...but it's not loving me back...yet

Offline moper

  • Resident
  • *****
  • Posts: 2368
Re: 440 Issues
« Reply #52 on: September 28, 2006 - 10:52:14 AM »
I think the Demon guy is full of something. But, I'm sure the notebook the phone guys have says "make sure fuel system is functioning" as item one. So, go with it. I'm a fan of whatever does everything I need a carb to do. The only ones I've never run are Predators. And that was because I did work with Fords VV(variable venturi) carbs in the late 70s and 80s. :puke:. As with all things, one must "figure them out". Demons just take different figuring than Holleys. I bought the book and it's right next to my Holley books and catalogs...lol. In your case, if the jets are changed and have no effect, going by the "How to tune your BG Demon carb" book, it syas the main air bleeds are probably too large, and it's running lean (not strong enough signal to the fuel in the meterring block) because of it. I've run six pacs thru 5/16 lines and run mid 12s with them, so perhaps that's why I question how such an efficient carb needs more volume...lol.

Offline 440Charger

  • Jr. Member
  • **
  • Posts: 104
Re: 440 Issues
« Reply #53 on: May 17, 2007 - 10:19:14 PM »
I'm digging up my old post here because I've updated the 440 -

Added the 3/8 fuel line and added the HP Carter pump...also replaced the sending unit with a 3/8 hole.  Made a nice difference from 0-120:) 

mopar I'm taking your advice and looking into changing the springs on the Mallory dist to help with pinging at high rpm.  I kinda overlooked your posts on that but I reread a few times and it finally clicked!  :worshippy

I'm still pinging over 3000rpm using 92 octane so hopefully mopar's advice is what I need.  Although I'm disappointed that I have to retard the timing to fix the ping...but I think he's right.  I don't want to add octane additive everytime I refill the tank.  Too late for me to change the 452 open chamber heads.

Neil I'd still like you have you down here, just need to figure out when.

- Doug
« Last Edit: May 17, 2007 - 10:21:42 PM by 440Charger »
I love my 440...but it's not loving me back...yet

Offline Chryco Psycho

  • Administrator
  • C-C.com Guru
  • *****
  • Posts: 36620
  • 70 Challenger R/T SE 70 tube Chassis Cuda now sold
Re: 440 Issues
« Reply #54 on: May 18, 2007 - 12:12:31 AM »
I aam glad you are getting closer
 we can figure out what works to get together at soem point

Challenger - You`ll wish You Hadn`t

Offline todd383

  • Jr. Member
  • **
  • Posts: 300
  • I'm a llama!
Re: 440 Issues
« Reply #55 on: May 18, 2007 - 07:15:43 AM »
 Hey 44o charger, dont mean too get off the subject, but u stated that u are runnin a 2 inch exhaust system,(mufflers) maybe a misprint :dunno: But if u are, its chockin the hell out of your engine :22yikes:

Offline 440Charger

  • Jr. Member
  • **
  • Posts: 104
Re: 440 Issues
« Reply #56 on: May 18, 2007 - 08:52:46 PM »
It's not a misprint, but I'll double check my papers.  If it really is 2'', what would you suggest instead?
« Last Edit: May 18, 2007 - 09:03:21 PM by 440Charger »
I love my 440...but it's not loving me back...yet

Offline Chryco Psycho

  • Administrator
  • C-C.com Guru
  • *****
  • Posts: 36620
  • 70 Challenger R/T SE 70 tube Chassis Cuda now sold
Re: 440 Issues
« Reply #57 on: May 18, 2007 - 11:56:19 PM »
a 440 can use 2.5 -3"

Challenger - You`ll wish You Hadn`t

Offline 440Charger

  • Jr. Member
  • **
  • Posts: 104
Re: 440 Issues
« Reply #58 on: May 19, 2007 - 12:11:56 AM »
thx Neil - trying you on skype now
« Last Edit: May 19, 2007 - 12:22:51 AM by 440Charger »
I love my 440...but it's not loving me back...yet

Offline todd383

  • Jr. Member
  • **
  • Posts: 300
  • I'm a llama!
Re: 440 Issues
« Reply #59 on: May 21, 2007 - 06:18:05 AM »
 Oh yea, 2 1/2-3" exhaust, from the headers to the back!!!!! :cooldancing: