Plug diagnosis - Moparts Forums

Register Log In Moparts Forums Unlawfl's Race & Engine Tech Plug diagnosis

Print Thread

Plug diagnosis #3087154 10/18/22 01:13 PM 10/18/22 01:13 PM
Joined: Apr 2022 Posts: 169 Kansas T Thelma133 OP member
Thelma133 OP member T Joined: Apr 2022 Posts: 169 Kansas	Changed fro AED 3 circuit (brand new from them) to a thumper 2 circuit. AED Would Not change it back to 2 circuit. It ran ok on top end, but the 3 circuit was blubbering at idle and sounded horrible. Plugged were always fouled. Aluminum low deck, original b-1, 1150 thumper, 35 deg timing at idle, Afr from logger says 14.8,at idle. Engine sounds so Much better now at idle. Mains are 94 square. I guess if you know how to tune a 3 circuit there is horsepower to be had. But it was not for me. Please give me your opinion on plug when you have a moment. Thanks, Bill

Re: Plug diagnosis [Re: Thelma133] #3087335 10/18/22 11:14 PM 10/18/22 11:14 PM
Joined: Aug 2003 Posts: 43,359 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,359 Bend,OR USA	I would like to see it in person with a 10X magnifeyer That picture probably doesn't do it justice. What I see I like Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Plug diagnosis [Re: Cab_Burge] #3087348 10/18/22 11:54 PM 10/18/22 11:54 PM
Joined: Apr 2022 Posts: 169 Kansas T Thelma133 OP member
Thelma133 OP member T Joined: Apr 2022 Posts: 169 Kansas	Thanks very much Cab. The high dollar AED WAS A MISTAKE. They told me they don’t even build 2 circuit carbs anymore. It sounded like you were pouring water down the Venturi at idle. Blueberry as hell. I won’t ever use a 3 circuit carb again unless maybe Dale Cubic dials it in. Thumper did this one and it sounds much better. Have you found Cab you need some help with the transfer slot to help it idle?? Mine does, it will die without help. I have a big roller in it with lots of overlap, so I blame it on that. Bill

Re: Plug diagnosis [Re: Thelma133] #3087354 10/19/22 02:33 AM 10/19/22 02:33 AM
Joined: Aug 2003 Posts: 43,359 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,359 Bend,OR USA	Try and make the idle circuit richer when warmed up, both front and rear with the mixture screws. If that doesn't help the transition from idle to light part throttle try reducing the idle mixture air bleeds holes up top with some very fine wire J hooks to drop into those bleeds to see if that helps. If you can fix it that way change them to a lot smaller size and then use some very small drill bits to fine tune it I have also drilled and tap the idle and transition fuel feed passages in the main bodies of Dominator carbs to use # 6 brass set screws and then drilled them out to half the size of the original hole I.D. You will need a pin vice and a set of numbered drill bits from #60 to #70, I think I ended up buying a set of numbered drill bit set from #1 to 100 I'm a carb tuning freak now Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Plug diagnosis [Re: Cab_Burge] #3087458 10/19/22 12:28 PM 10/19/22 12:28 PM
Joined: May 2011 Posts: 4,489 northern,Ohio,USA C Clanton master
Clanton master C Joined: May 2011 Posts: 4,489 northern,Ohio,USA	Originally Posted by Cab_Burge Try and make the idle circuit richer when warmed up, both front and rear with the mixture screws. If that doesn't help the transition from idle to light part throttle try reducing the idle mixture air bleeds holes up top with some very fine wire J hooks to drop into those bleeds to see if that helps. If you can fix it that way change them to a lot smaller size and then use some very small drill bits to fine tune it I have also drilled and tap the idle and transition fuel feed passages in the main bodies of Dominator carbs to use # 6 brass set screws and then drilled them out to half the size of the original hole I.D. You will need a pin vice and a set of numbered drill bits from #60 to #70, I think I ended up buying a set of numbered drill bit set from #1 to 100 I'm a carb tuning freak now if you go with drilling holes I have a list of brass set screws from McMaster Carr GOTBOOST!New improved with Victor heads. http://www.enginelabs.com/mopar-big-bloc...t-of-necessity/

Re: Plug diagnosis [Re: Clanton] #3087473 10/19/22 01:02 PM 10/19/22 01:02 PM
Joined: Jan 2003 Posts: 19,400 Las Vegas Al_Alguire I Live Here
Al_Alguire I Live Here Joined: Jan 2003 Posts: 19,400 Las Vegas	Hard to tell much by that plug. Assume it was just idle time? Only way to really check a plug at the track is install a fresh one make a pass shutting it off then look inside or cut the threads off and look for the ring. Also the way it looks has alot to do with the fuel you run in term of what to look for. As for the carb "debate" never knew a time when less tunability was a good thing...But yes three circuit stuff take a bit more work for a racecar. On a street car I could see where a two circuit would be preferred. "I am not ashamed to confess I am ignorant of what I do not know." "It's never wrong to do the right thing"

Re: Plug diagnosis [Re: Al_Alguire] #3087576 10/19/22 07:22 PM 10/19/22 07:22 PM
Joined: Apr 2022 Posts: 169 Kansas T Thelma133 OP member
Thelma133 OP member T Joined: Apr 2022 Posts: 169 Kansas	Thanks AL. You r correct idle time only. I have 65 idle air bleed front and rear. I am going to put in new plug Saturday and see what it looks like. I have NGK-8 in it now. It still looks a tad bit lean to me, but i am used to looking at a black plug for a long while. I wanted to change to a 63, and i also have a 60 idle bleed. What is your opinion on that. Thank you

Re: Plug diagnosis [Re: Thelma133] #3087577 10/19/22 07:25 PM 10/19/22 07:25 PM
Joined: Apr 2022 Posts: 169 Kansas T Thelma133 OP member
Thelma133 OP member T Joined: Apr 2022 Posts: 169 Kansas	Thanks Clanton!

Re: Plug diagnosis [Re: Thelma133] #3087788 10/20/22 12:53 PM 10/20/22 12:53 PM
Joined: Jan 2003 Posts: 19,400 Las Vegas Al_Alguire I Live Here
Al_Alguire I Live Here Joined: Jan 2003 Posts: 19,400 Las Vegas	My brutal opinion if it is a racecar I really don't care a lot what the plug looks like at idle..What matters is the timeslip and how it looks at WOT. If a cleaner idle makes the car faster then by all means worry about that, obviously if the plug is black at idle something is wrong. Just my opinion. On the two step/brake they are ALL PIG FAT it is what happens when you are dropping cylinders at the start and dumping fuel from the shooters. This is in the 9-1 AFR range when the button is let go. 8 O2's with a single 4bbl cast intake small block thats been 1.09 60' on a small tire at 2770. Screen shot from a not so good run but you get the idea. "I am not ashamed to confess I am ignorant of what I do not know." "It's never wrong to do the right thing"

Re: Plug diagnosis [Re: Al_Alguire] #3087908 10/20/22 08:06 PM 10/20/22 08:06 PM
Joined: Apr 2022 Posts: 169 Kansas T Thelma133 OP member
Thelma133 OP member T Joined: Apr 2022 Posts: 169 Kansas	Thanks very much for that Al. I appreciate brutal and your opinion. I’m very interested in tuning my own junk! My AED was a Huge Disappointment.

Moderated by Al_Alguire, Hotwheelsjr, moparts, not_a_charger, RangerDan440, tboomer

Hop To

Powered by UBB.threads™ PHP Forum Software 7.7.1