Author Topic: What can be said about my spark plugs?  (Read 11236 times)

Offline 1979C20

  • Senior Member
  • ****
  • Posts: 1659
  • Kyle Taulton.
What can be said about my spark plugs?
« on: April 08, 2011, 04:37:47 pm »
Number 2 plug wire was melted and it missfired often, so thats why its fouled. And I used a wire brush on number 1, but it looked just like 3 and 5. Other than that, whay can be said about these plugs? My carb was set very rich for quite a while. I have adjusted it leaner, but its still a little rich. Thats how I want it because it makes my cam more noticeable. Can I wire brush these plugs and reuse them or should I replace them? They are currently all gapped between .045 and .050. Should they be re gapped or left alone? Thanks guys.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline topp

  • Frequent Member
  • **
  • Posts: 498
Re: What can be said about my spark plugs?
« Reply #1 on: April 08, 2011, 06:30:10 pm »
Thats very rich.

The insulator should be a mild tan.  Also that crud on the electrodes is not good.
New plugs gapped right and lean out your carb...
'90 Suburban TBI 350

Offline 1980c10

  • Senior Member
  • ****
  • Posts: 1205
Re: What can be said about my spark plugs?
« Reply #2 on: April 08, 2011, 08:55:58 pm »
those look horrible; replace them, your wires and set your carb, timing etc properly. Also replace your cap and rotor if it's been a while.

Offline 1979C20

  • Senior Member
  • ****
  • Posts: 1659
  • Kyle Taulton.
Re: What can be said about my spark plugs?
« Reply #3 on: April 08, 2011, 09:56:18 pm »
Is it reasonable to say that 4, 6, 5, and 3 are decent comparitively? now, these are the same plugs that have been in the truck sonce june, so theyve been through lean, then super rich, then about normal. The timing is at 8°. Cap is brand new, rotor is fairly new. I replaced the burnt plug wire. Gonna look into plugs next week. R43TS's, where should I gap them? Stock 350 with a mild cam "biggest cam you can use with stock valve train". Stock qjet, usually runs about 175-190°
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline 1980c10

  • Senior Member
  • ****
  • Posts: 1205
Re: What can be said about my spark plugs?
« Reply #4 on: April 09, 2011, 12:49:46 am »
I  would gap them at .040 but it really depends on your heads etc you could try anything between .035-.055. I would try a little more adv and see how it runs after you get it running with new plugs and get your current problems solved. That is my opinion on your set up but there are probably more qualified people here and some may have better ideas than myself.

Offline 1979C20

  • Senior Member
  • ****
  • Posts: 1659
  • Kyle Taulton.
Re: What can be said about my spark plugs?
« Reply #5 on: April 09, 2011, 03:41:05 am »
They are stock heads. If I advance it too much but it backfires through the carb when accelerating or if I crack the throttle real quick.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline Irish_Alley

  • Tim
  • Senior Member
  • ****
  • Posts: 13333
  • Family is not an important thing. It's everything.
Re: What can be said about my spark plugs?
« Reply #6 on: April 09, 2011, 04:07:51 am »
shouldnt it ping before it backfires?
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline 1980c10

  • Senior Member
  • ****
  • Posts: 1205
Re: What can be said about my spark plugs?
« Reply #7 on: April 09, 2011, 08:48:56 am »
well get it running good . Your adv is fine at 8, I just a saw possible opening for a little better performance but if you know it doesn't work then you already have your answer. If you don't have headers they might be a nice next step if your budget allows.

Offline 1979C20

  • Senior Member
  • ****
  • Posts: 1659
  • Kyle Taulton.
Re: What can be said about my spark plugs?
« Reply #8 on: April 09, 2011, 02:07:03 pm »
I have headers. But with those headers came a horrible header leak because my flanges are warped. Im going to silicone around the ports like on sprint cars and call it good. My carb really needs a rebuild. The float is starting to stick and it leaks fuel into one of the vac lines. Once I get the carb rebuilt I will buy new plugs and shortly after new wires. Or should I get new wires then plugs. anf I will advance my carb a bit. The problem with advancing my timing is that I have to adjust my idle screw out a bit, and im already having problems with the throttle not wanting to return all the way to the idle screw. Thanks guys.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline bake74

  • Senior Member
  • ****
  • Posts: 5871
    • Build Thread
Re: What can be said about my spark plugs?
« Reply #9 on: April 09, 2011, 05:44:47 pm »
     1979C20, just a thought, I replace my distributor ( points ) with a hei today because my old dist. was toast and I wanted hei, when I pulled my plugs they looked like yours, check to make sure your dist. is putting out enough voltage.
#1: The easiest and most obvious solution to any problem is 99% of the time correct.
#2: There is no such thing as impossible, it just takes longer.
  74 k10, 77k10    Tom

Offline 1979C20

  • Senior Member
  • ****
  • Posts: 1659
  • Kyle Taulton.
Re: What can be said about my spark plugs?
« Reply #10 on: April 09, 2011, 05:48:51 pm »
Its hei, how do I check for proper voltage? I put a new cap and coil on in july. And the rotor, etc is used.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline bake74

  • Senior Member
  • ****
  • Posts: 5871
    • Build Thread
Re: What can be said about my spark plugs?
« Reply #11 on: April 09, 2011, 09:28:16 pm »
     First off since you said the rotor was used, take off the cap and make sure the rotor is clean with no carbon build up on the center or edge connection points.  Here is a good article on how to check your distributor for weak spark, bad pick up coil, etc,etc.  Hope it helps, and keep us informed on what you find.     http://www.ehow.com/list_7717560_signs-pick-up-hei-distributor.html
#1: The easiest and most obvious solution to any problem is 99% of the time correct.
#2: There is no such thing as impossible, it just takes longer.
  74 k10, 77k10    Tom

Offline 1979C20

  • Senior Member
  • ****
  • Posts: 1659
  • Kyle Taulton.
Re: What can be said about my spark plugs?
« Reply #12 on: April 10, 2011, 09:40:18 pm »
Okay, I leaned my carb one 1/2 turn on both sides, and advanced my timing. Can you guys explain how to read my timing tab. TDC is in the center of the circle, correct? That is when my number 1is tdc. What are the marks on the tab?
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline bake74

  • Senior Member
  • ****
  • Posts: 5871
    • Build Thread
Re: What can be said about my spark plugs?
« Reply #13 on: April 10, 2011, 10:07:41 pm »
     0 on your timing tab is TDC.  looking at the marks from the front of your truck, to the left is before TDC,  and to the right is after TDC.  It looks like you might need to clean up your timing marker, at least I could not see any numbers, each "tip" of the marker should be 4 degrees, at least on my 74 350 that I timed yesterday that is the way mine is set up.  Hope this helps.
#1: The easiest and most obvious solution to any problem is 99% of the time correct.
#2: There is no such thing as impossible, it just takes longer.
  74 k10, 77k10    Tom

Offline 1979C20

  • Senior Member
  • ****
  • Posts: 1659
  • Kyle Taulton.
Re: What can be said about my spark plugs?
« Reply #14 on: April 11, 2011, 12:29:57 am »
Okay. I cleaned my timing tab. I sprayed brake cleaner on it and scraped the paint/grease off of it. I reestablished tdc on the timing tab and then moved my rotor. I checked for carbon build up on the points. I put everything back together. When I started her up initial timing was at exactly tdc, then I adjusted it to 6-5. Then adjusted my idle to about 550-600. Starts fine, the plugs look exponentially better compared to before. I wire brushed the old ones and re used them until I get paid. Now they are golden brown, like a lightly roasted marshmallow. Before, my mixture screws were about 4 1/2-4 3/4 turns out. Now they are 5-5 1/4 turns out. rev to idle return is quick. Thanks a lot guys. Im going to buy new plugs soon and when I buy plugs I will check the wires with an ohm meter. Thanks a lot guys.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF