Moparts
White Plugs Burning Lean??
Posted By: weazel
White Plugs Burning Lean?? - 10/16/13 01:52 AM
Hi guys, I pulled my plugs and noticed that they are very white and not the typical brownish color. Here is my set up.
71 Dart/ LA360 with magnum heads, xe268 cam, air gap intake, street avenger 670 carb with factory jets.
Im wondering if its just a jetting issue that will take care of this or ??? Also will a engine that runs lean cause it to run hotter?
Posted By: RBSat66
Re: White Plugs Burning Lean?? - 10/16/13 02:23 AM
Yes and Yes
Posted By: weazel
Re: White Plugs Burning Lean?? - 10/16/13 02:26 AM
Ok, with out a A/F gauge how do you know what jets to put in? Is it trial and error? Do I try 1 size up or jump a couple sizes at a time?
Posted By: Cab_Burge
Re: White Plugs Burning Lean?? - 10/16/13 02:47 AM
Post a picture of the spark plugs on here
How many miles where on them when you looked at them? What heat range plugs and how much total timing are you running in the motor? Are you using the vacume advance? Last thing, do you know the true compression ratio? I like seeing my plugs clean, I do run a cold plug as lean as I can at part throttle cruise without pinging or detonation
Posted By: RapidRobert
Re: White Plugs Burning Lean?? - 10/16/13 06:23 AM
Unleaded gas does run cleaner but that's been around for decades. I'd jet up a bit & see how it acts. Might be a vac leak, might be too much timing, might be Ok as is. Without a meter I'd jet up & see what that does to the driveability (easy to do & easily reversible) & if it runs better stay with em
Posted By: slantzilla
Re: White Plugs Burning Lean?? - 10/16/13 07:40 AM
Is there any carbon built up on the threads? Where is the burn mark on the ground strap? Insulator color is pretty much meaningless anymore.
How is it running?
Posted By: GTX MATT
Re: White Plugs Burning Lean?? - 10/16/13 08:01 AM
The Street Avengers seem to be jetted very lean. My 770 Street Avenger on a stock 440 left the plugs very white out of the box as well.
Posted By: DaveRS23
Re: White Plugs Burning Lean?? - 10/16/13 02:59 PM
Jetting for WOT is the easiest. If you have a drag strip nearby, just go and jet to the best MPH.
Correct jetting for the cruise is more involved and will require a meter and some additional knowledge of the power circuit. And although this will cause some discussion, an inexpensive narrow band O2 will get you very close.
To be clear, I am recommending the narrow band for tuning only the cruise ratio right now.
Flame on..............
Posted By: weazel
Re: White Plugs Burning Lean?? - 10/16/13 05:17 PM
I will snap a picture of them tonight. The engine only had 300 miles on it and it dropped a cylinder so the engine shop rebuilt it again. Those plugs where white. The new plugs maybe have 75 miles on them. Still looking white.
This is a street car so it wont be doing much WOT, just cruising. One problem I have with it and why the jetting was suggested was first off the white plugs. Then there is the dead stop and hammering it. It bogs down big time until it seems to get into the main jets then takes off like a SOB. I also have my idle set at 800 and when put in gear it drops to about half that. I know the 268 cam has a somewhat loopy idle but I dont know if the jetting has anything to do with that.
If you guys think this is two different issues lets stick with the plugs first. I would like to make sure that is correct first.
Posted By: Cab_Burge
Re: White Plugs Burning Lean?? - 10/16/13 05:24 PM
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I will snap a picture of them tonight. The engine only had 300 miles on it and it dropped a cylinder so the engine shop rebuilt it again. Those plugs where white. The new plugs maybe have 75 miles on them. Still looking white.
This is a street car so it wont be doing much WOT, just cruising. One problem I have with it and why the jetting was suggested was first off the white plugs. Then there is the dead stop and hammering it. It bogs down big time until it seems to get into the main jets then takes off like a SOB.
If you guys think this is two different issues lets stick with the plugs first. I would like to make sure that is correct first.
If you have hammer the throttle already it may make reading the plugs for part throttle impossible, go ahead and post the pictires ofthe ones in it now. If you can and want to then put in all new plugs and drive it around for 10 to 20 miles at part throttle with no hammering and post those later As already mentioned there are several different circiuts in Holley type carbs that can and do affect the sprak plug colors We need to know what brand and spark plug number also as well as the type of fuel, if it is E10 or E15 or non Ethanol 
If your willing to work on it and make it better we might as well work together and make it perfect
Posted By: GTX MATT
Re: White Plugs Burning Lean?? - 10/16/13 05:49 PM
What did it do when you say it "dropped a cylinder"
Posted By: Rug_Trucker
Re: White Plugs Burning Lean?? - 10/16/13 06:07 PM
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I also have my idle set at 800 and when put in gear it drops to about half that. I know the 268 cam has a somewhat loopy idle
No alarm bells going off here guys? 
Posted By: VincentVega
Re: White Plugs Burning Lean?? - 10/16/13 06:24 PM
sounds like a timing or advance problem (initial timing partly coming from advance, which drops when going into gear)
Posted By: weazel
Re: White Plugs Burning Lean?? - 10/17/13 01:23 AM
I have pics of the plugs, but its very hard to tell the true color. I also noticed that not all the plugs where white. Some of them where actually the nice brownish color.
Also I shouldnt say that I hammered on the throttle but I did give it about half throttle to see if it would go. Otherwise it was cruising speed at 60-65.
This is a pic of the white plug.
Posted By: weazel
Re: White Plugs Burning Lean?? - 10/17/13 01:25 AM
There were only 3 plugs that were brownish and looked normal like this one.
Also the plugs are NGK ZFR6F. Im running 87 octane pump gas.
Posted By: weazel
Re: White Plugs Burning Lean?? - 10/17/13 01:28 AM
The #6 cylinder had two broken piston rings, so the engine shop took it back and rebuilt it again.
Posted By: weazel
Re: White Plugs Burning Lean?? - 10/17/13 01:37 AM
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I also have my idle set at 800 and when put in gear it drops to about half that. I know the 268 cam has a somewhat loopy idle
No alarm bells going off here guys?
Care to elaborate with some useful info or being sarcastic about something?
Posted By: weazel
Re: White Plugs Burning Lean?? - 10/17/13 01:41 AM
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sounds like a timing or advance problem (initial timing partly coming from advance, which drops when going into gear)
I am thinking I may have a distributor problem also, but not entirely sure. I may start another thread about that, but Im more curious as to what you think about my plugs. From what you can tell with the pictures I posted.
Posted By: Cab_Burge
Re: White Plugs Burning Lean?? - 10/17/13 02:03 AM
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I also have my idle set at 800 and when put in gear it drops to about half that. I know the 268 cam has a somewhat loopy idle
No alarm bells going off here guys?
Care to elaborate with some useful info or being sarcastic about something?
I think the remark was to illuminate the mechanical advance dropping back from say 10 degrees BTDC to say 4 degrees BTDC when put in gear, the less initial advance will make the motor drop more RPM when put in gear One of the accepted standards on RPM drop on initial timing and the mechanical ignition curve as well as setting the carb. up to idle on the idle circuit only is to have only 200 RPM drop from nuetral to in gear with a automatic trans that has a standard non racing converter, IE idles at 800 RPM in nuetral and drops to 600 RPM in gear The less initial advance you have at idle can lead to a bigger RPM drop if the total mechanical advance has to much in it IE if you have 13 degrees mechanical(26 total crankshaft degrees) advance in the distributor and you want to have 34 degees total advance you have to set the initial at 8 degrees BTDC, but if the distributor has 3 degrees mechanical advance in it at 800 RPM and drops 2 distributor degrees at 600 RPM you end up with 4 degrees initial in it at idle, most motors don't like to have 4 degrees advance at idle 
They do like 12 to 16 BTDC though at a 600 RPM idle speed 
Is that clear 
Lots of ways to make are hotrod motors run better, but it requires working on and modifying some of the parts to make them better
Posted By: hp383
Re: White Plugs Burning Lean?? - 10/17/13 02:28 AM
Just for reference:
Posted By: hp383
Re: White Plugs Burning Lean?? - 10/17/13 02:30 AM
On engines that i have installed the 284/484 or the 292/509 cam, i have always installed the light weight advance springs in the distributor.
Posted By: hp383
Re: White Plugs Burning Lean?? - 10/17/13 02:32 AM
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I have pics of the plugs, but its very hard to tell the true color. I also noticed that not all the plugs where white. Some of them where actually the nice brownish color.
Also I shouldnt say that I hammered on the throttle but I did give it about half throttle to see if it would go. Otherwise it was cruising speed at 60-65.
This is a pic of the white plug.
That broken insulator is a sure sign of pre-detionation.
Posted By: weazel
Re: White Plugs Burning Lean?? - 10/17/13 02:39 AM
I think the remark was to illuminate the mechanical advance dropping back from say 10 degrees BTDC to say 4 degrees BTDC when put in gear, the less initial advance will make the motor drop more RPM when put in gear One of the accepted standards on RPM drop on initial timing and the mechanical ignition curve as well as setting the carb. up to idle on the idle circuit only is to have only 200 RPM drop from nuetral to in gear with a automatic trans that has a standard non racing converter, IE idles at 800 RPM in nuetral and drops to 600 RPM in gear The less initial advance you have at idle can lead to a bigger RPM drop if the total mechanical advance has to much in it IE if you have 13 degrees mechanical(26 total crankshaft degrees) advance in the distributor and you want to have 34 degees total advance you have to set the initial at 8 degrees BTDC, but if the distributor has 3 degrees mechanical advance in it at 800 RPM and drops 2 distributor degrees at 600 RPM you end up with 4 degrees initial in it at idle, most motors don't like to have 4 degrees advance at idle They do like 12 to 16 BTDC though at a 600 RPM idle speed Is that clear Lots of ways to make are hotrod motors run better, but it requires working on and modifying some of the parts to make them better
Im pretty sure I follow you on what you mentioned. With that being said, I've always been stumped why the RPMs dropped so much with it in gear. I have already welded up the weight slots in the distributor so that it gives me 20* at the crank.
Now if Im following you correctly, because of my specific set up. When Im setting the initial with the car idling in park at say 11* and then put it into gear it may change that 11* to 5* because of the load now on the engine. So instead of 11* I should have 17* so that when its in gear its now at 11*???? Or there about?
Posted By: weazel
Re: White Plugs Burning Lean?? - 10/17/13 02:40 AM
Quote:
On engines that i have installed the 284/484 or the 292/509 cam, i have always installed the light weight advance springs in the distributor.
I am running 1 light spring and the factory light spring in mine, since it is not a race car.
Posted By: weazel
Re: White Plugs Burning Lean?? - 10/17/13 02:41 AM
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I have pics of the plugs, but its very hard to tell the true color. I also noticed that not all the plugs where white. Some of them where actually the nice brownish color.
Also I shouldnt say that I hammered on the throttle but I did give it about half throttle to see if it would go. Otherwise it was cruising speed at 60-65.
This is a pic of the white plug.
That broken insulator is a sure sign of pre-detionation.
That wasnt actually broken, its just weird white spots on the insulator. Its actually still in good shape. I think the pic was deceiving.
Posted By: Cab_Burge
Re: White Plugs Burning Lean?? - 10/17/13 02:57 AM
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I think the remark was to illuminate the mechanical advance dropping back from say 10 degrees BTDC to say 4 degrees BTDC when put in gear, the less initial advance will make the motor drop more RPM when put in gear One of the accepted standards on RPM drop on initial timing and the mechanical ignition curve as well as setting the carb. up to idle on the idle circuit only is to have only 200 RPM drop from nuetral to in gear with a automatic trans that has a standard non racing converter, IE idles at 800 RPM in nuetral and drops to 600 RPM in gear The less initial advance you have at idle can lead to a bigger RPM drop if the total mechanical advance has to much in it IE if you have 13 degrees mechanical(26 total crankshaft degrees) advance in the distributor and you want to have 34 degees total advance you have to set the initial at 8 degrees BTDC, but if the distributor has 3 degrees mechanical advance in it at 800 RPM and drops 2 distributor degrees at 600 RPM you end up with 4 degrees initial in it at idle, most motors don't like to have 4 degrees advance at idle They do like 12 to 16 BTDC though at a 600 RPM idle speed Is that clear Lots of ways to make are hotrod motors run better, but it requires working on and modifying some of the parts to make them better
Im pretty sure I follow you on what you mentioned. With that being said, I've always been stumped why the RPMs dropped so much with it in gear. I have already welded up the weight slots in the distributor so that it gives me 20* at the crank.
Now if Im following you correctly, because of my specific set up. When Im setting the initial with the car idling in park at say 11* and then put it into gear it may change that 11* to 5* because of the load now on the engine. So instead of 11* I should have 17* so that when its in gear its now at 11*???? Or there about?
The best way to check how much advance you have idling in gear and then in nuetral is to actually check it If it is idling at 17 BTDC and then drops to 11 BTDC you might want to use two light racing springs 
I like to see no drop on the initial advance from in nuetral to putting it in gear I have set up distributors with the Mr Gasket old GM light springs used in Mopar distributors to have all the advance in by 1200 to 1500 RPM That works very well 
Idles at 1000 RPM in nuetral at 14 to 16 degrees BTDC and idles with the same amount of advance at 800 RPM in gear
Posted By: hp383
Re: White Plugs Burning Lean?? - 10/17/13 03:01 AM
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The best way to check how much advance you have idling in gear and then in neutral is to actually check it If it is idling at 17 BTDC and then drops to 11 BTDC you might want to use two light racing springs I like to see no drop on the initial advance from in neutral to putting it in gear I have set up distributors with the Mr Gasket old GM light springs used in Mopar distributors to have all the advance in by 1200 to 1500 RPM That works very well Idles at 1000 RPM in neutral at 14 to 16 degrees BTDC and idles with the same amount of advance at 800 RPM in gear
This is the same way I do mine.
Posted By: weazel
Re: White Plugs Burning Lean?? - 10/17/13 03:09 AM
Ok, the way I have been setting my timing is as follows. First I set the dizzy to 11* and adjust idle screw so that its about 800rpm. Once I get that right on I lock the dizzy down.
Then I rev the engine to about 3k and check to see what my total is. Which is right about 31* with the 20* the mechanical is giving me. I would say its all in around 2400 to 2600 rpm. I dont believe it really starts to add any advance until around 1300rpm. Although those values may be off a couple hundred.
I dont believe its adding any advance right away. Its just killing the initial timing when going in gear. I do still have one light spring left that I can install but with the Mr. Gasket instructions it stated that if I was not racing the car not to use the second spring.
Am I following your guys correctly with the timing?
Posted By: Dunnuck Racing
Re: White Plugs Burning Lean?? - 10/17/13 03:44 AM
The 670 Street Avenger is extremely lean. I had to rework the idle circuit to get a fat enough mixture and jet up several sizes.
Its bad enough on non ethanol fuel,but e10 really kills it.
Keith
Posted By: Rug_Trucker
Re: White Plugs Burning Lean?? - 10/17/13 10:22 AM
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I also have my idle set at 800 and when put in gear it drops to about half that. I know the 268 cam has a somewhat loopy idle
No alarm bells going off here guys?
Care to elaborate with some useful info or being sarcastic about something?
400rpm? I would also like to see vacuum numbers neutral to in gear. White plugs can be a vacuum leak too. IIRC the MP distributors had 2 light weight springs out of the box. It worked good on a bone stock 383 magnum.
Posted By: weazel
Re: White Plugs Burning Lean?? - 10/17/13 12:44 PM
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The 670 Street Avenger is extremely lean. I had to rework the idle circuit to get a fat enough mixture and jet up several sizes.
Its bad enough on non ethanol fuel,but e10 really kills it.
Keith
Do you suggest jumping a couple jet sizes at a time? Then driving it and seeing how it does? I dont have a A/F gauge so I will more or less be guessing.
Posted By: weazel
Re: White Plugs Burning Lean?? - 10/17/13 12:53 PM
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I also have my idle set at 800 and when put in gear it drops to about half that. I know the 268 cam has a somewhat loopy idle
No alarm bells going off here guys?
Care to elaborate with some useful info or being sarcastic about something?
400rpm? I would also like to see vacuum numbers neutral to in gear. White plugs can be a vacuum leak too. IIRC the MP distributors had 2 light weight springs out of the box. It worked good on a bone stock 383 magnum.
I can tell you that I have 14-15 with the timing and carb mixture screws adjusted in park.
Im very curious now what my timing is going to be with it in gear. I will be checking that out this weekend when I have time.
Im curious on the benefits of getting my dizzy curved? Can someone explain to me what curving it does?
Posted By: DaveRS23
Re: White Plugs Burning Lean?? - 10/17/13 02:53 PM
Your engine probably cruises on the main jet circuit, If so, then the cruise A/F ratio will be set primarily by the main jets.
The idle mix and off idle transitions will be set by the Idle Fuel Restrictors and Idle Air Bleeds. And although these circuits overlap in use, they are 2 different jetting exercises. There is another thread running now that is into this.
In my experience, the only real way to get the cruise ratio where it needs to be is with an O2 meter. The idle however, can be dialed in with listening to what the engine likes.
That is because most of our engines like 14.4-14.7 +/- cruise ratio. And I don't know how you would achieve that by driving and listening. The idle mix however is very different combo to combo, and is usually best set by what the engine combo likes.
And although there are recommended guidelines and starting points, the initial timing and the timing curve is another area where experimentation with what the combo likes is often the best thing.
Even EFI set-ups on engines with more cam overlap are often locked out at idle and settings are fixed.
On my engines, the bigger the cam, the more idle lead they want. I have 25* advance at idle on the engine in the Cuda.
IHTH
Posted By: weazel
Re: White Plugs Burning Lean?? - 10/17/13 06:34 PM
Another question for you guys. Someone asked me what fuel Im running. Im only running 87 octane. Should I be running 91? Could that be part of my issue?
Posted By: Cab_Burge
Re: White Plugs Burning Lean?? - 10/17/13 11:18 PM
Posted By: weazel
Re: White Plugs Burning Lean?? - 10/17/13 11:24 PM
Just a update on one thing that may have caused my problems. I just had the dizzy at a shop and they threw it on a sun machine to curve it. They did the initial spin of it and found out that the timing started adding mechanical at 1000rpm and had it all in by 1500rpm.
They changed the springs and I think they said some other stuff and now its not adding until 1500 and all in by 2400.
Im hoping that getting that straightened out takes care of a lot of my problem. I will get it back tomorrow and retime my car and see how it is after that.