What is the temp crossover to AC plugs? it looks like it could be a 46, too hot for a performance app. What motor is this? if it is a 350 try AC 44's and work on the accelerator cam and squirters to fix the off idle stumble. Also make sure there is no (very very little) slack in the accel. pump linkage.
Ok i put in the AC44s like you said, seems like the pinging at high RPM has gone away, seemed to be idleing a little smoother as well. I pulled a plug from #1 and they were white! almost like when i had put them in. Ya so i know its lean. I drove around for 10 mins or so getting on really hard, sitting at stop lights, crusing at 55. I didnt have any of the lean signs though, backfire through the carb stubbling when i got on it.. So what would be the best way to fix this get some bigger jets for the carb? change the power valve? thanks... if you want a pic i can post it later but its lean.
I take it you have checked the float levels? if so, yes, try the jets. Since you said it did not have any signs of being lean I would only change the secondary jets if it is a double pumper. If it is a vac sec try setting the rear floats a little higher than normal instead(you can use the clear sight plugs for this if you want).
This will allow you to drive slightly lean for fuel economy and give the correct fuel ratio at WOT.
To check the plugs at WOT accelerate full throttle until about 4000 rpm and(without lifting off the throttle) kill the engine and pull the plugs.
Since you stated you were running lean due to the white plugs, like others have stated, check your float level. You should see the level of gas in the bowls just at the bottom of the clear sight plugs.
Then set your idle circuits with a vacuum guage. What is your vacuum rating in gear (if it is an automatic) or in neutral if it is a stick?
Your jets should be on from the factory.
HERE is a link to the document for your carb to adjust it properly.
Definite detonation, little silver balls under the side electrode give it away...otherwise the mixture looks Ok.
Try a little less curve depending on if it's doing it on top or down low in the rpm range. I would try limiting the mechanical advance a little before lowering the initial timing first...more initial is always beneficial if it's not detonating off idle through 2000 rpm.
Forget the split fires, buy champion cheapos for testing,,,,the nickel plating turning blue on the side electrode half way down means your mixture is good.
Straw color would be lean...
This is for a single full throttle pull mind you, normal driving will ruin the test coloring so do your plug chops and read the plugs in the field at 70F, 1000mb atmospheric pressure and 30% humidity.
Haha, let me know where you have weather like that...I have always wanted to test under perfect weather conditions.
definately detonation... looks like its been going on for a while, have you not been hearing spark knock?
I would say its time for a leakdown/compression test and get this crap solved before you bust a ring land or something. If it were mine I would pull all the plugs and see what the rest look like, see if you can track this problem down to a couple of slugs, or if its happening to all of them.
I might even pull the heads to make sure the slugs on it. In fact, if it were my mill, I definately would.
Hi thanks all for the feedback. Im going to check some stuff today, float levels ect..Ya there was some pinging going on but just at WOT when i got on it and after it switched to 2nd gear. you could just hear a little. Ive tried doing a few things, adjust timing, retarding it till it went away, but i just could never get it to go away so i tried changing the spings in the distributor so the advance wouldnt come on so early, i put stiffer springs in. that helped. So now i tried changing the plugs to the AC44's a colder plug than the splitfires i have in there. When i was pulling out all the Splitfires they all looked the same. This pic was when i was just driving around for about 10 mins getting on it, sitting at stop lights, ect