Topic: Can spark plugs cause pinging?
in Forum: C3 Engines
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Charleston AFB, SC - USA
Joined: 10/31/2007
Posts: 111
Vette(s): 1979 Cream Beige Coupe w/383 & 700R4
Well, I'm still having a ton of issues with my 383 pinging. I already have the timing lower than it should be and I'm running premium. It even pings with octane booster. I'm trying to decide if maybe my plugs could cause my problems. A long while back I replaced the plugs in the car and got some that had a different thread length. It caused some problems as I had to remove the headers to get them in, but they finally went in. Unfortunatly I don't remember if it pinged bad before or after that.
So my basic question is could getting wrong plugs cause my pinging issues (compounded with a high load at low RPMs from a torque converter lockup), or not at all? And with a higher compression, should I still get normal plugs made for a 79 350 or should I be running something different? Would colder plugs maybe help with this?Thanks as always!
-Josh
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Too hot a heat range on the plugs can cause detonation(pinging)...ya might try going to a colder plug...maybe two steps colder.
What plugs are ya runnin now?Adams' Apple 2008-05-25 20:51:59
What plugs are ya runnin now?
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Former Member
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Charleston AFB, SC - USA
Joined: 10/31/2007
Posts: 111
Vette(s): 1979 Cream Beige Coupe w/383 & 700R4
I'd be a liar if I tried to tell you. Probably the basic Bosch ones autozone recommends for a 79 corvette. I just remember having a much shorter plug coming out from the previous owner, so maybe he had colder plugs in there and for a reason. I can't tell you how happy I'd be if this fixes my pinging problem... it is a huge headache.
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Yelm, WA - USA
Joined: 7/12/2007
Posts: 356
Vette(s): 1979 L82 4 speed Scat 383 crank 190 cc Procomp Aluminum Heads 202 160 stainless valves GM Powder metal rods Speedpro H860CP Hypereutectic pistons 280 cam hydralic HEI Pro comp 1.6 roller rockers Mighty Demon 750 Sanderson CC1AP Hedders.
Dang brother I feel for ya! I got NGK plugs, I'll see if I got a box laying out in the garage with a part number, they go pretty good in my 383. There for aluminum heads though so I think they might be different???
I've been playing with mine just trying to learn but pretty soon it's going down to the vette shop to get dialed in here in a bit. Those guys are pretty salty down there so I'll be hangin over shoulders taking notes and asking rookie questions when it goes in.
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Charleston AFB, SC - USA
Joined: 10/31/2007
Posts: 111
Vette(s): 1979 Cream Beige Coupe w/383 & 700R4
Alright, I went to advance and got 8 new NGK plugs that are the same as the Motorcraft AGSP 32C plugs the previous owner had in it. At this point it looks like that may have corrected all my pinging issues :)
Only time will tell, but right now I'm really happy.
I had some serious issues with my 383 pinging under load. finally had my tuner calibrate the distributor and the carb and set the timing right. i`m on the edge of needing some racing feul mix with the 93. runs ok now. hope the plugs are your answer
Former Member
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Yelm, WA - USA
Joined: 7/12/2007
Posts: 356
Vette(s): 1979 L82 4 speed Scat 383 crank 190 cc Procomp Aluminum Heads 202 160 stainless valves GM Powder metal rods Speedpro H860CP Hypereutectic pistons 280 cam hydralic HEI Pro comp 1.6 roller rockers Mighty Demon 750 Sanderson CC1AP Hedders.
NGK V-Power Racing R5671A-7 NGK stock No. 4091 Not that I think these are anything special, just the ones that my engine was dyno'd and came with. They got so fouled when playing with my carb but they kept on burning.
This link has some good plug info on it. Tells ya a hot-cold range for the plug.
Just an FYI at this point.
Pinging is caused by too high of a temperature in the cylinder. At about 2500 deg F. ping occours. The hotter, the more ping. This also creates a lot of NOx, which is what the EGR is designed to control. Many of our cars do not have or never had EGR valves.
The heat range of the spark plugs makes a big difference. Too hot of a plug can cause severe ping to the point of engine damage.
All spark plugs have various heat ranges. They all also have different internal resistance. The hear range will be by vehicle application, but the resistance is not.
American vehicles get most of the ignition resistance in the plugs. Europeans get most in the Ignition system, Asians are in between.
Bosch plugs are excellent for most European cars, but due to the low resistance typically do not perform well with American ignitions. The result is a cold spark. Do not confuse this with the plug heat range, they are two different things.
Heat range is the temp of the plug material. Spark temp is the temp of the spark itself, not the plug.
Both are important. BUT when you start changing types of plugs around, it may work, but often does not. You get improper spark, blistered or fouled plugs. This even using the correct heat range.
Some cars are very forgiving, others are not forgiving at all. A set of Champions in a VW will burn up very quickly. A set of Bosch in a stock Chevrolet ususally start hard and tend to foul out.
THe NGK do seen to work very well with our C3s, with both stock and performance ignitions. I would stay away from the Bosch in our cars.
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Charleston AFB, SC - USA
Joined: 10/31/2007
Posts: 111
Vette(s): 1979 Cream Beige Coupe w/383 & 700R4
Wow. Thanks to everyone and especially kstyer for the excellent help so far. You guys are the best! 
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Charleston AFB, SC - USA
Joined: 10/31/2007
Posts: 111
Vette(s): 1979 Cream Beige Coupe w/383 & 700R4
I thought I should add that the plugs that work are NGK BKR6E-11. I couldn't find them on the product sheet 79rebuild listed so I'm not sure what the heat range is or anything.
Is there a way to figure out which plug I SHOULD be using, which gap/etc, or is it just a guessing game?
in Forum: C3 Engines
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