What’s your take on the plug.
- Thread starter hwy2
- Start date
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mopar head
DoD nuisance Alien/Squatch extermination team
Looks ok to me.
mopar head
DoD nuisance Alien/Squatch extermination team
You have to look down inside for the ring around the ceramic, some cut them apart for a better look.
Is that the correct heat range plug? Looks almost too perfect.
A56
Street Survivor
Nothing wrong with that.
TT5.9mag
Two atmospheres are better than one
So no load? And you’re trying to read the plug for what? There’s no reason to read a plug for light load cruise. It SHOULD be lean and have a ton of timing in it during that scenario.
I have been running her
hard. Changed all drums to disc. So lots spinning tires and stopping as well. Does the timing mark look ok? I think I could go up a degree or two.
hard. Changed all drums to disc. So lots spinning tires and stopping as well. Does the timing mark look ok? I think I could go up a degree or two.
I would agree with you, and just slightly rich.
TT5.9mag
Two atmospheres are better than one
You can’t judge the plug with a mix of driving. All scenarios color the plug differently and that includes the timing mark. Get a new set, make a wot pass and shut the engine off and coast to a stop. Pull the plug and read it. That’s when you will gleam the most useful information from a plug.
TT5.9mag
Two atmospheres are better than one
Plugs are expensive now a days. If you want to save some cash, buy a couple plugs and just pull the easiest one a few times after some hard pulls. I suggest cutting the shell off to get a good read on the fuel ring. And if that were mine I would immediately buy a set of plugs 2 heat ranges cooler. There’s not enough color in the threads.
mopowers
Well-Known Member
Probably a stupid question but, does reading a plug after a wide open pass provide valuable information if the car is primarily a street car that rarely sees WOT? In that scenario, wouldn't you want to see what the plug looks like during normal driving conditions, or maybe one at light throttle, one a cruise, etc.?
This ^^^^^
Do I need to post instructions on how to read plugs correctly? AGAIN? For the UMPTEENTH time? Ok. Here goes. PAY the FRIG attention.
Find a good straight stretch of road. Come to a stop. Now, STAND ON IT until it hits high gear. I mean BEND THE FLOORBOARD with the gas pedal. Get it? When it gets into high gear with your foot STILL ON THE GAS, cut the key OFF. Pull off the side of the road and read the plugs. Take pictures and post them here. THAT'S how it's done and that's the ONLY WAY to get an accurate read on plugs. You CANNOT read them after idling in the driveway. How STUPID is that?
TT5.9mag
Two atmospheres are better than one
It’s not a stupid question at all. But what are you trying to learn by reading a plug for part throttle? The only (and seriously Ive thought about it) useful information you can get is if the plug is stupid pig rich. That’s all.
I am making sure it’s not to lean after driving this motor about 50 miles after a complete rebuild from a 318 to a 392. I got a great spot for Rusty’s test and a new set of plugs one step
Cooler. I am also looking for a timing mark I think it needs a couple degrees. The purpose for this car is 1/8mile fun on Friday test and tunes. Working on my launches and not stumbling.
TT5.9mag
Two atmospheres are better than one
Excellent. But, when you’re just cruising around on the transfer slots, it’s SUPPOSED TO BE LEAN. AND have a bunch of timing, like 40-50 degrees. AND when you’re starting and stopping the timing swings all over the place so the ground strap shows a bunch of random markings. AND there’s no heat in the chamber. AND there’s lots of reversion, AND there’s probably some egr, AND all of these variables make reading the plug almost useless. I’m sure there are some engineers somewhere that have scienced out how to read a plug for part throttle emissions crap but we aren’t concerned with that stuff here. Read the plug for what the engine is doing at WOT so you know what’s going on when the engine can harm itself. The rest of the time doesn’t matter.
mopowers
Well-Known Member
Thank you. That makes sense. The only reason I asked that question was that guys will post up a photo of the plug in their street cruiser and get slammed because the plug reflected more than just a single WOT pass. To me, that would indicate that plug reading is only useful for WOT driving, but that's not the reality, is it?
For the other 99.5% of us who drive our cars on the street, how would we tune for other driving conditions by reading a plug that only saw WOT?
Speedy Pedi
Well-Known Member
I would expect the WOT pass will only then indicate your main jets are too rich or lean, not to be confused with the other modes of carb operation as far fuel mixture and indicate engine total timing at full advance.
TT5.9mag
Two atmospheres are better than one
You wouldn’t tune for other driving conditions by reading the plug. That’s what I’m getting at. Use a wideband O2 gauge and “feel”. For cruise afr if you don’t have an afr gauge you can lean it up till it surges then add 1-2 jet sizes in the primary. For cruise timing, keep adding timing at the same rpm/speed/load until it stops picking up speed/rpm.
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