reading spark plugs



reading spark plugs

Postby grumpyvette » November 20th, 2010, 5:15 pm

HEY GRUMPYVETTE?
Need some help reading plugs; are these running lean? They've got about 180 miles on them. The background is a sheet of white paper and a brown paper bag.


you might want to watch this video on swapping to low resistance ignition wire

https://www.youtube.com/watch?v=bjpI6nACxlM

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yes they are running a bit lean,under power and a bit rich at idle and your ignition timing is either about correct or marginally advance from ideal.if your not familiar with reading plugs, those plugs look better than most I see on street cars after 180 miles
theres a great deal of info here in these threads and sub links

viewtopic.php?f=70&t=202

viewtopic.php?f=70&t=5428
http://www.autorepairinstructions.com/?cat=7
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example
http://www.4secondsflat.com/Spark_plug_reading.html
and
http://www.strappe.com/plugs.html

basically your concerned with the color of the ash, the distance the heat ring on the ground strap moves toward the plug body and the look of the porcelain around the center electrode , gap the plugs at .045 and run the ignition advance so the engines fully advanced by about 3100rpm, for max mileage you want about a 15:1 fuel air ratio, for max power the fuel/air ratio will need to be closer to about 12.7:1

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: reading spark plugs

Postby grumpyvette » September 5th, 2011, 3:31 pm

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here we see some rather obviously well worm plugs coated with various levels of ash and fouling
knot knowing all the related tuning info hurts easy diagnosis
# 5 is obviously not firing and coated with oil,
a compression test, re-adjusting the valves, a leak down test and checking the ignition spark , ignition wire resistance and valve oil seal would be a good idea to locating the source of the oil fouling
the whole bunch of plugs look like they tend to be running a bit rich on average, looking at the base ring and the heat band on the ground strap indicates a bit lower than ideal cylinder temp range, I,d suspect the advance curve was a bit slow, the carburetor was a bit rich and the rings and valve seals were worn, but ID also do a few tests before assuming those were the correct locked in stone conclusions.
notice how the front 4 plugs look like they run a bit leaner? could indicate a small vacuum leak or the front jets are a bit small, or the float levels are not set correctly, idle jets are not set correctly, but the power valve is allowing the transition to richen it up. again, new plugs a few adjustments, knowing your float levels fuel pressure and advance curve sure helps with the diagnosis

READING this thread and sub links should help
viewtopic.php?f=70&t=5428

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heres a good indication of plugs running a bit rich at idle and real lean in the upper rpm range
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: reading spark plugs

Postby grumpyvette » August 11th, 2012, 3:21 pm

Are all these ok? I believe they are, but I am just making sure. The 3rd one back on the passenger side (7th and last photo here) is the one that gives me some concern. More white type residue and some darkening on the porcelain. Just trying to rule out 100% that the plugs are not causing my missing problem.

Photos
Driver side, front to back:
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[color=#BF0000]
Passenger side, front to back

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(This is the one I have concerns with)
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Another of the 3rd passenger side plug:
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In reading up online about what "good" plugs look like, it seems that the all are ok, other than maybe that passenger one. Would that contribute to a high speed "miss"?




Here are better pictures of the electrodes themselves.

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Grumpy, thanks for the info. I am reading through that now.

Just wondering if these need to be replaced, based on what everyone sees.

I'll be switching to 5W30 synthetic oil, next oil change, and I believe that will drop the oil pressure a bit. That may address some of the oil you see on the plugs, no?



Id say many of those pictures are really great pictures of your thumb, but spark plugs, not so much, I can,t take decent pictures either so thats not really a bitch just an observation based on reality


READ THRU THESE LINKS

http://www.verrill.com/moto/sellingguid ... rchart.htm

http://www.classic-car-magazine.co.uk/a ... chart.html

http://www.paradrenalin.com/pdf/Spark-P ... -Chart.pdf

http://www.denso.com.au/Products/Automo ... Spark-Plug



http://www.hioutput.com/tech/plug.html



http://forum.grumpysperformance.com/viewtopic.php?f=70&t=202

http://forum.grumpysperformance.com/viewtopic.php?f=70&t=5428

http://forum.grumpysperformance.com/viewtopic.php?f=70&t=3949

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=109

http://forum.grumpysperformance.com/viewtopic.php?f=70&t=4683


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ok heres one picture I picked you posted lets discuss it a bit
look at the outer threaded area, its dark greasy and oily obviously running a bit rich at idle to build that up,probably a cylinder thats burning a bit of oil, might be valve guides or valve seals or worn rings, nothing excessive but obviously some oil, so thats a factor, the heat band on the ground electrode goes nearly down too the base , indicating either to lean or too much ignition advance but clearly too much cylinder heat at times,the porcelain is nearly clean, obviously running a bit lean and most likely a bit too far advanced on the ignition spark curve, at least during much of the upper rpm range , Id suspect a slightly clogged injector or vacume leak if thats the only plug that looks like that, but they are not!
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now look at this one, a good deal more ash on the porcelain, and obviously running a bit richer, but still has the electrode heat band showing too much cylinder heat at times and running lean at times, looking at all the posted pictures Id drop the total ting curve back 2- degrees and swap to the next cooler range plug and see what the result was, but Id bet you need a step larger injector or a bit more injector pulse duration programmed into the CPU,
ID also do a leak down test and try to determine if its valve seals, valve guide wear or rings allowing oil into the combustion chamber, and ID verify my TDC and install a clearly marked damper , even on a LT1 just so I know whats going on, even if I can,t change it untill I get a chip reprogrammed or refresh my CPU info

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viewtopic.php?f=70&t=1015&p=16924&hilit=timing+tabs#p16924

viewtopic.php?f=70&t=4683


YOU SHOULD NEVER DEPEND ON A SINGLE SOURCE OF INFO<GET A INFRARED TEMP GUN AND LEARN TO READ SPARK PLUGS

(Ive used this one for years)
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http://www.professionalequipment.com/ex ... ermometer/
Wide temperature range from -58 to 1832°F (-50 to 1000°C)
viewtopic.php?f=44&t=579&p=743&hilit=ratio+meter#p743

viewtopic.php?f=55&t=109&p=44341&hilit=reading+plugs#p44341

viewtopic.php?f=57&t=4974&p=29925&hilit=reading+plugs#p29925

viewtopic.php?f=56&t=495&hilit=reading+plugs

viewtopic.php?f=70&t=3949&p=25952&hilit=reading+plugs#p25952

IVE come to use reading spark plug condition, as a viable and reliable cross check on fuel/air ratio meter readings, while the new fuel air ratio meters are great you can still learn a great deal reading spark plugs, checking a vacuum gauge, verifying exhaust back pressure and graphing your ignition advance curve and using a infrared heat gun to read exhaust temps
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: reading spark plugs

Postby grumpyvette » August 29th, 2012, 11:17 am

"hey grumpy? what do these plugs tell you?"

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the plugs are a good indicator of what is going on during combustion, but it also helps to know all you can tell me about your engine combo, operating temperature , ignition advance, carb used, fuel pressure and all other factors, plugs indicate your running rich and not getting a good burn, the ground strap heat ring indicates it runs closer to ideal under load and richer than ideal at idle and low speeds, Id suggest verifying your fuel pressure, so its at or just under 5.5- 5 psi at all times with a return style fuel pressure regulator, checking float levels, are not set too high, checking your ignition advance curve, and making sure the power valves or metering rods and jetting in the carbs is changed to lean out the fuel/air ratio.Id suggest stepping up to one hotter range spark plug and advancing the total ignition advance a couple degrees and leaning out the fuel air ratio slightly, you need to get that fixed and the info you needs in the above links, If your local I can help, this is USUALLY a simple tunning issue
look very closely at the specks of crud on the plug insulator ceramic , if its ash thats fine if its bits of aluminum it indicates occasional detonation, if you follow directions , are willing to verify all the component functions, and do a few tests,and post clear pictures of the plugs after each change and take things step by step I can walk you thru the corrections

http://forum.grumpysperformance.com/viewtopic.php?f=70&t=5428

http://forum.grumpysperformance.com/viewtopic.php?f=70&t=202

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=109

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=635

read thru the links above
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Site Admin
Site Admin
 
Posts: 14105
Joined: September 14th, 2008, 1:40 pm
Location: florida


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