look at this plug
09-18-2012, 09:22 AM
#1
look at this plug
[IMG]
[/IMG]This is a Cham RCY10YC4. Cylinder #2. I pulled one plug last night. It is N20 plug one heat range colder. I placed in car about 4000 miles ago. I have sprayed about 6 times last season and was very rich. I jetted leaner for N20. Not used N20 this season as chasing a misfire that was determined to be cap rotor and now fouled plugs. I am EFI and run CL EBL.
The ground electrode appears gray with a builup of gray where it meets the body of plug. The porcelin is caked with a gray deposit on one side only (prob facing away from intake valve). Other side has a black trace from center electrode down porcelin. The center electrode is black. A black deposit encompasses the flat base of plug facing combustion chamber.
Is that oil fouled? When we pulled the prior plugs RCY12C my friend thought oil foulded on #2 only. Others OK. I did not see plugs at that time. I see no evidence of oil at exhaust at idle. Heads are Edelbrock with 40K miles. Engine has 122K on it original motor. Blowby? Suggest a leakdown test?
Last edited by Ronny; 09-18-2012 at 09:39 AM.
09-19-2012, 05:12 PM
#3
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Car: 1991 Camaro RS
Engine: BBC 509 Merlin ii 9.6:1 pump gas
Transmission: ATI pro th350 sfi case. TSI 5500 st
Axle/Gears: Strange S60 4:10s
Re: look at this plug
Sure looks oil caked to me.
09-19-2012, 09:06 PM
#4
Re: look at this plug
yes...definitely oil fouled.....either oil getting in thru the intake port or a bad valve seal or possible cracked piston rings..........best bet would be to do a cylinder leak down test.....should be no more than 10% of your highest compression reading of the other cylinders
09-20-2012, 10:49 AM
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Car: 1982 Camaro
Engine: 555 BBC
Transmission: TSI Glide
Axle/Gears: Aluminum Moser 3.89
Re: look at this plug
I would reccomend not using a projected tip spark plugs in a nitrous application. Depending on the heat range i'd use NGK 5671a-7 -8 -9 -10 or -11. Until you find out the source of the oil I would not use the nitrous again. A leakdown or at least a compression check at the minimum should be done. It is quite possible that you valve guides are leaking once the car is shut off or the rings have just had it. Either way find the source of oil.
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