Hi Everyone,
I have a 2014 Z51 with a D1SC running 93/meth. Last weekend my front main spit up some oil (similar to “Oil Everywhere!!” By BlueDevilZ51) and I’m starting to dig into it. Last night I pulled all 8 spark plugs and tonight I’m going to run a compression test on all 8 cylinders. I started with the hard side, the passenger side then went to the driver side. What do you know the very last one I pull (#7) is not like the rest. All of them up to #7 were clean, white/light brown, with .035 gaps (I gapped them all in June this year after I threw a CEL for knock just that one time). #7 is measuring about .045 and and has a light grey film to the porcelain. Is there a chance I didn’t get #7 gapped down to .035 like all the others? Sure but 99.9% sure I gapped them all (all were 040-045 range from previous owner installing). I’m reading articles on how to read spark plugs for preignition, detonation, heat range, jetting, etc and I’m not really sure what I have here. What I’m finding on CF is what spark plug to use and how to do them not specifically how to read them. They’re NGK LTR7IX-11s. If any piston is suspected of excessive blow by popping the main seal, at this point I’d say #7 could be the culprit, but is this light grey film “normal variation”? Could it be my meth isn’t getting back to #7 adequately?
Appreciate all inputs and opinions!

 

Plugs look good to me, I gap mine to .030 you can look for speckles on the porcelain. That would be a sign of detonation

 

Close the GAP on those plugs, it will run alot better, lol!!!!!

 

Plugs look good man close them down to 28 to 30. THEN RELOOK AT THEM. Also how did you run the car before you killed the motor to check them. Robert

 

Sorry for the long delay in responding... I didn't get any email notifications saying anyone responded so I just thought no one cared to help/provide opinion haha. I've since got them all gapped down to .035. Had I seen your guy's responses before then I would've gone to .030 but all seams fine. I even threw a new plug in #7 as well as #5 just so I had another new plug to compare #7 to later.

I haven't really driven it since, I've only fired it up every few weeks and let it get to operating temperature to keep the oil circulating over the winter. I got the new LS3 front main seal (12585673) and plan on installing it between Christmas and New Years since I'm taking vacation to bridge the holidays. I also got a BlackStone Oil Labs kit and will send in a sample when I do the oil change at the same time just to see what the oil is telling me (my first oil change since buying it earlier this year).

When I changed the plugs, I also did a compression test (cold) when I changed the plugs. I guess I didn't know how many power cycles I'm supposed to let it crank and simply cranked each cylinder 4 cycles. and got 190psi on 2,4,6,8 and 1, then 170psi on 3,5,7. My basic understanding was atmospheric pressure (14.7) times CR (11.5) is 169 so I should get readings no less than that. Sometimes I didn't hit the start/stop button quick enough and it bumped a 5th time and read 210psi in those cases.

From here I think I'm just going to swap the seal for an LS3 seal then take it to a local performance shop and have them install a mighty mouse wild catch can (my current set up is a twin catch can that recirculates, idk the brand but I want something that's simpler and releases to the atmosphere) and do a couple dyno pulls to check power output and get a second opinion on the tune. I'd appreciate any tips for replacing the seal! I have a D1 Procharger (PC) so I've already ordered the longer crank bolt to accommodate for the PC dedicated drive pulley that's on top of the crank pulley, and I'm thinking I can just use the old bolt to start pressing on the crank pulley, then slap the PC lower pulley on and tighten the rest of the way, then back out and install the new crank bolt per PC instructions.

 

I agree with the gapping of .030, I run .032 on mine. . On my Magnuson SC Camaro I ran .025 on race fuel, some run less then that but I wouldn't go lower the that. They don't look bad as another said. Not rich and not lean.