Cracking spark plugs

Discussion in 'Mazdaspeed 3 Troubleshooting' started by mituc, Nov 7, 2019 at 7:30 PM.

Watchers:
7 users.
  1. mituc

    mituc Greenie Member

    Joined:
    Nov 8, 2018
    Posts:
    44
    Trophy Points:
    18
    Location:
    Iasi/Romania
    Ratings:
    +30 / -0
    So after wasting about $1500 trying to diagnose the issue here: https://www.mazdaspeeds.org/index.p...old-issues-still-haunting-after-rebuild.8988/ I figured my spark plugs crack for some reason. They crack in the coil boot area as you can see in this picture here:
    [​IMG]
    I finally realised that when I noticed similar marks on the supposedly new spark plugs after I pulled them after about 800 miles and compared with the old ones which also stayed in the engine about 250 miles and were replaced just as a precaution because I didn't know what else to do.

    So far this engine cracked within about 1200 miles from the rebuild:
    - two spark plugs on cylinder 1;
    - two on #2;
    - one on #3;
    - none on #4 (yet).

    Since the sparkplugs look normal on the cylinder side I'm not sure if I can blame the heat or anything else, since they worked absolutely fine with the previous engine which was pretty much identical less the CS cam shafts and the Mahle 4032 87.5mm pistons instead of the 88mm pistons I have now.
    [​IMG]

    So what's the catch here, why do they crack? I just threw in a new set yesterday and after a few pulls another one cracked.
    The sparkplugs are NKG 6510, purchased from EdgeAutosport only, and judging by their aspect, marks, markings, texture and everything there is absolutely no chance they are counterfeit.

    The spark plugs are installed with a spark plug socket, and I'm always careful not to lean sideways when torquing them. Also, it never happened before, it started happening with this engine only.
     
    Last edited: Nov 7, 2019 at 7:44 PM
  2. mituc

    mituc Greenie Member

    Joined:
    Nov 8, 2018
    Posts:
    44
    Trophy Points:
    18
    Location:
    Iasi/Romania
    Ratings:
    +30 / -0
    Since the only truly different thing is the CS cams, could it be that there's some weird vibration that is tearing them apart?
    I'm using Crower springs but this is what I had in the past with the other engine, on OEM cam shafts though.
     
    • Like Like x 1
  3. JohnnyTightlips

    JohnnyTightlips Platinum Member

    Joined:
    May 12, 2016
    Posts:
    692
    Trophy Points:
    93
    Location:
    Iowa
    Ratings:
    +1,016 / -0
    This is pretty crazy. Everything I read is saying it could be detonation but you don't seem to be having those issues.
     
    Last edited: Nov 7, 2019 at 10:49 PM
  4. Easter Bunny

    Easter Bunny Professional Engineer Silver Member

    Joined:
    Feb 11, 2016
    Posts:
    840
    Trophy Points:
    93
    Location:
    Earth
    Ratings:
    +1,280 / -5
    Have you always used the same brand of plug? I wonder if they are a hair longer than other brands and that combined with the new pistons you may not have enough clearance. Also try a different brand. There was denso I believe that was notorious for cracking at one time

    Did you deck the block when you chamged the pistons?
     
    Easter Bunny, via a mobile device, Nov 8, 2019 at 6:55 AM
    #4
  5. Easter Bunny

    Easter Bunny Professional Engineer Silver Member

    Joined:
    Feb 11, 2016
    Posts:
    840
    Trophy Points:
    93
    Location:
    Earth
    Ratings:
    +1,280 / -5
    Someone help me out and circle the crack. I can't see anything on my phone
     
    Easter Bunny, via a mobile device, Nov 8, 2019 at 6:57 AM
    #5
  6. JohnnyTightlips

    JohnnyTightlips Platinum Member

    Joined:
    May 12, 2016
    Posts:
    692
    Trophy Points:
    93
    Location:
    Iowa
    Ratings:
    +1,016 / -0
    [​IMG]
     
    • Like Like x 1
  7. JohnnyTightlips

    JohnnyTightlips Platinum Member

    Joined:
    May 12, 2016
    Posts:
    692
    Trophy Points:
    93
    Location:
    Iowa
    Ratings:
    +1,016 / -0
    I actually just looked at my last set when I thought I was having blow out issues and one of them was cracked pretty bad on the cermaic. I was using NGK 4 pc Iridium IX Spark Plugs - 6510 LTR7IX-11. I will take a picture when I can. I didn't even know this was a thing to look out for.
     
  8. Easter Bunny

    Easter Bunny Professional Engineer Silver Member

    Joined:
    Feb 11, 2016
    Posts:
    840
    Trophy Points:
    93
    Location:
    Earth
    Ratings:
    +1,280 / -5
    what the fuck? try a different brand
     
  9. mituc

    mituc Greenie Member

    Joined:
    Nov 8, 2018
    Posts:
    44
    Trophy Points:
    18
    Location:
    Iasi/Romania
    Ratings:
    +30 / -0
    Ok, went from bad to worse. Probably I just fucked up a 2000kms old engine.
    [​IMG][​IMG]
     
  10. mituc

    mituc Greenie Member

    Joined:
    Nov 8, 2018
    Posts:
    44
    Trophy Points:
    18
    Location:
    Iasi/Romania
    Ratings:
    +30 / -0
    There is a spring in the coil boot so if the spark plug is a bit longer, assuming it's not a lot longer, that spring will compensate for that.
    As for the pistons... the spark plugs need to protrude quite a lot into the head to comein contact with a piston, Like an inch or so. It's not physically possible.

    I thought about that. But the other decent brand is Denso, and the ITV22's used to crack (usually on the cylinder side) on stock cars with just a tune. I used them for a while back in 2012 while I had the GTX3071R... but I moved to NGK because some people reported these issues with the ITVs.
     
  11. StreetSpeed6

    StreetSpeed6 Welder Silver Member

    Joined:
    Mar 1, 2018
    Posts:
    339
    Trophy Points:
    43
    Location:
    Bedford, Indiana
    Ratings:
    +196 / -0
    I didn’t realize this was a thing either but I haven’t had any issues with my plugs doing this so far (knock on wood). So I take it that it melted the strap as well as cracked, or is the strap in the cylinder? Lol
     
  12. Mauro_Penguin

    Mauro_Penguin Punk in Drublic Motorhead Platinum Member

    Joined:
    Feb 10, 2016
    Posts:
    923
    Trophy Points:
    93
    Location:
    Jacksonville, FL
    Ratings:
    +1,015 / -2
    That last spark plug you pulled out looks like the strap snapped off from something like severe detonation.

    Have you started tuning the new engine with the new CS cams yet?
     
    Mauro_Penguin, via a mobile device, Nov 8, 2019 at 7:32 PM
    #12
  13. Eroler1

    Eroler1 Greenie Member

    Joined:
    Jan 27, 2018
    Posts:
    139
    Trophy Points:
    28
    Location:
    Hawaii
    Ratings:
    +43 / -5
    I wish I took a picture of mine, but lately I noticed 6510 are really easy to crack, I cracked 2 sets already one lasted 50 miles the other is like 150, mine cracks worst than that tho, as in falling apart. BUT 3 out of 4 of my coil pack are using copper rod, and 1 is using spring and the spring still cracks the plugs, I used a motorcraft platinum forgot the part number its like $16 for the set and this didnt cracked at all but to test the 6510 again I just bought another set of 6510 and gonna see if they crack again this time before I finally try their "rethuriam!??!?!" new plugs
     
    • Like Like x 1
  14. mituc

    mituc Greenie Member

    Joined:
    Nov 8, 2018
    Posts:
    44
    Trophy Points:
    18
    Location:
    Iasi/Romania
    Ratings:
    +30 / -0
    I was logging when it happened... KR was 0.7 during that pull.
    Yes, it's that engine...
     
    • Like Like x 1
  15. mituc

    mituc Greenie Member

    Joined:
    Nov 8, 2018
    Posts:
    44
    Trophy Points:
    18
    Location:
    Iasi/Romania
    Ratings:
    +30 / -0
    You know... some engine builder/tuner told me the same thing on a Facebook group (it's a good group, not one of those bull of BS).
    I used copper rods in the past when I was having a problem and those sets did not crack with or without the coils modification. Actually back then I was changing these spark plugs at 15-20k kms. This started happening all of a sudden with spar plugs I purchased from Edge in the last few months or so.
     
    • Like Like x 1
  16. JohnnyTightlips

    JohnnyTightlips Platinum Member

    Joined:
    May 12, 2016
    Posts:
    692
    Trophy Points:
    93
    Location:
    Iowa
    Ratings:
    +1,016 / -0
    [​IMG]

    This is the last set I pulled out when I was having issues. It is also cracked like this on the other side. Only one did this. I got mine from HERE
     
    • Like Like x 1
  17. JohnnyTightlips

    JohnnyTightlips Platinum Member

    Joined:
    May 12, 2016
    Posts:
    692
    Trophy Points:
    93
    Location:
    Iowa
    Ratings:
    +1,016 / -0
    This is also something to think about.

    Detonation Problems in Turbocharged Engines with Direct Injection
    Some late model turbocharged engines with Direct Fuel Injection can experience detonation at low RPM following a cold start or after prolonged idling. The problem seems to be due to gasoline mixing with residual motor oil on the cylinder walls in the upper cylinder area. Many motor oils contain large amounts of sodium as part of their detergent additive package. When the sodium mixes with fuel, it forms a compound that can easily detonate when the engine is lugging hard under load or accelerating. The cure is to switch to a motor oil that contains less detergent, or less sodium in its detergent additives.
     
    • Like Like x 2
Loading...

Share This Page

Users Viewing Thread (Users: 0, Guests: 0)