Spark plug crushed... how bad am I screwed
May 21, 2009, 01:38 PM
#16
While I can't say for sure without pulling the head, I'm 99% convinced that the top of the piston cracked.
Some more inspection under the borascope leads me to believe that's the case. Compression & leakdown are both still good, so it didn't quite shatter apart like eflove. I'll get the head off eventually to confirm, and I'll post some pics.
Some more inspection under the borascope leads me to believe that's the case. Compression & leakdown are both still good, so it didn't quite shatter apart like eflove. I'll get the head off eventually to confirm, and I'll post some pics.
May 21, 2009, 02:24 PM
#17
While I can't say for sure without pulling the head, I'm 99% convinced that the top of the piston cracked.
Some more inspection under the borascope leads me to believe that's the case. Compression & leakdown are both still good, so it didn't quite shatter apart like eflove. I'll get the head off eventually to confirm, and I'll post some pics.
Some more inspection under the borascope leads me to believe that's the case. Compression & leakdown are both still good, so it didn't quite shatter apart like eflove. I'll get the head off eventually to confirm, and I'll post some pics.
May 21, 2009, 03:22 PM
#20
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130's are not bad for a IX. Perfect compression on a IX is 145psi.
I had a spark plug come apart on me before due to what I figured was detonation, it cracked the insulator and then smashed the strap into the electrode on my Talon.
I am afraid to run denso's, have heard some bad stories about them.
I had a spark plug come apart on me before due to what I figured was detonation, it cracked the insulator and then smashed the strap into the electrode on my Talon.
I am afraid to run denso's, have heard some bad stories about them.
May 21, 2009, 05:18 PM
#21
Data from the quarter mile run that blew it...
I don't see any obvious problems aside from just too much power for the stock block. The knock is brief during shifts, except for the top of 4th which I'm guessing was a symptom of the break, not the cause)
It was taking 22 deg of timing up top
I don't see any obvious problems aside from just too much power for the stock block. The knock is brief during shifts, except for the top of 4th which I'm guessing was a symptom of the break, not the cause)
It was taking 22 deg of timing up top
May 23, 2009, 08:53 PM
#24
UPDATE: The head is coming off tomorrow, but after taking the valve cover off, I found that one of the exhaust rocker arms for this cylinder had fallen out of place. I don't have any experience in engine failures, but I take it that that valve stopped opening and possibly the cylinder overheated and caused the piston to crack.
May 24, 2009, 02:46 AM
#27
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Ehh geeze I hate internet diagnosing. There are so many scenarios running through my head. There's too many variables that are un answered to give a proper diagnosis.
Based on what little info given about your mods and the end result my best assumption would be that you experienced valve float and the valve crashed into the piston which then hit the spark plug. The piston hitting the valve is what knocked the rocker arm off. You're doing the right thing by removing the cylinder head. I hope the evo isn't your daily driver.
Based on what little info given about your mods and the end result my best assumption would be that you experienced valve float and the valve crashed into the piston which then hit the spark plug. The piston hitting the valve is what knocked the rocker arm off. You're doing the right thing by removing the cylinder head. I hope the evo isn't your daily driver.
May 24, 2009, 02:53 AM
#28
I have FP 4R cams and stock valvetrain... starting to regret not trusting my better judgement and doing springs & retainers. I'm gonna write FP and tell them to take this nugget of anti-wisdom OFF their site:
The grind can be safely operated beyond the stock redline to 8krpm with the stock springs in place
Last edited by recompile; May 24, 2009 at 02:56 AM.
