 Dropped intake seat, Made a mess. |
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| rjames |
 Mar 16 2023, 03:38 PM
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#21
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I'm made of metal  Group: Members Posts: 3,911 Joined: 24-July 05 From: Shoreline, WA Member No.: 4,467 Region Association: Pacific Northwest 
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Agree that a wideband sensor is important, especially with all of the rebuilt MPSs out there that may not have been calibrated for the engine they are being used with.
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| gnomefabtech |
Mar 16 2023, 10:08 PM
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#22
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Member Group: Members Posts: 94 Joined: 27-December 22 From: Los Angeles Member No.: 27,063 Region Association: None |
How do the other cylinders look? It's possible that just one hole had a clogged injector or something that caused that pinging but it's unlikely. I think it's just the valve seat falling out and the resulting carnage that caused all that piston damage. Detonation erosion that I've seen usually shows up in the ring lands and sometimes gets so bad that you can see the top piston ring with the head off because the piston wore away.
What's the head look like? Is the exhaust valve burned? |
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| TrailerParkBoy |
Mar 20 2023, 10:17 AM
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#23
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Newbie Group: Members Posts: 8 Joined: 7-February 23 From: PNW Member No.: 27,145 Region Association: Pacific Northwest |
Pulled it apart and this is what we found, remember this is an original 2.0 head on 96mm pistons In a motor I’ve been running a long time.
- no lean condition. The pistons in 1/2/3 look slightly rich, plugs the right colour, no signs of stress on piston tops, valves, rings. - lifter rod was smashed on end, enough material removed to shorten rod by half inch. - we assume the seat worked loose and then bounced around for many miles (perhaps I should have been listening!) before finally resting on angle and smashing piston top - we assume material from seat and piston caused the piston top pitting prior to landing on angle, this explains the metal condition. - no metal in crankcase - number four liter and cam lobe “scuffed” due to piston contact. We will replace all internals New Build: - we have 039 heads from Jonathan at AA (would love to have them… but don’t have the budget for Ken’s $5k heads). 78mm crank counterweighted, 96 pistons, stock rods, everything balanced including flywheel and alternator. Thank you everyone for questions, comment, opinion and advice on all of the above. Cheers, Attached thumbnail(s)   
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| gnomefabtech |
Mar 20 2023, 07:18 PM
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#24
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Member Group: Members Posts: 94 Joined: 27-December 22 From: Los Angeles Member No.: 27,063 Region Association: None |
Dayum! That's a crazy failure.
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| r_towle |
Mar 20 2023, 07:38 PM
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#25
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Custom Member Group: Members Posts: 24,560 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States
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Lean, detonation evidence on the other cylinder.
When you get it redone, you must address A/F mixture and timing issues |
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| Dave_Darling |
Mar 20 2023, 10:05 PM
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#26
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914 Idiot Group: Members Posts: 14,980 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California
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That looks depressingly familiar.
Could be caused by heat as well. If so, the other intake seats are likely getting ready to do the same thing. (Don't ask how I know that.) --DD |
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