Let the guessing game begin as what broke in 502 mag EFI
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mcollinstn (10-21-2021)
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That ticking you heard beforehand could be a diverter in the Corsa exhaust.
#13
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i see no signs of a lean cylinder so a broken forged piston is not likely,a borescope through the plug hole would be what i would do if i thought it had detonated a piston.mpi engines can and do have injector issues from time to time and if nothing gets done to correct the bad injector bad things can happen.the op said it was still running fine just making noise so i would rule out other problems before i pulled the engine out.edit in,i see no peppering,only carbon build up but without close inspection with a magnifying glass i would not see it anyway.
Last edited by mike tkach; 06-01-2015 at 10:27 AM.
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mcollinstn (10-21-2021)
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i have seen them knock from a bad sparkplug wire..called spark knock...should have pulled plug wire one by one until the knock went away,,if it did not then its not a rod bearing..
#16
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A sid "knock" is more often a spun bearing and the rod beating crank, but like Mike T said it could be many things.
Heads been done before? Could be non inconel and exhaust valve broke and beat things up, but that pretty much always messes a plug up, I broke one it was a clean break went right out exh without barely damaging anything...
Heads been done before? Could be non inconel and exhaust valve broke and beat things up, but that pretty much always messes a plug up, I broke one it was a clean break went right out exh without barely damaging anything...
i see no signs of a lean cylinder so a broken forged piston is not likely,a borescope through the plug hole would be what i would do if i thought it had detonated a piston.mpi engines can and do have injector issues from time to time and if nothing gets done to correct the bad injector bad things can happen.the op said it was still running fine just making noise so i would rule out other problems before i pulled the engine out.edit in,i see no peppering,only carbon build up but without close inspection with a magnifying glass i would not see it anyway.
Im searching youtube now for the same noise I have. I dont think im the first person to ever have this noise HAHA.
#17
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Yeah I got ya. It's just in the last 2-3 years I've seen more detonated boat motors than in the last 10. There is definately peppering on that plug. Is it from running lean? Hard to tell after the motor has been idled. Wasn't really my thinking. If I'd pinched a ring which usually happens with a forged piston and minor detonation a borescope isn't going to tell you much. There is definate signs of detonation on the plug it's hard to tell from the other plugs cause when you supersize it gets very blury.
To the OP the black speckling on the porcelain is oil the got past the rings from detonation. If you get a high powered magnifying glass and examine the porcelain carefull I bet you will see more black spots and some aluminum shiny spots. Black is oil shiny is aluminum from the piston.
To the OP the black speckling on the porcelain is oil the got past the rings from detonation. If you get a high powered magnifying glass and examine the porcelain carefull I bet you will see more black spots and some aluminum shiny spots. Black is oil shiny is aluminum from the piston.
#18
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Deffentley NOT like this . This I would call a thud.
https://www.youtube.com/watch?v=1aHz4yZoNzA
This is close just louder.
https://www.youtube.com/watch?v=Pu2RHsIGBXU
https://www.youtube.com/watch?v=Pk1zX_0mKjg
Also Engine ran fine, no miss, no rough idle, nothing.
https://www.youtube.com/watch?v=1aHz4yZoNzA
This is close just louder.
https://www.youtube.com/watch?v=Pu2RHsIGBXU
https://www.youtube.com/watch?v=Pk1zX_0mKjg
Also Engine ran fine, no miss, no rough idle, nothing.
#19
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He has an MPI / ECM controlled engine not the best choice just start yanking plugs wires while engine is running You can do a cylinder drop test with proper scan tool.
I could not see pepper specks on the white insulators of the spark plugs in that one pic. If you do, that is a sign of detonation.
possible Rod bolt ????
Plugs out spin motor by hand - does it feel normal and sound ???
comp test and leak down test or start pulling the heads since the exhaust manifolds are off.
I could not see pepper specks on the white insulators of the spark plugs in that one pic. If you do, that is a sign of detonation.
possible Rod bolt ????
Plugs out spin motor by hand - does it feel normal and sound ???
comp test and leak down test or start pulling the heads since the exhaust manifolds are off.
#20
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From ManofWar's thread.
This is what my ticking sounds was before it turned into a knock knock joke.
https://www.youtube.com/watch?v=P2FnlFBM5_A
This is what my ticking sounds was before it turned into a knock knock joke.
https://www.youtube.com/watch?v=P2FnlFBM5_A