Can engine or head be saved? - 99 Chevy Tracker

Tiny
TWOCYCLEMANIA
  • MEMBER
  • 1999 CHEVROLET TRACKER
  • 65,000 MILES
While changing plugs a small piece of metal (probably the head of the bolt that holds the plug wire harness in place since one is broken off) was apparently in the plug tunnel hole from the last plug change. I didn't see it and it unknown to me it fell into the engine. When started it sounded like marbles in a blender. Pulled the new plug and found the tip bent and the ceramic broken. Tried to fish the piece/pieces out but the damage is apparently done. Compression 135 on that cylinder and 155 on the other three cylinders. I believe the valves are damaged. Piston looks okay from plug hole but what are the chances the piston, rings and cylinder walls are not damaged. How much scoring would be acceptable? Am I looking a new engine or just the head redone? It was a costly spark plug change. Could the injector also be damaged as it was idling okay when started but died under load.
Thursday, November 24th, 2011 AT 4:25 PM

10 Replies

Tiny
CJ MEDEVAC
  • MECHANIC
  • 11,004 POSTS
HOW LONG DID IT RUN?

HAVE YOU RETRIEVED ALL OF THE FOREIGN MATTER?

JUST ONE PIECE OR MANY?

HAVE YOU RAN IT SINCE?

THE MEDIC
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Thursday, November 24th, 2011 AT 4:38 PM
Tiny
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Thanks for the help! It was started and run about a half dozen times for a total of maybe 5 minutes run time. I didn't know what was wrong at first or I would not have run it.
I retrieved two very small flat pieces (maybe 1/8 inch long) via magnet. I don't know if everything is out or if they're any more pieces. The small bolt head I mentioned is most likely it but I can't be positive. I'm sure the head will need to be pulled but I'm trying to get an idea as to how bad it's likely to be. Thanks again! Happy Thanksgiving!
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Thursday, November 24th, 2011 AT 6:27 PM
Tiny
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There is a very good chance that the piston and/or cylinder wall could be damaged. The best way to find out is with a high quality boroscope. Most techs have one these days Many can record video and/or pictures. Even is you only dented the piston, the sharp points will get hot and melt in time.
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Thursday, November 24th, 2011 AT 6:49 PM
Tiny
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Thanks for the input. I'm having it looked at with a boroscope at a local repair place. What I need to know is; if there are any nicks or scratches in the cylinder wall what is the save or scrap point. The engine has only 60K on it and I'd like to salvage it if possible even though the head will probably have to be redone. Any idea on the cost of reconditioning the head in this case? Thanks
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Monday, November 28th, 2011 AT 1:37 AM
Tiny
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If you have piston, cylinder wall or head damage, there won't be any reconditioning of those parts.
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Monday, November 28th, 2011 AT 1:43 AM
Tiny
CJ MEDEVAC
  • MECHANIC
  • 11,004 POSTS
JUST TO GIVE YOU A LITTLE HOPE!

MY 1946 WILLYS JEEP HAD A SMALL AND UNKNOWN HEAD GASKET LEAK

COOLANT LEAKED INTO #4 AND "DETONATION" STARTED HAPPENING (FOUND THAT OUT AFTER REMOVING THE HEAD)
A ONE INCH PIECE OF THE TOP COMPRESSION RING ON #4 CYLINDER OF RIPPED THRU THE THE TOP OF 1/4 INCH OR SO OF THE PISTON

IT WAS LAYING ON TOP OF PISTON AND WAS TAPPING THE HEAD---I DROVE IT ABOUT 2 MILES HOME REALLY SLOW.

I THOUGHT I HAD A ROD BEARING PROBLEM--FINALLY AFTER PULLING THE HEAD, DID WE FIND THE PROBLEM

THE CYLINDER WALL WAS PERFECT!

THE HEAD WAS NOT DAMAGED!

I DID HAVE TO BUY A FULL SET OF PISTONS TO GET "ONE"---I INSTALLED THEM ALL, W/ NEW RINGS--ALONG WITH NEW ROD BEARINGS, AS I WAS ALREADY IN THERE ANYWAY.

I GOT OUT FOR LESS THAN $225. DIY

GOOD LUCK--I'M PULLIN' FOR YA!

THE MEDIC
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Monday, November 28th, 2011 AT 2:39 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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If you are able to clean out the cylinder through the plug opening, chances are it will be fine with a new plug. Clean it out and check compression. I feel confident that it will be okay. If compression is low, then remove the head and check for damages.
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Monday, November 28th, 2011 AT 4:51 AM
Tiny
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Compression would not be the only indicator of a problem. Physical damage to a piston, cylinder wall or head will develop into more serious issues if the engine is run.
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Monday, November 28th, 2011 AT 10:39 AM
Tiny
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Thanks everybody for the input! The local shop called me to take a look as they put a scope with a mirror down the spark plug hole. There appears to be scraping or marks on the cylinder wall. Either metal or damage along the edge of the piston all around. There's a small piece of metal stuck in the valve. Hard to tell but there may be a small hole in the top of the cylinder. The top of the head surrounding the valve looks like someone took a punch and hammer to it. The mechanic was also concerned about the 'hammering' on the cylinder that could do damage to the rod/bearing. All in all I'm calling it quits with the motor. I have a motor with similar mileage from a wreck on the way. Thanks again!
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Tuesday, November 29th, 2011 AT 10:27 PM
Tiny
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That's the right thing to do. The big issue is that all those sharp edges it created will superheat and melt under compression and lead to failure, not to mention unseen cracks.
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Tuesday, November 29th, 2011 AT 10:32 PM

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