valve spring problem

1998 BUICK CENTURY
177,000 MILES • 3.1L • V6 • 2WD • AUTOMATIC
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MIKE LUCKEY
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Hi, my car started misfiring and shut off. I checked for spark, all good. so I checked compression, had three cylinders around 180, two cylinders 120 and one (number six) with 0. Thinking possible broken valve spring. just wondering with the compression being so different, should I even bother fooling around with it. any help would be appreciated, thank you!
Mar 23, 2018 at 7:51 AM
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PATENTED_REPAIR_PRO
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Yes, I would go ahead and remove the valve cover and see if anything is obvious.
Mar 23, 2018 at 7:55 AM
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MIKE LUCKEY
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I sure will, just wondering, if the compression is so different on the other cylinders is the engine even worth working on? Btw, the compression test was done on a cold engine, because it wouldn't start. thank you, Mike.
Mar 23, 2018 at 11:12 AM
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PATENTED_REPAIR_PRO
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I would not commit to any work just yet, just diagnosis. You might also consider a cylinder leakdown test on the cylinders that were low to determine where the loss of compression is coming from.
Mar 23, 2018 at 11:27 AM
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MIKE LUCKEY
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Okay, so I pulled the valve cover and no apparent broken springs. I decided to turn the engine over with a wrench on the crank pulley. The rocker arms do not move! I am assuming this means a broken timing chain? It does not make any weird noise when it turns over though. Would it not sound pretty bad if a timing chain were broken in there? Also, is it an interference engine? Could I have bent valves too?
Mar 23, 2018 at 6:41 PM
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PATENTED_REPAIR_PRO
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I am wondering how you got any compression readings at all if the timing chain was broken.
Did you remove both valve covers and check the other side, too?
I do not think the 3.1 is a interference engine.
I assume you could have landed on a cylinder that had both valves closed when doing the compression test.
I am getting conflicting results on whether or not it is an interference engine. I have always thought the interference engines could only be ones with a timing belt, but I could be wrong.
Mar 24, 2018 at 7:44 AM