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Post by RustyJusty on Jul 26, 2004 15:41:12 GMT -5
A really loud clicking/knocking sound?
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Post by JLantz on Aug 4, 2004 1:29:10 GMT -5
From what I've gathered and experienced, initial Rod bearing failure will be most pronounced at start up, after the engine has sat for enough time for it to cool. It will make a knocking noise and then disapear when oil pressure has established, as the oil will take up the excessive clearance, or at least, dampen it.
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DBA
I'm going to rallye with a Justy
Posts: 121
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Post by DBA on Aug 4, 2004 5:36:39 GMT -5
Really loud knocking could mean that your bearings are as bad as mine were. One piston was hitting the head constantly, which made the loud knocking. The engine won't last really long if it's that bad.
Greetings, Klaus
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Post by SUBIEJIM on Aug 4, 2004 17:04:41 GMT -5
A sharp rapping noise down low in the crankcase. Rod knocks are always load sensitive and are typically caused by excessive oil clearences between the bearing and journal. Low oil pressure at idle is a telltail sign of bearing wear. Usually, rod knocks will decrease in severity and pitch as rpm increases....This happens because the oil pump puts out more pressure as rpm increases, the extra pressure causes the oil to pump into the space between the bearing and journal faster than it is leaking out....So knock decreases (Provided that the 2 rod bearing shells have not welded themselves to the crankshaft rod journal and spun inside one another!) this will cause a severe knock at all rpm ranges. To isolate which cyl has the knock one try this; With the engine running at idle disconnect the number 1 spark plug wire from the spark plug and short it to ground (the exhaust manifold heat shield will do) you will notice an rpm drop and if # 1 is the bad rod the knock will almost go away. If no change in knock than that cyl is probably Ok, provided bearing is not spun as described earlier. Reconnect the sparkplug wire and do the same for the other cyls. NOTE: Use insulated plyers to remove and install sparkplug wires to prevent possibility of electrical shock! Hope this helps, Jim
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