When bore scoring isn't (997.2 bore scoring fear)
#61
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I believe the proper term is that cold weather is a ‘contributing factor.’
And I don’t think we know for sure if the method of bringing up to temp has been finalized and solidified, although I agree that it’s highly suspect and well documented. More scientific testing would need to be done here to prove it completely.
And I don’t think we know for sure if the method of bringing up to temp has been finalized and solidified, although I agree that it’s highly suspect and well documented. More scientific testing would need to be done here to prove it completely.
AFAIK - there is a general consensus that engines need to be warmed up under load and that any aggressive accelerations shouldn't occur until the engine components have reached what might be called a thermodynamic homeostasis or equilibrium. This might take up to 20 minutes depending on the ambient temperatures.
Additionally, with DFIs, there is a tendency of excess fuel to wash the cylinder walls of lubricant with unburnt fuel accumulating during long idle periods. This would be a situation where one wouldn't want to do a hard acceleration after sitting in the McDonalds drive thru or some of the exceptionally long lights that can be encountered during rush hours. I know of several that take up to 10 minutes to get through because the programming is poor for the actual traffic loads E-W and N-S.
Jake and other engine experts could probably list 100 other mechanical failures or weaknesses that can be factors in kabooming an engine. Sometimes it just might be bad luck.
When we were at the P factory my buddy was paying real close attention to the engine assembly line where there were several duplicate stations putting engine components together. He noted that one worker used almost all of the three minutes to lube the part thoroughly before installing it while the worker in the adjacent station just dabbed the grease on and slapped the component into place in about 1/6th of the time. My friend observed this 4 times in a row. All else being equal, I know which engine I'd want in my car.
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RacerWannabe (07-21-2019)
#62
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Good points all. Just says "1 month or 1,000 mile, bumper-to-bumper warranty". No exclusions listed. I told the seller already that I dropped off the car on Wednesday to be inspected for the cause of the knocking sound.
#63
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Yes, I think you will be good if you stand your ground. Fingers crossed it's good but if not and the warranty company they use kicks it, they should take care of it.
#65
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#66
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My 09 C4S with 23K miles has that ticking noise as well. I think it's normal. I will check tonight to see if that thumping noise is normal or not.
#67
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I think, and any RL’ers feel free to chime in here, that we’ve agreed that yes, the ticks are normal. The knocking/slapping sound isn’t..
#68
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Originally Posted by RacerWannabe
I think, and any RL’ers feel free to chime in here, that we’ve agreed that yes, the ticks are normal. The knocking/slapping sound isn’t..
#69
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When we were at the P factory my buddy was paying real close attention to the engine assembly line where there were several duplicate stations putting engine components together. He noted that one worker used almost all of the three minutes to lube the part thoroughly before installing it while the worker in the adjacent station just dabbed the grease on and slapped the component into place in about 1/6th of the time. My friend observed this 4 times in a row. All else being equal, I know which engine I'd want in my car.
I believe Porsche allows as much as a quart every 600 miles as ok but also sets that as the limit for acceptable/normal oil consumption.
#70
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There are about 6 taps per second which indicates a tap every 2 revs at idle (720 rpm). I’d say this rules out bore scoring which would be every rev so double this frequency. It appears to be something running at cam shaft speed.
#71
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Doesn’t the piston slap against the bore on the ignition cycle (every 720 degrees)? Rod knock has a similar sound - it’s the same as the cam timing (720) because the ignition is what causes the rod to knock, but doesn’t always happen on the other revolution because there’s not as much pressure.
#72
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I drove it back from LA to KC and while it was losing power all the way (it really struggled in the Rockies) - it made it all the way to Topeka KS before finally giving up.
Yep - same sound.
#73
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Seems like it's taking an awfully long time to get some answers back on engine knocking?
Hope results lead to good news.
Hope results lead to good news.
#74
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It's a definite slap in the face. And it makes me sick because my very first Porsche was sold to me with a bum engine and I'm certain the seller knew it.
I drove it back from LA to KC and while it was losing power all the way (it really struggled in the Rockies) - it made it all the way to Topeka KS before finally giving up.
Yep - same sound.
I drove it back from LA to KC and while it was losing power all the way (it really struggled in the Rockies) - it made it all the way to Topeka KS before finally giving up.
Yep - same sound.
PPI would have found the engine noise in the current op's engine I believe. Hard to miss it.
I'm really hoping OP gets good news.
#75
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PPI performed. Was told engine performed and sounded normally. It does seem to perform normally, with a very slight misfire just off idle only. Can’t believe this was thought to sound ‘normal’