996 turbo loud chain rattle after engine rebuild
#16
06-24-2015, 02:33 AM
Hello to all Porsche fans!
it's been 2 years after engine rebuild and driving with the darn rattle.
I was driving my car about a week ago and suddenly the PSM light went on, then the CEL, then the engine shut down. I tried to restart it, it would rev, but wouldn't start. I had the car towed to my place, after that tried to start the engine several times again, and finally, it stopped turning, like it was stuck. I hooked up a Durametrics cable and it shows signal below limit, implausible signal on camshaft 1.
I took the car to the shop and the diagnosis is: the timing chain on bank 1 (that's on the left), broke, TADAaaa!!
And while the engine is being worked on now, I found some gruesome stories on the net of valves bent, chain being wrapped around the IMS, IMS breaking in half, crankshaft breaking and finally, engine case cracked!
I guess I won't get much sleep for a couple of days before the tech gets the engine completely torn apart...
it's been 2 years after engine rebuild and driving with the darn rattle.
I was driving my car about a week ago and suddenly the PSM light went on, then the CEL, then the engine shut down. I tried to restart it, it would rev, but wouldn't start. I had the car towed to my place, after that tried to start the engine several times again, and finally, it stopped turning, like it was stuck. I hooked up a Durametrics cable and it shows signal below limit, implausible signal on camshaft 1.
I took the car to the shop and the diagnosis is: the timing chain on bank 1 (that's on the left), broke, TADAaaa!!
And while the engine is being worked on now, I found some gruesome stories on the net of valves bent, chain being wrapped around the IMS, IMS breaking in half, crankshaft breaking and finally, engine case cracked!
I guess I won't get much sleep for a couple of days before the tech gets the engine completely torn apart...
Good luck with it and please keep us posted.
Cheers
Jim
good luck, really.
#20
06-25-2015, 01:57 AM
Hello to all Porsche fans!
it's been 2 years after engine rebuild and driving with the darn rattle.
I was driving my car about a week ago and suddenly the PSM light went on, then the CEL, then the engine shut down. I tried to restart it, it would rev, but wouldn't start. I had the car towed to my place, after that tried to start the engine several times again, and finally, it stopped turning, like it was stuck. I hooked up a Durametrics cable and it shows signal below limit, implausible signal on camshaft 1.
I took the car to the shop and the diagnosis is: the timing chain on bank 1 (that's on the left), broke, TADAaaa!!
And while the engine is being worked on now, I found some gruesome stories on the net of valves bent, chain being wrapped around the IMS, IMS breaking in half, crankshaft breaking and finally, engine case cracked!
I guess I won't get much sleep for a couple of days before the tech gets the engine completely torn apart...
it's been 2 years after engine rebuild and driving with the darn rattle.
I was driving my car about a week ago and suddenly the PSM light went on, then the CEL, then the engine shut down. I tried to restart it, it would rev, but wouldn't start. I had the car towed to my place, after that tried to start the engine several times again, and finally, it stopped turning, like it was stuck. I hooked up a Durametrics cable and it shows signal below limit, implausible signal on camshaft 1.
I took the car to the shop and the diagnosis is: the timing chain on bank 1 (that's on the left), broke, TADAaaa!!
And while the engine is being worked on now, I found some gruesome stories on the net of valves bent, chain being wrapped around the IMS, IMS breaking in half, crankshaft breaking and finally, engine case cracked!
I guess I won't get much sleep for a couple of days before the tech gets the engine completely torn apart...
#23
01-23-2016, 12:24 PM
Join Date: Jan 2012
Location: Russia, Moscow
Age: 49
Posts: 31
Rep Power: 14 
I guess I should have posted an update a while ago. Sorry for that. 
In fact, the reason is still a mystery. We replaced the chain tensioner (the one that has the 959xxxxxxxxx number and costs around EUR 320), both chains, all other parts resposible for chain tension, the IMS sprocket which had the broken chain on (it was loose, teeth bent and worn out), also the IMS had a crack and we had it restored professionally.
All these parts replaced, the rattle is gone. Funny thing, though, sometimes when engine is started cold, there's the same rattle for about 2 seconds, then it's gone. So, I guess it was the chain tensioner. However, I have no idea what's happened to it, the old tensioner looks 100% fine, no leaks, no nothing.
The tech also said he found a small piece of debris stuck inside an oil pump which, however, did not seem to affect its functionality. I personally think there might have been some debris stuck inside oil flow channels which prevented the tensioner from functioning. But I'm pretty sure it was bad chain tension (it's obvious from the sound).
In fact, the reason is still a mystery. We replaced the chain tensioner (the one that has the 959xxxxxxxxx number and costs around EUR 320), both chains, all other parts resposible for chain tension, the IMS sprocket which had the broken chain on (it was loose, teeth bent and worn out), also the IMS had a crack and we had it restored professionally.
All these parts replaced, the rattle is gone. Funny thing, though, sometimes when engine is started cold, there's the same rattle for about 2 seconds, then it's gone. So, I guess it was the chain tensioner. However, I have no idea what's happened to it, the old tensioner looks 100% fine, no leaks, no nothing.
The tech also said he found a small piece of debris stuck inside an oil pump which, however, did not seem to affect its functionality. I personally think there might have been some debris stuck inside oil flow channels which prevented the tensioner from functioning. But I'm pretty sure it was bad chain tension (it's obvious from the sound).
Last edited by AngelOfGrief; 01-23-2016 at 12:35 PM.
#27
01-23-2016, 07:24 PM
Ah yes just noticed it, thank you.
OP glad its all back together and running well.
OP glad its all back together and running well.
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