Broken timing chain...
#16
Firstly sorry to hear of your pain i know what your going through,this happened to my car a couple of years ago whilst in germany on the nordschleife.
A friend of mine who lives there took me to manthey racing to speak to Olaf Manthey when i hadn't diagnosed the problem. He told me he had seen it many times before on road cars and race cars. Apparantly a fast spin on track can cause this in the following way, if your travelling at reasonably high speed and have a moment and the car goes into a spin and you don't engage the clutch straight away the force of the spin can cause the wheels to go from turning forward to backward very quickly which in turn can highly stress the chains in the process. Olaf said on race cars with slicks this has been know to snap chains instantly, and also this can stress the chains enough to cause weakness then a failure at a later date.Makes sense if you think about the forces it would be under in this kind of situation.
hope the explanation was clear and you understand what i mean.
The 9k over rev obviously won't help but i wouldn't have thought this as a one off would be a problem given the cars low mileage still.
Has the car been used on track that you know of.
A friend of mine who lives there took me to manthey racing to speak to Olaf Manthey when i hadn't diagnosed the problem. He told me he had seen it many times before on road cars and race cars. Apparantly a fast spin on track can cause this in the following way, if your travelling at reasonably high speed and have a moment and the car goes into a spin and you don't engage the clutch straight away the force of the spin can cause the wheels to go from turning forward to backward very quickly which in turn can highly stress the chains in the process. Olaf said on race cars with slicks this has been know to snap chains instantly, and also this can stress the chains enough to cause weakness then a failure at a later date.Makes sense if you think about the forces it would be under in this kind of situation.
hope the explanation was clear and you understand what i mean.
The 9k over rev obviously won't help but i wouldn't have thought this as a one off would be a problem given the cars low mileage still.
Has the car been used on track that you know of.
#17
For sure I can see that being a problem as the chians are only designed to run in one direction. X50 and the gt2 do not have the gt3 rsr pump in them. I would think about the 997.1 TT intake manifolds. You will need new fuel rails and have them tap the secondary air port in the exhaust valve bowl and plug them. Of course the hard pipe to the inlet of the turbos. Boattail the cases will free up some power also. As for the valve guides, the 997tt guides are about a 1/4 shorter then the 996tt ones. one of the reason the 997 motor flows more. Stud the heads is a no brainier.
#19
I'd have to throw out the BS flag on the 9K rpm story the dealer fed you. On the 996tt, the ECU only records Range 1 (rev limiter) and Range 2 (beyond rev limiter). However, there is NO recording of how far past the limiter the engine was over-reved. The 997tt rectified this with additional Ranges recorded by the ECU.....
#20
I'd have to throw out the BS flag on the 9K rpm story the dealer fed you. On the 996tt, the ECU only records Range 1 (rev limiter) and Range 2 (beyond rev limiter). However, there is NO recording of how far past the limiter the engine was over-reved. The 997tt rectified this with additional Ranges recorded by the ECU.....
In response to the previous guys question, the only way I can figure one of these engines could rev that high would be on a "spirited" shift meant for 3rd or 4th gear that ended up in 1st or 2nd respectively? It is my understanding that the rev limiter will kick in on the up-shift, but not the accidental down-shift? I'm just guessing though as I really don't know for sure.
#21
I stopped by the shop for a few minutes last evening... There were some very small traces of metal (looked like little splinters) in between some of the filter "flaps"... They weren't in every single one though. By no means "caked" in there like you see on a grenaded engine. I've not yet seen the oil pump, but I'm assuming it's not in horrible shape as well?
It really looks like I "lucked out" with this failure. On more than one occasion I've seen where the broken chain will get wrapped around the IMS sprockets and very quickly seize the motor up. It would seem that my cam broke just before the IMS and ended up mostly towards the cam side of the motor... so there was no violently spinning chain destroying the inside of my case and all of the components within... I guess you would call that "luck" in a funky kind of way.
I'm hoping my builder will crack the case today so I can be fully aware of the rest of the damage - if any. We are both thinking that the rest of the motor will be fine - save for some trace metal shavings throughout.
Thoughts anyone?
It really looks like I "lucked out" with this failure. On more than one occasion I've seen where the broken chain will get wrapped around the IMS sprockets and very quickly seize the motor up. It would seem that my cam broke just before the IMS and ended up mostly towards the cam side of the motor... so there was no violently spinning chain destroying the inside of my case and all of the components within... I guess you would call that "luck" in a funky kind of way.
I'm hoping my builder will crack the case today so I can be fully aware of the rest of the damage - if any. We are both thinking that the rest of the motor will be fine - save for some trace metal shavings throughout.
Thoughts anyone?
#22
And I have no reason to believe that the car has ever been tracked. From what I was told it was babied almost all of it's life. And the same service advisor had serviced it since 2003. Who really knows though at this point...
#25
Good luck, Justin. Hopefully everything else looks good ands it's an easy re-build.
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991.2 GT3 RS Weissach Racing Yellow
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991.2 GT3 Chalk (Manual)
2022 Cayenne White
former 1972 911T white, 1984 911 3.2 Targa black, 993 cab white, 993TT arena red, 993TT silver, 996TT speed yellow, 991.1 GT3 white
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991.2 GT3 RS Weissach Racing Yellow
991.2 Turbo S GT Silver
991.2 GT3 Chalk (Manual)
2022 Cayenne White
former 1972 911T white, 1984 911 3.2 Targa black, 993 cab white, 993TT arena red, 993TT silver, 996TT speed yellow, 991.1 GT3 white
www.speedtechexhausts.com
info@speedtechexhausts.com
Testimonials facebook SpeedTech Exhaust Videos
#28
Sorry to hear about all your troubles. I read through all of your previous post trying to diagnose and this post. On the plus side, once all this is done you are going to have a better than brand new engine capable of a lot of HP. Keep us apdated on the build.
#29
What a bummer, Been reading your previous post.
Nothing more I can say because everyone else has expressed what I feel
My motor will be coming out soon for a Tip upgrade ( MKB ) so I'm having large hard pipe intake as well. Also coolant pipes changed and cam solenoid valves and sensors checked ( brackets can snap).The aux air pump and all rubber hoses associated with it to be removed.
keep updating as you go along.
Sadly for you but a very interesting post for the rest of us.
Frank
Nothing more I can say because everyone else has expressed what I feel
My motor will be coming out soon for a Tip upgrade ( MKB ) so I'm having large hard pipe intake as well. Also coolant pipes changed and cam solenoid valves and sensors checked ( brackets can snap).The aux air pump and all rubber hoses associated with it to be removed.
keep updating as you go along.
Sadly for you but a very interesting post for the rest of us.
Frank
#30
Que Sera Sera...
Thanks for the condolences... I've always been an avid believer in 'if it's meant to be, it will...' so this whole ordeal was obviously in my cards. Might as well play with the cards I'm dealt...
So, you're the 2nd person to suggest I remove the secondary air pump... I don't know much about this process. It is obviously a performance based mod (or delete), but my concern would be emissions... will I have a problem passing them after the fact?
So, you're the 2nd person to suggest I remove the secondary air pump... I don't know much about this process. It is obviously a performance based mod (or delete), but my concern would be emissions... will I have a problem passing them after the fact?