Flywheel bolts reuse
10-06-2006, 01:53 PM
#1
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Flywheel bolts reuse
Looking at a 996, wrench had flywheel off for turning as put of clutch job ( thought you couldn't turn a dual mass) and reinstalled with original bolts. Other P cars require new bolts. He said AllData shows OK to reuse and torque properly. Fact or Fiction? Good news was he said RMS looked good and was dry. Any info appreciated.
10-06-2006, 07:36 PM
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Originally Posted by alan911sc
Looking at a 996, wrench had flywheel off for turning as put of clutch job ( thought you couldn't turn a dual mass) and reinstalled with original bolts. Other P cars require new bolts. He said AllData shows OK to reuse and torque properly. Fact or Fiction? Good news was he said RMS looked good and was dry. Any info appreciated.
DMFs can only be machined using a proper surface grinder. They cannot be turned in a lathe. This is precise work and turning a DMF in a lathe is strictly verboten. This work is for a specialist machine shop which should be in possession of the correct machining figures and tolerances. It is very easy to unbalance the front section of the DMF which results in vibrations, squeals and damage to the engine and clutch assembly.
Porsche once included these warnings in the DMF section of the manual, but for the 996, disassembly, repair and assembly procedures for the DMF are no longer included as they were for the 964 and 993.
If the flywheel mounting bolts are not stretched or overtorqued I suppose you could reuse them. Having had these bolts fatigue and fail on me in the past I replace them. The cost is small.
Sadly again Porsche do not provide such guidance anymore in their manuals as they used to. Once they included the measurements for the bolts to be able to check if they still within tolerance. Based simply on this lack of information and not being able to check them against a known standard I would replace them if I were doing the job.
Ciao,
Adrian.
10-06-2006, 08:10 PM
#7
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Originally Posted by Adrian
Alan,
DMFs can only be machined using a proper surface grinder. They cannot be turned in a lathe. This is precise work and turning a DMF in a lathe is strictly verboten. This work is for a specialist machine shop which should be in possession of the correct machining figures and tolerances. It is very easy to unbalance the front section of the DMF which results in vibrations, squeals and damage to the engine and clutch assembly.
Porsche once included these warnings in the DMF section of the manual, but for the 996, disassembly, repair and assembly procedures for the DMF are no longer included as they were for the 964 and 993.
If the flywheel mounting bolts are not stretched or overtorqued I suppose you could reuse them. Having had these bolts fatigue and fail on me in the past I replace them. The cost is small.
Sadly again Porsche do not provide such guidance anymore in their manuals as they used to. Once they included the measurements for the bolts to be able to check if they still within tolerance. Based simply on this lack of information and not being able to check them against a known standard I would replace them if I were doing the job.
Ciao,
Adrian.
DMFs can only be machined using a proper surface grinder. They cannot be turned in a lathe. This is precise work and turning a DMF in a lathe is strictly verboten. This work is for a specialist machine shop which should be in possession of the correct machining figures and tolerances. It is very easy to unbalance the front section of the DMF which results in vibrations, squeals and damage to the engine and clutch assembly.
Porsche once included these warnings in the DMF section of the manual, but for the 996, disassembly, repair and assembly procedures for the DMF are no longer included as they were for the 964 and 993.
If the flywheel mounting bolts are not stretched or overtorqued I suppose you could reuse them. Having had these bolts fatigue and fail on me in the past I replace them. The cost is small.
Sadly again Porsche do not provide such guidance anymore in their manuals as they used to. Once they included the measurements for the bolts to be able to check if they still within tolerance. Based simply on this lack of information and not being able to check them against a known standard I would replace them if I were doing the job.
Ciao,
Adrian.
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10-06-2006, 08:32 PM
#8
Well actually the flywheel is very much more than hand tight. 18ft lbs + 120 deg, which is darn good n tight last time i put one on. As for the bolts, they are micro-encapsulated from porsche. Which basicly means that they come coated with a type of tread locker. Instructions per porsche are to replace them! I have seen them be re-used with no problems. However that was before porsche sent out the suplement raising the angle torque from 90deg to 120deg. I say why take a chance.
06-04-2007, 05:17 PM
#10
Flywheel bolts are inexpensive compared to the chaos and additional labor $ if they are stretched and reinstalled. Not on a P-car, but I have seen the flywheel and pressure plate bolts visibly stretched on my Hondas once removed.
Each their own but on my cars, I'll spend the few extra bucks on critical parts.
Each their own but on my cars, I'll spend the few extra bucks on critical parts.
