Flywheel bolts for 996

[bjersr]

So I don't want to start a big argument, but want to know the truth. I just did a clutch job on my 03 996. Found after disassembly the pressure plate went bad. The actual clutch disk was worn but not too bad and the release bearing seemed fine as well. Because of the bad pressure plate the flywheel had significant discoloration on it so changed it as well. RMS was leaking so changed it also. It has a replacement engine due to a prior IMS bearing failure and had an 05 or later factory reman engine. The kind where the IMS bearing can't be replaced unless you disassemble the engine.

So here's the question. Are the flywheel bolts on the 996 torque to yield bolts? one time use kind of things. Yes I know it's a good idea to replace them. Yes I know the instructions on this site says always replace them. Yes I know it's cheap insurance. I have a PDF file factory service manual and it does not say you have to replace them. It does say in other areas when you must replace a particular bolt but not for the flywheel. Also it gave an actual torque value for the bolts themselves (63 ft/lbs)not the torque to 19 ft/lbs and then an additional 90 or 120 degrees. I ended up buying new factory bolts because I didn't want to wait for them to be shipped to me. I'm just wondering if anyone actually knows if they are TYB (torque to yield bolts) or not. From my research most torque to yield fasteners are undercut in the shank portion, these bolts are not. I asked the parts counter guy at the dealership and he did not know. If and when I do the job again I will probably change them again, but I was just wondering if they were TYB or not.

[JFP in PA]

Originally Posted by bjersr

So I don't want to start a big argument, but want to know the truth. I just did a clutch job on my 03 996. Found after disassembly the pressure plate went bad. The actual clutch disk was worn but not too bad and the release bearing seemed fine as well. Because of the bad pressure plate the flywheel had significant discoloration on it so changed it as well. RMS was leaking so changed it also. It has a replacement engine due to a prior IMS bearing failure and had an 05 or later factory reman engine. The kind where the IMS bearing can't be replaced unless you disassemble the engine.

So here's the question. Are the flywheel bolts on the 996 torque to yield bolts? one time use kind of things. Yes I know it's a good idea to replace them. Yes I know the instructions on this site says always replace them. Yes I know it's cheap insurance. I have a PDF file factory service manual and it does not say you have to replace them. It does say in other areas when you must replace a particular bolt but not for the flywheel. Also it gave an actual torque value for the bolts themselves (63 ft/lbs)not the torque to 19 ft/lbs and then an additional 90 or 120 degrees. I ended up buying new factory bolts because I didn't want to wait for them to be shipped to me. I'm just wondering if anyone actually knows if they are TYB (torque to yield bolts) or not. From my research most torque to yield fasteners are undercut in the shank portion, these bolts are not. I asked the parts counter guy at the dealership and he did not know. If and when I do the job again I will probably change them again, but I was just wondering if they were TYB or not.

Yes, they are torque to yield bolts, and should NEVER be reused. In fact, none of the pressure plate or flywheel bolts should be reused due to the loads on them. And the correct torque on the flywheel bolts are 19 ft. lbs. plus 120 degrees. If anyone reused the bolts, I would tell them seriously consider taking it apart again and doing it correctly. Very risky...………..

You could also prep the engine as though you were doing an IMS (locked at TDC, cams locked, tensioners removed) and then pry out the rear seal on the oversized IMS bearing, which would give it continuous lubrication.

Both of the above are cheap insurance, and should be done on any car that is apart.

[bjersr]

I stated in the very first sentence that I did't want to start an argument, and I find you quoting my post slightly antagonistic.

Where are you getting your information from as far as the bolts are actually TYB? Is it from a manual? If so what manual? Where are you getting your torque values? is this from a manual also? I got the torque values directly from a factory service manual that's over 2000 pages long.

[JFP in PA]

Originally Posted by bjersr

I stated in the very first sentence that I did't want to start an argument, and I find you quoting my post slightly antagonistic.

Where are you getting your information from as far as the bolts are actually TYB? Is it from a manual? If so what manual? Where are you getting your torque values? is this from a manual also? I got the torque values directly from a factory service manual that's over 2000 pages long.

My shop owns the 16 volume set Porsche published for the 996, and we have all of the Boxster manuals as well, and the over 100 updates and addendums:



That is where the information came from, and it has been confirmed by the online system Porsche switched to in 2004 (PIWIS TSI).

I cannot account for what your PDF file says, as Porsche never published information in that format, or on disc.

Oh, and just for your information, the 63 ft. lb. flywheel torque spec is for 993 air cooled engines, not the water cooled 996.

[JTT]

Originally Posted by bjersr

I stated in the very first sentence that I did't want to start an argument, and I find you quoting my post slightly antagonistic.

Where are you getting your information from as far as the bolts are actually TYB? Is it from a manual? If so what manual? Where are you getting your torque values? is this from a manual also? I got the torque values directly from a factory service manual that's over 2000 pages long.

I've got no skin in the game, but recognizing you are relatively new around here, I can assure you that JFP is extremely knowledgeable and experienced with these cars and is exceptionally helpful to all, without being argumentative or condescending. If you read "tone" into his message, I can assure you that you were mistaken.

[bjersr]

Originally Posted by JFP in PA

My shop owns the 16 volume set Porsche published for the 996, and we have all of the Boxster manuals as well, and the over 100 updates and addendums:



That is where the information came from, and it has been confirmed by the online system Porsche switched to in 2004 (PIWIS TSI).

I cannot account for what your PDF file says, as Porsche never published information in that format, or on disc.

Oh, and just for your information, the 63 ft. lb. flywheel torque spec is for 993 air cooled engines, not the water cooled 996.

Can you show me where it says the bolts have to be replaced? Or they are TYB? There are lots of people who say thing are this way and that way. You may be very well informed and you may be 100% correct. But I have this obsession to know if things are backed up by some reference or are they long standing beliefs. I trust what I can read not anyone's opinion or beliefs. I've worked on cars my 30+ years and while i'm new to the Porsche world I'm not new to cars. Frame off restorations, dozens of engine rebuilds, transmission rebuilds, transfer cases etc. The whole point of this post was to find an actual verifiable source like a factory service manual. No one is under any obligation to provide this information this is an open forum, but someones word is not what I'm looking for.

I wouldn't say 4 years is new either.

[yelcab1]

Originally Posted by bjersr

Can you show me where it says the bolts have to be replaced? Or they are TYB? There are lots of people who say thing are this way and that way. You may be very well informed and you may be 100% correct. ...

I thought you said you did not want to start an argument?
For my own use, I replace the 996 flywheel bolts.

[JFP in PA]

Originally Posted by bjersr

Can you show me where it says the bolts have to be replaced? Or they are TYB? There are lots of people who say thing are this way and that way. You may be very well informed and you may be 100% correct. But I have this obsession to know if things are backed up by some reference or are they long standing beliefs. I trust what I can read not anyone's opinion or beliefs. I've worked on cars my 30+ years and while i'm new to the Porsche world I'm not new to cars. Frame off restorations, dozens of engine rebuilds, transmission rebuilds, transfer cases etc. The whole point of this post was to find an actual verifiable source like a factory service manual. No one is under any obligation to provide this information this is an open forum, but someones word is not what I'm looking for.

I wouldn't say 4 years is new either.

See the photo above, which (unlike your PDF file) is the actual factory service manual; that's were it came from, as well as Porsche's online system.

As for publishing it here, this website, like many others, have rules about not reproducing copyright protected intellectual property as Porsche is utterly draconian about reproducing their materials, and takes that out legally on the site holders.

And as YOU seem to be the antagonistic in this discussion and all but calling me a liar for trying to correct your obvious ignorance on the subject, you can either go out and try and buy the 16 volume set, if you can find one (originally sold for around $2500) or buy a subscription to the PIWIS TSI system (around $5,000 per year) to fulfil your curiosity.

I, meanwhile, am done with both you and this conversation.

[bjersr]

I asked a question. Specifically are these TYB. Because they don't look like other factory TYB, and how do you know? Because I don't want to take someones word for it. What is so wrong with wanting to know for sure.

JFP in PA you seem to take offence because I just won't take your word for it. That's exactly what I said I did not want from the very beginning. I'm looking for something very specific if you can't provide that then you should not have commented on it. I'm not calling you a liar I just want you to back up what you say. You showed me a picture of some grey notebooks you can't even read what is on their spine.

[JFP in PA]

Originally Posted by bjersr

I asked a question. Specifically are these TYB. Because they don't look like other factory TYB, and how do you know? Because I don't want to take someones word for it. What is so wrong with wanting to know for sure.

JFP in PA you seem to take offence because I just won't take your word for it. That's exactly what I said I did not want from the very beginning. I'm looking for something very specific if you can't provide that then you should not have commented on it. I'm not calling you a liar I just want you to back up what you say. You showed me a picture of some grey notebooks you can't even read what is on their spine.

The information you deny exist can be found in the real factory service manual (not the PDF version that does not recognize the difference between air cooled and water cooled cars), in Group 3, Volume 1, Section 30-3, page 2, towards the bottom.

Happy hunting...…………………………………...