e46 M3 torque spec thread-- every bolt on the car on diagrams

[sapote]

The torque spec for the transmission is questionable: It said M12 for the bolts holding the gear box to bell housing with the spec 76Nm or 56 ftlbs. This torque seems too high and can damage the bell housing. Where did this information come from?

[bavarian3]

I'm not sure if someone wants to verify this before adding to the PDF, but I think I found the torque values for the oil pump send and pickup tubes. I remember bimmerfan08 broke one of the M5 bolts trying to torque it to an approx. value. After cross-referencing the two bolts, I saw that these bolts are also used on the E36 and other E46 models.

According to the TIS for the E36 and E46, the M5x16 (number 6, pn 07129903041) is 5NM and the M6x16 (number 11, pn 07119904524) is 10NM.

S54 oil pump is on page 49.

The TIS seems to also state to wash and oil the replacement M10 rod bolts before installing.

Thank you for this. I was also a victim of busting one of the M5x16 bolts torquing it to 10nm. FCP actually recommends this in their video which is what I went with since I couldn't find a spec. Had to get it extracted, super fun.

[Nate047]

Thank you, is there a link we have for the TIS?

[Slideways]

Maybe this is a dumb question, but does this doc include, or is there another doc, that mentions which fasteners need to be torqued under load vs which ones can be torqued with the car off the ground?

One or two might be in the doc, but it is always good to check the online TIS for the full instructions which mention special procedures.

Anything with a rubber bushing, a metal sleeve and a bolt going through it needs to be torqued at ride height.

Rear lower shock mount bolt
Bolt that goes through RTAB
Upper rear spring perch bolt
Upper rear camber arm bolt

[Nate047]

Maybe this is a dumb question, but does this doc include, or is there another doc, that mentions which fasteners need to be torqued under load vs which ones can be torqued with the car off the ground?

[ac427]

This is a great work and i have been following the updates to the PDF since Flow made it.

I was wondering, could the pages be re-ordered though, to match the list as shown on RealOEM and the EDK ?

Then you could step through both without a lot of paging up and down to find the page in the PDF and the same on RealOEM ?

[heinzboehmer]

I'd prefer to leave the TIS value in but note it seems to be wrong.

Bentley says 45Nm without the angle torque which seems reasonable.

Fair enough! Looking at this again, I agree with you. Updated.

[Shonky]

I'd prefer to leave the TIS value in but note it seems to be wrong.

Bentley says 45Nm without the angle torque which seems reasonable.

[heinzboehmer]

Okay, so, the spec for the seat rails to chassis in the pdf aligns with what TIS says:




However, I'm fairly convinced that this is a typo in TIS (as evidenced by the three fasteners that I destroyed a couple weeks ago trying to stick to the spec). I dug through TIS and couldn't find a suitable alternative spec, so I'm just going to remove it from the doc and leave a note.

File in first post updated.

[chris.erdei]

OMG the PDF's in first post are gold !!!

[Feffman]

Thanks to Flow, back on M3forum:

Original Flow PDF: http://sawashie.free.fr/M3/TorqueSpe...SPECS%20LR.pdf
Updated PDF with suggestions from this thread: https://drive.google.com/file/d/1NMI...ew?usp=sharing

Thank you OH so very much!

Feff

[Shonky]

Do they perform tests to figure out how many lb/ft is too tight and what's too loose?

Some would largely be just based on fastener size and material and in that case the main thing is usually getting even and consistent clamping force across a number of fasteners like an oil pan or simply adequate clamping without stripping e.g. spark plugs.

There are lots where based on feel is just fine hence plenty of "clicks" from YouTube mechanics.

Very critical ones like head gaskets, big end bolts, main bearings etc are based on calculated clamping force. Torquing to specific torques results in fairly precise clamping forces. Torque to yield bolts where the bolt is in the elastic region provides even better consistency in the clamping forces generated.

[Seano666]

Do they perform tests to figure out how many lb/ft is too tight and what's too loose?

[Seano666]

Serious question, how does the factory figure out how tight fasteners should be torqued?

[JudahJD904]

thanks again to the author! this saved my biscuit today.