Torqueing the head down

[CJHenderson]

The instruction sheet that came with the head gasket said to torque to 70 Nm cold which equates to Approx. 53 FT Lbs. but the Haynes puts it at 100Nm/70FT Lbs. which is right?

[Pawel66]

A very detailed description of the process you will find in our Tech Manual. That is what I followed.

[mrfatboy]

Here is Metric Motors documentation. May or may not be the same in the tech manual.

[ja17]

Yes, I have seen this information. Not sure how relevant it is since it calls for a torque angle of rotation on the last pass. Torque angle of rotation is normally used with "stretch type" head bolts. M130 engines in Pagodas never used "stretch type" head bolts and no angle of rotation spec. is relevant or specified, with the original head bolts.  With stretch type head bolts, it is recommended that they be replaced after every use since they are meant to stretch and may permanently deform. Since the original head bolts are not stretch type, replacement after each use is not required. Stretch type bolts along with new improved gasket materials, were used in more modern engines and were believed to eliminate the need of re-torqueing the head. Considering the tendency with modern MB engines to have leaky head gaskets, I'm not sure how well stretch bolts really work. I have chosen to follow the original Tech Manual and BBB manual procedure without problems. This is an interesting point of discussion and conjecture.

[CJHenderson]

That's the instructions that I followed. I did skip the first torque setting of 40Nm since the head and gasket had been setting on the block for a week with the bolts just snugged down before we could get back to it due to my job. On page 18 of the Haynes book under 280SL it shows only final torque setting but does not give the interim torque settings just there where several settings without specific torques.