Torque sequence G13B

Hi everybody!

what is the meaning of “a” in the picture, ad why do you start the torqing sequence with bolt #2? In the last torqing sequence instead of #1 

Well it's not black magic!
(a) because it's the first letter of the alphabet and start at no.2 because, well why not? You start in the middle with one bolt and tighten it but not fully. You move across and ditto then opposite and so on. The idea is to tighten evenly and gently. In the factory all bolts are tightened to full torque at the same time. Why the start at no.2? why not - shrug of the shoulders at that point!

Roger

haha I never knew this, just did them evenly from my own pattern. Just knew the torque. 20 years ago the manuals wasn't to be found online just yet.

I might have missed something here but the manual says ‘numerical’ order so shouldn’t bolt number 1 be the first? I couldn’t see the relevance of the mark (a), but didn’t check all of the pages either side.

Anytime I have a casting that needs torquing down, I always do it in stages, run the bolts in hand tight first, then just nip up to seat the gasket. Then torque to 2 or 3 intermediate torque settings. After the final torque go round twice, or possibly with 1nm more just to make sure they are all the same. It takes a bit longer, but much less time than stripping and rebuilding if something goes wrong.

If you don’t do it in stages you stand a chance of it not sitting flat and then possibly warping the head.

In the absence of a torque pattern always start in the middle and work your way out diagonally.

Robin