F355 Con rod bolt torque value Help.

I'd be guessing what it means. Not good in such circumstance.

Hopefully someone will be along shortly with correct interpretation. Good luck.

 

With certainty, I can state that:

precarico = preload

and that in F documentation they seem to use what we (in the US) would call a "division" symbol to mean "to" (i.e., they are giving a torque range of 55 to 70 Nm -- meaning that the real "spec" is based on the total angle of the nut rotation on page B55, and, when you do that action, the sanity check is that the torque applied to meet that total angle should be in that 55 to 70 Nm range).

I don't like that they don't mention any preloading step on page B55, but putting the two together, I'd say that the WSM documentation says:

1. wash and lube the threads with special lubricant.
2. preload each nut to 15 Nm.
3. then turn each nut an additional total angle of 60 degrees (and do this in two alternating steps of 30 degrees each).
4. to reach the total angle of 60 deg (from the preload state), the final torque should be in the 55 to 70 Nm range; if otherwise, you should be worried that something else is wrong.

JMO...

 

Steve is one of the guys I would use to verify somebody else's opinion.
Second opinion....Steve's correct.

 

Just a footnote to what your dealing with.....Torque-to-yield fastener - Wikipedia, the free encyclopedia

 

I would go to Steve Magnussen for his opinion, and stop there. No need to go any further.

 

I have a 1994 manual. Steve's interpretation looks fine. My Torque summary table for Conn. Rod , page B86 states, thread size 10 x 1 (mm) torque 65 Nm. FYI - Mains cap's size 12 x 1.5 (mm) and torque of 88Nm. Hope this helps, all the best with the build.

 

The later manuals don't say 65nm, because that is not the correct method of tightening the rod bolts anymore. Read the shop manual, read Steve's post and read about torque to yield fasteners like Turbopanzer suggested.

You clean and lube the bolts
Preload torque them to 15nm
Then angle torque them to 60 Degrees (which can be done in 2 steps of 30 degrees)
The final torque value should be between 55-70nm.

Torque to yield fasteners have been around for a while, and have a more precise clamping force.

They also have a limited life. Some manufacturers recommend replacement after one use, some after three uses. Rod bolts are something that you should not mess around with, unless you like big holes in the side of your engine block.

 

Haha LOL.

 

Normally I don't say anything because anybody's opinion/thought/experience usually covers mine. This though gets a response. Motob answered your post within 36 hours after you posted your initial query so 'days' is a bit of a stretch. Second if I were to compare posts, yours seems the hostile one. Third, if you reread his post, you can see that he actually added something that the others didn't.
Actually never mind all that. This is why I wrote this. Motob works at what could be called the Ferrari of Ferrari shops. He is one of the few people that when he writes, I read and reread over again to let whatever he wrote sink in. We need 1000 of him before we need one of you. Unfortunately we have only a handful of him and a lot more of you. Have some respect for the contributors on this board who really do make a difference. You're still too new here to understand that enough of you have chased away truly great mechanics who used to post here offering sound advice and perspective and history.

 

Bad form!