deliriousga

I am checking everything while I have the clutch out, and the flywheel bolts say they are torqued to "70+4". Does that mean they should all be torqued to 70 first then to 74 after that or is there some other meaning?

TIA!

IcemanG17

John
I think you have it right.....after they are all at 70 then go back and set them all at 74......seems kinda pointless....but I'm sure there is a reason?

deliriousga

Thanks Brian. I was thinking they do that with spinning parts to make sure they are aligned perfectly to prevent wobble. I'm guessing, but it seems like if you have 9 bolts on a spinning part and you tighten one to torque, then the part is a little crooked so the next bolt is not "really" to torque. The second set of a little higher torque would be done after the part is flattened out so all of the bolts would be at the actual torque value. Just a guess, but it seems logical.

Vilhuer

Either that or anything between 70 and 74 Nm and 70+4 is just different way of saying 72 +/- 2 Nm. In any case 74 is fine.

deliriousga

Sorry, I need to clarify, the manual is calling for 70+4 ft/lbs. Just didn't want anyone to think it was Nm and over-tighten their bolts.

Vilhuer

Good point John. 70 sounded so nice round number I automatically thought it was Nm. Many times ft/lbs is not rounded to 10 or 5 as original measurements are in Nm.

While at it, one more though about original question. WSM makes many assumptions about mechanics abilities and knowhow of good procedures. This meaning that many obvious things are left out. That it's good to mount flywheel straight could be one of them. Thus I think 72 +/- 2 ft/lbs is equally likely explanation as two stage torquing. Normally 1st stage would be much smaller than 2nd.

Bill Ball

If an item requires 2-stage torque, the manual says so. This is just an unfamiliar way to state a range.

Fogey1

Bill Ball wrote: "If an item requires 2-stage torque, the manual says so. This is just an unfamiliar way to state a range."

Or a typo that left out the "-"

I usually do at least a two-stage torque anyway.

Vilhuer

XX + Y Nm is used in several places in some old factory documents and WSM pages to describe range. Maybe factory typewriter didn't have easy way to make +/-.

mulik51

I don't think there would be really a point of having a two stage tighteting sequence, with first stage being 70 and second 74. As Erkka said, first stage is usually closer to being half of second stage. So, they are probably stating a range there...

Klim

Jim bailey - 928 International

Tech spec book printed 03/90 shows in Nm first stage 40 nm second 90 nm for flywheel bolt M10 x1.25