LCGB Forums

Hi Guys

Can someone give me the Torque Settings for the engine bolt please. I have seen the figure as high as 50 Nm,

I am using BGM Mounts and Nyloc Nuts.

Thanks in advance.

torque setting ! just do it up as tight as you can using a decent socket bar

missing lynx wrote:torque setting ! just do it up as tight as you can using a decent socket bar

And then back it off a little, in my opinion. You want a little give although I suspect that relates to the size of the bar.

I think there is a preoccupation with torque setting or is because I've been working on Lambrettas for nearly 40 years and you get a feel for how tight something should be I only use a torque wrench on the rear hub

There's no published torque setting for the main engine stud nuts. Ideally the centre tubes in the mount need to pull in enough to compress the cones which grip on the bar and hold it solid. The rubber then flexes around that as the engine moves up and down with suspension travel.

missing lynx wrote:I think there is a preoccupation with torque setting or is because I've been working on Lambrettas for nearly 40 years and you get a feel for how tight something should be I only use a torque wrench on the rear hub

It's much better to be preoccupied with ensuring a certain level of cleanliness and general condition of the thread. A poor dirty thread will have a much different retention value than a good clean one with the same torque applied. The same applies to all taperlock fasteners like the flywheel and rear hub. A little care and experience here and you shouldn't need a torque wrench.

As so many have already pointed out, there are no official torque values for the engine pivot bolt & it is certainly one area that I personally have never used a torque wrench on.

Despite that fact, it’s not unreasonable to be able to apply something like an appropriate torque because many fasteners are designed to be stretched within their function. Too little, or too much, can cause a failure in certain areas & although most of us will be thinking ‘rear hub nut/layshaft’ (as it is the same thread) I have known the identical thread of the rear suspension mount studs to be stretched beyond the elastic limit by a heavy handed, well intentioned individual lending a hand. Not a good scenario @ a race meeting where the rear suspension can be off & on frequently simply to check the spark plug. Obviously, not everybody has a ‘feel’ for these things...

Based on GKN data for an M16 x 1.5 Grade 8.8 fastener, the torque recommendation is 27.3 kgf/m (197 lb/ft or 268 Nm) which is hardly surprisingly close to the rear hub nut torque figure.

I doubt that I ever apply that much torque to the rear suspension mount studs & reason that if I were to apply a known torque, I’d use that for a Grade 4.6 which is only 10.3 kgf/m (75 lb/ft or 101 Nm)

I hope that helps the OP

Ok thanks guys,

The reason I was looking for a figure is because as we all know everyone is stronger/weaker than the next person hence looking for a ball park figure!

Did not want to overtighten in case damage the BGM mounts by crushing, also not to lose so can cause damage that way!

Will tighten up as hard as I can and go with the ' feel of it' Torque.