Torque Settings

[Monty]

Folks,

I am thumbing through the BMW repair manual for the bumble and checking the torque settings for various bolts. It looks like a load of torque settings were changed in 1991 when the revised models were released. I am not sure whether to use the earlier or later torque settings on my 1988 bike?

In other words, are things like the engine mount bolts, shock mount bolts, frame bolts etc any different on the later bikes to justify the different settings? I have some previous experience of BMW updating or modifying settings during or after production of a model, so not sure what is best.

The difference on the shock mounts is from 29 to 47 Nm, and that is too big a difference for me just to ignore.

Yours paranoid and geeky,

Matt

 

[Steve the Kiwi]

Torque Settings are for girls...use a power bar until you hear it crack and then back it off a 1/4 turn...

 

[(RIP) Proff]

IIRC the changes in Torque settings were mainly on the engine.
It was to stop the amount of crankcase threads stripping and letting the studs go
Mainly due to them changing from a premium Aluminium Alloy to
Monkey metal You would not believe how many were changed under warranty after 6000 miles service after head were pulled down to correct [pre monkey metal lb/feet ] torque....
At WBC we used to "explain" that there was an update needed and yes you could use our R100 rs loan bike for as long as it takes .
Then onto Bracknell to order new set of crankcases to be retro stamped with correct numbers, old crankcases to be destroyed and portion with engine number on to be returned to Bracknell to confirm destruction...
Funny tho' It was NEVER made public
Shortly after this debacle, revised torque sheet was issued

pre 89 engine crankcases are far superior in metal quality

 

[Monty]

That may explain some of the changes, but some of the values for frame fasteners, shock mounts etc are higher post 1991. Should I use the higher values? I can see no reason why not as the frame, shock mounts etc look identical, but I do not want to damage anything

 

[Paul Rochdale]

With a few exceptional fasteners such as in the engine and gearbox, I've never used a torque wrench. I know some people get obsessive about these things but it's been at least forty years since I stripped a thread. Can't say I've ever found a bolt has loosened off either. Just get used to the effort a spanner needs. I think the only nuts I put my foot on the spanner are the main axle nuts.

 

[VAL. H.]

That may explain some of the changes, but some of the values for frame fasteners, shock mounts etc are higher post 1991. Should I use the higher values? I can see no reason why not as the frame, shock mounts etc look identical, but I do not want to damage anything

Surly if you have an 88 bike you should use the 88 recommendations

Or have you got a 92 frame on your 88 bike or something????

My general rule is: Tight's tight, and too tight's fu****


Val.

 

[Monty]

Surly if you have an 88 bike you should use the 88 recommendations

Or have you got a 92 frame on your 88 bike or something????

My general rule is: Tight's tight, and too tight's fu****


Val.

I don't think it is quite that simple though. Sometimes settings are changed during a production run depending on feedback from dealers or further research. What I wanted a feel for is whether the altered settings ARE to do with it being a different frame, for example.

Are you actually aware of any difference in the frames or fasteners between 1988 and 1992 that would mean altered torque settings? I do not know if this is the case, and hence my post. I can just use the 1988 values, but if experience subsequently showed it better to use the revised values it would be a bit retarded just to blindly follow the original spec.

I have had this before, for example with the volume of fork oil in the 75/6. The recommended volume was changed by BMW years after the 75/6 ceased production, presumably for good reason. I am sure the earlier volume would be ok, but if there is a better one then it seems to make sense to use it?

Happy New Year.

Matt

 

[(RIP) Proff]

I don't think it is quite that simple though. Sometimes settings are changed during a production run depending on feedback from dealers or further research.

Happy New Year.

Matt

Thats what happened with the monkey metal crankcases

 

[Redboots]

I don't think it is quite that simple though.

Sounds like paranoia...

What you need is a set of Technical Service Bulletins... buggered if I knows where you would get them though and then all the wading through them for torque changes and then which chassis/engine they apply to... big job. I go with the manual for the model of bike plus any known oddities like the head bolts, (95 GS).

John