One for the tech heads

[craigieeb]

Hoping someone will know the answer to this..

30mn+90°+90°= what in nm?

Reason behind the question,
I'm installing a "cut ring" head gasket (m50) that requires no head or block modifications and also a set of ARP's

The tightening sequence is the same as standard,
I have just done the torque settings, but want to be 110% sure they are all absolutely spot on,
so want to set the torque ratchet to the answer of the question above, just to put my own mind at ease

[Grrrmachine]

Nm - Newton metres. It's what people not born in the Jurassic era use instead of ft/lb.

30Nm = 22ft/lb.

[Brianmoooore]

Nm - Newton metres. It's what people not born in the Jurassic era use instead of ft/lb.

30Nm = 22ft/lb.

But anyone can see what 22ft/lb means - pull with a force of 22lb on a socket and tee bar twelve inches long, 44lb on one six inches long, or 11lb on one two foot long, etc.
Same thing applies if the torque figure was given in Kg/m - easy to see exactly what it means, but Nm????; could mean anything.
There was a whole raft of these 'new' measurements introduced a few years back, supposedly honouring notable scientists, but in reality, just confusing things. Pressure measurements are another one. Pounds per square inch means exactly what it says on the tin, but Pascals????

[Partridge]

Isn't he asking how the rotation tightening equates to a torque setting? Answer is, it doesn't.

[craigieeb]

What I'm asking is,
what should the final torque value be at the end of the torque sequence.

in either ftlb or Nm, what ever people feel comfortable using

quite a simple question really

[DanThe]

There isn't one, thats why they tell you to do 2 90° turns

[gromgsxr]

http://arpinstructions.com/instructions/201-4302.pdf

tighten the nuts in three equal steps to 85 ft lbs
with ARP ULTRA-TORQUE FASTENER ASSEMBLY LUBRICANT

[stevesingo]

Nm - Newton metres. It's what people not born in the Jurassic era use instead of ft/lb.

30Nm = 22ft/lb.

But anyone can see what 22ft/lb means - pull with a force of 22lb on a socket and tee bar twelve inches long, 44lb on one six inches long, or 11lb on one two foot long, etc.
Same thing applies if the torque figure was given in Kg/m - easy to see exactly what it means, but Nm????; could mean anything.
There was a whole raft of these 'new' measurements introduced a few years back, supposedly honouring notable scientists, but in reality, just confusing things. Pressure measurements are another one. Pounds per square inch means exactly what it says on the tin, but Pascals????

Pound and a kilogram are both units of mass, so when tightening a fastner whick sits on a horizontal plane (wheel nut), then hanging a 100lb off a 1ft bar or a 10kg off a 1m bar will give you 100lb/ft or 10kg/m of torque.

If you are tightening a fastener in the vertical plane (head bolt), if you hang your 100lb off your 1ft lever or 10kg off your 1m lever the lever will fall off the bolt head.

That is why we use units of force which is the Newton. Because weight is the force of a mass being acted on by gravity. Force is force and is independent of gravity.

[maxfield]

http://www.ebay.co.uk/ulk/itm/201312733347

[gromgsxr]

The stock are torque to yield(stretch bolts) hence the turn through 90 twice, where as arp are not so are torqued to a specific torque setting.

[DanThe]

http://www.ebay.co.uk/ulk/itm/201312733347

If you need one of those to turn something 90 degrees you shouldn't be allowed near an engine!

[Brianmoooore]

http://www.ebay.co.uk/ulk/itm/201312733347

If you need one of those to turn something 90 degrees you shouldn't be allowed near an engine!

Exactly! After the initial torque, I draw a line on each bolt head with a permanent marker, then, after the two 90 degree turns, you can clearly see, at a glance, if they are all torqued correctly, and won't have that doubt that you've missed one of the steps on one of the bolts.

[DanThe]

My memory is still ok for tightening head bolts, I obviously have this to look forward to

[Brianmoooore]

You'll get there one day!

[motormanmick]

craigieeb,

as gromgsxr posted below, you need to fasten the head bolts to the spec in the link below, you are using after market ARP bolts not BMW genuine bolts which are tightened then 90 + 90 to stretch

http://arpinstructions.com/instructions/201-4302.pdf

tighten the nuts in three equal steps to 85 ft lbs
with ARP ULTRA-TORQUE FASTENER ASSEMBLY LUBRICANT

gromgsxr posted again

The stock are torque to yield(stretch bolts) hence the turn through 90 twice, where as arp are not so are torqued to a specific torque setting.

If you try to torque the ARP as you would BMW genuine head bolts you will either over tighten and snap them due to expansion when the engine warms up or under tighten and possibly blow the head gasket

Listen to gromgsxr he is correct.