Small petrol engine - cylinder head bolt torque?

I'd check again. The bolts on my SD1 cylinder head are approx 3/8 and go into aluminium threads. 70 ft.lb.

A rule of thumb is using the correct ring spanner rather than socket set will give approx the right torque with a good pull. You couldn't achieve

They're 7/16" which is not even remotely "approx 3/8".

How come nobody appears to be able to read the units properly? in-lbs != ft.lb, it's a factor of 12 different.

(you're at least the third person to make this mistake on this thread, and I think the other two I've seen have indeed gone "D'oh" or some such equivalent).

snipped-for-privacy@davenoise.co.uk...

Thanks Clive - isn't that what caused one of the Mars landers to come a cropper ?!!

Rob

Err, 7/16 against 6/16ths on this sort of discussion? You're being picky again...

But in any case makes it all the more obvious the 140 lb.ft is nonsense.

Came late to the thread. However, in defence, the normal way to quote torque figures for this sort of app in the UK was lb.ft.

Mars Climate Orbiter, pounds force instead of newtons.

in-lbs.

Ian

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Rob G saying something like:

It was common enough here too, for values under 15~20ft/lbs, depending on the specifier's whims. Round about that kind of figure you'd be on a smaller torque wrench because the larger ones wouldn't be accurate enough.

I've never seem lb.in used for engine stuff though - although my experience is only really with older UK cars. Lb.in is used in auto boxes for some things - I've got a torque screwdriver specifically for this.

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Dave Plowman (News)" saying something like:

Hours of fun can be had when Haynes mis-appropriately use the wrong units (fairly obvious) or even just give the wrong figures in the right units (not so obvious, but explains why so many cam holders on older Suzukis are stripped), especially on alloy castings.