Thread: Torque setting method

It varies between manufacturers instructions A LOT. Some req an initial torque setting followed by up to 3 angle settings.(Td5) the Tdi has only 2 angle settings after initial torque setting. Some instuctions even include a 'rest' time, to allow the head bolts to 'normalise' during the torque down process.

I would say that maybe CAT require a 1/4 turn though I am not familiar with these engines. I do know however that quality of CAT bolts is extremely high, so unlikely to be a problem 'overtensioning' them this little amount? Maybe HE had been told to do that by someone else? These 6 cyl engines have been around for a while .(?)


JC

For a number of industrial engines I was told the correct method was to torque up to the correct value in the proper sequence,have a long tea break and re-torque again to the specified value.
It was understood that bolt threads and under the head were lubricated.
Perhaps allowing time for the lubricant to spread.
Usually something like a 1/8 -1/4 turn more would bring them back to specs.

Trev.

Thanks I remember him saying something about letting it settle in. What do you mean by angle setting is that when the bolt is turned a so a number of corners of the bolt head passes one point?

correct torquing is critical... first up go read the manual, some things require torquing then re torquing after a given event (time, heat, run, cool down whatever) some are a one shot deal. once you've worked out if re torquing is or isnt required youve got to then torque it up properly (how goods your torque wrench)

with or without lubricated threads.
with or without lube under the heads
in how many stages and at what torque for those stages
does it use angle torque to finish it.

If it specifies a torque setting without going for angle torque you should always go over all the bolts with the torque wrench after youve done up the last one and do that in the same sequence as the pattern.

If its angle torqued leave it alone

Some high performance gear specifies fastener stretch. You then need to measure the length of the fastener with a micrometer before and after tensioning until the correct stretch is obtained.

I think the key point to the above is that there is no one correct way of torquing everything. Manufacturers have different methods, often different methods for different products from the same manufacturer - so read the manual and do what it says!

As vehicles move to more performance and less weight, higher stresses and less "unnecessary" mass and closer tolerances, torque settings have become more and more critical in more and more places. Up until the 1930s torque wrenches were unheard of in motor workshops, although tightening sequences had started to be used. By the end of WW2 the use of a torque wrench on head bolts was pretty much standard. For example, the Series 2a workshop manual has no index entry on torque settings, and I think I am correct in saying that a torque wrench is only listed as required for head bolts and a few other engine fasteners such as bearing caps.

Today, most fasteners in mechanical parts of your Landrover have specified torque settings, and it has become a necessary tool to do pretty near anything, although detailed tightening procedures and sequences remain fairly rare.

John

Torque specifications were the only workshop information of any kind supplied by the makers for Offenhauser/ Meyer & Drake racing engines. They assumed that if you were assembling and tuning one of these, that you knew what you were doing.

Still would like to know what "angle setting, is. Have never come across this before.