No life (a.k.a. DattoMaster) ![](http://datsun1200.com/uploads/rank49ca09456da4d.gif)
Joined: 2008/10/10 22:02
From Melbourne Australia (and likely under the car)
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You're not alone on that one. What I'd maybe suggest is not doing them too many times. I used to do it 3 times, 4 max.
There's a bit of difference of opinion (and I honestly don't have anything I could put forward to favour one over the other) as to 'how' to retension them. This is a general - 'not specifically datto a series' comment mind you
Some people raise issuesthat if you loosen and re-tension the bolts (by just cracking them loose, one at a time, then retensioning, then moving to the next, loosening and re-tensioning, in the same order you'd tension them first time around) - that oil or other fluid could get under the bottom of the bolt and hyraulically 'lock' and stop the bolt going tighter, but it'll register on the torque wrench as being tight. SO they just go one by one, don't loosen any bolts, and just re-tension.
THe 'other' side raises the issue that the bolts can slightly 'seize' and need to be 'cracked' then re-tensioned, or that stickiness will otherwise just make the torque wrench read a high value, but the actual clamping force isn't as high as it could be.
Both have some relevance I guess. For whatever it's worth, I've done the 'loosen one, then re-tension' then move to the next one etc method on practically all motors.
I tend to run studs on anything that has to be re-tensioned a lot. That way the threads in the block won't wear out, they are only pulled once in a blue moon, if changing the head gasket altogether. SO that saves the threads in the block. It also means that you are only loosening the nuts at the top, not the stud, so you have no worries at all with the 'crack one loose, then retension' method. It also was a bit of a bonus on things like holden red motors, as they have bolts going into the water jackets, so you need to run sealer (instead of anti-seize lube) on the threads to prevent seepage past the threads - which is then a real pain when you have to re-tension them (and arguably the sealer also leads to slightly less consistent torque wrench readings for the same clamping force. But with nuts at the top, you can seal the threads in the block, and use anti-seize on the top threads/nuts.
For a streeter i wouldn't bother too much with studs, but they have a decent advantage with more competition oriented stuff.
Posted on: 2011/11/17 9:50
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