Cylinder Head nut Torque Sequence and Re-torque Sequence and Process

Started by John Gervais, October 24, 2021, 02:35:43 PM

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John Gervais

I've just found something interesting, and perhaps it's not a big deal, but I'm wondering if there's a difference...

What I've noticed, is that my workshop Haynes manual has a different cylinder headnut torque sequence than the old workshop manuals have. 

I'm also wondering 'what' is the best way that I should re-torque my recently re-installed cylinder head.  Should I use the installation sequence or the removal sequence for re-torqueing? 

Loosen 1/4 turn and re-torque then move to the next sequential nut? 

I hope these pictures make sense:
- Pave the Bay -

MiniDave

John, the top tightening sequence you posted is how I've always done it - and I've paid little to no attention to how I take them off - in fact I use an impact wrench to remove the nuts!

and yes, on re-torque - back 1/4 turn then see how far it goes past that on the way back - if any.

BTW, I now do the first re-torque at 140* of temperature after first start up.....taught to me by Kent Prather of Prather racing - I used to always let them cool off first before retorquing but he says torque it,  fire it up, get it up to 140* and re-torque it immediately - then check the valve clearances again, then go ahead and run it.

I've never had one fail using either method.....
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

John Gervais

Thanks Dave - Just to be clear, what sequence do you use for the re-torque?  1-2-3?   or 9-8-7?
- Pave the Bay -

MiniDave

Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

John Gervais

Cool - I'll drive it back up to the garage tomorrow and take care of it as it cools down - it's too late to try 'first start-up', I took it fishing yesterday.  (didn't catch anything either, 'cept for cold feet...)

Thanks for helping! 
- Pave the Bay -

John Gervais

I just noticed a small trace of oil at the junction of the cylinder head and block behind the number 1 exhaust valve / number 1 cylinder.

So I pulled the plugs and peered at the tops of each piston and noticed a tiny pool of oil on each one - a trace, amounting to probably no more than a drop or two on each one.

I'll re-torque the head again (it's now got around 200 miles), one nut at a time, and see what happens - it probably won't do anything for the piston tops, but maybe it won't leak from the corner.
- Pave the Bay -

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