Omega Owners Forum - Head torque values/angles

Tezray

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Head torque values/angles
23. Aug 2006 at 20:03

I just want to confirm the head torquing process before doing it! The haynes book says 25NM, then 4 stages of 90 degree's.....however i've also been told that haynes talks out there bum lol and it should be 25NM and then 3 stages of 90 degree's. Which is correct? I must admit 4 stages of 90 degree's does sound hefty and a possible block cracker! Would the 90 degree stages be it? Or would i finish them all off with an extra 15 degree's or something? All help appreciated

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JasonH Senior Member Offline Posts: 953 Bristol Gender:	Re: Head torque values/angles Reply #1 - 23. Aug 2006 at 20:35 I'm seem to recollect Geffd saying it was 3 stages and the TIS was wrong. Haynes have probably based it on the TIS.
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Tezray Intermediate Member Offline Posts: 264 Bristol Gender: Drives: Omega MV6	Re: Head torque values/angles Reply #2 - 23. Aug 2006 at 20:46 Cheers mate I think i will do 3 stages of 90, unless someone severly warns me otherwise! lol I'm sure that'll be fine....
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omegav6cd

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Re: Head torque values/angles
Reply #3 - 23. Aug 2006 at 21:24

Tezray wrote on 23. Aug 2006 at 20:46:

Cheers mate Wink

I think i will do 3 stages of 90, unless someone severly warns me otherwise! lol I'm sure that'll be fine....

Hello mate,
i have done a lot of work on the past with regards to engine critical joints such as bearing caps, flywheels, cylinder heads, oil pans etc. The nightmare of a joint such as cylinder head is the bolt relaxation, so whatever you do do not lubricate the bolts and allow as much time as you can between the stages that way you will get a much better result. PM me your email adress if you would like and i will send you some stuff that might help you.

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Marks DTM Calib

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Re: Head torque values/angles
Reply #4 - 23. Aug 2006 at 21:35

Well Vaux state it as 25Nm plus 270 deg + 15 deg but, I would do 25Nm +90 +90 +90 +15 (you may well be ok not worrying about the 15deg).

Abviously you would apply 25Nm to all bolts, then tighten all by 90 and then all by another 90 etc.

Remember when tightening head bolts you work from the inside ones out tightening diagonaly opposite bolts ie

7 1 3 5
O O O O
O O O O
6 4 2 8

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« Last Edit: 23. Aug 2006 at 21:38 by Marks DTM Calib »

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v6man54deg Geffd

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Re: Head torque values/angles
Reply #5 - 24. Aug 2006 at 07:48

This is correct 25NM + 3x 90degs- the 15 degs is for tollerance, make sure you have a good quallity T55 socket - not nice when they snap off - I can vouch for that - it bloody hurts!!!!!!

Marks DTM Calib wrote on 23. Aug 2006 at 21:35:

Well Vaux state it as 25Nm plus 270 deg + 15 deg but, I would do 25Nm +90 +90 +90 +15 (you may well be ok not worrying about the 15deg).

Abviously you would apply 25Nm to all bolts, then tighten all by 90 and then all by another 90 etc.

Remember when tightening head bolts you work from the inside ones out tightening diagonaly opposite bolts ie

7 1 3 5
O O O O
O O O O
6 4 2 8

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V6 problems solved

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Tezray

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Re: Head torque values/angles
Reply #6 - 24. Aug 2006 at 10:03

Well here's where the haynes has sent me wrong!!

-It told me to lightly lubricate the head bolts with engine oil (i did)
-There tightening sequence works from the inside, to the outside, but not in a diagonal way! Just opposite....

I've tightened all my bolts to 25NM, is it too late to remove them, clean the oil off and then re-tighten in the way you 2 said? Because i'm worried about hydraulic pressure now cracking the block Undecided

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Marks DTM Calib Administrator Offline Ex Member Posts: 25671 Northern Hemisphere Gender: Drives: Astra J, Mum Bus, Dexta Tractor, 108 DMU wip	Re: Head torque values/angles Reply #7 - 24. Aug 2006 at 10:41 Well when lubeing them I never use oil.......a very runny parafin oil mix at the most. If it was a VERY light coating then they should be ok....if soaked then they might hydraulic....
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omegav6cd

Ex Member

Re: Head torque values/angles
Reply #8 - 24. Aug 2006 at 10:42

Tezray wrote on 24. Aug 2006 at 10:03:

Well here's where the haynes has sent me wrong!!

-It told me to lightly lubricate the head bolts with engine oil (i did)
-There tightening sequence works from the inside, to the outside, but not in a diagonal way! Just opposite....

I've tightened all my bolts to 25NM, is it too late to remove them, clean the oil off and then re-tighten in the way you 2 said? Because i'm worried about hydraulic pressure now cracking the block Undecided

I prefer tightening cylinder heads in a diagonal as Mark has said but spiral is as good. I'm not keen on the oiled bolts as they increase dramatically the clamping load eg instead of 80kN you get 100kN for the same torque applied on the bolts.

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nixoro Omega Baron Offline Posts: 3104 Hitchin, Herts Gender: Drives: 56 Plate - Zafira 1.6	Re: Head torque values/angles Reply #9 - 24. Aug 2006 at 10:54 I think Tezrays main concern is whether he can remove the bolts and redo Personally I would have thought he couldn't though as they may have stretched when he tightened them to 25Nm.
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omegav6cd

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Re: Head torque values/angles
Reply #10 - 24. Aug 2006 at 11:13

nixoro wrote on 24. Aug 2006 at 10:54:

I think Tezrays main concern is whether he can remove the bolts and redo

Personally I would have thought he couldn't though as they may have stretched when he tightened them to 25Nm.

No, he can definately remove the bolts as the yield region is really a lot above the 25 NM. Only if yo uapply all the angle stages the bolt streches into yield.

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Tezray

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Re: Head torque values/angles
Reply #11 - 24. Aug 2006 at 11:34

Nixoro, correct that is my concern! OmegaV6cd, i'll be removing them now then! lol

I'll re-tighten them in a spiral method though just because that's how i did it first time and i wouldn't want to upset them. I didn't soak them in the first place, but i'll remove them and clean them off and then re-tighten, as there will be some oil left in the thread. I will also probably ignore the 15 degree's torque angle at the end.....

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nixoro

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Re: Head torque values/angles
Reply #12 - 24. Aug 2006 at 11:44

omegaV6CD wrote on 24. Aug 2006 at 11:13:

nixoro wrote on 24. Aug 2006 at 10:54:

I think Tezrays main concern is whether he can remove the bolts and redo

Personally I would have thought he couldn't though as they may have stretched when he tightened them to 25Nm.

No, he can definately remove the bolts as the yield region is really a lot above the 25 NM. Only if yo uapply all the angle stages the bolt streches into yield.

learn something new, Tezray been following this quite abit well impressed i dont think I would have the guts or knowledge to do what you're doing, so far I have done a clutch and cambelt renewal on mine but looking at the v6 for me is scary.

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Tezray

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Re: Head torque values/angles
Reply #13 - 24. Aug 2006 at 14:12

Cheers dude

I imagine changing the clutch isn't much fun on the omega though....Although i'll be changing the flywheel as well as the clutch once she's up and running! lol

Well i'm back on track! Slackened off all the head bolts in the reverse sequence and then removed one at a time, cleaned it, put it back in finger tight, removed again and cleaned again and repeated this about 3-4 times on each bolt! Got the majority of the oil out....Tbh i only dipped the tip (about an inch) of each bolt in oil, scraped off the excess on the oil container top and then fitted the bolts, so i don't think it was excessive in the first place, but better safe than sorry.

So now the head bolts are re-torqued to 25NM, PAS pump re-fitted (along with earth cable and supporting bracket), water pump fitted and torqued, a couple of coolant pipes. Now i'm waiting on my torque angle gauge (my mates bringing one round today) so i can finish torqueing (sp?) the heads, then fit the cams, the PAS pump pulley, crank pulley, water pump pulley and then it's time to get her timed up Cheesy

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« Last Edit: 24. Aug 2006 at 14:13 by Tezray »

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rpont

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Re: Head torque values/angles
Reply #14 - 24. Aug 2006 at 17:26

Tezray wrote on 24. Aug 2006 at 14:12:

Now i'm waiting on my torque angle gauge (my mates bringing one round today) so i can finish torqueing (sp?) the heads, then fit the cams, the PAS pump pulley, crank pulley, water pump pulley and then it's time to get her timed up Cheesy

Don't put the water pump or crankshaft pulleys on until you have timed her up. You won't be able to get the cranshaft lock on Cry

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