Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: amba on 27 October 2011, 12:59:44
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Can somebody just confirm the torque for the 4 plenum bolts :y
Think its 20nm but just want to check :)
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I have 8nm in my head...
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I have 8nm in my head...
For the cam covers, yeah.. but for the plenum?
20Nm, per here: http://www.omegaowners.com/forum/index.php?topic=90519.0
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I can't actually see the plenum value on that list.
Where is the list sourced from?
I note it says "Oil filter housing cover to oil filter housing 25nm" - whereas we all know this value is 15nm (it's even stamped on the casing) :y
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8nm!
I thought it was 20nm at the Aldershot meet. I was wrong, as proved by Haynes. Doh!
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I can't actually see the plenum value on that list.
Where is the list sourced from?
I note it says "Oil filter housing cover to oil filter housing 25nm" - whereas we all know this value is 15nm (it's even stamped on the casing) :y
sure it's 25!
...or is it 20? ;D
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8nm!
I thought it was 20nm at the Aldershot meet. I was wrong, as proved by Haynes. Doh!
...although I never bother torquing, just do em up sensibly.
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8nm!
I thought it was 20nm at the Aldershot meet. I was wrong, as proved by Haynes. Doh!
...although I never bother torquing, just do em up sensibly.
That's what I was going to say ................ ::) ::) ::)
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I can't actually see the plenum value on that list.
Whoops you're right, I read the first of the two 'Intake ...' lines wrong :-[
I'll get me coat.
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I can't actually see the plenum value on that list.
Where is the list sourced from?
I note it says "Oil filter housing cover to oil filter housing 25nm" - whereas we all know this value is 15nm (it's even stamped on the casing) :y
sure it's 25!
...or is it 20? ;D
I thought it was 15..
But all I did was do mine 'up', so to speak.
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I have always tightened the Plenum Bolts to 20nm. These bolts are 8mm bolts that go into the ali inlet manifold.
The Cam Cover Bolts are tightened to 8nm which are 6mm bolts that also go into ali......
How can they be the same torque setting?
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I have always tightened the Plenum Bolts to 20nm. These bolts are 8mm bolts that go into the ali inlet manifold.
The Cam Cover Bolts are tightened to 8nm which are 6mm bolts that also go into ali......
How can they be the same torque setting?
Because the clamping force needed to seal the plenum O-rings is minimal :y
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I have always tightened the Plenum Bolts to 20nm. These bolts are 8mm bolts that go into the ali inlet manifold.
The Cam Cover Bolts are tightened to 8nm which are 6mm bolts that also go into ali......
How can they be the same torque setting?
Because the clamping force needed to seal the plenum O-rings is minimal :y
Why use 8mm bolts then and not 6mm?
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I have always tightened the Plenum Bolts to 20nm. These bolts are 8mm bolts that go into the ali inlet manifold.
The Cam Cover Bolts are tightened to 8nm which are 6mm bolts that also go into ali......
How can they be the same torque setting?
Because the clamping force needed to seal the plenum O-rings is minimal :y
Why use 8mm bolts then and not 6mm?
I would guess that a slightly thicker bolt provides a more consistent clamping force across all of the inlet ports, taking into account the weight/dimensions of the plenum?
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I don't agree I'm afraid....
Bigger bolts will be a higher torque setting than a smaller bolts... else we would have 6mm bolts for Head Bolts.
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I don't agree I'm afraid....
Bigger bolts will be a higher torque setting than a smaller bolts... else we would have 6mm bolts for Head Bolts.
But surely the torque setting is based around numerous other variables, such as the weight of the item / clamping force needed - not solely determined by the thickness of the bolt?
The logic about having 6mm bolts for cylinder heads is a red-herring, because such a bolt wouldn't be able to structurally withstand the torques / stresses required, to hold down the weight of the heads on the block...
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I can't find any references to plenums at all in Mr Haynes, but I'd say that 8Nm is far too little - it's little more than a nip. 20Nm/15lbsft sounds more like it
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I don't agree I'm afraid....
Bigger bolts will be a higher torque setting than a smaller bolts... else we would have 6mm bolts for Head Bolts.
But surely the torque setting is based around numerous other variables, such as the weight of the item / clamping force needed - not solely determined by the thickness of the bolt?
The logic about having 6mm bolts for cylinder heads is a red-herring, because such a bolt wouldn't be able to structurally withstand the torques / stresses required, to hold down the weight of the heads on the block...
I think your totally missing the point
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I can't find any references to plenums at all in Mr Haynes, but I'd say that 8Nm is far too little - it's little more than a nip. 20Nm/15lbsft sounds more like it
I was also sceptical, the first time I read it - but I'm almost certain it's 8nm....
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I can't find any references to plenums at all in Mr Haynes, but I'd say that 8Nm is far too little - it's little more than a nip. 20Nm/15lbsft sounds more like it
I was also sceptical, the first time I read it - but I'm almost certain it's 8nm....
Yep :y
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Torque required is a function of the preload required on the bolt.. so I was reading the other day as I read the tech articles in the ARP catalogue.
A bolt works best when considered as a spring, so the desired torque setting is given to produce a desired 'stretch' in the bolt - assuming you are mating two incompressible things together..
When you're mounting something with a compressible separator, the preload is - I imagine - determined by the springiness & compressibility of the separator. O-rings in this case (very springy, highly compressible = little torque?) vs. headgasket (not springy, hard to compress = high torque required to achieve consistent preload across the life of the item?)
Something like that, anyway.. IANAME (I Am Not A Mechanical Engineer ;D)
So sorry DLK, I tend to agree with James - I think you're missing the point ;)
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Seems to small....but James is correct, direct from TIS :
Intake Plenum, Remove and Install (Y 26 SE, Y 32 SE)
Remove
Disconnect ground cable from battery.
Detach air intake hoses (1) from housing for resonance pipes switchover valve and throttle body.
Disconnect wiring harness plug (2) from throttle body.
Detach vacuum hose (4) from throttle body.
Detach coolant hoses (3) from throttle body.
Detach brake servo vacuum line (4) from intake plenum – counterhold on screw-on port.
Detach vacuum hoses (3) and engine vent hoses (2) from engine vent adapter.
Remove fastening bolts (6) from intake plenum and lay bracket aside.
Remove fastening bolts for sealing cap from intake plenum.
Remove fastening bolts (1 and 5). Carefully lay intake plenum aside – note seal rings.
Caution
Mask intake ducts – foreign objects can cause engine damage.
Detach vacuum lines (1) from solenoid valve for intake plenum switchover valve.
Detach wiring harness plug (2) from solenoid valve for intake plenum switchover valve.
Remove intake plenum and seal rings.
Install
Place 6 new seal rings (3) on intake bridge – ensure correct installation position.
Attach vacuum line and wiring harness plug to solenoid valve for intake plenum switchover valve.
Note: The intake bridge has two guide pins (arrows) for locking the intake plenum.
Attach intake plenum (1) to intake bridge – ensure correct seating – tightening torque 8 Nm / 6 lbf. ft.
Attach fastening bolts for sealing caps to intake plenum.
Attach brackets to intake plenum – 3 off.
Attach vacuum hoses and engine vent hoses to engine vent adapter.
Attach brake servo vacuum line to intake plenum – counterhold on screw-on port.
Attach coolant hoses to throttle body.
Attach vacuum hose to throttle body.
Attach wiring harness plug to throttle body.
Attach air intake hoses to resonance pipes switchover valve housing and throttle body.
Connect ground cable to battery.
Top up cooling system – see operations "Cooling System, Top Up and Bleed" and "Cooling System, Check for Leaks".
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Personally I don't care... in my opinion 8nm is not tight enough for an 8mm bolt.
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The precise torque value is 8021.923166667 Nm ;D :D :y
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Personally I don't care... in my opinion 8nm is not tight enough for an 8mm bolt.
I have a friend like that.. to him every bolt is considered 'tighten to yield' ;D I have to keep him away from the tools during reassembly... (It took me 8 years to teach him to stop tightening when something is cross threaded, too.. ;D )
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The precise torque value is 8021.923166667 Nm ;D :D :y
surely that'll strip the threads in the ally!!! ::) ::)
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Personally I don't care... in my opinion 8nm is not tight enough for an 8mm bolt.
I have a friend like that.. to him every bolt is considered 'tighten to yield' ;D I have to keep him away from the tools during reassembly... (It took me 8 years to teach him to stop tightening when something is cross threaded, too.. ;D )
Cross threading is something totally different than stripping a bolt from over tightening... maybe you should try teaching yourself first ;D
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The precise torque value is 8021.923166667 Nm ;D :D :y
surely that'll strip the threads in the ally!!! ::) ::)
8.021923166667 Nm
That better ;D ;D
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Personally I don't care... in my opinion 8nm is not tight enough for an 8mm bolt.
I have a friend like that.. to him every bolt is considered 'tighten to yield' ;D I have to keep him away from the tools during reassembly... (It took me 8 years to teach him to stop tightening when something is cross threaded, too.. ;D )
Cross threading is something totally different than stripping a bolt from over tightening... maybe you should try teaching yourself first ;D
Er. I know that, thanks. I also know the difference between yield in a bolt and stripping the threads out of something. ::)
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The precise torque value is 8021.923166667 Nm ;D :D :y
surely that'll strip the threads in the ally!!! ::) ::)
8.021923166667 Nm
That better ;D ;D
I wouldn't use the torque wrench anyway so wouldn't know ............ ::) ::) ::)
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Personally I don't care... in my opinion 8nm is not tight enough for an 8mm bolt.
I have a friend like that.. to him every bolt is considered 'tighten to yield' ;D I have to keep him away from the tools during reassembly... (It took me 8 years to teach him to stop tightening when something is cross threaded, too.. ;D )
Cross threading is something totally different than stripping a bolt from over tightening... maybe you should try teaching yourself first ;D
Er. I know that, thanks. I also know the difference between yield in a bolt and stripping the threads out of something. ::)
That is not what you wrote though ::)
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Personally I don't care... in my opinion 8nm is not tight enough for an 8mm bolt.
I have a friend like that.. to him every bolt is considered 'tighten to yield' ;D I have to keep him away from the tools during reassembly... (It took me 8 years to teach him to stop tightening when something is cross threaded, too.. ;D )
Cross threading is something totally different than stripping a bolt from over tightening... maybe you should try teaching yourself first ;D
Er. I know that, thanks. I also know the difference between yield in a bolt and stripping the threads out of something. ::)
That is not what you wrote though ::)
Yes, it is. The section in brackets is an additional comment, unrelated to the first, as shown by the ", too.." at the end of it.
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By (over)tightening a plenum to 20nm, as opposed to the required 8nm, could this extra clamping force potentially distort the plenum O-rings, or flatten them too much, and therefore introduce air leaks
(especially if the plenum is removed again in the future, and then re-assembled using the same rings?)
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Personally I don't care... in my opinion 8nm is not tight enough for an 8mm bolt.
I have a friend like that.. to him every bolt is considered 'tighten to yield' ;D I have to keep him away from the tools during reassembly... (It took me 8 years to teach him to stop tightening when something is cross threaded, too.. ;D )
Cross threading is something totally different than stripping a bolt from over tightening... maybe you should try teaching yourself first ;D
Er. I know that, thanks. I also know the difference between yield in a bolt and stripping the threads out of something. ::)
That is not what you wrote though ::)
Yes, it is. The section in brackets is an additional comment, unrelated to the first, as shown by the ", too.." at the end of it.
Ooooooooooooooohhhhhhh nnnoooo it wasn't ;D
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Ooooooooooooooohhhhhhh nnnoooo it wasn't ;D
He's behind you!
Wait.. wrong script..
Ohhhh yess it wasss! ;D
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Ooooooooooooooohhhhhhh nnnoooo it wasn't ;D
He's behind you!
Wait.. wrong script..
Ohhhh yess it wasss! ;D
No it wasn't, no it wasn't, no it wasn't, no it wasn't ...........infinity :P
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Ooooooooooooooohhhhhhh nnnoooo it wasn't ;D
He's behind you!
Wait.. wrong script..
Ohhhh yess it wasss! ;D
No it wasn't, no it wasn't, no it wasn't, no it wasn't ...........infinity :P
I'm rubber and you're glue...
This could go on for a while folks, best grab a cuppa... ;D ;D
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P.S. I bet poor amba still doesn't know who to believe at this point.. ;D
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Ooooooooooooooohhhhhhh nnnoooo it wasn't ;D
He's behind you!
Wait.. wrong script..
Ohhhh yess it wasss! ;D
No it wasn't, no it wasn't, no it wasn't, no it wasn't ...........infinity :P
I'm rubber and you're glue...
This could go on for a while folks, best grab a cuppa... ;D ;D
Better carry on in the General Diss Area then or else we end up in trouble ;D
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P.S. I bet poor amba still doesn't know who to believe at this point.. ;D
Well 20
-8
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12 what about that? :D
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By (over)tightening a plenum to 20nm, as opposed to the required 8nm, could this extra clamping force potentially distort the plenum O-rings, or flatten them too much, and therefore introduce air leaks
(especially if the plenum is removed again in the future, and then re-assembled using the same rings?)
I shouldn't think the tightness would make any difference as the o rings sit in grooves and the plenum is bolted down to the inlet metal to metal,the seals are just to be sure its air tight
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P.S. I bet poor amba still doesn't know who to believe at this point.. ;D
Well 20
-8
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12 what about that? :D
;D Works for me! (Lets face it, most folks torque wrenches probably have at least that margin of error, anyway)
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P.S. I bet poor amba still doesn't know who to believe at this point.. ;D
Well 20
-8
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12 what about that? :D
;D Works for me! (Lets face it, most folks torque wrenches probably have at least that margin of error, anyway)
Yours and James' does it seems :D ;D
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I seem to remember 30Nm for these ones, but tbh I just give them a good strong nip after putting a smear of fresh oil on the O rings :y
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Well as my internet was down during my refit >:(,and I didnt have the benefit of the knowledgeable ones advise :y I have torqued them down to 20nm which seemed consistant with the injector manifold and sandwich plate. :D
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Well as my internet was down during my refit >:(,and I didnt have the benefit of the knowledgeable ones advise :y I have torqued them down to 20nm which seemed consistant with the injector manifold and sandwich plate. :D
In the real world, it's unlikely to do any harm :y
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Like it or not, the official value is 8Nm.
Its just tight enough to seal the 6 o rings, without crushing them to buggery
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Like it or not, the official value is 8Nm.
Its just tight enough to seal the 6 o rings, without crushing them to buggery
Are you of the opinion that tightening them beyond that could damage the rings then TB?
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How can the o rings be crushed or damaged? They sit in a grove designed for that diameter o ring. Its not possible to crush them unless an o ring is unseated and gets trapped.
All the bolts have to do is compress the rubber to seal until the plenum is tight to the manifold. That takes 8nm to achieve. Any more is over tight for the purpose of squashing the o rings, obviously a bolt that size will take more, as will the thread in the inlet fanimould, although I would think that's the week point.
IMO just do em up, making sure the o rings remain seated correctly while locating the pegs. Far more important than a couple of "nums".
4 pages, Lordy!
Oh, I can believe the cam shaft caps are 8nm either. But they are! :)
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Like it or not, the official value is 8Nm.
Its just tight enough to seal the 6 o rings, without crushing them to buggery
Are you of the opinion that tightening them beyond that could damage the rings then TB?
Not in the short term.
Given the depths of the grooves, probably not in the long term either.
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So after 4 pages ;D ;D ;D the definitive answer is 8nm :y ; but if they were torqued down to 20nm that would still be fine ;D :y
Anyway that is what I have done mine to :)
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So after 4 pages ;D ;D ;D the definitive answer is 8nm :y ; but if they were torqued down to 20nm that would still be fine ;D :y
Anyway that is what I have done mine to :)
split the difference with 14 ........ ::) ::) ;D ;D
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Perhaps it would be nearer that with the accuracy of some torque wrenches ;D ;D