Head gasket bolts / tightening

[RustyNuts]

Hi all!

 

A few years back i dismantled an old safrane engine (volvo 850 lump) as it was going for scrap and i fancied peeking inside it.

 

The headbolts were a royal pain to undo - i had a 3-4ft workshop trolley jack handle on the end of my 2 ft breaker bar (total of 5-6 ft) and even then it took all my might to break the bolts loose.

 

Now my spare engine may need a new gasket as it was not stored with coolant inside it. I don't have the wonga for a pro to do it and was mulling over a DIY job until i remembered how tight the bolts were to undo.

 

Now on retightening they're supposed to be done up to 2 daN.m (20 Nm), 6daN.m (60 N.m) and then another 150 degrees.

 

Unless I use a chain block / pulley fastened to the nearest oak tree and attasch the other end to the torque wrench / normal wrench (for the 150) I'm somewhat stumped how this is supposed to be achieved! My old neighbour was a big bloke with serious muscle and he once struggled to do a steering wheel for me at 70N.m!

 

Other than swallowing some Sci-Fi potion and turning into the incredible hulk, whats the secret to this?

[Captain Furious]

not sure I'm understanding the problem, 60nm is about 45lb/ft, which is just over finger tight ..

 

Another 1/3 turn beyond this shouldn't take any great feat of human strength

[RustyNuts]

I assume you have muscles the size of boulders then   60Nm can't be that loose if its holding on a 5 cylinder head..

 

My neighbour did our old megane years ago... took him a lot of effort to do those bolts too and he had some muscle (unlike me).

[twosmoke300]

2ft breaker bar and 2 man up pills!

 

If your neighbour struggled to do 70Nm then dont let him do any wheel nuts as they are usually 100-120 Nm

[Asimo]

Why assume the gasket will suffer from storage without coolant? It isn't made of wood!

 

60Nm is nothing, really it isn't. Get a proper torque wrench; and measure - not guess, that angle.

 

Head bolts are often designed to be usable only once - they are stretched by the last part of the tightening process to guarantee even force is applied to the gasket by each bolt. If such bolts are used again, the force will not be controlled in this way and gasket failure will result.

[Captain Furious]

Lol, I'm not being flippant, it really isn't that tight.  A driveshaft hubnut is usually around 230nm, now that could be described as 'quite well nipped up' but 60nm would be typically be done up with a 3/8 drive torque wrench, not even a big one.

[castros_bro]

60Nm would be a 6kg weight on the end of your one meter breaker bar with the pull of one normal earths gravity so if you can lift a bag of spuds in Tescos*  (other supermarkets are shit as well) with one hand then you can do this , the 20Nm then 60Nm is for the tightening sequence. The +150 degrees will really jam everything together and you'll struggle to undo the now stretched bolts.

[derskine]

60nm really isn't that much.

[RustyNuts]

2ft breaker bar and 2 man up pills!

 

If your neighbour struggled to do 70Nm then dont let him do any wheel nuts as they are usually 100-120 Nm

 

I usually stand on the end of my breaker bar for the wheels lol

 

Lol, I'm not being flippant, it really isn't that tight.  A driveshaft hubnut is usually around 230nm, now that could be described as 'quite well nipped up' but 60nm would be typically be done up with a 3/8 drive torque wrench, not even a big one.

 

Ah for the driveshaft nuts I use my 3T trolley jack on the handle of my breaker bar lol

 

Thanks for all the other replies..

[3VOM]

Head bolts are often designed to be usable only once - they are stretched by the last part of the tightening process to guarantee even force is applied to the gasket by each bolt. If such bolts are used again, the force will not be controlled in this way and gasket failure will result.

I suspect someone re-using one-time-use head bolts might leave this situation.

[Junkman]

I usually stand on the end of my breaker bar for the wheels lol

 

RU nuts???

Torque them with the correct torque, ffs!

You'll be surprised how little effort it takes.

 

What you are doing is risking your wheel bolts snapping during hard cornering!

 

[AMC Rebel]

Highly confused by this - as many contributors have said, the torque figures aren't that high - I used a dial gauge I bought for a fiver at a lorry show for the new stretch bolts on my KV6, but you can do it with a cardboard one as described in one of my many (can't remember which one) HBOLs.  

 

Also agree no need to stand on a breaker bar to tighten wheelnuts.

[Captain Furious]

In the absence of a suitable torque wrench, wheel nuts should at the very most be done up using the wheel brace that's kept in the car. Otherwise you run the risk of getting a puncture, breaking the standard wheel brace by standing on it to try and undo the wheel nuts you did up with a 2ft breaker bar, having to borrow an air compressor and hurriedly drive round looking for a halfords before it goes flat again to buy an extendable wheel brace to undo them, so you can change the wheel in their car park in your shirt and tie

 

Ask me how I kn....

[Steve_R1979]

As the others have said, its nothing

I did the fly wheel bolt up on my aprilia today to 95lb.ft with a short torque wrench and didn't even need to put my weight behind it.

I think you are making a mountain out of a mole hill

[Rusty_Rocket]

In the absence of a suitable torque wrench, wheel nuts should at the very most be done up using the wheel brace that's kept in the car. Otherwise you run the risk of getting a puncture, breaking the standard wheel brace by standing on it to try and undo the wheel nuts you did up with a 2ft breaker bar, having to borrow an air compressor and hurriedly drive round looking for a halfords before it goes flat again to buy an extendable wheel brace to undo them, so you can change the wheel in their car park in your shirt and tie

 

Ask me how I kn....

 

Exactly this!  The wheel brace supplied with the car is deliberately the length it is, so the average person does the bolts up to about the correct torque necessary to keep the wheel on and not damage anything.  Of course, if you've been to Kwik Fit recently, you'll need a scaffold pole and the strength of Hercules to undo the (tiny) nuts/ bolts, but there you go!

[RustyNuts]

RU nuts???

You did see my username right? lol

 

Torque them with the correct torque, ffs!

You'll be surprised how little effort it takes.

 

What you are doing is risking your wheel bolts snapping during hard cornering!

 

Car has been sorn for the last six years anyway (health, money, technical problems) so that really isn't a risk at present but I take your point.

 

As the others have said, its nothing

 

I did the fly wheel bolt up on my aprilia today to 95lb.ft with a short torque wrench and didn't even need to put my weight behind it.

 

I think you are making a mountain out of a mole hill

 

Not intentionally making the mountain... but (unless I am completely and utterly feeble - which wouldn't surprise me) I seem to remember having a hard time going about 30-40. That or my memory simply isn't what it used to be but I remember our neighbour doing the head on an old megane we had years ago and he struggled with it - with muscles like boulders.

 

I suppose the only thing to really do is go and try out some higher torque values on some nuts and bolts... engine crane has quite a lot so i'll try with that... (big thick threads I can't strip too).

 

Anyhow lads, thanks for your time and help

[twosmoke300]

30-40 really is one hand on a decent ratchet right . Iirc Honda sump plugs are 35nm !

[jon928se]

30-40 really is one hand on a decent ratchet right . Iirc Honda sump plugs are 35nm !

 

If they use alu or copper crush washers 35Nm is into stripping threads out of the sump territory. Probably more like 16 or 18.

 

Always always always follow the WSM instructions on tightening critical bolts to a specified torque or angle - no adding grease or oil to the threads or washer if it says tighten dry - something like 50% of the measured torque applied is just to overcome friction - adding lube can result in up to double the tension in the bolt it was designed for.

[dieselnutjob]

The crank pulley bolt on the Jag diesel was 100Nm plus another 90 degrees, which is damned tight.

I used a 3/4" T bar with a 4 foot pole over it and it was fine.

[twosmoke300]

44nm according to autodata

Thats a civic 01-06 petrol

[Eddie Honda]

Jazz sump plug: 39 N·m(4.0 kgf·m, 29 lbf·ft) Do not overtighten

 

Solid ally washer, doesn't crush much.

[lisbon_road]

Plenty of good advice above.  I agree that it won't be too difficult to get the torque needed on head bolts and that a proper angle gauge is worth having and not too expensive.

 

Of course wheel bolts should be the right torque.  Very easy for them to break if overtorqued.  I have seen it happen on an old Peugeot, which had a broken bolt, which I replaced before any more went.  I know that the previous owner had over tightened them with a breaker bar, a fine tool for undoing them only.  

 

One point mentioned above is the torque on crankshaft bolts, which is quoted as very high sometimes.  A professional mechanic has previously told me to just get them tight, say about 100 Nm and not worry about getting them to the quoted level as well.  Hasn't caused me any problems.  I now always undo them on the starter, with some bits of wood, just works too well.  Stand well back.  (Funny to think I used to undo them with a collection of extension bars, and massively long poles and all sorts).  

[twosmoke300]

Most crank bolts now are a lowish torque followed by an angle tighten. Makes it much easier - hold the pulley by hand for the nm part then mark the bolt head with paint and make another mark the 120 or what ever degrees away then buzz it with an impact gun

[oldford]

One of my torque wrenches is calibrated in pounds-inches and Kg-metres, so I need to remember to divide by 12 to get pounds-feet and multiply by 10 to get newton-metres, I know that I should be multiplying by 9.807 to get the nm, but 10 is a lot easier to do by brain power.