Classic cars forum & vehicle restoration.

[Roger-hatchy]

Had a water leak from the head gasket, slight weep from the front corner (E93a) manifold side.

Damn thought I another head gasket, so ordered one.
Then though I'd check the torque and add a quarter turn.

Set the torque wrench and started to check.
All studs/nuts took at least half turn to torque down, even so still added quarter turn.

Been out a few miles since and no sign of the leak.
And, more psychological I think, she seems to have a bit more go.

I can remember a few years back some engines had to be torqued twice, once when cold, then after a set mileage, or not, had to be re-torqued hot.

Was this standard practice across most engines, or is it best to just check every few months

Or do the studs need replacing

Roger

[Kelsham]

Hi, If it has cured the leak I would accept it and be thankful.

BMC used to advise tightening critical joints leave them overnight and then retighten. When I did this on my 1800 Morris I was surprised how much the tension had relaxed overnight.

The TR7 head gasket advice is to retighten more than once, I doubt the studs are stretching.

Regards Kels.

[Roger-hatchy]

Hi Kels

As you say leave it alone for now, now that the leak has gone.
Well at least I have a spare head-gasket, been meaning to get a spare.

Like most things with classics, just keep an eye on things.

Got a couple of hundred mile round trip on Sunday that should tell.

Roger

[Greg]

Hi Roger,
I had a similar problem recently on my Pop 103e, but also reground the valves etc so fitted a new head gasket anyway.
Reading the workshop Manual it does give torque settings for hot or cold!!
But also says that if fitting the head 'cold' when the bolts have been torqued down, run the engine to working temperature, then with the engine warm re-torque them....as you say, there was at least quater of a turn on each nut!
I followed this and so far it's been spot on

[Rick]

And remember to reset the torque spanner back to zero after use. You probably knew that anyway I didn't though until a few years ago, and snapped a stud on my E83W as a result

R
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[Keith D]

I've always tensioned head gaskets at least twice, especially the copper/asbestos (or modern equivilent)/copper type. They definitely compress after initial use and require re-tensioning.

With a lower compression, side valve engine you can generally get away with painting the pre-used head gasket with aluminium paint both sides, (we call it silver frost over here) then tighten down to it's required tension and have no problems.

Keith

[Jim.Walker]

[Greg]

Yes I am reading it properly although I've always done head-work 'cold' I would have thought the manual means at least 'warm' because as you say 'how would you work with it hot'??
But from the Ford of Dagenham workshop manual it says:

(4) Install the cylinder head nuts and tighten them down equally from the centre outwards in the order shown in Fig.1. The correct degree of tightness is when a torque of 35 lbs. Feet is applied. This may be reduced by 5 lbs. Feet if the engine is hot.

[Jim.Walker]

Very curious - unless it is a Haynes Manual!
Jim.
_________________
Quote from my late Dad:- You only need a woman and a car and you have all the problems you
are ever likely to want". Computers had not been invented then!

[47Jag]

Greg,

I would read that as: Tighten the head and when re-torquing after it's warmed up use a setting of 5ft/lbs less. IE 30ft/lbs.

Art

[Jim.Walker]

[Kelsham]

Jim, what happens to the water when you release the nuts before retorqueing?

I would be concerned that it could leak into the cylinders.

I have always just started with them tight and checked the nuts with the torque wrench.

regards Kels

[Jim.Walker]

As long as you ensure the radiator pressure cap is released (if it has one) and you do not disturb the head there should not be a problem (stickage, if there is such a word). IF there is any leakage it will be negligible in the time the studs are loose. And even if it is internal, the heat of the engine will quickly clear it. Every gallon of petrol burnt produces a gallon of water inside the engine (hence steam from a cold exhaust). The engine is used to water!
If you do not release the nuts/bolts you will often get a false torque. Again from "stickage"
In any case by "release" all that is necessary is to loosen them to take most of the tension off them.
Jim.
_________________
Quote from my late Dad:- You only need a woman and a car and you have all the problems you
are ever likely to want". Computers had not been invented then!

[Churchill Johnson]

I would never ever release cyl head bolt's or nut's to re-toque them, if a manufacture of anything that need's a torque setting then that is what should be applied, and never oil a bolt or nut unless again it is specified as this will increase strain on the bolt or nut,if a cyl head has been of for any reason or is being re-fitted then stud's or hole's in the block should be cleaned with a tap or die, and again if an eng should have hardened washer's under the nut's or bolt's then don't fit mild steel one's,most so called modern eng's have a lot of elastic or stretch type bolt's fitted one reason being that they retain their setting and are tensioned with an angle meter again as laid down by the manufacture's which alleviate's a stiff bolt or nut,but i would still clean the thread's first, i might add that as having worked on engine's from lawnmower's to v8 diesel's i have yet to find any manufacture that req's the head to be released and re-tightened,i have somewhere torque figure's for bolt's oiled and dry and they are different!.

[Jim.Walker]

I have seen in many manuals, instructions to clean and lightly oil threads on cylinder head fixings. I have NEVER seen instructions not to do so.
If a torque wrench is used to tighten as opposed to RE-tighten the head the static friction (which I like to call "stiction") on the threads will usually suggest the nut or bolt is tight enough or even over tight. Static friction is many times sliding friction, as can be felt when driving when tyres lose their static friction and start to slide. It is also the reason (corrosion aside), why a bolt often seems to need so much torque to start it moving when trying to release it - quite often with a "crack". Which is where, I imagine, the expression "cracking" a bolt or nut comes from.
I stand squarely behind what I posted. And is what I have taught over many years as a Technical College Motor Vehicle Lecturer.
Even angular tightening which does not apply in this case demands an accurate initial torque so the same arguments stand.
Jim.
_________________
Quote from my late Dad:- You only need a woman and a car and you have all the problems you
are ever likely to want". Computers had not been invented then!