torque up after heating

[johnnynova]

one of my haynes (green) says 25/30 nm torque then 3 x 60 deg or 2 x 90 deg.

the blue says 25/30 nm torque then 2 x 60 deg 1 30 deg then after you run engine up to heat let it cool down and do another 30deg

or 90 x1 the 60 x1 then 30x 1 after heating and cooling

does anyone do this extra turn after then egine has run and cooled?

just asking as there is a little oil leaking from one of the bolts (yes i did torque properly and do the deg stages.)

[Adam]

Which one did you do?
What engine is it

[johnnynova]

did 90 deg x 2

but there is a little oil leaking from one of the headbolts, rang my mechanic and he adivsed another 30deg once its cool.

i havent done so yet.


shall i?

head was skimmed before doing this, all new gaskets, surfaces cleaned, wanted to do it properly.

[Stuart]

i tend to do to the torque on the wrench. then 3* 60 and a list 30ish

[CP]

I've had problems with head gasket going after using the Haynes/Vaux method. I think its a **** method for fixing older cars.

I experimented using the above method but i also ascertained the torque readings for each stage by a bit of trial and error. I could feel, and it was shown up in the torque readings that some bolts go in tighter and others looser for any given degree turn you care to use - generally the middle tighter and the ends looser. This was after having carefully blown out all the stud holes and putting a little copper grease on the bolt threads, the washers and the underside of the bolt heads to ensure that nothing was hanging thru frictional forces. At the end of the day you want all bolts clamping up with even force - the amount of turns the bolt is in within reason is immaterial.

I have also torqued head bolts way up (180 degrees extra) and they were fine and came out again no probs. I tend to go around 90 degrees tighter on the tightest feeling 1 and make sure the corresponding torque setting is matched on the others irrespective of degrees turned. Even on heavily tuned cars I've not had any problems and had no need to faff about doing any other procedure

Also in the pre-tightening stage i go round a lot of times a bit below the required torque setting and then at it to make the heads gone down nice and even cos its quite easy to get it wrong at this stage.

[CP]

Final point i was reading somewhere a review by some mechanic engineer of torque wrenchs. He pitted himself against a number of different models ranging from cheap to expensive. He was very suprised to find he was more accurate than all of them in all tests.

[CP]

I've had problems with head gasket going after using the Haynes/Vaux method. I think its a **** method for fixing older cars.

I experimented using the above method but i also ascertained the torque readings for each stage by a bit of trial and error. I could feel, and it was shown up in the torque readings that some bolts go in tighter and others looser for any given degree turn you care to use - generally the middle tighter and the ends looser. This was after having carefully blown out all the stud holes and putting a little copper grease on the bolt threads, the washers and the underside of the bolt heads to ensure that nothing was hanging thru frictional forces. At the end of the day you want all bolts clamping up with even force - the amount of turns the bolt is in within reason is immaterial.

I have also torqued head bolts way up (180 degrees extra) and they were fine and came out again no probs. I tend to go around 90 degrees tighter on the tightest feeling 1 and make sure the corresponding torque setting is matched on the others irrespective of degrees turned. Even on heavily tuned cars I've not had any problems and had no need to faff about doing any other procedure

Also in the pre-tightening stage i go round a lot of times a bit below the required torque setting and then at it to make the heads gone down nice and even cos its quite easy to get it wrong at this stage.

[johnnynova]

cheers cp,

will give the middle ones another 30-60deg and the outer ones another 30. sound slike the haynes method doenst tighten them up enough!

the engine has run up to temperature about once/twice. is it still ok to give the bolts the few extra degs now (obviously once its nice and cold, ie 2moro morining)

[mikey14sr]

What touque figure did you end up with CP? I only ever do 45lb/ft(gradually to ensure the head goes down nice and flat) and then 2 90deg turns.

[craig green]

Overtightening will crush the fire rings of the gasket.

Worth bearing in mind as tighter bolts dosent necessarily mean a better seal.

CG

[johnnynova]

i tightened my bolts as per cp's advice.

but looking from a birds eye view of the engine standing in front of the car, the bolt next to the top right one has oil around it. oil was leaking from it before i tightened the bolts as per cp's advice, and it is still coming out of there now, not as much as before tho.

why could this be? the head was skimmed and head bolts tightened as per haynes instruction then following cp's advice.

ideas?

[Stuart]

cam box could be slightly warped and causing the leak

[treeted]

to be fair ive done mine the haynes way (blue book) and its been fine ever since and that was 4 years ago.

[Geth]

Sadly I have just this minute realised that my head is pissing oil and water all down the front of the engine. :cry:

I only rebuilt the engine about 2 months ago. As it was my first engine rebuild I'm guessing I screwed it up somewhere so I'm just gonna refit the head from scratch.

[Geth]

Thinking about it. If I'm going to be refitting the head this is probably a good chance to change the head. I have an old 1.2 head in the shed (that rhymes lol ). Is it worth swaping the head over for higher compression or are there other benefits to the 1.3 head?