What is the Torque sequence for a SR16VE Head?


I found this but i think its for a SR20DE:
Tighten all bolts to 29 ft-lbs
Tighten all bolts to 58 ft-lbs
Loosen all bolts completely.
Tighten all bolts to 33 ft-lbs
Turn all bolts 90 , then turn another 90 degrees
*Note: When putting the headbolts in please dip them in oil before install.

Would this work?

No that wont work.

Torqing to the correct stretch then backing off is fine.

However you cant torwque to 33, then turn another 90. Every bolts strecth will be different and when your torquing to an unstretched range you wont know the correct torque value. I would go to 72 on your final spin. Stating from the centre out in opposites.

No that wont work.

Torqing to the correct stretch then backing off is fine.

However you cant torwque to 33, then turn another 90. Every bolts strecth will be different and when your torquing to an unstretched range you wont know the correct torque value. I would go to 72 on your final spin. Stating from the centre out in opposites.

Why not?

The above sequence is correct, it's straight out the fsm for the sr20 engine family.

Why not?

The above sequence is correct, it's straight out the fsm for the sr20 engine family.

If he is reusing old bolts it will be different.

No harm in being mor accurate then the FSM

If he is reusing old bolts it will be different.

No harm in being mor accurate then the FSM

LOL, how is your way more accurate than Nissan?

Your recommendation to go 72 ft/lb for the final torque is very inaccurate because is affected by the lubricant and condition of the surface of the bolt and cylinder head. But don't take my word for it.

Here a quote from George Lorimer, Retired. G.M. Powertrain Fastener Lab.

"one of the biggest variables that affects the proper tightening of a joint...friction...
When you tighten with a torque wrench, you are in effect measuring the amount of friction being generated by the mating surfaces in the joint and as the clampload is increased so is the torque. You can see that there is some relationship between torque and clampload. This relationship is determined by the amount of friction in the joint as well as the clampload being developed... The really big problem is that you cannot measure or predict what the absolute value of the friction is in the joint. If we could , there would be no need for tightening procedures other than torque. We can however, minimize the effect of friction by using lubricants, and zillions have been tried with varying degrees of success. among these have been grease, chicken fat, oleo, mayonnaise, graphite, teflon, plastics and encapsulated formulas that smash and liquify under pressure. however sophisticated they have all fallen short of the goal of absolute friction control. What can we do if we can’t control this continuous variable thing called friction?? The simplest is to utilize the fastener itself to obtain the clampload by rotating a given angle from some starting point called a threshold. The threshold is usually a low level of torque chosen because the clampload variation is less at low torque. the bolt is then turned to an angle and the result is an acceptable level of clampload. And you say ....why? And I say, because now that we are turning through an angle we no longer care about friction and its effect. Remember the thread around the bolt is a continuous spiral and if one turn is straightened out you have an inclined plane that has the height of one pitch of the thread in 360 degrees or one turn."

LOL, how is your way more accurate than Nissan?

Your recommendation to go 72 ft/lb for the final torque is very inaccurate because is affected by the lubricant and condition of the surface of the bolt and cylinder head. But don't take my word for it.

Here a quote from George Lorimer, Retired. G.M. Powertrain Fastener Lab.

"one of the biggest variables that affects the proper tightening of a joint...friction...
When you tighten with a torque wrench, you are in effect measuring the amount of friction being generated by the mating surfaces in the joint and as the clampload is increased so is the torque. You can see that there is some relationship between torque and clampload. This relationship is determined by the amount of friction in the joint as well as the clampload being developed... The really big problem is that you cannot measure or predict what the absolute value of the friction is in the joint. If we could , there would be no need for tightening procedures other than torque. We can however, minimize the effect of friction by using lubricants, and zillions have been tried with varying degrees of success. among these have been grease, chicken fat, oleo, mayonnaise, graphite, teflon, plastics and encapsulated formulas that smash and liquify under pressure. however sophisticated they have all fallen short of the goal of absolute friction control. What can we do if we can’t control this continuous variable thing called friction?? The simplest is to utilize the fastener itself to obtain the clampload by rotating a given angle from some starting point called a threshold. The threshold is usually a low level of torque chosen because the clampload variation is less at low torque. the bolt is then turned to an angle and the result is an acceptable level of clampload. And you say ....why? And I say, because now that we are turning through an angle we no longer care about friction and its effect. Remember the thread around the bolt is a continuous spiral and if one turn is straightened out you have an inclined plane that has the height of one pitch of the thread in 360 degrees or one turn."



yes you are right.

The one major problem with threshold loading is that it does not increase the surface to thread area contact - at any given time the torque is always being trasnferred along the thread surface, changing in peak points as you turn the bolt.

However

Oil compresses - only 15% of a thread on average comes into contact with the mating surface (ie block). The oil will carry an extra 30-40 of the surface friction - to which point it compresses - and eventually through engine cycles will move (oil is a fluid - ***).

This is why you use a copper cote (koppa kote) paste - as the paste will never move - but will increase thread contact by over 50%!!! This gaurantees what you read on your gauge is accurate - hence no need to extend the torque. ELIMINATING the need to angular torque.

The other issue with turning past torque and aiming for angular load is because the bolt may stretch out of its tensile state - because of fatigue and heat. You may end up with a situation where the bolt has gone to 42ftlb - turned 90 - but all of a sudden has copped a heap of stress and will no longer retain an accurate 42lbs of pressure at the nose.

IF you follow a procedure of torquing - then undoing and retorquing - the oil that is applied to the bolts will spread mostly evenly up and down the thread - and you can near assured your torque reading is accurate.



I always torque my metal gaskets up for a day - let the steel compress and stretch - then the following day crack the bolts and re torque.