head torque

[supraman508]

I'm about to torque my head down after getting it plained and new valve job.i know to do 3 torque reps.I've only done 20 pounds rite now.I was thinking of 20lbs-40lbs-and 60lbs-.would anybody have a better sequence.could anybody share their sequence so i won't feel stupid again,thanks

 

[castrol supra]

I guess it depends on how high you want to go.

I wouldn't skip 20lbs at a time.
IMO, that's too far a reach between stopping points.
It could lead to a premature retorque.

The more reps you have, in theory. The better it will hold.

Try skipping in 10 and 5 lbs reps.

It seriously can't hurt to torque in more than 3 reps.

To me 3. Is the bare minimum.

 

[supraman508]

I guess it depends on how high you want to go.

I wouldn't skip 20lbs at a time.
IMO, that's too far a reach between stopping points.
It could lead to a premature retorque.

The more reps you have, in theory. The better it will hold.

Try skipping in 10 and 5 lbs reps.

It seriously can't hurt to torque in more than 3 reps.

To me 3. Is the bare minimum.

makes sence.thanks

 

[supraman508]

I guess it depends on how high you want to go.

I wouldn't skip 20lbs at a time.
IMO, that's too far a reach between stopping points.
It could lead to a premature retorque.

The more reps you have, in theory. The better it will hold.

Try skipping in 10 and 5 lbs reps.

It seriously can't hurt to torque in more than 3 reps.

To me 3. Is the bare minimum.

before i was going to do 20-40-60.but would'nt that only equal to 60lbs total?

 

[MA70witBoost]

before i was going to do 20-40-60.but would'nt that only equal to 60lbs total?

yup... only 60. tourque wrenches are designed to click at the specified tourque. no passing that unless you dont know how to use a tourque wrench.

 

[TurboFreak]

Hmmmm. Why have I never know to torque them in sequence???? WTF?

 

[suprarx7nut]

You can read my lengthy explanation in my sig.

Shouldn't you be going past 60? I thought around 70-75 is where you want to be for the bolts. :dunno:

The studs were @ 80 per ARP's instructions.

 

[castrol supra]

Yes. Above 60 is your friend.

I took my ARP studs to 85lbs. The 1st session.

I'm going to 90lbs on my retorque.

Now to be fair. Some people say it depends on the head gasket used as well.
I don't think you would hear too many people say below 70lbs.

 

[IJ.]

I do mine in sequence using 3 passes ending in 5lb's under the desired setting, I then run the car through 3>5 heat cycles and retorque +5lbs.

The idea with the 3 passes is so you're NOT bending the head at the bolt/stud you're pulling down.

 

[castrol supra]

I'm not sure I follow, nor am I seeking conflict.

But if you're going to the same torque spec. at the end of the tweaking.

How does it put less force on the head by going lower reps and a higher torque spec with each pass?

Just the duration of time it takes to do the entire sequence? It seems like it would put less stress on the head, to go more reps and a lower torque spec. Reaching the original objective.

 

[cuel]

Most manufacturer's torque specs use 15 to 25 ft. lbs between passes, with an initial pass from 20 to 30. I.E.: The 3.1 v-6 Chevy I did last week was 22, 35, 55, then 55 again. Loosen one turn(bolt sequence in reverse), then tighten to 22, then 90 degrees(1/4 turn).

I'd probably start at 25 ft. lbs, then 45 ft. lbs, then 60 ft. lbs, then 72 ft. lbs., on my own 7m with stock bolts. If you'd prefer to use IJ's method of doing the last pass after a few heat cycles, I'd do 25, 40, 55, 70, run the heat cycles, then 75. For ARP's, use the torque ratings they recommend in the instructions.

 

[IJ.]

Cuel: Ummm that's EXACTLY what I said wasn't it?
(apart from only 3 passes)

 

[cuel]

Yeah, I know; I was hoping that a more detailed description would, be more helpful to the OP, and future readers. I was also hoping to refute the 5 to 10 lbs at a time theory, which would take all day for a half hour job, and isn't necessary. No offense

Edit: aluminum is soft, but we're not talking about lead here. It won't become misshapen, or stressed, under a 20 lb. difference. Especially not something as thick as this head is. Unless, of course, its already been damaged due to extreme overheating, which has been pointed out numerous times by those wiser than I.

 

[castrol supra]

If all instructions were right we would be torquing these things to 59lbs and calling it good.

One of you says the head can bend at the stud you're tightening and one of you says it won't.

If I were a complete nube. I'd say someone is full of it. But I know niether of you are.
Well, completely anyway :icon_razz.

Joke guys.

The place where the washers sit is not quite as thick as the entire head.
Again not being hostile? Just trying to get to the bottom of some things and I appreciate everyones time.

Thank you all very very much.

 

[IJ.]

My point about the head deforming is when noobs pull it down to 85ft/lbs in one pass.

3 passes is plenty.

The heads on these motors aren't as "strong" as you seem to think, I was shocked when I sectioned one.

 

[suprarx7nut]

The heads on these motors aren't as "strong" as you seem to think, I was shocked when I sectioned one.

Pics of said sectioning? Please?

 

[IJ.]

[thumb]http://ij.supramania.com/head6.jpg[/thumb]

 

[suprarx7nut]

Whoa, very cool, IJ. Thanks!!!

Right click save as...

 

[IJ.]

I have a bunch more but I wanted good res so they're HUGE files

I did this BEFORE handing my brand new head to the porter so there wouldn't be any "wet surprises" when I got it back.

 

[Tanya]

I torqued mine (5M head) 25 > 50 > 75ftlbs. Then I stupidly forget to retorque after a couple days of driving. Waited a month and found that the bolts and worked themselves down to around 55 ft/lbs. Retorqued to 75. Will probably check them again in a week or so.