turbo

iTrader: (10)

Most of you know that Chevy decided to use degrees a lot in torqueing bolts. Well I found out through science and math that on the tq wrench what each click equals.

When bolting heads on, you have to tq them down to 22 foot lbs. 2nd pass of 76degrees and 3rd pass of 34 degrees for the shorter bolts.(From GM manual).

9 clicks equals 77 degrees.
4 clicks equals 34 degrees.

Now what you do is set your TQ wrench on the bolt. Go 9 clicks from where you first put it on the bolt. Then TQ is down to where you started.

On most tq wrenchs the clicks are the same. I have 5 different TQ wrenches and they are all the same.

But, who knows if a lot of these TQ wrenches do this. Just thought id share this tid bit info. It worked like a charm for me.

Casey

[ December 24, 2001: Message edited by: turbo ]

[ December 25, 2001: Message edited by: turbo ]</p>

ABNRNGR (Aka Dean)

iTrader: (1)

second and third pass are 90 now,after the 22lbs just mark the head bolt at 12 o'clock and then use the 3 and 6 position

Raughammer

I just use a black magic marker. After reaching the 22 pounds of torque. I mark them at 12 o'clock.

After the first pass they should all be in the 3 o'clock position.

After the second pass, they should all be in the 6 o'clock postion. (The smaller ones on the ends should be adjust to 50 degrees, about the 4.30 postion.

I use an angle gauge and the marker to double check myself.

So far no probs.

But thanks for the tip on the torque wrench.

"On most tq wrenchs the clicks are the same. I have 5 different TQ wrenches and they are all the same."

I wonder if all torque wrenches would click at the same spot...hmmm, next buddy i help out, maybe I can verify what my wrenches click at?

p.s., Y'all put a little moly under the bolt head before tightening it down? (I do)

Thanks again for the tip.

jmX

I 2nd, 3rd, 4th whatever the magic marker idea. I cant imagine it being much easier than that...no counting involved, just look at the lines.

This is the method I descibe in my head-swap document in the sig.

turbo

iTrader: (10)

Where you get 90 degrees and 50? GM manual says 76 and 34...

Dunno but I just went with the what the manual told me.

John your method is very good too. But how do you see the lines while TQing them down? I was going to do that till we started to mess with this idea and it ended up working really well and fast. Either way will work great IMO.

I have the formula in the garage.

Casey

[ December 25, 2001: Message edited by: turbo ]

[ December 25, 2001: Message edited by: turbo ]</p>

jmX

[quote]Originally posted by turbo:
<strong>Where you get 90 degrees and 50? GM manual says 76 and 34...

Dunno but I just went with the what the manual told me.

John your method is very good too. But how do you see the lines while TQing them down? I was going to do that till we started to mess with this idea and it ended up working really well and fast. Either way will work great IMO.

I have the formula in the garage.
</strong><hr></blockquote>

My big fat GM manual for 2000 says 90 and 50 degrees. You turn the wrench what you think is 30-40 degrees, inspect the line, turn it some more, inspect the line again, etc...repeat until the lines are properly oriented.

Pro Stock John

iTrader: (34)

Turbo, you lookin at an older manual?

Check, but it's my understanding that GM revised the tq specs in 1998 to the bigger #'s. That's what all the shops use.

We did the magic marker idea or something like it.

turbo

iTrader: (10)

Ya, theres 2 different ones I guess I have the older one. Bah I will torque the other ones to 50 I guess. The 76-90 ones should be fine though. Who knows, I dont feel like take the valve covers, rockers, etc off.. <img src="gr_sad.gif" border="0">

But think of all the stock 98s out there from factory with those tq settings, or did they goof and just put the wrong tq settings in the book?

What do you guys think? retorque the outside ones but leave the bolts in the middle the same?

Casey

[ December 25, 2001: Message edited by: turbo ]</p>

MrEracer

iTrader: (3)

TURBO has hit on a process we call 'wrench arc' in the aerospace industry... It works great, but I think he did not communicate the process very well...
Let me try... Any ratcheting type (torque) wrench has a fixed number of 'clicks' per revolution which works out to 'X' degree's per click. You can figure this out for your own wrench... NOTE: the 'angle displacement' part of the (GM) bolt tightening process does NOT require a torque wrench, just a ratcheting style wrench handle.
The process is to apply the appropriat initial torque on the bolt using a 'torque wrench'. Then, knowing the number of clicks required to finish the job, place the ratchet/socket on the bolt head and visually note the location of the handle as referenced to some fixed feature that lines up with it. Now, without lifting the wrench off the bolt, BACKOFF the number of clicks required to equal your predetermined angle. Now tighten the wrench back to the original visual reference position you selected for the handle. Wah Lah, you have applied the correct angle to the bolt without having to mark the head and check it several times to get the position correct. This will also be more accurate than the 'marked bolt head' method. If you use the 'wrench arc' process it is important to take all the slop out of the socket/bolt joint IN THE DIRECTION of tightening when you select your reference line/position.
If this is still unclear, ask me your questions and I will try to clarify this method...
Thanks TURBO for bringing this method to our attention...
Shirl

PS, As an Aerospace Engineer, I have studied and analyzed the bolt tightening/retension process to the extreme and you might call me some kind of 'expert' on the subject...
SD

just me

well hell that is a fantastic idea and procedure!
That would be much easier than marking the bolt or using an angle gauge.
Nice tech tip guys.

Steve
www.tech-ls1.com

Terry Burger

iTrader: (4)

Most shops use a torque wrench. <img src="gr_images/icons/wink.gif" border="0">

Smoke_ur_5.0

iTrader: (2)

I think I would feel better seeing the black magic marker lines at certain positions rather than hope my clicks were adequate.

I personally did the marker idea and like it.

Terry Burger

iTrader: (4)

The whole angle torque method is lame. Just use a torque wrench and take them to 25/45/75 #/ft.

jmX

[quote]Originally posted by Terry Burger:
<strong>The whole angle torque method is lame. Just use a torque wrench and take them to 25/45/75 #/ft.</strong><hr></blockquote>

Yeah, screw GM. They dont know what they are doing anyways. <img src="images/icons/rolleyes.gif" border="0">

<img src="gr_grin.gif" border="0">

laSSt one

Federal Mogul makes a cheap angle torque tool Part number TRQ-1.Makes doing the job simple and pretty foolproof.Not completely,but closer than just guessing.

1320

iTrader: (6)

I would bet money that the reason GM decided to do it that way was two part.....

1. an accountant figured out a way to do it cheaper......more bolts pass as ussable , so they use less overall, they don tbuy torque wrenches, other wrenches are cheaper.....or the machine that does it can calculate degrees easier then ft lbs.....same as cheaper.....maybe cause it gets rid of a step or possibly a human possition....

2. People are not bright enough to effectively use a torque wrench.......so looking at lines and knowing time is easier....

Either way the bolt is designed to supply a clamping force with out breaking......so the questions are:

Are oem bolts one use, torque to yeild bolts? or reusable?

Next what is the acceptable strech to acheive adequate clamping?

A couple simple tests can show the answer.....

turbo

iTrader: (10)

Terry, not all the steps are in foot lbs. Its degrees. But unless you measured how many degrees is foot lbs then so be it.

I tinkered with this idea and it worked great. Just trying to help thats all.


Casey