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S&S Torque specs

Started by Don D, January 16, 2020, 06:58:03 AM

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Don D

All over the place is all I can say. In the 128 instructions front has a degree method, rear different just tq values. Front up to 35 then 90 deg.
With their torque plates 10, 26, 1/4 turn 90deg same front and rear. I may be old school but always thought tq plates should be torqued the same as and simulate head load on the case and barrel. Thoughts.

kd

It looks to me like they consider the torque plates have less yield than the cases and require less torque for the same tension.  If so there may be a difference between OEM cases and S&S also.
KD

Don D

I get your point. Certainly hardened steel vs aluminum.  The case is harley as there is no S&S part yet. I am not sure many realize how high the actual torque is on these new motors.  35 ft lbs and 90 deg.
Far exceeds values we see on the twin cam. The studs are 7/16 as are the threads. I do see the objective and relevance of not reusing the head bolts.

rbabos

Quote from: HD Street Performance on January 16, 2020, 07:50:20 AM
I get your point. Certainly hardened steel vs aluminum.  The case is harley as there is no S&S part yet. I am not sure many realize how high the actual torque is on these new motors.  35 ft lbs and 90 deg.
Far exceeds values we see on the twin cam. The studs are 7/16 as are the threads. I do see the objective and relevance of not reusing the head bolts.
35+90* is pretty dam tight. Have you checked with a torque wrench where that comes in or foot lbs?
Ron
Ron

Don D

Yes agreed, I am using cometics recommended proceedure. The same as the moco.

rbabos


JMHD

I have seen on a digital torque wrench using factory gaskets and factory torque sequences that after the 90° turn it ends up in the high 50's and low 60's ftlbs.

Admiral Akbar


Nastytls

Quote from: Admiral Akbar on January 16, 2020, 06:18:10 PM
https://www.youtube.com/watch?v=5KS9uk1vguU

What could be done to stop the unevenness of this, more steps in smaller increments? Or is this simply a case of "it is what it is". Also, is this the head deforming or the bolt, or both?

Don D

January 17, 2020, 08:08:15 AM #9 Last Edit: January 17, 2020, 09:03:30 AM by HD Street Performance
I would guess the bolt is stretching beyond its limit, torque to yield bolts reused, and then breaking but Bruce can give us his opinion.


I had not see this video and it is very interesting.

Consider that rebuild shops use torque plates to simulate the load of a head and the bolt torque on top of the barrel. The tech was throwing around methods and numbers faster than I can count but with every change he is changing the preload on the barrel. The barrel dimensionally moves and ring seal can be affected. When done properly in plates, the cylinder leaves a shop on size, true and straight. I hone cylinders, send them out and then the customers use one of a half dozen tightening methods, different head gaskets, and different head bolts? Doesn't sound good. This was not an issue on twin cams as all of this is well established and we were dealing with lower torque values plus studs that had yield, by design.

S&S provides with their torque plate kit G8 7/16-20 x 7 bolts, hardened steel plates, and a torque sequence that leaves the bolts closer to 60 ft lbs after the last 90 deg turn to get their cylinders to measure right. I am not onboard with that.

I may have spoken too soon on a solution.
Bore and hone and ring seal, are very important to a performance build. I will purchase the cylinders unfinished and bore and hone with my plates made out of 6061 with the S&S bolts, factory studs, and cometic head and base gaskets, and S&S procedure published for the bolts. Won't work for every customer due to the cost but at least I can ensure the quality is better and the installation method matches the way they were machined, as close as can be duplicated. Then I will provide instructions for the parts to use, head gaskets and bolts, and method of tightening.

On a side note:
Have a look at SAE J429 for a 7/16-14 bolt torque values for GR8 and GR 5 bolts. It will be an eye opener.

kd

On a side note:
Have a look at SAE J429 for a 7/16-14 bolt torque values for GR8 and GR 5 bolts. It will be an eye opener.


Very interesting at the drop in grade from 2 to 1 if the bolts are longer than 6".  I wonder if that's because of the torsional stress on bolts being torqued as opposed to studs?  I also wonder how the length effects the higher tensile steel studs in grade 5 or 8.
KD

Admiral Akbar

Quote from: HD Street Performance on January 17, 2020, 08:08:15 AM
I would guess the bolt is stretching beyond its limit, torque to yield bolts reused, and then breaking but Bruce can give us his opinion.


When I saw the video, it made sense to me why I've seen evo studs pull out of the cases after a bunch of miles when torqued that way using cometic head gaskets.  IIRC some guy here had a similar issue with a sporty and millennium cylinders (it was likely the procedure and gaskets).  I don't understand why commetic and SnS use the HD M* torque procedure.  Why does SnS use the HD procedure on their cylinders but say to step up to 45 fp on their bolts?

Don D

January 20, 2020, 05:18:50 AM #12 Last Edit: January 20, 2020, 08:30:11 AM by HD Street Performance
A few observations.
The guy in the video does not understand what breakaway torque is. I believe S&S had to change their procedure because the bolts are G8 or better. No more broken bolts and the hardened large studs won't pull out because they have longer amount of thread in the case. I am still concerned about bore distortion. Something has to give.

rbabos

Quote from: HD Street Performance on January 20, 2020, 05:18:50 AM
A few observations.
The guy in the video does not understand what breakaway torque is. I believe S&S had to change their procedure because the bolts are G8 or better. No more broken bolts and the hardened large studs won't pull out because they have longer amount in the case. I am still concerned about bore distortion. Something has to give.
That was the first big error in that vid. :up:
Ron

Admiral Akbar

So instead of using buzz words, why don't you guys describe what the issue is?  I don't see it. What is the guy doing wrong?

Don D

For me there is an issue with multiple specs floating around and a 4 bolt head clamping system with high torque values. That distorts the barrels when installed and there isn't a good way to control bores and assure good ring seal. A manufacturer such as S&S even has conflicting tightening methods. Then in a warranty situation you need to use their plates with gr8 socket head cap screws and steel plates to check the bores. There is a lot of ambiguity. I still don't have specifications from them as to what plus and minus is allowed from the theoretical bore size they consider acceptable.
Bruce you work, or did, in an engineering environment. Something like this would not be acceptable in most industries. Right?

Admiral Akbar

Quote from: HD Street Performance on January 20, 2020, 10:11:36 AM
For me there is an issue with multiple specs floating around and a 4 bolt head clamping system with high torque values. That distorts the barrels when installed and there isn't a good way to control bores and assure good ring seal. A manufacturer such as S&S even has conflicting tightening methods. Then in a warranty situation you need to use their plates with gr8 socket head cap screws and steel plates to check the bores. There is a lot of ambiguity. I still don't have specifications from them as to what plus and minus is allowed from the theoretical bore size they consider acceptable.
Bruce you work, or did, in an engineering environment. Something like this would not be acceptable in most industries. Right?

Well I guess you could leave the head bolts loose? Then you wouldn't have distortion issues.   LOL

I think the thing to do, is to pick a way of torquing the head bolts that is the same for both honing and running.   With HD breaking one common head bolt and the guy finding torque issues with the bolt that is breaking, I pick steps all the way to final.

I still don't understand what "break away torque" has to do with what the guy in video found.

The is a big difference as far as documentation  goes  between, figuring out what is acceptable, and what ends up happening. 

IMO this issue started with HDs procedures and going to a cometic gasket.   My bet is that the stock head bolts will work just fine if the torque to final method is used.  Distortion will be less also. 

VDeuce

S&S torque procedure using their new black head bolts is:

All in proper sequence:

1. Finger tight
2. 10
3. 20
4. 30
5. Alternately back off bolts quarter turn till they are loose
6. Finger tight
7. 10
8. 20
9. 25
10. 30
11. 35
12. 45
13. Wait 15 minutes
14. Recheck torque at 45.

I just did this. Front head was still tight after 15. Rear head had one bolt a little loose after 15.

Durwood

Quote from: VDeuce on January 20, 2020, 05:37:54 PM
S&S torque procedure using their new black head bolts is:

All in proper sequence:

1. Finger tight
2. 10
3. 20
4. 30
5. Alternately back off bolts quarter turn till they are loose
6. Finger tight
7. 10
8. 20
9. 25
10. 30
11. 35
12. 45
13. Wait 15 minutes
14. Recheck torque at 45.

I just did this. Front head was still tight after 15. Rear head had one bolt a little loose after 15.
Those were the S&S specs prior to the introduction of the new S&S bolts also.

rigidthumper

Are any of you using ARP ultra torque on the head bolts?
Ignorance is bliss, and accuracy expensive. How much of either can you afford?

build it

Prescale or "pressure paper" is the only way I'm aware of that gives an indicator of similarities between clamping between torque plates or a block and cylinder head.
Get the principles down first, they'll never change.

Don D

I can see no reason not to use the ARP lube. Consistent preload is a good thing.

kd

Proper procedure for fasteners before assembly has always been a drop of oil applied to the clean and dry threads and surface contact area.  This prevents galling and imparts an even smooth rotation under pressure of the clamping tension.  When a company as focused on high quality "threaded" fasteners as ARP comes out with and recommends their Ultra-Torque Fastener Assembly lube, I see no reason to not use it.
KD

Don D

January 21, 2020, 07:50:51 AM #23 Last Edit: January 21, 2020, 07:57:55 AM by HD Street Performance
So there is a "K" factor in the tightening formula. Zinc plated, dry, cad plated, black oxide, and lubricated all influence the K= number. Without actually measuring the influence of the addition of the arp lubricant on clamp load there is an unknown as far as the required torque. It is likely to be less than if motor oil is used. I am sure ARP have this information available.
By the way a g8 7/16" bolt at 75% yield "waxed" tightens to 38 ft. Ibs. , for example

Herko

Quote from: rigidthumper on January 21, 2020, 05:37:00 AM
Are any of you using ARP ultra torque on the head bolts?

Used it every time on Twin Cams since finding the product.
Would use it on Milwaukee 8s without hesitation if I were still actively in the game.


On Twin Cams:
MLS head gaskets
Thread chaser over the existing stud threads then cleaned
Used new OE nuts, (they were cheap and looked pretty) chased those threads and thoroughly cleaned
(Chasers—not taps and dies)
ARP Ultra Torque
Torqued per Cometic guidance
Never a problem
Maybe I did not need to use ARP UT
But, slept good knowing I had done what I could to equalize clamping load

Cheers.
Considering a power upgrade?
First and foremost, focus on your tuning plan.

Don D

Quote from: build it on January 21, 2020, 06:23:58 AM
Prescale or "pressure paper" is the only way I'm aware of that gives an indicator of similarities between clamping between torque plates or a block and cylinder head.

I have heard of the NASCAR shops measuring stud stretch. Has to take a while on a V8 and not suggesting we go there on these motors.

build it

Quote from: HD Street Performance on January 27, 2020, 04:40:19 AM
Quote from: build it on January 21, 2020, 06:23:58 AM
Prescale or "pressure paper" is the only way I'm aware of that gives an indicator of similarities between clamping between torque plates or a block and cylinder head.

I have heard of the NASCAR shops measuring stud stretch. Has to take a while on a V8 and not suggesting we go there on these motors.

Measuring stud stretch is sop in a good automotive build. My suggestion was born of the fact that Measuring stretch isn't a viable procedure.

Some shops would have their torque plates cast, point is, this is all pretty important and you can actually measure it.
Get the principles down first, they'll never change.