Crank slip? maybe easy fix.

[SilverDemon]

Let me rephrase my statement.

You was able achieve 250lb ft on the bolt before the 90° as stated in the FSM?

[phate]

Originally Posted by SilverDemon Let me rephrase my statement. You was able achieve 250lb ft on the bolt before the 90° as stated in the FSM?

Correct, I hit 250lb-ft well before the 90°.

[SilverDemon]

It sounds like dturboman needs a refund from the shop that built his motor then...because the new unicorn ARP bolt is not going to do squat.

I would like to calculate the amount of torque that I put on my crank bolt then, I used ultra lube and was almost able to achieve the full 90°

[Tomas]

Not surprised about the massive amounts of torque going on that crank bolt.
I did the stock head bolt torque to angle equivalent tests but the results were a little skewed and I have to redo them again with the block secured on some king of jig.

Using ARP ultra torque - from the initial 35 lbs going to first 90* angle I set the torque wrench on 60 lbts and the bolts turned 59,51,69,51,59,51,58,79,51,69 degrees. So 60 lbs on the torque wrench didn't even get me past the first 90 pass.

After that I set the torque wrench on 80 lbs and got all bolts to the first 90 deg.

After that I set the torque wrench to 90 lbs and that's where the results got all fucked up. I got 75,40,48,15,70,89 degrees till it clicked and 4 of the bolts went all the 90 degrees without passing 90 lbs. The problem is that the block on the engine stand was moving all over the place and there was no concistency in the way I was holding the TW to clamp down the bolts so as said earlier, I need to redo this with some kind of jig or on an engine installed in the car.

Don't want to sound all allmighty and righteous but for 427th time I am telling you the ARP torque specs for the head bolts are way way below what they should be. Angle > torque. Like Phate showed above it seems it's the same story for the crank bolt.

[Dano]

Originally Posted by phate Correct, I hit 250lb-ft well before the 90°.

I was def in the camp of thinking that 90* adds a shit ton of TQ. When your laying on the garage floor, holding a 3' breaker bar in one hand, spanner in the other and trying to wedge yourself against the bumper support to get traction...well it's a lot of force.

I ended up placing my spanner against the LCA with a 4x4 between the two to make up the slack. Even then it is a motherfucker to get to 90*...I think my back is still curved to one side.

So what we have learned so far is a dry bolt at 250lbs will NOT be tight enough by a long shot. Good god 360ft/lbs

in for the lubed results.

ya think the bolt and threads can handle a fully lubed run to 75+ 90*? guess we'll find out.

Thanks Phate!!

[timjs]

I'm not a heavy guy and I can tell you it takes a 4 foot breaker bar for me to get the 90 degree turn after the 75ft lb initial torquing.

[phate]

Just so you guys know, I didn't hold the crank pulley with anything except that little bolt ♥ It wasn't until I wasn't thinking and tried to go backwards did it shear the bolt off, haha....nothing to hold the crank until you turn it a ways.

[Dano]

Same here the 1st time around so idk what happened on my fail turn. Well I know what happened but not why. Lol.


Tappin

[superskaterxes]

so using a 500 ftlb impact wasent such a bad idea after all eh? haha

[phate]

Originally Posted by superskaterxes so using a 500 ftlb impact wasent such a bad idea after all eh? haha

Unless you measured rotation, it was probably not such a good idea.

[superskaterxes]

Originally Posted by phate Unless you measured rotation, it was probably not such a good idea.

the mazda god and 3 500whp builds say differently haha

[dturboman]

well fuck me, 250+ shit... dam you ARP and your 155 tq spec.

[Tokay444]

How many are running?

[phate]

I fixed my timing cover long enough to finish the testing

Same setup for the Ultra Torque:

Step 1) 25lb-ft to 76lb-ft: 21.5° Dry -- 25.5° UltraTorque
Step 2) Let cool, double check after 25 minutes, no further movement
Step 3) Increments of 10lb-ft, measuring rotation at each step

Here's all of the data combined into one table. Far right columns are Ultra Torque, I just tacked these onto the original dry thread table so I could use a pivot chart to compare.



And here's the graph of the data, comparing the rotation vs torque between the two setups:


As you can see, 250lb-ft still wasn't enough to reach 90° of rotation after the initial 75lb-ft. We got way closer - ~20°, but still not there.

I'm really not sure that a linear projection would apply to the bolt beyond the ~80° total rotation. Since the bolt didn't stretch at 77° total in the first test, but did stretch in the second test somewhere immediately after that point, we're getting into the plastic behavior of the metal.

Since the bolt for the dry test didn't stretch, I used it for this second test. That gave me an extra bolt to test with, so I went with the FSM suggested sequence of 75lb-ft + 90°, and got a stretch measurement for it, as well. Here are all of the initial, final, and stretch measurements.



Why the 76° bolt and 90° bolt are stretched exactly the same, I'm not sure. It could be the accuracy of my caliper isn't great enough to measure the difference. 14° of rotation is ~4% of a total turn, and the threads are say 1.5mm....giving us a stretch of ~.0023". Again, not sure why we aren't seeing this in the stretch measurement.

Moral of that whole story:

For the OE bolt, go by the FSM for tightening this bad boy. If you don't use anything on the threads, you might consider going an additional 5-10° to overcome that little bit of friction encountered going to 75lb-ft.


PS - I uploaded the workbook if you want to check it out.

Edit - As of 6/7/2013, we have some data for the ARP crank bolt - The most awaited build in MSF history

[ms3blackmica]

Plastic deformation is no bueno

[phate]

Originally Posted by ms3blackmica Plastic deformation is no bueno

Plastic deformation is what TTY bolts are designed for, no?

[ms3blackmica]

Originally Posted by phate Plastic deformation is what TTY bolts are designed for, no?

Yes they are. Sorry somehow this ipad decided to put "no" in front of bueno lol

What I meant was that on your 2nd test you were able to discover that the bolt did stretch (no longer in the elastic region). This is bueno because we now have an idea of where the yield point is and uniform plastic deformation begins.

If the bolt enters into a nonuniform plastic deformation region then you have loaded it beyond its ultimate strength and the bolt is wasted.

FWIW, I have access to tension test equipment at school in the Mechanical Engineering lab. I have done tension tests on steel rods several times. I can perhaps try and test the factory and ARP bolts and plot stress vs strain for you guys.

[Tokay444]

Do it.

[phate]

Originally Posted by ms3blackmica Yes they are. Sorry somehow this ipad decided to put "no" in front of bueno lol What I meant was that on your 2nd test you were able to discover that the bolt did stretch (no longer in the elastic region). This is bueno because we now have an idea of where the yield point is and uniform plastic deformation begins. If the bolt enters into a nonuniform plastic deformation region then you have loaded it beyond its ultimate strength and the bolt is wasted. FWIW, I have access to tension test equipment at school in the Mechanical Engineering lab. I have done tension tests on steel rods several times. I can perhaps try and test the factory and ARP bolts and plot stress vs strain for you guys.

That would be cool if we could equate the strain to rotation Do you think it would be a direct comparison?

Glad to see you're back @Tokay444.

[Tokay444]

Thank you. Glad to be back. Even if it is as Kermit.

[ms3blackmica]

Originally Posted by phate That would be cool if we could equate the strain to rotation Do you think it would be a direct comparison? Glad to see you're back @Tokay444.

Not sure. I may have to pull out the text books to answer that question in confidence. However, at least to answer you with something..

If you can develop the stress vs strain diagram for the bolt, you can easily determine the corresponding strain where the ultimate strength point lies. If you know the strain @ the ultimate strength (from graph), the original length and the length after loading then you could determine at what value of torque/rotation the bolts ultimate strength was achieved.

strain = (change in length) / (original length)

For example, lets say the ultimate strength point lies at 0.2 in/in and the original length is 2". That would mean that the ultimate strength is reached when the bolt elongates by 0.4".

A test like that would require you to waste bolts however which is costly and there are some margins of error but you could be in the ballpark. Let me see what I can dig up for you.

I assume ARP has already done such testing, perhaps we could request such data from them? I would like to see the stress vs strain diagram of the arp bolt vs the stock bolt. I think I need to do this

[Tokay444]

The question is, do we exceed uniform plastic deformation with the factory procedure?
Are we in turn, lessening our maximum clamping torque by going the full 90*?
I would/hope not. But with phate's TW only goes to 250lb/ft, we need a better test bed.

[Rokusek]

Good work so far @phate; this is definitely something I'm going to be following. Hopefully you guys get some more info on this before this weekend!

[Ziggo]

We would need to know the relationship of the ultimate strength to the yield strength to determine the effect on preload, to get that you just need the material of the bolt and then look up the information. No need to repeat tests.

Usually those ME lab tensile testers are not strong enough to handle much other than small coupons. This bolt would probably overload it.

[ms3blackmica]

IIRC the one we use can apply over 75,000 pounds of force

Originally Posted by Tokay444 The question is, do we exceed uniform plastic deformation with the factory procedure? Are we in turn, lessening our maximum clamping torque by going the full 90*? I would/hope not. But with phate's TW only goes to 250lb/ft, we need a better test bed.

That is basically my point.

You would be in fact lessening your clamping force if you went beyond uniform plastic deformation. Does anyone know the factory crank bolts material?

[jmhinkle]

Pretty sure it is unicorn cock.

[06Speed6]

Im gonna be pissed if the ARP bolt is weaker than the oem bolt.

If I am understanding you guys correctly, on the ultra torque graph I would not want to torque past 215'lb because the actual clamp is lower? Arp specifies 244'lb for their bolt which should be the maximum stretch before their bolt yields. If I am compairing apples to apples that makes their bolt 13ish% stronger than the oem bolt.

[Ziggo]

Originally Posted by ms3blackmica You would be in fact lessening your clamping force if you went beyond uniform plastic deformation. Does anyone know the factory crank bolts material?

No, just because it's plastic deformation does not mean you are losing preload. The ultimate tensile strength can be significantly in excess of the yeild strength, it just depends on the material.

Zigatapatalka

[ms3blackmica]

Originally Posted by Ziggo No, just because it's plastic deformation does not mean you are losing preload. The ultimate tensile strength can be significantly in excess of the yeild strength, it just depends on the material. Zigatapatalka

You are 100% correct ziggo.

The ultimate tensile strength can in fact be significantly greater than the it's yield strength.

My assumption is that these guys are looking for the maximum clamping force the bolt could provide

[Dano]

Originally Posted by superskaterxes so using a 500 ftlb impact wasent such a bad idea after all eh? haha

Originally Posted by phate Unless you measured rotation, it was probably not such a good idea.

Originally Posted by superskaterxes the mazda god and 3 500whp builds say differently haha

back tracking just a bit here but that is def not a very precise way to torque the pulley bolt, or any bolt for that matter. Too many variables with an air impact gun..the older they are the less power they output just like a motor...air escapes past the cylinder and you get less TQ. Not to mention even on a brand new one keeping the air supply regulated to the gun is difficult and the multiple "impacts" more than likely have undesired results on a TTY bolt and stretch.

OEMs use air TQ wrenches to assemble motors but those are a totally different animal.

Great work Clint...very telling indeed.

[dturboman]

I'm still thinking the LS1 style pin kit is something worth looking at for those who are not pulling their motor.

[Tokay444]

That's a quick easy fix, if this is ACTAULLY a problem, and not an issue with whoever is building your motors.

[dturboman]

Originally Posted by Tokay444 That's a quick easy fix, if this is ACTAULLY a problem, and not an issue with whoever is building your motors.

guess we will never know... but its cheap and easy insurance.

all LS1 that push high HP must have this pin kit, they say they will slip when you start adding more power to them as well.

This might be the easy fix.

[Ziggo]

They all also drive a few more cylinders worth of valves and the high power ones all have high lift cams and probably stiffer valve springs.

Zigatapatalka

[silvapain]

Originally Posted by Dano back tracking just a bit here but that is def not a very precise way to torque the pulley bolt, or any bolt for that matter. Too many variables with an air impact gun..the older they are the less power they output just like a motor...air escapes past the cylinder and you get less TQ. Not to mention even on a brand new one keeping the air supply regulated to the gun is difficult and the multiple "impacts" more than likely have undesired results on a TTY bolt and stretch. OEMs use air TQ wrenches to assemble motors but those are a totally different animal. Great work Clint...very telling indeed.

OEMs also calibrate their pneumatic wrenches daily.


Tapadatass

[dturboman]

Originally Posted by Ziggo They all also drive a few more cylinders worth of valves and the high power ones all have high lift cams and probably stiffer valve springs. Zigatapatalka

if pinning works for their 1000+hp builds it should be a nice little piece of insurance for us.

$75 fix.

[06Speed6]

Ide have to look at our crank and balancer again, I dont remember it looking very easy to pin.

[dturboman]

Originally Posted by 06Speed6 Ide have to look at our crank and balancer again, I dont remember it looking very easy to pin.

Give the pulley/crank a little tack and drill at the pulley/crank seam... insert pin = win.

[Tomas]

You make it sound like drilling into the surface hardened snout of the crank is so easy. I don't think a carbide bit would do the trick. More like some kind of abrasive would be necessary.

[dturboman]

Originally Posted by Tomas You make it sound like drilling into the surface hardened snout of the crank is so easy.

I know , I also prefer to use C4 when i drill.