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Thread: Crank Tech
06-15-2012, 08:26 PM #61
08-01-2012, 05:12 PM #62
Just wanted to throw something out about the 9/16" stud.
Going off the part number Ed sent for the 9/16 stud I called ARP to ask about a torque. I believe it was Sam I spoke with. He mentioned I should torque the nut up to about 140ft-lbs. He said I could go more(up to 160ft-lbs), but said to only do so if I have lots of thread engagement.
What have you guys that have done this torqued your nut on the stud up to?
Also another question for you Ed. Now that the hole is larger the damper install tool won't work. Did you pull the damper on with the nut and washer for the stud or did you find a different install tool that is built for the 9/16" hole and then install the stud into the snout after you installed the damper?
08-01-2012, 05:28 PM #63
If you bore the hole to the depth in the drawing you will have 2.5 diameters of thread engagement, maybe a little more. When it is in steel it's more than adequate to properly torque the damper. Additionally you would have a very high percentage thread engagement. While I don't recall the exact number off the top of my head I believe it was in the high 70's like 75 to 78 per cent range. The ARP torque spec for a 9/16" ARP 8740 fastener is 180 ft/lbs with ARP UltraTorque. The spec for a ARP 2000 9/16 fastener is 200 ft/lbs using Ultra Torque. 140 ft/ lbs is below their spec for a grade 8 fastener and 140 is off the bottom of the chart.
The stud can be used to pull the damper onto the snout. It has adequate length to get the job done. You could mke a 9/16 specific tool if it was adequately important to you - it just wasn't for me.
Last edited by eschaider; 08-02-2012 at 11:15 AM. Reason: spelling
08-01-2012, 07:39 PM #64
So crank the stud down to 180ft-lbs then Ed? I ended up having to get a slightly shorter stud then the 5.25 you have as mine wasn't tapped as deep. So I have a 4.75" stuf. Still the same amount of threads on either end though. I should go at least to 170ft-lbs then correct?
08-02-2012, 12:08 AM #65
You are right on the money Schyler. In fact as long as you had to buy the 250 ft/lb torque wrench to get to the 170 number you ought to go to 180.
The difference between 8740 and 2000 steel is not as much as people think. ARP used to say 8740 steel could be heat treated to deliver tensile strengths between 180,000 and 210,000 psi. I have attached a page from an earlier catalog where they talk about their steels. The 8740 steel has a tensile strength ceiling between 180,000 and 210,000 psi according to ARP. By way of comparison ARP 2000 is rated from 215,000 to 220,000 psi. The 2000 steel strength window is both narrower and higher than the 8740 window but it is not a lot higher.
In later catalogs ARP began to compare 2000 steel to L19 instead of 8740 and they also changed their claimed UTS window to reflect 180,000 to 200,000 psi for 8740 steel. I suspect the earlier published closer mechanical properties for 8740 and 2000 steel was pulling sales from the 2000 steel products. In an effort to position the product, the 8740 numbers were apparently de-emphasized and L19 was used as the comparison standard.
The bottom line to all this marketing and product positioning is that 8740 is pretty tough stuff and to under torque it invites failures of the type ARP discusses in their catalog section metallurgy for non-metallurigical engineers. I would use the 180 ft/lb spec they publish for the material with UltraTorque (be sure to use UltraTorque) and live happily ever after. Remember you are after improving the clamp load on the damper to prevent it from moving on the snout. This stud definitely does it at 180 ft/lbs and you are still safely inside the stretch and load windows for the steel - although 180 ft/lbs is a grunt to tighten to.
08-02-2012, 02:43 PM #66
- Join Date
- Jul 2006
- San Jose, CA
Would it make sense to throw the damper into the oven for a while before you install it?
08-02-2012, 03:00 PM #67
Ford actually built a small lead in chamfer onto the damper, Mark. A little oil on the snout OD and the damper ID should be all you need to get them together nicely.
The problem with the oven alternative is the degenerative effect on the elastomer holding the damper hub and ring together. As attractive as the heating solution is for assembly reasons, I would shy away from it because of potential damage to the elastomer.
08-02-2012, 03:07 PM #68
- Join Date
- Jul 2006
- San Jose, CA
My next question, had you said yes, would have been "what temperature?"
I was actually wondering why they say not to use the stock bolt to install the damper, unless it is TTY bolt. Then I got to wondering if the interference between the crank and damper would screw up the torquing process...
08-03-2012, 03:04 PM #69
In general I am not particularly impressed with metric fasteners in their commercially available property classes. The exception to that comment is the ARP metric fasteners. ARP uses the same super steels in their metric fasteners as they do in their SAE fasteners. Other than ARP all things being equal my preference would be to replace the metric fastener with an SAE fastener of approximately equivalent size.
For our Terminator application I would give considerable thought to replacing the OEM 12MM metric fastener with the 9/16" ARP stud modification I have written about on the site. I think the 12MM fastener in the end may be a contributing factor to various engine failures we have seen. At the very least the 9/16" stud will push out the failure horizon. One of the nice by products of the 9/16" stud mod is it makes damper installation a breeze.
02-01-2013, 07:08 PM #70
Ed, I'd like to re-visit this thread. I understand the rationale for stud use on Terminators...or any high torque/horsepower setup. I have thought of going the stud route on my 2V N/A motor...not because it's a high torque/horsepower setup, but rather because it is no longer stock. I have recently installed high seat pressure valve springs, and will utilize IronHand Racing 12mm cam stud setup. But that got me to thinking about "the other end" so to speak...the crank gears. I will be using the Trick Flow 2 piece adjustable crank gears, and thought the stud solution for my crankshaft would be good insurance, and a increased clamp load on those 2 crank gears. The cast 2V crank I utilize has the same undercut filet you mention early in this thread. I have a solution in hand that will not involve any drilling or tapping of the crankshaft. Obviously not any good for Terminators...but it may have application for other engine setups. Thoughts?
02-02-2013, 12:18 PM #71
I would certainly be and I believe others would also be interested in your approach. As you can see from what follows my entire snout fix is somewhat demanding and requires substantial work. That's the down side. The upside is it is the best fix so far that addresses all of the OEM design shortcomings. If your fix does also it is something we should give a lot more visibility to because my fix is neither easy nor inexpensive. For convenient reference I have packaged the whole fix and problem resolutions to this post.
The studded crank snout was/is not just for engines with a substantial power draw off the snout of the crank, although it is especially welcome there. It is for any ModMotor snout even n/a snouts.
The challenge with our crank design is that the snout diameter Ford gave us is relatively small to start with, which means the twisting force necessary to literally twist it off the front of the crank is smaller than a larger snout like an LS series GM engine. Naturally aspirated this is not good but it is also not a show stopper. The problem is aggravated by the undercut radius ford puts at the juncture of the end of the first snout journal and for that matter every other journal on the crank. Put a PD blower on top of the engine and drive it off the front of the rank and everything changes.
If you use a harmonic damper, that actually works, it adds yet another torsional torque load to our already fragile crank snout. The OEM crank bolt aggravates the issue by effectively trying to pull the crank's snout off the front of the crank as you tighten it down to hold the damper, timing gear(s) and reluctor wheel to the front of the crank. The OEM fastener approach is the rough equivalent of standing on a board with a bucket nailed to it and then pulling up on the bucket's handle while twisting the bucket back and forth simulating the effect the damper is imparting to the crank but in our example we are imparting to the bucket.
As we all know this is how you go about tearing the bucket off the board if you have no way to remove the nails. In practice this is exactly what the damper is doing to our crank snout. Well lets just remove the damper you say. Not so fast the crank has a natural oscillation it experiences, in service, that if allowed to continue undamped will break the crank. So we need a damper that actually works, without itself breaking the crank. That is the reason for the crank stud modification.
By anchoring a larger, stronger stud deep in the crank and then tightening the nut down we not only get a much greater clamping force holding things like the timing gears in place we also benefit from what I call the sandwich effect. Now instead of trying to pull the stid off the front of the crank like that bucket off the board, we are using the stud to clamp everything together with an impressively high clamp load and removing any tensile loading that had previously tried to pull the snout off the crank. At this point the crank snout only has to survive the (not insignificant) torsional loading from the damper and the blower drive.
To aid the snout in this endeavor it needs to be increased in diameter. The snout diameter increase was the last part of my fix. in this step I increase the snout diameter to 1.400" and use gentle radii to bring the snout diameter back into the next journal on the front of the crank. This next journal is the one that is normally used to drive the OEM oil pump. This journal is increased to 1.875" as you can see from the drawing below.
Once you do this you can not use an OEM oil pump which is sort fo good because you eliminate a frustrating cause of lost engines. You now have to use a external oil pump. It can be a dry sump or an external wet sump where the oil pickup enters the side of an otherwise stock oil pan using something as simple as an AN bulkhead fitting.
Below is a picture of my finished crank. To get a sense of how much larger the snout and surrounding area are, compare those diameters to the #1 main journal and you will get a sense of just how robust the front of the crank has become. When you do this it is more cost effective to start from a clean sheet of paper and do the crank as a billet.
You will also need a custom damper to accommodate the new larger diameter snout. You will also need new timing gears because of the upgraded snout. I used a pair of cloyes billet timing gears and machined them to be identical single gears but with increased width and key contact for both stability and precision in indexing. This involved a little puzzle time to maintain the drive chains correct position relative to their corresponding driven cam gears and still maintain proper positioning relative to each other. While I was at it I added multiple keyways for advancing and retarding the exhaust cams to make cam phasing easier for me. Here is a drawing of the gear.
If you elect to do something like this you can have the advance retard marks laser marked on the finished gear.
Last edited by eschaider; 06-12-2016 at 05:46 PM. Reason: forgot timing gear drawing
02-02-2013, 01:58 PM #72
OK, picture first...explanation to follow in a bit:
01-24-2016, 10:15 PM #73
- Join Date
- Dec 2014
Guys running the stud on the 03-04's does the stud/nut interfere with the stock caged lower?
Kind of picture it sticking out too far not allowing the caged lower to fully thread on.
Ed can you confirm part numbers for the stud, washer and nut?
Thanks in advance everyone
01-25-2016, 10:23 AM #74
This chart should help with fastener specs and part #'s Dave.
p.s. unless you are using an external oil pump and other similar gadgetry you want the 4.75" long stud hence the 4.75 in the part #
Last edited by eschaider; 01-25-2016 at 10:26 AM. Reason: Added postscript.
01-25-2016, 03:38 PM #75
Ed, since this thread popped up again I am going to head over to the shop and get the mfg and part number of my after market damper.
I wanted one that didn't have the elastomer in it, but would still allow the crank support to be used and I could only find one. I got it used from an 03 Cobra owner that was going turbo and didn't need it any more.
Found the info. It's made by Innovators West http://www.innovatorswest.com/813-MOD-Damper.html
I will be sending it into them to be checked out before I use it. Do you have any opinions on them or changes I need to make in either the crank studding process or anything else?
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