Ad: VTT "Spline Lock" Crank Hub Solution Now Available!

Oct 24, 2016
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VTT is proud to finally announce our "Spline Lock" crank hub solution for the N54/N55/S55 BMW platforms. After 8 months of testing, and 10+ design changes we arrived at our final design, and exhaustively tested it on the bench, and in our shop test vehicle!
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The way this product works is very much like a Splined extractor -for example: https://www.toolsource.com/images/pr...200Wx1200H.jpg.

You have an extractor with splines machined into it that is pressed or hammered into a broken off nipple or fastener. As you turn the extractor one direction it will lock itself to the nipple, and spin it out. Our hubs are machined to a very close tolerance and are a specific press fit for the crank. You use the crank bolt to install the hub just as you would a stock hub, but for these, you have to lock the crank first, and as you tighten the bolt you will press the splines into the crank creating teeth, and it will be locked. The teeth are designed in such a way that if you have an event that would normally slip a stock hub the teeth will be forced deeper into the crank not allowing it to spin. The benefits of these are two-fold.

1. A positive locking hub.

2. No additional labor to completely disassemble your motor, drill, and pin your crank.



Some may wonder why did not make a complete CNC hub including the oil sprocket -a good question, and one we tried while testing. We found the oil sprocket is almost never to blame when you slip a hub. You are trying to maintain the crank to cam timing, and this is lost either two ways in almost every test we saw. The most common failure method was the single grip disc between the timing sprocket and the hub would slip first. Going with a one-piece hub/timing sprocket locked to the crank eliminates that failure point. The second most common failure method is the bolt itself would spin loose causing this first grip disc to slip, and timing to be lost. Coupling the "Spline Lock" hub with our Crank Bolt Capture eliminates this failure point as well, which is why we suggest running the CBC with the Splined hub.

Couple photos (Yes we know the oil gear is on backward, was easier to get the splines in the photo that way)

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We created a testing rig using cut off the end of an N54 crank, and a hydraulic pump to simulate the crank spinning on the hub. We used this to see how easily we could slip a stock hub compared to our new design, after about 10-12 revisions we had one that broke the rig before slipping. We went with that design, and have since had it in our shop car without issue spinning high RPM, and making around 900WHP.

The hubs are CNC machined from very tough hardened 14-7SS, and can take anything we can throw at them.

The hubs are available in these configurations, and we will run an intro special for the rest of the week (until Monday 10/22/18).

We offer the hubs in 3 configs:

  • Hub Only - $699 (Intro Price $599)
  • Hub plus OEM bolt, OEM Oil pump sprocket, OEM oil sprocket retainer - $749 (intro Price $649)
  • Hub Plus OEM bolt, OEM Oil pump sprocket, OEM oil sprocket retainer, and VTT Crank bolt capture - $799 (Intro Price $699)

IN STOCK READY TO SHIP
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Here are a few photos of the testing process (please note these are early samples, the tooth design was revised to perfectly match the stock hub) We spent north of 5K doing this testing (one off samples are expensive!) as it was something very important to us as it has cost us probably triple that is ruined heads dealing with these issues.

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Oct 24, 2016
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A great question was asked on facebook regarding the crank, and its hardness in that area to hold the spline created by the hub. When we cut the cranks up for our test rig, Tony took one to the local company that does our annealing, hardening, heat treating, metal analysis, etc. BMW has the crank in that area very hard for durability and longevity. This information was incorporated into the development phase. 17-4 is a SS that can be hardened through annealing and heat treating. We made sure even though the crank was very hard in that area, our hub was even harder to ensure proper spline creation when the hub is pressed into the crank. For comparison, a stock hub would not even read on the Rockwell scale when tested.... that's how soft they are!

Hardness specs as tested:

Crank journal (nitrated, tested for fun): 43-47 Rockwell VERY VERY hard as you would imagine it should be for a journal

Crank hub area: 23 Rockwell (this is very hard)

Our crank hub: 37 Rockwell (extremely hard, and when you anneal 17-4 it becomes a very durable SS even at that hardness)

Stock Hub: hardwell machine would simply put dimples in it, and not read. (Extremely soft)
 

doublespaces

Administrator
Oct 18, 2016
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For someone doing this on a lift, how long would you say it takes to install?
 

Erichale77

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Nov 14, 2016
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Did you finally make an anodized CBC for the ATi dampner as well or is it the same steel one I got when dampner was released?
 
Oct 24, 2016
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For someone doing this on a lift, how long would you say it takes to install?

Normal hub install. 6-7 hours typically for a qualified technician but of course YMMV.

Did you finally make an anodized CBC for the ATi dampner as well or is it the same steel one I got when dampner was released?

It’s chromoly but no, no plans to make more for the ATI dampener. We removed ours. Too many issues and Tony suspects the fluid filled stock one is better.
 
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Sshec152

Corporal
Nov 3, 2016
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well...nice product.
but expensive.

I have bought your crank hub capture, and use some high temp (250C) . Plastic thread, now it works well for over 1year.

I have crank hub spin one year ago
how would you consider this expensive? look at the other options on the market. they are twice as much price wise, before install, twice as long to install and are a permanent mod.
 

Jake@MHD

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Nov 7, 2016
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Perhaps a dumb question, but do you have to drop the oil pan to clean out the shavings / material this digs out of the crank when installing? What about when it might dig in further instead of a future "spin" event?
 

fmorelli

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Aug 11, 2017
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The splines compress metal. They don't create shavings.

On cost - I think this is a bit of a red herring statement:
  1. Marketplace wise, VTT's crank hub solution is competitively priced (if not significantly cheaper than existing, "equivalently secure" solutions)
  2. For the end product that shows up for the price, let us not confuse a hunk of metal with the amount of R&D investment that went into having a solution that a) one knows works, and b) is not likely to screw up what's already there. THAT is what one is paying for.
On #2 my experience on this platform is that customers are often beta (and some times alpha!) testers. I wouldn't be so fast to put that on the vendors, btw, because our predilection to buy cheaper significantly influences this.

My hat is off to VTT for investing R&D money where it matters. For example, IMHO, their aluminum outlet is likely more than good enough for what most would do (i.e., that is, in the whole vs PSP thing) ... this crank hub solution, "good enough" is a much higher bar (i.e., typically higher HP, destroy motor consequence). Good on you guys for knowing the difference! I hope others appreciate this and you recapture the cost and make some dough!

Filippo
 
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kayzrx82

Corporal
Apr 4, 2018
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Normal hub install. 6-7 hours typically for a qualified technician but of course YMMV.



It’s chromoly but no, no plans to make more for the ATI dampener. We removed ours. Too many issues and Tony suspects the fluid filled stock one is better.

This looks pretty good. I'm impressed. Just a few questions about the splines. I watched the video you guys have on this and it was mentioned that if the hub tried to slip the splines would grab pulling it further into the crank . Is it possible that the splines could still slip if the hub is bottomed out against the oil pump gear or is the splined hub grabbed into the crank while tightening the stock bolt? I understand how spline lock / extractors work but if the hub is bottomed out against the oil pump gear and front of the crank, what is giving to allow the splined hub to pull in further? Does the kit come with an upgraded bolt as I was under the impression that the factory bolt sometimes stretches leading to slips and doesn't always back out.
Edited:
Also whats involved with getting this hub out if anything ever needs to come apart for servicing? Can the hub and crank be reused after being pressed in and still have the same grip?

Also curious what issues you guys are seeing with the ati dampeners as I was going to get one?
 
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  • Agree
Reactions: Rob@RBTurbo
Oct 24, 2016
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There is no real reason to remove it, but if you want it can be removed with no issue -just like the splined extractor if you remove the bolt then rotate it the opposite way it will come out, the cut splines remain in the crank. You can at that time put in a stock hub or if you want to put it back in, just align the teeth before tightening the bolt.

As far as shavings, no shavings are made when pressing the hub in any of our testing, but even if they were would be captured in the nose of the crank.
 
Oct 24, 2016
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Scottsdale, AZ
This looks pretty good. I'm impressed. Just a few questions about the splines. I watched the video you guys have on this and it was mentioned that if the hub tried to slip the splines would grab pulling it further into the crank . Is it possible that the splines could still slip if the hub is bottomed out against the oil pump gear or is the splined hub grabbed into the crank while tightening the stock bolt? I understand how spline lock / extractors work but if the hub is bottomed out against the oil pump gear and front of the crank, what is giving to allow the splined hub to pull in further? Does the kit come with an upgraded bolt as I was under the impression that the factory bolt sometimes stretches leading to slips and doesn't always back out.
Edited:
Also whats involved with getting this hub out if anything ever needs to come apart for servicing? Can the hub and crank be reused after being pressed in and still have the same grip?

Also curious what issues you guys are seeing with the ati dampeners as I was going to get one?

It'll break things before it slips, you're talking HUGE torque well beyond anything we're seeing on this platform. Bolt is stock and is intended to stretch by design. Add CBC for a complete solution that addresses both primary and secondary causes of slipped hubs.

Removal q answered above.
 

The Convert

Captain
Jun 4, 2017
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Can you say how much total area is in the engaging faces of the splines for the hub?

Also, what Rockwell scale was used for all of the testing? There are numerous Rockwell “scales”. Even rubbers and elastomers can be measured on the Rockwell scale.
 
  • Agree
Reactions: Torgus and Jeffman
Oct 24, 2016
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The Rockwell scale doesn't really matter since the same scale was used on all the parts... focus on the relative vs. the absolute. I mean, we could contact the shop and find out.... but I'm not going to. :grinning: xoxo

As far as area, it depends on how you define it. That's really beyond the scope of a customer discussion, unless I'm misreading your question and you're asking something more simple. Feel free to shoot me an email if you're more specific or I'm not reading your q quite correctly.

Chris