Whiteline Watts Link Failure

Hey guys,

I am hoping this is the right place to put this.

My Watts Link failed last night on my drive home from work. Sitting in traffic, I took a right hand turn and heard a very loud roaring and grinding sound.

Then when I took the next left at around 15 miles an hour the rear started wobbling pretty bad. I immediately stopped and pulled over. Luckily this all happened about a block from my house and I was able to make it home driving about 10 mph and making the 2 required turns at about 2 mph.

I expected that a bolt had backed out, or that something was not torqued down well enough. It was already dark so I was not able to check what the problem was until today.

I jacked up the car and crawled under to take a look and this is what I found.









So the top arm attachment point had completely failed. The bolt is still strongly in place. All the other bolts were still strongly in place.

I am going to contact Whiteline about the issue.

I am posting here because I am interested in whether any of you guys have had similar issues with this particular part. I am worried about this happening again going down a mountain road at speed, or at the track going 90mph around a turn.

This is not exactly confidence inspiring. I know there are always defects in the manufacturing process but the way that the pivot sleeves are attached does not seem very robust.

By the way the second half of the bushing is still in the arm, in case anyone is wondering.

I'm sure Whiteline will get you taken care of but this is one of the reasons why I like to preach double sheer over single sheer with bolts like this. Sure the Fays2 Watts is single sheer at the main mounting point but it's a massive bolt and is pretty well secured, however the arm attachments are double sheer and are still massive bolts.

I don't believe there is any possible way to make that bolt in to a double sheer as it is a pivot point.

What actually happened is that the point where the sleeve is attached snapped and completely came out.

That's not too bad. No damage. .

NoTicket said:

I don't believe there is any possible way to make that bolt in to a double sheer as it is a pivot point.

What actually happened is that the point where the sleeve is attached snapped and completely came out.

Click to expand...

Definitely possible to put it in double sheer but not in the way they designed it. Look at the way Jim Fay did it:


Combine that with a double sheer pivot (like Cortex/Griggs does it) and you'd have a pretty durable setup.

Anyway, I digress. Hopefully they get you taken care of and keep us up to date on the progress.

Yeah the part that failed is equivalent to if one of those bolts failed. Unless I am not looking at that correctly. It looks like each arm terminates in a single bolt.

However that does look like a potentially more robust setup.

The cortex and griggs units also spin around a single bolt at each connection.

The part that is in double sheer is what connects the pivot point to the diff cover. In this case the whiteline unit is in sextuple sheer.

However, I am skeptical of the wisdom of the way the pivot points are attached to the propeller.

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This is the first I have heard of this type of failure on the watts. I know Terry at Vorshlage has ran the Whiteline watts on his racecar and beat the shit out of it with no failures. Maybe he can chim in. I'm sure Whiteline will make it right. Keep us informed on the outcome!

NoTicket said:

Yeah the part that failed is equivalent to if one of those bolts failed. Unless I am not looking at that correctly. It looks like each arm terminates in a single bolt.

The cortex and griggs units also spin around a single bolt at each connection.

Click to expand...

Damn that's not good. I'm sure they will make it right

As far as the design differences quoted above between the Fay's/Giggs/Cortex Watts units go I think the use of Rod Ends in these other designs may play a role in how much bind is seen between the propeller and watts arm attachment points.

Certainly not trying to point any fingers by saying this but be prepared to answer questions about Torque specs used during install when calling the vendor. This may be in your favor if they go that route though because you easily bring up the fact that they still haven't found the time to update their install guide torque specs found on the website....

I think 2013DIBGT is probably on it about the torque spec/install. That's key. Considering Vorshlag is pushing that car with probably as wide as tire as you can get and run the car hard.

There have been problems in the past with watts link, PJ Saleen edition watts and early Techo units. Those problems are notthe same here. I would definitely be suspect of the torque spec. Maybe you should see how much torque is on the other arm that is still connected to the prop.

edit- nevermind checking the torque. you took both off.

NoTicket said:

Yeah the part that failed is equivalent to if one of those bolts failed. Unless I am not looking at that correctly. It looks like each arm terminates in a single bolt.

However that does look like a potentially more robust setup.

The cortex and griggs units also spin around a single bolt at each connection.

The part that is in double sheer is what connects the pivot point to the diff cover. In this case the whiteline unit is in sextuple sheer.

However, I am skeptical of the wisdom of the way the pivot points are attached to the propeller.

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Click to expand...

All of the connections on the Whiteline unit are single shear. The Prop bolt as well. Single shear has nothing to do with the number of bolts holding something but how those bolts are held:
(image stolen from Google)


The only single shear bolts on the Fays 2 unit are the two driver side bolts for the brace, the axle end attachment for the arms and the center pivot point. The center pivot point is "braced" by the aluminum spacer in the unit which has a wider base on it than the bolt is to help distribute some of the lateral loads better but it is still single shear and the axle tube clamp towers have a massive gusset on them and the bolt is almost as long as the tower is to spread the load. It's over engineered to deal with the faults of single shear connections.

I don't think there is any double shear bolts on the Whiteline unit. Cortex and Griggs do have single shear for their arm ends at the pivot but I believe they are in double shear at the chassis attachments and the center pivot bolt (the most stressed bolt in the whole setup) is double.

BMR's 1st gen Camaro Watts link is all double shear FWIW. It also attaches rather cleverly to their torque arm setup for the 1st gens too rather than the differential cover solely (although I think it does use that as a mounting point. Kelly can you clarify?)

Quick question, how many miles have you put on the watts since the install?

NoTicket said:

So the top arm attachment point had completely failed. The bolt is still strongly in place. All the other bolts were still strongly in place.

Click to expand...

Exactly how are those cylindrical attachment points retained on the propeller? Or are they only fixed in place by bolt clamping force?


Can you provide a picture looking at the back side of the propeller (diff side as installed on the car, from the right in the above picture)?


About those six bolts that fasten the plate to the diff proper . . . they are not loaded in shear at all, not even in the "single shear" situation that might appear to be the case. Most bolted connections work via the friction developed as a result of the bolt clamping force (which then goes back to the actual bolt torque). If this kind of bolted joint ever loads a bolt in any significant amount of shear, the joint itself has been compromised by loss of enough friction to permit relative motion between/among the parts clamped together.


Norm

Thanks Whiskey, I was clearly confused about what double shear meant.

In this case the propeller mounting points for the arms are all single sheer. The chassis mounting points for the arms are double sheer.



The driver side is similar, with the bolt going through the drop bracket and being secured on the other side by nuts.

Fwiw, the center bolt is similarly engineered on the Whiteline unit. It has a large metal sleeve to distribute the load.

I can see the advantages of the Fays2. However I would rather stick with PHBs than use them as I do not want to live with the insane clunking that they transmit in to the cabin. My car is otherwise stock, and the handling and ride quality improvement from the Watts has been huge.

Roadracer350 said:

Quick question, how many miles have you put on the watts since the install?

Click to expand...

I have put 1 track day and about 800 miles total on the car since installation.

Everything was torqued correctly. And being that it has been only about 6 weeks since I installed it, and the bolt isn't even backed out at all in the snapped off sleeve, I am sure they will replace the propeller.

What I am wondering is if other people have had this happen. I know that the Vorshlag guys are running this unit on their TT 2011 car that is running on 305-315 slicks. They probably experience about two times the lateral load that I do in my car. I am wondering if they have had this type of failure occur. Or for that matter if ANYONE else has.

Given that searching the internet has turned up no results I am willing to give Whiteline the benefit of the doubt here in the aftermath of being so frustrated yesterday, and say this was just a standard bad sample.

Though clearly this particular failure would be impossible if the bolts/sleeves were in double shear.

Norm, just saw your post.









The sleeves are welded in to the propeller. The weld goes down several threads inside the sleeve. As you can see, the weld itself was ripped out completely.

And thank you for the clarification about shear and bolts. I was previously confused due to every discussion about double vs single shear also talking about a single bolt being used, vs multiple on the Cortex/Griggs. But Whiskey cleared that up for me and I went back to some book learnin.

I just looked at mine and it is welded also... I wonder why they didn't machine it out of a solid piece...

I'm sure it's all a matter of costs. The best way they could have done it was to cast the whole piece and then add threads.

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That would be good but the BEST way would have been to machine the entire piece out of a solid piece.

Do you mean billet? Isn't cast pretty much always more durable than billet?

By add threads I meant machine threads in the single piece cast.

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Actually I'm thinking machining out of a solid piece of billet steel. You could do Stainless or maybe 4140. We deal with castings at work all the time and their will be voids and crap inside so on average the castings the cust sends us we scrap 1/3 due to voids. I can ask out engineer tomorrow which is stronger for that piece. The weld itself may have had some perosity in it so it would be week and fatigue. Looks like it was welded with Mig.