ideola

No more cheeseheads and no more safety wire for me!

I've been working with Stage8 to develop a locking CV bolt kit for the entire range of 924-944-968 cars. All of these cars utilize the twenty-four M8x48 cheesehead bolt to attach the half shafts at the transaxle stub axles and the outer hubs (six bolts per CV joint). As many of you know, the cheese head bolts are a royal PITA to deal with and will strip out if you're not careful. And for track driven cars, there have been multiple reports of the bolts backing out mid-session with catastrophic results. Many guys are safety wiring their bolts, and this was the approach I was planning to take on the UWB project until a 924board member mentioned Stage8 (for a header bolt application).

The Stage8 system utilizes a so-called GrooveLok bolt, which has a 12-point head and a special groove in the head. Once the fastener is torqued down, any number of retainer shapes are available, which lock onto the 12-point bolt head, and are then retained using either an E-clip or spring clip. Here are some photos using the samples they sent to me installed on a late offset 944 CV joint, boot, and outer stub axle:

M8x65 GrooveLok bolt (the standard size would be M8x50)


Teardrop and D-Style retainers; spring clip and E-clip


D-style retainers installed, E-clip on left, no clip on the right (I didn't have a spring plier small enough at home)


Teardrop retainers installed (again, no spring clips, but they would normally have the spring clips installed)


Directional Pricing
Stage8 currently do not have a kit for our cars, but they will soon! I am going to have these made up for my own application even if nobody else wants them. Their standard domestic CV kits only include 12 bolts, and are listed at ~USD$50, so directional pricing for a complete kit for our cars, consisting of 24 bolts with retainers and clips, is $100 per set. I am ordering one set regardless, maybe two. We can start getting into group discount with as few as 5 participants, and preliminary indications are that the discount ramps pretty significantly in increments of 5 sets. I'm hoping to hammer out all of those details early this coming week. In the meantime, would really like to gauge interest, as I think these are a fantastic alternative to guys that are tracking their cars.

Specifications
• Bolts Are Aircraft Quality Grade 12.9 – 4130 Alloy Steel
• Retainers are 5052-H32 Polished Aluminum
• Snap Rings & Clips Are Spring Steel

Questions? Interest? Let me know!

Techno Duck

Are the bolts reusable or still one time use? I think i would be interested in a set.. the triple squares are so annoying, i always dread pulling those out of the tool box.

ideola

That's a good question, I will find out tomorrow when I talk to them.

schwank

I am likely interested... even moreso if you answer Jon's question in the affirmative.

ideola

Another good question came up on 924board regarding the availability of retainers in different offsets, such that you could pick and choose the best offset retainer for snug fitment against the abutment once the bolt is torqued down. Stage8 has indicated that they can accommodate a number of permutations on the shape of the retainers and the placement of the groove, so I'm also going to see if we could get kits that would have a variety of offsets to pick from.

Van

Quite clever.

If you stamp the start cutout in the moon clips just right, you should be able to flip it over to get the "half step".

Adds too much rotating mass, however. Just teasin'

genikz

I'm game. I paid $90 for a new CV joint after all my bolts fell out after a track day. Thankfully it was on the tow home that they all fell out, but nonetheless, a serious concern for me.

I had all the bolts painted to visually check for torque, but I still got caught out. I'd buy a set of these in a heart beat.

ideola

I'll start a participation / interest list later today.

In the meantime, here is Vaughan Scott's reaction posted over on 924board. Always nice to get an experienced racer's perspective:

theedge

I would take a set.

ninefiveone

I'm interested

ideola

OK, got some answers to our questions:

Q: Are the bolts reusable?
A: Absolutely

Q: Which clip style is preferred
A: Since the CV joint is a rotating assembly, the full circle engagement of the spring clip is preferred. Either will work, but the spring clip is probably best

Q: Which style of retainer is preferred?
A: No preference, either style can be used

Q: Can retainers with different indexes be developed for snug abutment?
A: Both the D-style and the teardrop retainer are reversible with different "indexation" on each side

There was also a question on 924board regarding the material and tensile strength. They informed me that the 12-point bolts are actually 12.9, which is actually a grade 9 bolt, not a grade 8 as I posted (info pulled from their literature). Grade 9 is rated in excess of 150,000 pounds. These style of locking CV bolts are also used in all of the Formula Cars used at Bob Bondurant's racing school in Phoenix.

I should have pricing information later today.

JimV8

Safety wiring is PIA. It looks like a great idea, but how important are the snap rings. I hate the little buggers and that many at that angle would make me crazy.

ideola

You have to have some method of keeping the retainer in place, so it's either the snap ring or the e-clip. The e-clips are ridiculously easy to install (just press on) and remove (just pop off with a screw driver). When I pressed the guy at Stage8 for which design was better, he said they have never had an e-clip come off, BUT, if he were pressed to choose between the e-clip vs. snap ring, he would choose the snap ring because it would be almost impossible for it to come off due to the full circle engagement.

Now, I asked about mixing and matching orders, making it an option to pick what style of retainer and what style of clip. It is totally doable, but it will add a layer of complexity to managing the group buy. I'll do whatever you guys want...but for my money, I'll live with a little bit of inconvenience and go with the spring clips. You should easily be able to install three spring clips per side, per inner and outer, then rotate the wheel and do the next three. With a good set of spring clip pliers, they really shouldn't be too much more difficult to install than the e-clips.

ideola

Forgot to point out...the groove required for the e-clip is different than the groove required for the spring clip, so you can't mix and match...the bolt has to be cut specifically for the style of clip you want to use...

ideola

OK, folks, we're on. Looks like we have sufficient interest, and I have pricing info, as follows:

1 to 4 participants: $106 per set (24 bolts, retainers & clips)
5-9 participants: $100.70 per set
10-14 participants: $95.40 per set
15-19 participants: $90.10 per set
20-39 participants: $84.80 per set
40 or more: $79.50 per set

Shipping will be add'l. I forgot to inquire if Stage 8 will drop ship or if they will want to send the whole order to me for sorting and shipping. I'll post back later with details on shipping, but I don't expect shipping to be more than $10 per order in the worst case scenario (for domestic...international will be a little more).

The group buy will be run just like we did the IMI Gear Reduction Starter. I will issue invoices to confirmed participants. Since I think there's a high likelihood that we'll hit 20 or more sets, I'll hold off invoicing until we get that many confirmations. I'm not in a particular rush, so there's no need to pick an arbitrary cutoff date at this point. The production lead time from the time I place the order until shipment of goods is a whopping ONE WEEK. Gotta love that!

Participant list moved to page 5.

For those that have expressed interest, please CONFIRM your interest by sending me a PM. If you haven't participated in one of my group buys in the past, please also send me your shipping information and email address.