New topic, but still related to service bulletin's on the FC 8.8For the past several months we've been looking into a few FC 8.8 halfshaft failures that seemed to occur at relatively low power levels (<500 rwhp). Here's one:
http://www.norotors.com/index.php?topic=5084.msg269114#msg269114 Admittedly this was a little confusing because we had shafts holding up well on cars making hundreds of HP more. Full disclosure: there have been a total of three bars which have failed out of something like 50-60 FC 8.8 kits we've sold. That's 100+ shafts on the road, all in cars seeing hard lives (they sprung for an 8.8 rear end after all).
In all three cases the broken shafts were replaced free of charge (they carry a lifetime warranty from our supplier that we pass through to our customers), we even threw in extra CV boots to get folks taken care of.
Effectively the process went like this: If this was one shaft only we could write that off to some internal metallurgic flaw. The second failure says something more significant was going on, hence we had the first two failed axles sent back to us for further review. We examined them closely, took a bunch of pics for reference, and then sent the shafts off to our manufacturer for lab testing. That was already in works with the first two shafts just before the last failure was posted online (link above).
Post mortem analysis is extra work for both Ronin and our supplier that's a pure overhead expense so I sympathize that this was a pain to track down. I was following up yet again pushing for answers about a month ago. Results were still slow in forthcoming, but instead they offered to do a proof load test to prove this wasn't something systemic. As such, Ronin sent them back two brand new shafts from our stock and had those tested.
The good news is that I finally got results back today from both lab testing and proof load testing. Both of the new bars which underwent proof load testing passed with flying colors. Both broken bars in question hadn't achieved the specified hardness level. The follow on lab tests showed that the material on the two broke bars
wasn't 4340 hence they didn't take the heat treat and hardness expected. Our supplier apologized profusely but stated they were confident that this was an isolated incident where a few bars of inferior material had been accidentally mixed in with their 4340 stock. That means the material on a few bars wasn't truly better than stock hence why "standard power" v8 cars could still manage to break them.
Are there any other bars out there with wrong materials? We don't know. The good news is that we have an answer as to what's been going down, and some evidence that our 8.8 kit is what we say it is. In the meantime we have three things we can offer:
1) If you want to have your shafts proof load tested--it's a percentage of rated capacity--please tear them down to bare shafts and send them back. We'll have our supplier test them (they've offered). Any bars that survive will be returned and considered known good. Any bars that fail testing will be replaced. That said, tearing down shafts is a bit of a pain, at a minimum you need need new boot clamps etc.
2) All Ronin halfshafts have an unconditional lifetime warranty. The batches where the issue seems to originate were built more than a year ago, so if your car hasn't blow one, it's unlikely that will. Call it in-field proof load testing. This is what I'm doing on my own car.
3) If you're concerned about your shafts and running events where a failure would be terrible, but also don't want to tear it down without good reason, we have plenty of shafts from the most recent batch which we just tested and are known good. We can sell you a spare or spares so you'll have extras standing by.
Shoot at a line at roninspeedworks@gmail.com in regards to any of the above if we can help.
To the three guys who broke, thanks for giving us the time to run this to ground. We appreciate our customers and want to be sure we're treating y'all right.
-Joel Payne
(for RSW)
