Well, it looks like 43 year old parts don't like autocrossing. I had a right hub fail right at the end of my first (and only) run. Took quite a bit to get the car on the trailer, will be getting a winch for sure now. Luckily the disc brakes held the wheel in place enough. The caliper pins bent for sure and possibly the abutment as well. Rotor was chewed up some from contact with the abutment. I will know more once I get them off and the drivers side off so I can compare them. Good to keep an eye on stuff like this, even though I couldn't find any signs of cracks beforehand.

Here are a couple picts of the carnage
Hub
http://i967.photobucket.com/albums/ae160/rjpajer/81%20Camaro%20CP%20car/hub1.jpg

Hub now a 2-piece design
http://i967.photobucket.com/albums/ae160/rjpajer/81%20Camaro%20CP%20car/hub2.jpg
http://i967.photobucket.com/albums/ae160/rjpajer/81%20Camaro%20CP%20car/hub3.jpg

Wow randy. I am glad you and your camino are ok. I have never seen that on a street car. I have seen that on old street stock circle track cars though, and broken axles too. What are your plans for repair/replacement?

Short term I will be using another stock hub. I would like to upgrade to some billet hubs like Kore3 has, money is a bit tight right now. Hopefully I don't have to replace too much of the brake parts.

Using wheel spacers or wheels with incorrect geometry?

Wow. Breaking parts like that means you were driving it right! :thumbsup: Your pics make me glad I coughed up the extra cash for the billet hubs.

Surprised to see that I would have expected a bearing failure before that happened.

Using wheel spacers or wheels with incorrect geometry?

No wheel spacers at all, wheels are 17x9 with 5" backspace with Kumho V710 tires. Autocrossing was probably putting more strain on the hub than it was willing to put up with after 43 years.

Wow. Breaking parts like that means you were driving it right! :thumbsup: Your pics make me glad I coughed up the extra cash for the billet hubs.

I was having fun right up until the failure. Even with just one run, I still managed to be 3rd out of 5 drivers. :D It failed on the last part of the run, just made it across the finish line.

Glad you're ok. I had a LCA failure last year and it makes me realize how old our cars really are but more so in that they just simply aren't designed to take on the abuse we're putting them through. I'm starting to get worried about driving it hard and I do drive mine hard in the canyons. So many weak points like the LCA chassis mounting location, hubs, spindles, LCAs, etc... It's just getting daunting on all the parts I/we should consider reinforcing or replacing. I mean.. where do you stop?

I'm thinking of tossing-in the Pro-Touring towel and just dumping this thing on bags, cruise it and be done with it. I don't like the thought in the back of my head every time I head into a canyon turn thinking something will break and throw me off the edge :(

No need to give up on your car. There are things you can do to help ward off problems, whether it is replacing parts or reinforcing them. Plenty of ideas here and on other sites. You just need to be in the habit of examining the parts on a regular basis to try and catch problems before they happen. The hub never gave me any warnings, just gave up. There is always a risk involved with any car, no reason to stop living the dream.

Wow….thanks for sharing. I will be keeping my drum hubs for a C5 brake swap this winter.

Yikes. Luckily it went out at the autox. Now I'm glad my drum hubs were long gone and not an option when doing my brake swap. The Kore3 hubs will also drop some weight off the front. Mine have been running good so far. Glad nothing got torn up bad and you were safe. Had you trailered the car to the autox?

Stock diameter and knurl wheel studs?

What are you going to replace the stock hubs with?

Yep, I trailered the car to the event, just in case. Glad I did.

The studs are 3" long 1/2" ARP with larger knurls. I will be going with another drum hub for now. The hub that broke is different than the one on the other side. The backside of the flange has some scalloped areas (see the photos) while the other is smooth on that side and a little thicker as well. We will be magnafluxing the hubs to be sure.

I am building a Camaro for dedicated autocross duty, to be more competitive at divisional and national levels. The El Camino does well at a local level, with more work it could be more competitive, but I'm not going to cut it up just to run bigger wheels/tires and a cage. Don't think the hubs would stand up to big slicks anyways. If I was going to keep running the El Camino, I would get the Kore3 hubs for it. I actually have the El Camino up for sale and even have someone wanted to look at it. Luckily they are understanding and willing to wait until I fix it to come see it.

I am building a Camaro for dedicated autocross duty, to be more competitive at divisional and national levels. The El Camino does well at a local level, with more work it could be more competitive, but I'm not going to cut it up just to run bigger wheels/tires and a cage.

Lets see this Camaro!!! I've been seriously considering building a 2nd gen Camaro into a full-prep CP car. Decent 2nd gen bodies are cheap and plentifull enough that I wouldn't feel guilty about cutting it up to meet minimum weight.

On the other hand, for a whole lot less, I could just buy a Miata and be in a nationally competitive car for less than it would cost to build a CP engine...

on the other hand, for a whole lot less, i could just buy a miata and be in a nationally competitive car for less than it would cost to build a cp engine...
+1

Lets see this Camaro!!! I've been seriously considering building a 2nd gen Camaro into a full-prep CP car. Decent 2nd gen bodies are cheap and plentifull enough that I wouldn't feel guilty about cutting it up to meet minimum weight.

On the other hand, for a whole lot less, I could just buy a Miata and be in a nationally competitive car for less than it would cost to build a CP engine...

Ah yea, but you haven't been to an epic CP party at Nationals. Plus there are too many Miatas anyways. You actually don't need a lot of engine, mild motors do quite well, suspension/wheels/tires will get you farther.

Here are some initial picts of my car over on NastyZ28.
http://www.nastyz28.com/forum/showthread.php?t=184672

And here's another one being built by another member.
http://nastyz28.com/forum/showthread.php?t=131539

Randy,
I have seen similar failures on crankshaft snouts caused by the timing gear not having a proper radius and not seating properly against the step on the crankshaft. When you get your replacement hub, before you put the studs in it, glass bead it then spray or brush some machinist die on it. Then place it into the back of the wheel and spin it while putting pressure against the wheel. See if the wheel is contacting the flat area on the hub properly. Also, the step in the middle of the hub should be a "snug" fit on the wheel to keep it centered. They studs should not be keeping the wheel centered, the hub should.

Then again, it might just have had enough after 40 years :)

Thanks for the info Bill. I have the replacement hub now.

We did find out more about the broken hub. There was a void in the casting right along where it broke. You can kinda see it in these pictures, sorry my camera didn't take better shots. It's the area I circled on each shot, kinda the darker area.

http://i967.photobucket.com/albums/ae160/rjpajer/81%20Camaro%20CP%20car/hubvoid.jpg
http://i967.photobucket.com/albums/ae160/rjpajer/81%20Camaro%20CP%20car/flangevoid.jpg

Thats a pretty serious void/casting flaw. One would hope that such flaws are a rarity rather than commonplace in the GM castings.

Ouch!

Glad everything is okay... I used the drum hubs for my last C5 swap, and already stock pile a few sets for the next swap... I guess I'll have to step up to the billet hubs...

The drum hubs aren't all bad, this one was different than the driver's side and the replacement hub I have (both of which are thicker in the flange area). Keep an eye on them and they can work. I decided to stay with drum hubs (mainly for cost reasons) and just keep a watchful eye on it with regular inspections. Here is some info from someone on Pro-Touring.com about the hubs.

Wow, luckily it wasn't worse and you and the car are ok. Randy (proBell) had this happen at the XV challenge down at pocano a few years back, split one of those hubs but length wise through the bearings not around in a ring like that. The aluminum ones are good for most purposes but the bearings in those are still too small for serious road course work. I've made up a few sets of aluminum ones with larger bearings for higher load rating, or for a real heavy set custom spindles with grand national hubs on them. There really isn't a perfect fix that I've seen, even the vette sealed bearing hubs like in the ATS spindles will fail in road course applications. Tracking vettes we have to change bearings every couple years.

Ah yea, but you haven't been to an epic CP party at Nationals. Plus there are too many Miatas anyways. You actually don't need a lot of engine, mild motors do quite well, suspension/wheels/tires will get you farther.

Here are some initial picts of my car over on NastyZ28.
http://www.nastyz28.com/forum/showthread.php?t=184672

And here's another one being built by another member.
http://nastyz28.com/forum/showthread.php?t=131539

Hey Randy, I just bought a '79 Camaro (bare shell w/ subframe) this weekend to build as a CP car... I have a few more things to do to my Chevelle yet before I can start putting money into the Camaro, but it should be a fun project... I'm really looking forward to building something that I don't have to be afraid of cutting up. :yes:

It is fun when you don't have to worry about "messing up" a good car. Do what ya want, cut away. You can get the doors and fenders pretty light without spending money (other than electricity for sawall or other tool of choice). Plus it is a great stress reliever. If you want to bounce any ideas off me, send me an email. A few people with Camaros have given me some good ideas. :beers:

Back on topic, I got the Elco back together Saturday and drove it some. Works like a charm. Bad news was the 2 guys that said they were coming to see it, didn't show, call or anything. Seems to be par for the course in the Atlanta area.