274 replies to this topic

[Karl]

Hello there.  

 

First, regarding the studs.  Can someone please post a picture of the failed stud.  I need to see the fracture point head on.  Until then I can only assume that we have an embrittlement issue that CAN BE RESOLVED.  I am still trying to figure out which studs are failing and from which lot they came.  Until then, PLEASE bake the studs at 400F for 14 hours.  This is not a case of more is better.  These are 200 ksi studs and the book says 14 hours so no need to waste energy.  

 

I am working with Scott / Charlie to see that anyone who has an issue will be compensated fairly.  So, so sorry about the problem.

 

Frank, you have two kinds of studs in your picture.  Two 1.6 (front or rear) and mine (the black one) which ONLY fits the 1.8 rear.  I have not read all the posts after, but it seems like that may have been clarified.  If so, forgive the redundancy.

 

Second, the hubs are a pain.  The only hub body worth using is the NTN.  EVERYTHING else I have tested, even with the super expensive BBs has failed prematurely.  I have developed a different kind of locknut for the hubs, so the preload can be set with the wrench rather than the designed in clearance, but that requires modification of the internal races.  You also have to completely redefine CLEAN if you are repacking, reballing the NTN bodies.  The NTNs are hard enough to hold up to hours IF the internals are COMPLETELY free of dust, water, etc.  By the way, I have never seen an NTN ball cage break under use.  They can break on removal if you are not careful, but not during use.

 

Lastly....NO hub will survive if you keep hitting holes at track out or high apex curbs, etc.  If you want a really long lasting hub, take an empty NTN body to a heat-treater and see if he will do another induction run on the inner race surfaces.  It should be an interesting discussion. :-) 

[TPW]

Is This Karl Zimmerman??.... If so..... Karl I have been trying to reach you for years regarding the SM engine I graciously let you borrow while at the 2009 Nasa champs after your motor quit.......You did not send me back my engine as agreed nor have you returned any of the dozens and dozens of calls I've made over the years in an attempt to retrieve.

 

My number is still the same, 702-326-5681. Please step up and take care of this!

 

Tim Weaver

 

 

 

[Ron Alan]

Karl,

I'm sending you a PM with my phone #. If you text me I can send you a picture of the failure I had. I bought 2 different times frame Saferacer about 6 months apart? The failure I had last week was a front 1.8 hub with studs I bought maybe 18 months ago. I have both pieces of the failed stud. The other failure I may have had came from studs from maybe 1year ago. I say may have because there wasn't much left of the wheel or studs after the wheel came off. And at the time we assumed it was human error of some type and didn't look close
The single stud failure has been on the hub about 4 weekends. The rear hub failure was first session on track...it was a back up upright that had been in the spares pile ready to go.

I'd prefer not to have to replace what I have left(27 studs)but running my oven for 14 hrs isn't going to make my wife happy!

[Karl]

Based on the pictures, I'd like you to check to be sure that the rotors are not touching the taper / knurl section of the studs.  I thought we already spread the word on this, so you might already be checking this.  

 

Not saying that we don't have an embrittlement problem (which as I said is solved by baking at 400F for 14 hours), but with several thousand sold, this is the first that I have seen this.  If I did the math correctly, this is a failure rate of less than 1% (which is still "less than 1%" too much) which makes me want to look a bit deeper.  

 

Is it asking too much to snap a picture of the inside of the rotors?  You are looking for smaller than larger holes with no chamfer.  

 

@Tim....sent you a text from my Swiss cell phone.  If that did not make it through, my texting app 817 580 7168 which I check maybe once a week, but will now check daily, or my old gmail address appliedracingtech.  It's still sitting in the same place it was the last time we talked. :-) 

[Keith Novak]

Incidentally, it's worth measuring the hole diameters when pressing in studs.  I bought some Timken rears for spares on my '95, and although they're supposed to be OEM replacments, the hole diameters are about 14.1 mm (hard to measure with the knurl marks) and the ARP knurl diameter for a 1.8 rear is 14.7. 

That's a tight interference fit.

[Ron Alan]

Based on the pictures, I'd like you to check to be sure that the rotors are not touching the taper / knurl section of the studs.  I thought we already spread the word on this, so you might already be checking this.  

 

Not saying that we don't have an embrittlement problem (which as I said is solved by baking at 400F for 14 hours), but with several thousand sold, this is the first that I have seen this.  If I did the math correctly, this is a failure rate of less than 1% (which is still "less than 1%" too much) which makes me want to look a bit deeper.  

 

Is it asking too much to snap a picture of the inside of the rotors?  You are looking for smaller than larger holes with no chamfer.  

 

@Tim....sent you a text from my Swiss cell phone.  If that did not make it through, my texting app 817 580 7168 which I check maybe once a week, but will now check daily, or my old gmail address appliedracingtech.  It's still sitting in the same place it was the last time we talked. :-) 

OEM turned rotors...big relief in the back. Not sure on the first wheel failure...aftermarket rotors and the stud shoulder could have been the issue.

 

Frank said he had 4 break...hopefully he has been in contact with you Karl

[Steve Scheifler]

Would someone please post pictures illustrating the rotor issue? I don't have these but someone locally does and I'd like to help them check theirs. They broke two studs recently.

[FTodaro]

OEM turned rotors...big relief in the back. Not sure on the first wheel failure...aftermarket rotors and the stud shoulder could have been the issue.

 

Frank said he had 4 break...hopefully he has been in contact with you Karl

I have been in contact with Karl sending my studs to him.

 

If you go back and look at the pictures i posted, i do not believe the issue is contact with the rotors. if you look at the collar, that presses into the hub it is shorter not longer than the stock studs and it does not stick out far enough to contact the rotor, i think that is part of the problem is that there is not enough support at that point. IMO. 

[Ron Alan]

I have been in contact with Karl sending my studs to him.

 

If you go back and look at the pictures i posted, i do not believe the issue is contact with the rotors. if you look at the collar, that presses into the hub it is shorter not longer than the stock studs and it does not stick out far enough to contact the rotor, i think that is part of the problem is that there is not enough support at that point. IMO. 

Did you have rears as well...and have you removed those? I have 2 different designs of the same stud(rear). One has the shoulder(which can interfere with a rotor that does not have a relief)and one looks exactly like your picture Frank...only the 1,8 rear version. My front version of this was also what broke exactly as you described. 

[Keith Andrews]

I have been getting a bunch of grease on the inside of my wheels from the Mazda Heavy Duty front hub.  So I decided to investigate.  I took it apart to see what things looked like.  Everything looked ok no metal but just the slightest amount of grease left in there.  Anyone else see this?  I'm going to put my magic lube back in there.  The ball cage on this one is the black plastic version.  I've never had a front hub bearing sling grease before.   

 

FWIW on the other side I've had a stock NTN (Timken box) that has performed just as well as the HD (one weekend longer actually) with no grease slinging.

[FTodaro]

I have been getting a bunch of grease on the inside of my wheels from the Mazda Heavy Duty front hub.  So I decided to investigate.  I took it apart to see what things looked like.  Everything looked ok no metal but just the slightest amount of grease left in there.  Anyone else see this?  I'm going to put my magic lube back in there.  The ball cage on this one is the black plastic version.  I've never had a front hub bearing sling grease before.   

 

FWIW on the other side I've had a stock NTN (Timken box) that has performed just as well as the HD (one weekend longer actually) with no grease slinging.

that is a sign that you are using to much. If you use to much grease it will also build up heat from that, or you are using real thing grease. I personally do not like Red line CV-2 but some here do.

[Keith Novak]

that is a sign that you are using to much. If you use to much grease it will also build up heat from that, or you are using real thing grease. I personally do not like Red line CV-2 but some here do.

It can also mean too much grease on the spindle, rather than in the hub.  When you slide the hub onto the spindle, excess grease will get pressed towards the inboard side of the hub, where you can't see it and the 1st time you use that hub, it will go everywhere.

 

I've had very good luck with the CV-2 grease.  I re-grease them frequently (more for good measure than they seem to need it looking at the grease) and don't use a ton of grease.  When I pull them apart, it looks like the same amount I put in.

[Keith Andrews]

that is a sign that you are using to much. If you use to much grease it will also build up heat from that, or you are using real thing grease. I personally do not like Red line CV-2 but some here do.

 

I agree.  I didn't grease the hub it was a brand new Heavy Duty Hub from Mazda.  That's why I was surprised it was slinging so much grease.  I've never seen that with other out of the box hubs or the ones I've greased.

 

I don't use CV-2 either.  I use secret magic grease.

[Todd Green]

I've had one hub do this.  It was a rebuilt/blueprinted one by one of the Miata race shops.  After the excess grease seemed to work its way out the hub worked fine.
 

[tom1977]

As far as grease fliinging from random hubs... I have a feeling there are many people out there that are getting a chance to build these hubs, and with that said, everyone has there own style of rebuilding these hubs to their liking.  I doubt that there is one man with a gram scale that measures the weight of the necessary grease for each and every hub, and has 100% luck NOT cracking the nylon cage inside the hub/bearing unit.  I feel it is best to do this job myself at this rate...

[Keith Andrews]

As far as grease fliinging from random hubs... I have a feeling there are many people out there that are getting a chance to build these hubs, and with that said, everyone has there own style of rebuilding these hubs to their liking.  I doubt that there is one man with a gram scale that measures the weight of the necessary grease for each and every hub, and has 100% luck NOT cracking the nylon cage inside the hub/bearing unit.  I feel it is best to do this job myself at this rate...

 

 

That is kind of what I'm thinking I experienced from MazdaSpeed.  I thought they had this stuff figured.  Maybe not.  The grease that was used had completely liquified.  The grease remaining on the ball bearings was minimal and likely used up if I had run them another weekend.   

[Todd Green]

Some more anecdotal evidence.  I found a junker Miata (1.6) with 190K miles on it that some friends and I turned into an enduro car for NASA E3.  EVERY expense was spared on the car (think Chumpcar). It still has the original hubs that came with the car.  It has done at least three 6 hour enduros, another 3 hour, numerous sprint races, at least two rain races that I can remember.  It has been driven (way) off track with the salty/fine Utah dust a couple of times.  Two years on and the front hubs are fine (Knock on wood).  Hubs have never been touched/repacked etc.  The same tires I use on my SM car (Hoosier SM7/Toyo RR/BFG R1) have been run on this car.

 

Again, I don't think the issue is the tires or anything other than suspect manufacturing of recent hubs.  If this isn't some weird anomaly, I'm going to start getting my hubs from junk yards.

Another 6 hour enduro (running Hoosier R7's) and 6 more sprint races (and TT sessions etc.)  on our original hubs.  Still no problems.  Still never repacked/touched the hubs.  It isn't the tires.

[KW78]

Hey Todd, 

 

What did you get towed in for?  Looked like you pitted for fuel, new driver out for a lap or two, and parked in 5???  

 

Hubs, we went thru 4 hubs (across 3 cars)(3 front 1 rear) friday and saturday.   Original hubs made in 90's are just better feeling and harder.  New processes I believe are poorer.  We try every brand, and I can almost predict short lived vs long lived by the look of the induction hardening ring...  non scientific to be sure.  I clearly see same root supplier indications mix thru all brands also, btw.  

 

HAS ANYONE TRIED the drop spindles that recieve MR2 spider hubs on a track day car or st, ep, etc car?  Wondering if an alternative existing part combo would be worth the effort to get legal.  

 

Great racing todd, although I think you were just pacing me watching your mirrors... I was going to do the enduro solo but had a brake failure going into windup at hour 3 or so.  Brake bracket pin litterally sheared off, never seen that failure before....

 

 

Kyle

[Todd Green]

What did you get towed in for?  Looked like you pitted for fuel, new driver out for a lap or two, and parked in 5???

We didn't even make it a lap, that was on the out lap. Let's just say that in the 14 hour thrash to do the motor/tranny swap that someone didn't torque the tranny drain plug to spec. Brought the car in, grabbed a spare plug, put two quarts in and ran the rest of the race.  This was a 140K tranny that I picked up at a salvage yard on Thu (when the team decided to do the enduro )  What was crazy was that there wasn't a drip on the floor after quali.  Thermal cycling must be harsh.  The car stopped firing on the #3 cylinder on my out lap on Sunday despite no issues for 6+ hours on Sat.  Of course I lost the motor in my blue car, which is why you did't see me at all on Sunday. 
 
Late in the race we had the throttle cable fall off twice where the rubber grommets attach to the intake.  The first fix was just finger tight on track. I think the rubber just hardened too much to clamp well.  We ended up kinda bummed because Race Monitor showed us finishing 3rd, but there was a misclassed car that showed up in the final results that bumped us down to 4th.  In the end given that we had a car with a broken motor and tranny the day before the event, didn't practice driver changes, ran on stock headlights (which are a parachute for drag I'll add) and managed to finish the race with no penalties was pretty miraculous.
 

Great racing todd, although I think you were just pacing me watching your mirrors...

It was great having you guys out here as usual. We really appreciate you guys making the long tow! I was pacing you. I can comfortably turn low 19's in that car (quali was an 18.4 in traffic), but the crew asked for 20's so as long as I had a good gap I was just cruising to leave a good car for the other drivers.  Of course full-blown PTE/E3 cars can do 16's (as seen at the 2013 NASA Nats.)
 

Brake bracket pin litterally sheared off, never seen that failure before....

 
I've had it happen twice and others have had it happen as well.  Also check your bracket bolts.  They'll loosen and fall off.  I've gone to loctite for the bracket bolts.  The rumble strips at Miller are really hard on our cars.

 

Hope we have a track next year and you guys keep coming out.  Our guys are talking about trying to make the enduro at HPR and hopefully the SpecZ guys will make it out for the sprint races.

[FTodaro]

I wanted to bring back the old Hub failure thread, to ask a question. I came upon some old hubs I am repacking and found a hub design that I have not seen in the past.

 

It looks to be OEM hub that has an inner metal dust seal on the OUTSIDE of the hub. It looks to help keep water and dirt out of the bearing, I have never seen this before, just wondered if anyone has seen this and knows if its specific to a production year.

 

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