Spindle fatigue?

[Paul Workman]

The FBI gang had a great pizza night last night: Around the tables was Ken Windisch, Dominic, =Jeff=, Pete, Fred Haraf, Marc Haibeck, yours truly. I always learn something new at these gatherings, and this one was no different.

Marc didn't bring his Z, because he has it apart in order to change spindles...(and the surprise to me) as a routine preventative meassure against twisting one off on the drag strip. (We've seen this happen a few times on recent outings).

Al showing off his "spindle" at Beach Bend during the BG gathering.

http://i185.photobucket.com/albums/x220/6PPC_bucket/BGBeachBendAlshalfshaft.jpg

Anyway, I think Marc said he changes them after about 100 runs, give or take, against fatigue/stress hardening? (Marc, pls correct me if I didn't get that right - memory is a terrible thing to depend on!) I thought that was very interesting!

P.

[Bob Eyres]

Interesting, but that begs the question, if you're doing a lot of drag racing why not upgrade the spindle so you don't have to change it out periodically?
Is there a readily available HD (forged?) spindle that will do the job? :confused:

[FU]

I believe that Al has a very good remedy for this.

[WARP TEN]

The FBI gang had a great pizza night last night: Around the tables was Ken Windisch, Dominic, =Jeff=, Pete, Fred Haraf, Marc Haibeck, yours truly. I always learn something new at these gatherings, and this one was no different.

Marc didn't bring his Z, because he has it apart in order to change spindles...(and the surprise to me) as a routine preventative meassure against twisting one off on the drag strip. (We've seen this happen a few times on recent outings).

Al showing off his "spindle" at Beach Bend during the BG gathering.

http://i185.photobucket.com/albums/x220/6PPC_bucket/BGBeachBendAlshalfshaft.jpg

Anyway, I think Marc said he changes them after about 100 runs, give or take, against fatigue/stress hardening? (Marc, pls correct me if I didn't get that right - memory is a terrible thing to depend on!) I thought that was very interesting! P.

Sorry I missed it; sounds like a good time with the FBI gang. Hopefully next time I can get away early from work. --Bob

[Paul Workman]

I believe that Al has a very good remedy for this.

Yes, as does Bob G who broke his stock spindle four months later at a local Corvette drags shootout. It would be a good "FYI" article, methinks.

Big motors (especially) tend to ferrit (sp?) out other weak links in the drive train!

P.

[Bob Eyres]

Surely, there's got to be somebody out there who has made the Corvette IRS relatively bulletproof.
If you've got enough traction, every part between the clutch and the spindles is at risk on every run.

[FU]

The spindle shaft is awfully small , check out where the spindle is broken in the picture.

[Jagdpanzer]

Wish Al would show us a little more leg on the big spindle solution he teased us with a while back.

[LancePearson]

Even on my relatively low powered '76 with 210 hp I lost a small side yoke out of the differential on a half shaft in a parking lot...not even from my jacking the car at starts but just from prior usage over time. We replaced both of them with much stronger forged ones while the differential was out. The mode of failure just looked to me like metal fatigue of sort of a granular twisting nature as the steel just eventually let go at 2 mph in the parking lot. A 500 hp or more would surely need stronger shafts, yokes, spindles, etc. than normal automotive steel for even a standard C4 back in the day. I'd think the process the steel part is made by and the type steel would be paramount in determining life and fatigue failures. In aluminum nowadays in aircraft alloys they not only can predict when the metal will crack but at what rate the crack will propagate and steel should easily be as knowledgeable. Just got to get away from the cost versus warranty life decision by someone in an auto company making millions of cars.

[LancePearson]

Sorry I missed it; sounds like a good time with the FBI gang. Hopefully next time I can get away early from work. --Bob

I can't exactly tell whether the broken part of the spindle/shaft is a smaller diameter than the remaining part. if it is then if it was machined down from steel bar stock of some type to get the smaller diameter or perhaps fastened via welding either process could introduce heat into the steel and when you do that if it's enough heat you can start annealing or softening the steel. The softer, the sooner it will twist or torque off with the kind of power your group runs. Forged and machined at low speed or however it's made would be the thing I'd think...of course, it would be interesting to think about titanium but the cost would be prohibitive likely.

[Pete]

We have 2 choices.
Forged billet stock replacement 27 spline.
&
Al's type set up forged billet 31 spline with new bearing/hubs.

Get in touch with Al he has a package for the 31 spline set up.

Pete

[XfireZ51]

We have 2 choices.
Forged billet stock replacement 27 spline.
&
Al's type set up forged billet 31 spline with new bearing/hubs.

Get in touch with Al he has a package for the 31 spline set up.

Pete

Al's shaft is impressive!

[Paul Workman]

We have 2 choices.
Forged billet stock replacement 27 spline.
&
Al's type set up forged billet 31 spline with new bearing/hubs.

Get in touch with Al he has a package for the 31 spline set up.

Pete

I seem to remember Al's solution was a 33 spline spindle, and it was Bob G that rounded up a 31 spline spindle, NO? I seem to recall that the difference, besides the obvious, was where Al had to do some minor(?) fabrication/fitting for the "33" solution, wheras the 31 that Bob got was more or less "off the shelf"... Or, did I imagine it while under anesthesia?

P.

[GOLDCYLON]

Its been said before however a lot of folks spend a lot of money on all the performance goodies for the motor however neglect the business end where the power goes to. Its not a weakness in the car but all the above out engineers what GM intended performance wise. How much does ALs setup range and what are ALL the options? Or has Pete answered half of that question already? :cheers:

[GOLDCYLON]

I seem to remember Al's solution was a 33 spline spindle, and it was Bob G that rounded up a 31 spline spindle, NO? I seem to recall that the difference, besides the obvious, was where Al had to do some minor(?) fabrication/fitting for the "33" solution, wheras the 31 that Bob got was more or less "off the shelf"... Or, did I imagine it while under anesthesia?

P.


Something numming was involved Paul lol

[Corbusa]

This really has my interest.

[Paul Workman]

Its been said before however a lot of folks spend a lot of money on all the performance goodies for the motor however neglect the business end where the power goes to. Its not a weakness in the car but all the above out engineers what GM intended performance wise. How much does ALs setup range and what are ALL the options? Or has Pete answered half of that question already? :cheers:

IDK... But, I'm intrigued too, with Pete's response. Gonna need a writeup on diss here, methinks!:salute:

[LancePearson]

I read somewhere that the number of splines has a bearing on better power transfer and life...the less splines, the less effective. I'm no engineer but if that's true then the 31 spline would be a more effective joint to transfer power better than the 27. If you looked at the failure mode of my 76 side yoke, the spindle, it really looked more like granular steel in cast form than forged or wrought steel but we never found out, just replaced with drop forged on both sides which I thought was important so each side handled equal force and was equal material. They aren't comparable but I'll attach a photo of the failed spindle for example.

[ALZR1]

I read somewhere that the number of splines has a bearing on better power transfer and life...the less splines, the less effective. I'm no engineer but if that's true then the 31 spline would be a more effective joint to transfer power better than the 27. If you looked at the failure mode of my 76 side yoke, the spindle, it really looked more like granular steel in cast form than forged or wrought steel but we never found out, just replaced with drop forged on both sides which I thought was important so each side handled equal force and was equal material. They aren't comparable but I'll attach a photo of the failed spindle for example.

Hi Lance,I can see that you twisted the splines on your shaft whereas we break them at the shoulder.It looks like if you had more splines you would not have that problem.

AL.


Al.

[LancePearson]

Al, whatever was done on my 76 was done by previous owners which is unknown to me. It isn't raw power at 210 hp but something else in past use habits. My 91 Z if a side yoke spindle breaks would probably be at the shoulder though it isn't one of your 5-600 hp versions, closer to stock. Gold is right...it ain't all engine when you start with these horse powers.

I also assume that broken side yoke in the photo was factory OEM equipment and design factors were substantially less than what any of our Z's would need...at least I hope so.

If they break at the shoulder is that a "joined" area where welding attached the shaft to the yoke type fitting?

I'd love to have access to the suppliers who make these various things in more detail, especially with design specifications.

[ALZR1]

Al, whatever was done on my 76 was done by previous owners which is unknown to me. It isn't raw power at 210 hp but something else in past use habits. My 91 Z if a side yoke spindle breaks would probably be at the shoulder though it isn't one of your 5-600 hp versions, closer to stock. Gold is right...it ain't all engine when you start with these horse powers.

I also assume that broken side yoke in the photo was factory OEM equipment and design factors were substantially less than what any of our Z's would need...at least I hope so.

If they break at the shoulder is that a "joined" area where welding attached the shaft to the yoke type fitting?

I'd love to have access to the suppliers who make these various things in more detail, especially with design specifications.

not at all it's A one piece deal.it's just small in diameter it measures 1.240"
just under 1.250", the ones I have now measure 1.450" or 1.460" at the shoulder,33 splines and are made out of much better material.

AL.

[Bob G]

I have the 31 spline spindles & rebroched bearing -hubs I will bring them to Marks on the 21st For everyone to fondel
Bob G

[LancePearson]

I'll keep that in mind, Al, in case I ever do break a side yoke spindle or whatever the correct term is that connects the differential to the half shafts to the wheels on my 1991 Z. Looks fairly much like similar logic if different specs. Glad it's better steel/material.

[Paul Workman]

OK! After some searching, I found the pix Al sent me of his new spindle.

This is a topic that needs proper treatment, so I'll just post a couple of the pix for now, and get "into it" with Al n Pete n Bob G later.

I counted the "points" and I believe there are 33 here, but not 100% sure as the photo isn't all that clear around the entire hub. That aside, it is easy to see the huge difference in the size of the spindle, compared to stock. (I believe the stock was welded at the shoulder as a reconstruction for the sake of the photo...would be my guess.)

I counted 33, but see if your eyes are better than mine (good chance of that!)

The hub...

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/ZR-133spline7_zps39b6ad61.jpg

Spindle comparison

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/ZR-133spline6_zps8813b130.jpg

As suggested...This might be an SOP upgrade against eventualities, yes?

I want some!
P.

[Pete]

Yes,my mistake.

31 and 33

Pete

[Fully Vetted]

Subscribed

[LancePearson]

That's interesting...With the photos it looks like you are talking about the outboard end of the half shaft U joint mechanism that goes into the hub with the wheel studs. Oddly enough, the C3's that broke, including mine, broke on the other end inside the differential! The outboard ends were pretty good. Mine inside the differential on both sides now are drop forged and better than oem quality so I don't worry too much about it any more. Maybe outboard ones did too and I just never knew it. the l48 76 motor does not have the power these guys do so that may well explain it.

[sammy]

what does it cost for the upgraded spindles and bearing assemblies?

[Ronstar]

I'm interested. Does Al ( or bob) make these?

[RHanselman]

Al's shaft is impressive!

Wow, you said that out loud!

[Blue Flame Restorations]

That's interesting...With the photos it looks like you are talking about the outboard end of the half shaft U joint mechanism that goes into the hub with the wheel studs. Oddly enough, the C3's that broke, including mine, broke on the other end inside the differential! The outboard ends were pretty good. Mine inside the differential on both sides now are drop forged and better than oem quality so I don't worry too much about it any more. Maybe outboard ones did too and I just never knew it. the l48 76 motor does not have the power these guys do so that may well explain it.


The 63-82 factory differential side yokes were not hardened. The ends would wear and fatigue. The replacements "are" hardened.

[ALZR1]

Wow, you said that out loud!

I swear he has never seen my shaft.

AL.

I have the shafts made out of 4340 and heat treated through out,then I rework the spindles to fit the new bearings.
The cost of the stub axles is $1150.00 bearings,studs and the lug nuts another $400.00 and $600.00 for labor.

AL.

[XfireZ51]

I swear he has never seen my shaft.

AL.

I have the shafts made out of 4340 and heat treated through out,then I rework the spindles to fit the new bearings.
The cost of the stub axles is $1150.00 bearings,studs and the lug nuts another $400.00 and $600.00 for labor.

AL.

Al,

You are too modest.

[Fully Vetted]

I swear he has never seen my shaft.

AL.

I have the shafts made out of 4340 and heat treated through out,then I rework the spindles to fit the new bearings.
The cost of the stub axles is $1150.00 bearings,studs and the lug nuts another $400.00 and $600.00 for labor.

AL.

So, supposing one were to upgrade to this setup, what is the next weakest link that would most likely fail? Or, is there one?

[ALZR1]

So, supposing one were to upgrade to this setup, what is the next weakest link that would most likely fail? Or, is there one?

When I break the next item I'll let you guys know.but if I had to guess I would
say the halfshafts.

AL.

[WARP TEN]

This is a very interesting thread. Al showed me his new spindle when I stopped at his shop a while back--very impressive. I solve the problem by having cheap tires that don't hook up too well. --Bob

[LancePearson]

very interesting and informative....this is sort of the opposite of the road racing setup Z owners thread...power, yes, but much more attention on the suspension and especially the brake system working well at high stress loads. Two different key emphasis situations.

[XfireZ51]

This is a very interesting thread. Al showed me his new spindle when I stopped at his shop a while back--very impressive. I solve the problem by having cheap tires that don't hook up too well. --Bob

Bob,

That what I said! Al's shaft or spindle was impressive.

BTW, the cheap tires that don't hook well, not such a good idea when you hit second gear.

[WARP TEN]

Bob,

That what I said! Al's shaft or spindle was impressive.

BTW, the cheap tires that don't hook well, not such a good idea when you hit second gear.

I didn't want to say it quite the way you did...;). And on the tires, the Sumis hook up reasonably well for street tires, especially if I drop a few pounds of pressure. But as you point out, one should be careful. --Bob

[FU]

BTW, the cheap tires that don't hook well, not such a good idea when you hit second gear.

Experience has few reward's :mrgreen:

[rkreigh]

So, supposing one were to upgrade to this setup, what is the next weakest link that would most likely fail? Or, is there one?

gee, you're pretty proud of that shaft. I'm sure I don't want to see it!!

but do you think you can offer a discount on those lug nuts

sounds like they are made out of unobtanium to me =D>

[Jagdpanzer]

So, supposing one were to upgrade to this setup, what is the next weakest link that would most likely fail? Or, is there one?

My guess is the spider or side gears in the differential.

[tf95ZR1]

When I break the next item I'll let you guys know.but if I had to guess I would
say the halfshafts.

AL.

What kind of RWHP are we talking about to do this kind of damage?

[Fully Vetted]

My guess would be north of 550 whp and nothing short of slicks.

[FU]

My guess is the spider or side gears in the differential.

I'd bet on that :handshak:

[ALZR1]

gee, you're pretty proud of that shaft. I'm sure I don't want to see it!!

but do you think you can offer a discount on those lug nuts

sounds like they are made out of unobtanium to me =D>

They are not the stock 12mm they are upgraded to 1/2" ARP. just like bearings and stub axle.they are all upgraded.
if you would like I can do better than A discount give me your address and I'll send you A lug nut.

AL.