Broke E-Shaft Today.
 

After feeling good with the tune the past month. I was all set for the dyno on Monday. But it was short lived. Earlier today while messing arround on the highway with my buddy Jess (1100 RWHP 97 Camaro). The e-shaft decided to let go. From looking at the datalog it happend at 6150 rpm at 25.5 psi in 3rd gear. We have done numerous runs with no issues. This motor has held up for 2 years of abouse after studding it. Last yeat running 24-25psi on race fuel and the this year on E85.

I just finished pulling apart the motor. All housing look good, I still need to check them for warp. I will to replace a rotor and a stationary gear from the preliminary inspection. I was happy to see virtually no wear on the housings. The Klotz Benol is doing it job premixed with e85.

Now to figure out what caused the failure. E-shaft flex, spun center bearing, or detination? I also will need to decide to go with an aftermarket or stock shaft again.

Here a pics

Do you see much evidence for a spun bearing? Check for all the signs.

Man, my condolences. Are you going to try a Jeff Bruce shaft next?

wow.

Was the rotating assembly balanced?
Lightweight rotors?


It matters...

was it a stock 3rd gen e-shaft?

um ... 20B section ...

sorry, I wasn't paying attention when I clicked on the thread earlier on as it was on the main page...

The front portion of the eshaft was siezed to the center bearing. I had to use a press to remove it. The front stationary gear did have a few damaged teeth. I'm not sure if it ws part of the cause or a result of the failure. I was able to check the housings last night there is no damage or warp, thank god.

The assemby was not balanced. The new one will be!!

would you mind taking a good detailed picture of the surfaces of the break (macro if you've got it)? I'd like to see how the fracture propogated across the surface

Pics of break
the smooth spots center of the left piece was caused from the press.

http://i21.photobucket.com/albums/b2...7/100_0251.jpg
http://i21.photobucket.com/albums/b2...7/100_0250.jpg
http://i21.photobucket.com/albums/b2...7/100_0249.jpg
http://i21.photobucket.com/albums/b2...7/100_0248.jpg

Wow. Condolences! It's possibilities like this that made me switch back to a 2rotor for racing purposes :(

damn man , just as i was following youre whole gto tranny upgrade , damn
any ideas of what whp you where pushing ?
some people argue that the limit for the shat is around 700 hp , i beg to differ though
or maybe just lots of street abuse?

I was going to find out on the dyno today. I was shooting for 800+rwhp with this turbo which is maxed out. I can't quite keep up with Jess, He pulls away from me gradually. He keeps tellimg me to go to a 88 or 91mm, he's running a 94mm on a 383.

I am happy with the performance now, just neet to get it reliable. Drivability is great except for the clutch. I'm looking at carbon setups that can be slipped for smoother starts on the street. Tranny is holding up fine. Jess is still running a t-56 at 1100rwhp with a viper output shaft. We both powershift at 8000+, you can tell the GTO box is smoother shifting vs. the camaro box.

One Idea that was brought up is that the last tank of gas was winter blend E85 which is only 70+% ethonal vs 83+%. I only added 8 gallons that morning to top off the tank. The tank was down to about a 30% when it happend. So with the fuel sloshing back under hard acceleration there is a slight chance dropping fuel pressure. But the afr's in the log look fine. 10.9-11.2 under full boost.
Who knows, it was something to chew on.

Any potential that the place that made your adapter plate misaligned the input shaft? It seems like a stretch, but I could imagine the resulting stress on the flywheel, as subtle as it would have to be to go unnoticed, fatiguing the shaft over enough time.

If it was misaligned, I think it would affect the input shaft bearing or pilot bearing more than the E-shaft. Both are in good condition.

Definitely. . . the bearings would be destroyed completely.

Were you data logging? If the ethanol content dropped, the mixture should've richened, but not that significantly. . . hmmmm.

Hope you get to the bottom of it. Any thoughts as to which route you're going to go? OEM replacement? GURU? MPS?

What letter code eshaft was this?

i dont think it could be the adapter plate , it would have fucked up some time ago , you got some time already hogging it right ?
maybe just stress ??

The Shaft is from a B Series. The only marking on it is 746, that I can remember. I just flew back to CA this morning for 2 weeks.

I have emails back from Xtreme Rotary and Japan2LA win pricing.

Does someone have a contact to purchace the Jeff Bruce shaft?
And a recomended shops to lighten the rotors then balance the assembly?

I have all winter to get it fixed. That is the only plus about breaking at this time of the year.

Shouldn't that e-shaft have a letter as well? Hmm maybe someone switched it? Either way, since you have a lofty goal, I would just pony up for the aftermarket e-shaft. Glad your having great results with the GTO tranny. That is something I will most definetly do in the future.

The motor had all matching #'s on the housings when i bought it. I am sure the motor was never opened before. I still have all the original housings but they need to lapped. When I studded the motor I was came accross a good deal on all 4 new in box side housings for $1250.

^--nice!!

That's part of your problem. C & D series had upgraded shafts and backing plates for a reason; earlier shafts were prone to flexing and eventually snapping.

You mean the 3-piece shaft? Yea, I can get it for you.

Yep; I work w/ the same guy who balances the rotating assembly for RacingBeat. You'd have to send the entire assembly, and if you wanna go all out, include the clutch, flywheel, & counterweight too.

~Ramy

I can sort the shaft from here if you like...

And I have never seen a letter on a shaft yet... just numbers & they dont relate to the number on the block either...

I was referring to shafts from a C & D series *motor,* not a # on the shaft itself.

Interesting...

I have an A series that sees 10k RPM fairly often....

Has nothing to do w/ how high you rev it. At that kind of rpm, the shaft is more likely to snap from housing flex (if the block isn't purpose-built) than anything else. The problem I'm referring to was a problem Mazda originally recognized with sudden torque surge.

mad20B maybe it is because you are running an N/A it doesn't have the snap torque effect that a forced induction motor suffers from (What Ramy is refering to)

:withstupi

Gt4788r

So it's a matter of time then:)

I have pricing for a few options now. I am going to hold off on a decision until I get confirmation of my next project for work. I want to make sure I have some job security and my pay rate before choosing an option.

I have just read the Teread on e-shafts.
https://www.rx7club.com/showthread.p...ght=jeff+bruce

very informative.

U can also contact Richard at Green Brothers racing in NZ they get there parts straight from Jeff Bruce. They are sourcing out my 4 rotor kit as we speak :)

richard@greenbrothers.co.nz

JT

I just found that thread yesterday, and I agree, awesome :)

Yea there is a TON of really good, solid info in this subsection - if ya look around and know what to read & what to ignore ;)

Here is an update

I ordered the Shaft direct from Precission. The exchange rate was awesome 2 weeks ago and it only cost be $1480 USD shipped. I could not pass that up. I should see it in the next week or so.

I'll post picture when it arrives. I want to get the car together soon. I'll b taking the car out to California in May when my next project start. Another bonus is there is a bunch of gas stations starting to carry E85 in the Sacramento area.

That's unreal. Did you still fiind out what made it snap like that?

How much do the 3 peice shafts run?

Never did ask Jeff when I talked to him.

I'm sure my old one failed do to the HP level and not having the assembly balanced .

so youre going to run E85?

Was there a dedicated oil feed to the thick center housing?

Yes I want to keep running E85. I am looking at adding an ethonal content sensor to the ECU. This will allow me to run regular gas when E85 isn't arround. I've also been looking at the AI forum just checking out that option too. Right now I just want to get it together and break the motor in.
I was told my eshaft arrived Friday. I won't be able to check it out till next weekend when I am home.

No, but there will be on this time.
Like I said before the motor was in there for quite awhile and took alot of abuse over the last few years untouched sense it was studded.

Please post pics of it once you get it in your hands..

I am sure I am not the only one who wants to see the quality of the E-shaft..

Also curious to know if you will check the run out of the E-shaft?

I ask this because....a few bigtime rotary guys I have talked to in the past said the NZ 3 rotor and 4 rotor E-shafts had too much run out... curious to know if this is fact or fiction..

Will do, I have a set of V-blocks and a dial indicator.

Hopefully it wil read ZERO...

Finally made it home.
First thing I did was a runout check.
Having the v blocks on the 1st and 3rd bearing showed less than .0003 3/10,000th
Having the v blocks on the 2nd and 3rd bearing showed less than .0005 5/10,000th
The high point is either side of the keyway. The milling of they keyway could of caused it.
I'd say that is pretty damn straight.

http://i21.photobucket.com/albums/b2...7/100_0336.jpg
http://i21.photobucket.com/albums/b2...7/100_0332.jpg

http://i21.photobucket.com/albums/b2...7/100_0335.jpg


You can see there is less material in between the 2nd and 3rd lobes

http://i21.photobucket.com/albums/b2...7/100_0333.jpg
http://i21.photobucket.com/albums/b2...7/100_0331.jpg

Looks to be a quality piece :icon_tup:

mad20b, yours may of had a gt47 bolted to it but it still only made the power of a n/a 20b:lol::lol::lol: 140mph was it???:lol::lol:

Jeff Bruce cranks are good and do the job fine,have seen them many times after being abused in 1000+hp 3 rotors, bearings are always fine.No signs of flex.