Re: Heat treating my own output shaft on a 904?
[Re: Hunted Duck]
#708039
05/26/10 03:55 PM
05/26/10 03:55 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
ok. I guess if I can get my hands on a stock one that someone broke or was bent I could take it to work and have the lab guys look it over to tell me what I would be dealing with. Thanks again 
Find a old/bent shaft and cut it into about 3 pieces,
check the material on one then have the lab determine
what the rockwell C is then figure what it might need
to be (rockwell C) then after hardening do a torsional
test on it.... otherwise your just guessing and
even then you still dont know if it can take the
shock
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Re: Heat treating my own output shaft on a 904?
[Re: MR_P_BODY]
#708040
05/26/10 05:11 PM
05/26/10 05:11 PM
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Joined: Apr 2005
Posts: 1,880
USA
Ron Silva
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USA
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This one broke in the MAJOR Diameter right after the heat treat. I think if you heat treated the whole thing I am sure it would help. This was in my Demon, 3100 pound 9.90 car. Broke right on the launch, sounded like a gun going off inside the car.
I did not know they had Billet OUTPUT shafts yet for the 904. Who has them??
SRT DEMON ONE SEAT
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Re: Heat treating my own output shaft on a 904?
[Re: Ron Silva]
#708044
05/26/10 06:46 PM
05/26/10 06:46 PM
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Anonymous
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Anonymous
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Quote:
This one broke in the MAJOR Diameter right after the heat treat. I think if you heat treated the whole thing I am sure it would help. This was in my Demon, 3100 pound 9.90 car. Broke right on the launch, sounded like a gun going off inside the car.
I did not know they had Billet OUTPUT shafts yet for the 904. Who has them??
That's wild  .......I've never seen one break  .......
Usually when something like that breaks, it's because of a lack of power......what I mean is like when someone comes out of the burnout box with the slicks spinning and the tires hit dry pavement and you hear that loud tire "chirp" as the motor is yanked down.....I've seen rods kicked out and axles twisted like that too....... 
Wayne
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Re: Heat treating my own output shaft on a 904?
[Re: DusterW2]
#708045
05/27/10 02:28 PM
05/27/10 02:28 PM
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Joined: Dec 2006
Posts: 3,533
Indiana
Fury Fan
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master
Joined: Dec 2006
Posts: 3,533
Indiana
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Quote:
The aftermarket input and output shafts are 300M steel. Increasing the hardness of the stock shaft (Not sure of the steel composition, maybe 1540) may make it more susceptible to fatigue and fracture. Detailed analysis would be required for best results.
In addition to that, the hardness you end up with must still be somewhat similar to the hardness of the mating components, otherwise hard part chews up soft part eventually. If you can't get much stronger while still in the same hardness range, then a stronger base material (at lower hardness) is needed. If the OEM shaft is already harder than the mating components, there's probably no room to increase.
If I had the type of car that needed a stronger shaft, I wouldn't risk saving $600 on a shaft against the colateral damage if an 'experimental' shaft had a problem whilst under power.
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Re: Heat treating my own output shaft on a 904?
[Re: Fury Fan]
#708047
05/27/10 05:24 PM
05/27/10 05:24 PM
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Joined: Jan 2005
Posts: 3,635
Oakland, MI
dizuster
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master
Joined: Jan 2005
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Oakland, MI
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Quote:
In addition to that, the hardness you end up with must still be somewhat similar to the hardness of the mating components, otherwise hard part chews up soft part eventually. If you can't get much stronger while still in the same hardness range, then a stronger base material (at lower hardness) is needed. If the OEM shaft is already harder than the mating components, there's probably no room to increase.
If I had the type of car that needed a stronger shaft, I wouldn't risk saving $600 on a shaft against the colateral damage if an 'experimental' shaft had a problem whilst under power.
Sorry man, not true. Nearly every planetary carrier on the planet is aluminum with steel shafts. Nowhere near the same hardness.
Also, its necessary to run a bronze gear (soft material) on a billet cam core (hard material). As I understand it, it's important that the two components actually DO NOT have the same hardness.
I wouldn't be afraid to try it. If the stock shaft may already break, what do you have to loose if this one breaks? I've been thinking of sending mine out for cryo treatment. I know some of the 4-cyl turbo guys do it...
You know the other thing I'm really surprised is that the 904 output shaft is weaker then the aluminum splines on the front planetary. I would have thought for sure that planetary would have stripped before breaking the output shaft...
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Re: Heat treating my own output shaft on a 904?
[Re: dizuster]
#708048
05/27/10 07:12 PM
05/27/10 07:12 PM
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Joined: Apr 2005
Posts: 1,880
USA
Ron Silva
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top fuel
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USA
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Well, mine broke after I put taller gears in the rearend. I had gone from 4.10 to 3.55 gears with a 474 CI R3W9 Motor. The taller the rear gears the more stress on the trans. I ended up going back to 3.91 gears after that. The trans did not seem to be as happy on the upshifts either.
SRT DEMON ONE SEAT
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Re: Heat treating my own output shaft on a 904?
[Re: Ron Silva]
#708049
05/27/10 09:33 PM
05/27/10 09:33 PM
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Anonymous
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Anonymous
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Quote:
Well, mine broke after I put taller gears in the rearend. I had gone from 4.10 to 3.55 gears with a 474 CI R3W9 Motor. The taller the rear gears the more stress on the trans. I ended up going back to 3.91 gears after that. The trans did not seem to be as happy on the upshifts either.
Also with the taller gear, you lost power/torque and there's more wheel speed coming out of the burnout box and more of a wheel speed RPM drop if the tires grabbed and yanked it down..... 
I can't imagine putting a steady load of your HP times the low gear ratio would twist that in half.....It had to be "snapped" really quickly.....
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Re: Heat treating my own output shaft on a 904?
[Re: dizuster]
#708050
06/01/10 04:48 PM
06/01/10 04:48 PM
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Joined: Dec 2006
Posts: 3,533
Indiana
Fury Fan
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Joined: Dec 2006
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Indiana
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Quote:
Quote:
In addition to that, the hardness you end up with must still be somewhat similar to the hardness of the mating components, otherwise hard part chews up soft part eventually. If you can't get much stronger while still in the same hardness range, then a stronger base material (at lower hardness) is needed. If the OEM shaft is already harder than the mating components, there's probably no room to increase.
Sorry man, not true. Nearly every planetary carrier on the planet is aluminum with steel shafts. Nowhere near the same hardness.
If they have a tight spline fit the impact loading is reduced and hardness matching becomes less of an issue.
Quote:
Also, its necessary to run a bronze gear (soft material) on a billet cam core (hard material). As I understand it, it's important that the two components actually DO NOT have the same hardness.
Keep in mind, bronze usually contains lead, which is a lubricant, so on a distributor gear that's a whole different ballgame.
Quote:
I wouldn't be afraid to try it. If the stock shaft may already break, what do you have to loose if this one breaks? I've been thinking of sending mine out for cryo treatment. I know some of the 4-cyl turbo guys do it...
You know the other thing I'm really surprised is that the 904 output shaft is weaker then the aluminum splines on the front planetary. I would have thought for sure that planetary would have stripped before breaking the output shaft...
As I don't deal with this every day, I reviewed the question with a guy that has been designing planetary components for at least 25 years, and there's truth in what both of us said. There's a lot of science (and a little magic) to material type, spline fit and hardness matches, and depending on a bunch of little details, sometimes hardness helps, sometimes it causes other problems -- and you won't know until afterward.
I stand behind my original line of thought, that possible failure of a 'home-brewed' shaft is a big gamble compared to the cost of an aftermarket shaft that has some real-world testing under its belt.
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