Diff explosion
02-28-2009, 05:58 PM
#1
Cpt. Slow
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Location: Oregon City, OR
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Diff explosion
I'm sure you guys have all seen pictures like this before, but I thought I'd share anyways.
1.6 running about 200hp and tracking fairly regularly at Portland International Raceway. 225 Toyo Proxxes 4's were apparently transmitting a pinch too much grip to the diff, which I think was a viscous.
It started making some weird noises in the last 2-3 minutes of the last session with the ORPCA (Oregon region Porsche club o' America) so I pulled off track, packed up and headed home. It blew up trying to leave the parking lot. Talk about perfect timing!
Open 1.8 from a 1999 cost me $130 and is already in less than a week after it broke. Next is either tires, since I won't feel bad putting even more grip on the drive train, an RX7 LSD, or transmission, but that's only if it blows up soon.
Which it probably will.
It was pretty cool tearing it apart, its actually called a hypoid bevel gear. That means it is a spiral bevel gear that mates below the center line of the ring gear. Actually very common in differentials, but still cool (to me).
1.6 running about 200hp and tracking fairly regularly at Portland International Raceway. 225 Toyo Proxxes 4's were apparently transmitting a pinch too much grip to the diff, which I think was a viscous.
It started making some weird noises in the last 2-3 minutes of the last session with the ORPCA (Oregon region Porsche club o' America) so I pulled off track, packed up and headed home. It blew up trying to leave the parking lot. Talk about perfect timing!
Open 1.8 from a 1999 cost me $130 and is already in less than a week after it broke. Next is either tires, since I won't feel bad putting even more grip on the drive train, an RX7 LSD, or transmission, but that's only if it blows up soon.
Which it probably will.
It was pretty cool tearing it apart, its actually called a hypoid bevel gear. That means it is a spiral bevel gear that mates below the center line of the ring gear. Actually very common in differentials, but still cool (to me).
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02-28-2009, 06:02 PM
#2
Cpt. Slow
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Oh, forgot to mention this. If anyone in the NW region needs 1.6 diff parts (beyond the gears obviously), axles, or drive shaft, I have them all available in Beaverton for the next week or so, then they'll probably be in Oregon City, PM me for details.
If I should move that bit to the For Sale section, I gladly will, just thought I'd post it here for reference.
If I should move that bit to the For Sale section, I gladly will, just thought I'd post it here for reference.
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03-01-2009, 02:28 AM
#5
Cpt. Slow
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maz-toys in troutdale, OR.
They told me about two, a '97 and a '99. One was a torsen, one was the open that I bought and installed. I forget if this was the 4.3 out of the '99 or the 4.1 out of the '97. Either way, I still only paid $130. He quoted $200, and then gave me a 20% discount cause I race, which brought it to $160. I was working on it at my friend's shop, and he's sponsoring me. Not much in this economy, but he pays for a few little things and lets me use his shop, in exchange for some small shop banners (1'x2'ish) on my doors. He said he'd pay for half, which brought my price down to $80. Then I realized I needed the axles and drive shaft (give me a break, it was my first time swapping to a 1.8), which the wrecking yard charged me $50 for. So grand total of $130 for an open 1.8 diff. Even if it was the full $210, sounds like it'd still be a killer deal, no?
I took about 2 hours to take it out on Monday after I used his car dolly to get it from the track to his shop, and then spent an hour on Thursday putting the housing in (this was before I had the drive shaft and axles) and then another 1.5 hours today buttoning everything up. I'd definitely be faster if I had to do it again, I took my time with it and made sure everything was to my satisfaction. That and the damn passenger side axle nut was a bitch to get off!
One question though, I reused the 1.6 diff's drive shaft bolts and nuts, which are smaller, right? They seemed a little loose but that's all I had at the moment. I won't race the thing if they're going to shift back and force and sheer off after a couple hard launches. I'm guessing they went from M6 to M8 bolts? Or maybe M8 to M10? I forget just how big they were.
They told me about two, a '97 and a '99. One was a torsen, one was the open that I bought and installed. I forget if this was the 4.3 out of the '99 or the 4.1 out of the '97. Either way, I still only paid $130. He quoted $200, and then gave me a 20% discount cause I race, which brought it to $160. I was working on it at my friend's shop, and he's sponsoring me. Not much in this economy, but he pays for a few little things and lets me use his shop, in exchange for some small shop banners (1'x2'ish) on my doors. He said he'd pay for half, which brought my price down to $80. Then I realized I needed the axles and drive shaft (give me a break, it was my first time swapping to a 1.8), which the wrecking yard charged me $50 for. So grand total of $130 for an open 1.8 diff. Even if it was the full $210, sounds like it'd still be a killer deal, no?
I took about 2 hours to take it out on Monday after I used his car dolly to get it from the track to his shop, and then spent an hour on Thursday putting the housing in (this was before I had the drive shaft and axles) and then another 1.5 hours today buttoning everything up. I'd definitely be faster if I had to do it again, I took my time with it and made sure everything was to my satisfaction. That and the damn passenger side axle nut was a bitch to get off!
One question though, I reused the 1.6 diff's drive shaft bolts and nuts, which are smaller, right? They seemed a little loose but that's all I had at the moment. I won't race the thing if they're going to shift back and force and sheer off after a couple hard launches. I'm guessing they went from M6 to M8 bolts? Or maybe M8 to M10? I forget just how big they were.
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03-01-2009, 03:32 PM
#9
Cpt. Slow
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I know I was hoping you'd beat me, but looks like I won! I feel like more of a looser though...
I have a motorcycle camshaft that snapped into 3 pieces at 9000rpm, the head that went along with it, and now this gear set. My offerings to the gods of speed are growing a little too fast for my liking...
I met a spec miata guy at the track day, he gave me his sympathies at the end of the day when my diff blew up. He called me yesterday during another track day. "Dude, do you know anyone with a spare diff?" That's the first story I've heard of one actually blowing up on stock power. I suppose that's racing it with sticky rubber though.
I have a motorcycle camshaft that snapped into 3 pieces at 9000rpm, the head that went along with it, and now this gear set. My offerings to the gods of speed are growing a little too fast for my liking...
I met a spec miata guy at the track day, he gave me his sympathies at the end of the day when my diff blew up. He called me yesterday during another track day. "Dude, do you know anyone with a spare diff?" That's the first story I've heard of one actually blowing up on stock power. I suppose that's racing it with sticky rubber though.
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03-10-2009, 03:07 PM
#16
Cpt. Slow
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The funny thing is I threw in some new gear oil, and did a huge burnout from the back of the garage (3 car lengths or more) to the front and both wheels spun the entire way. WTF I thought opens wouldn't do that.
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