HOW TO: Field strip an OBX LSD
09-15-2006, 01:57 AM
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HOW TO: Field strip an OBX LSD
This is my first LSD (it's for a D-series if that matters). I got it in the mail recently and decided to open it up and make sure OBX didn't send me a faulty diff. I took the diff. apart and studied the internals all night. None of my steps are guesses - I made sure I understood the theory behind each part so that I could create a detailed and accurate write-up. Enjoy.
<U>
PART 1: DISASSEMBLY</U>
1. Remove the 9 bolts holding the LSD together. This is the worst step of the tear-down because it's when you realize that OBX products are junk and monkeys working in the OBX factory don't know how to torque a bolt down
2. You are now looking at this:
3. Remove the LSD cover and set it aside:
4. Remove the 5 highest (top-most) spiral gears and set them aside. Don't worry about which way they were facing (dimple up/dimple down) because it doesn't matter.
5. Remove the axle gear:
6. Remove the collar that goes around the washer sleeves:
7. Remove the upper washer sleeve:
8. Remove the 3 upper compression washers as a set:
9. Remove the lower washer sleeve and lower 3 compression washers as a set:
10. Remove the second set of (5) spiral gears:
11. Remove the lower axle gear:
Now if I were you, I'd hose everything down with brake cleaner. There were a lot of metal shaving floating around inside the case, not to mention a lot of dirt and gunk.
Modified by Enzo Speed at 2:31 PM 9/15/2006
<U>
PART 1: DISASSEMBLY</U>
1. Remove the 9 bolts holding the LSD together. This is the worst step of the tear-down because it's when you realize that OBX products are junk and monkeys working in the OBX factory don't know how to torque a bolt down
2. You are now looking at this:
3. Remove the LSD cover and set it aside:
4. Remove the 5 highest (top-most) spiral gears and set them aside. Don't worry about which way they were facing (dimple up/dimple down) because it doesn't matter.
5. Remove the axle gear:
6. Remove the collar that goes around the washer sleeves:
7. Remove the upper washer sleeve:
8. Remove the 3 upper compression washers as a set:
9. Remove the lower washer sleeve and lower 3 compression washers as a set:
10. Remove the second set of (5) spiral gears:
11. Remove the lower axle gear:
Now if I were you, I'd hose everything down with brake cleaner. There were a lot of metal shaving floating around inside the case, not to mention a lot of dirt and gunk.
Modified by Enzo Speed at 2:31 PM 9/15/2006
09-15-2006, 02:04 AM
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Re: HOW TO: Field strip an OBX LSD (Enzo Speed)
<U>PART 2: REASSEMBLY</U>
1. First in is the lower axle gear:
2. Install it with the CHAMFERED SIDE DOWN:
3. In case you mixed up the two axle gears and can't tell them apart, the LOWER axle gear that you're supposed to be installing is the THICKER one. Here is a side-by-side pic to help you distinguish the two axle gears:
4. After installing it, you should be looking at this. Notice the un-chamfered side is now facing up:
5. Grab the 5 lower spiral gears. In case you accidentally jumbled up the 10 spiral gears, don't worry - they are impossible to install wrong. It doesn't matter if they are dimple up/dimple down. Also, it's impossible to mix up the two sets of 5 gears because the first 5 are cut to the right, and the second 5 are cut to the left. If you mixed them up, just keep going through them and try to install each one. The ones that are cut opposingly will obviously not fit and the ones you should be installing will drop right in.
6. So now you are looking at this:
7. Next, grab the washer-sleeve collar and drop it in (it doesn't matter which way, both sides are the same):
8. You are now looking at this:
9. Next up - the lower washer sleeve:
10. It gets installed FLAT SIDE DOWN:
11. In case you mixed up the upper and lower washer sleeves, the LOWER sleeve is the one that's THINNER:
12. After installing it (flat-side down!) you should be looking at this:
13. Next, install the 6 compression washers:
14. Drop them into the washer sleeve one by one. The order should be as follows: )()()( :
15. You are now looking at this:
16. You will notice that the washers don't line up after you drop them in. In order to line them up, use a screwdriver/drill bit/etc. and push it through the center of all the washers. I used a 31/64" drill bit because it was a perfect fit and left the washers perfectly aligned:
17. You are now looking at this:
19. Next up - the upper washer sleeve:
20. Now, unlike the lower sleeve, this upper sleeve does not have a flat side. Both sides have a lip. The sleeve needs to be installed with the NARROW groove down. The wider groove faces up:
21. After installing the sleeve, you should be looking at this: (note how the upper sleeve sits slightly higher than the collar - that is normal)
22. Now you're ready to install the second set of spiral gears:
23. Which looks like this:
24. Next - the upper axle gear:
25. It gets installed with the UN-CHAMFERED SIDE DOWN. The chamfered side should face up:
26. Here it is installed:
27. Once again, use the scredriver/drill bit to align the washers. You want them to be as perfectly aligned as possible when you put the case back on:
28. Now put the case back on. Notice the size of the gap between the two case halves. That is normal. When you torque the casing bolts down, the washers inside will compress and the case will fit together.
29. There, that wasn't so bad was it? Now go have a beer.
Modified by Enzo Speed at 11:52 PM 9/19/2006
1. First in is the lower axle gear:
2. Install it with the CHAMFERED SIDE DOWN:
3. In case you mixed up the two axle gears and can't tell them apart, the LOWER axle gear that you're supposed to be installing is the THICKER one. Here is a side-by-side pic to help you distinguish the two axle gears:
4. After installing it, you should be looking at this. Notice the un-chamfered side is now facing up:
5. Grab the 5 lower spiral gears. In case you accidentally jumbled up the 10 spiral gears, don't worry - they are impossible to install wrong. It doesn't matter if they are dimple up/dimple down. Also, it's impossible to mix up the two sets of 5 gears because the first 5 are cut to the right, and the second 5 are cut to the left. If you mixed them up, just keep going through them and try to install each one. The ones that are cut opposingly will obviously not fit and the ones you should be installing will drop right in.
6. So now you are looking at this:
7. Next, grab the washer-sleeve collar and drop it in (it doesn't matter which way, both sides are the same):
8. You are now looking at this:
9. Next up - the lower washer sleeve:
10. It gets installed FLAT SIDE DOWN:
11. In case you mixed up the upper and lower washer sleeves, the LOWER sleeve is the one that's THINNER:
12. After installing it (flat-side down!) you should be looking at this:
13. Next, install the 6 compression washers:
14. Drop them into the washer sleeve one by one. The order should be as follows: )()()( :
15. You are now looking at this:
16. You will notice that the washers don't line up after you drop them in. In order to line them up, use a screwdriver/drill bit/etc. and push it through the center of all the washers. I used a 31/64" drill bit because it was a perfect fit and left the washers perfectly aligned:
17. You are now looking at this:
19. Next up - the upper washer sleeve:
20. Now, unlike the lower sleeve, this upper sleeve does not have a flat side. Both sides have a lip. The sleeve needs to be installed with the NARROW groove down. The wider groove faces up:
21. After installing the sleeve, you should be looking at this: (note how the upper sleeve sits slightly higher than the collar - that is normal)
22. Now you're ready to install the second set of spiral gears:
23. Which looks like this:
24. Next - the upper axle gear:
25. It gets installed with the UN-CHAMFERED SIDE DOWN. The chamfered side should face up:
26. Here it is installed:
27. Once again, use the scredriver/drill bit to align the washers. You want them to be as perfectly aligned as possible when you put the case back on:
28. Now put the case back on. Notice the size of the gap between the two case halves. That is normal. When you torque the casing bolts down, the washers inside will compress and the case will fit together.
29. There, that wasn't so bad was it? Now go have a beer.
Modified by Enzo Speed at 11:52 PM 9/19/2006
09-15-2006, 02:03 PM
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Re: (swoyEKr.)
thank you for the write up.
the 6 washers are they installed correctly? )))((( I thought earl recommended )()()(
not trying to start anything, just curious.
the 6 washers are they installed correctly? )))((( I thought earl recommended )()()(
not trying to start anything, just curious.
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09-15-2006, 02:42 PM
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Re: (Chris22215)
<U>WASHER THEORY</U>
Here is the story behind the washers (also known as "Bellville washers" or "Bellville springs").
In the early years of the Quaife LSD design, there were no washers in the center of the differential. The unit worked fine as an LSD, however, the spiral gears and axle gears inside the diff moved around slightly when the differential was not in a full torque-biasing mode. What that means is that the differential was noisy, especially when taking turns.
To fix the problem, Quaife started using the Bellville washers inside the diff to PRE-LOAD the axle gears. Pre-loading puts tension on the axle gears and keeps them from clunking around.
Therefore: the washers are SUPPOSED to raise the differential housing. When you torque the differential housing on, the washers compress, thus pre-loading the differential gears.
It all makes sense now, right? This explains everything! For starters, we all wondered why OBX couldn't tighten a simple set of bolts without stripping them; well now we know - it's because the springs were preloading the case. If you don't slowly and carefully tighten the bolts in a star-pattern, it will cross-thread the bolts. Also, how often have you heard about people complaining that their LSD is noisy? Again, now we know - it's because whatever their washer configuration was, it was not preloading the diff which results in clunking noises.
So this brings up a few issues. First and foremost, which washer configuration is the best? Here are all the possible washer configurations, as well as their resulting heights:
1. )))((( -or- ((())) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.35"
2. ))()(( -or- ())(() -or- )(())( -or- (()()) . . . . . . . . . . . . . . . . . 0.45"
3. ()()() -or- )()()( . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.50"
So from that, I can tell you that the #1 configurations offer zero preload. Using those configurations, the differential case sits above the axle gears with zero clearance. If you use the configurations in #2, you will definitely have preload, but not nearly as much as the configurations in #3. Which is best? According to my research, the best configuration is one that offers maximum preload. In other words, either ()()() or )()()( .
Further examination of the washer sleeves has lead me to believe that washer failure may be caused by misaligned washers. The washers are often misaligned because they don't fit within the washer sleeves when properly stacked. The two pictures below demonstrate what I'm referring to.
1. ()()()
2. )()()(
Notice with the ()()() configuration, the washer edges sit higher above the sleeves than they do in the )()()( configuration. Since we want to avoid misaligned washers, it's best to have all 6 washers fully contained within the sleeves. Clearly, the )()()( configuration will have a better chance of doing that once the case it put together and the washers are compressed.
Therefore, it is my belief that the )()()( configuration is going to be better than the ()()() in the long run.
Modified by Enzo Speed at 12:04 AM 9/20/2006
Here is the story behind the washers (also known as "Bellville washers" or "Bellville springs").
In the early years of the Quaife LSD design, there were no washers in the center of the differential. The unit worked fine as an LSD, however, the spiral gears and axle gears inside the diff moved around slightly when the differential was not in a full torque-biasing mode. What that means is that the differential was noisy, especially when taking turns.
To fix the problem, Quaife started using the Bellville washers inside the diff to PRE-LOAD the axle gears. Pre-loading puts tension on the axle gears and keeps them from clunking around.
Therefore: the washers are SUPPOSED to raise the differential housing. When you torque the differential housing on, the washers compress, thus pre-loading the differential gears.
It all makes sense now, right? This explains everything! For starters, we all wondered why OBX couldn't tighten a simple set of bolts without stripping them; well now we know - it's because the springs were preloading the case. If you don't slowly and carefully tighten the bolts in a star-pattern, it will cross-thread the bolts. Also, how often have you heard about people complaining that their LSD is noisy? Again, now we know - it's because whatever their washer configuration was, it was not preloading the diff which results in clunking noises.
So this brings up a few issues. First and foremost, which washer configuration is the best? Here are all the possible washer configurations, as well as their resulting heights:
1. )))((( -or- ((())) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.35"
2. ))()(( -or- ())(() -or- )(())( -or- (()()) . . . . . . . . . . . . . . . . . 0.45"
3. ()()() -or- )()()( . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.50"
So from that, I can tell you that the #1 configurations offer zero preload. Using those configurations, the differential case sits above the axle gears with zero clearance. If you use the configurations in #2, you will definitely have preload, but not nearly as much as the configurations in #3. Which is best? According to my research, the best configuration is one that offers maximum preload. In other words, either ()()() or )()()( .
Further examination of the washer sleeves has lead me to believe that washer failure may be caused by misaligned washers. The washers are often misaligned because they don't fit within the washer sleeves when properly stacked. The two pictures below demonstrate what I'm referring to.
1. ()()()
2. )()()(
Notice with the ()()() configuration, the washer edges sit higher above the sleeves than they do in the )()()( configuration. Since we want to avoid misaligned washers, it's best to have all 6 washers fully contained within the sleeves. Clearly, the )()()( configuration will have a better chance of doing that once the case it put together and the washers are compressed.
Therefore, it is my belief that the )()()( configuration is going to be better than the ()()() in the long run.
Modified by Enzo Speed at 12:04 AM 9/20/2006
09-15-2006, 03:00 PM
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Re: (Enzo Speed)
<U>SUPPLEMENTAL INFO</U>
Here is the patent info describing what the washers do:
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Patent Office »</TD></TR><TR><TD CLASS="quote">Differential with preload spring
Document Type and Number: United States Patent 5524509
Abstract: An improved differential mechanism of the holdout ring type, characterized by the provision of a pair of annular thrust blocks engaged by sets of Belleville disc-spring washers which bias a pair of side gears axially outwardly apart against a pair of annular thrust washers, respectively, non-rotatably supported by the differential housing. By loading the side gears in the axial direction, the side gear radial freedom of movement is restricted, whereby the differential chatter and noise level during operation are significantly reduced. </TD></TR></TABLE>
Furthermore, I found this link which kicks ***. Notice his chosen washer configuration, which provides maximum preload:
http://rbryant.freeshell.org/obx_washers
He also advocates replacing the washers with higher quality ones, which is something I might look into. Especially after seeing the broken washer in this thread:
https://honda-tech.com/zerothread/1381146
This link explains how the LSD works:
http://www.sportcompactcarweb....rt_4/
General info on Belleville washers:
http://www.raymondasia.com/cat_belleville.htm
Modified by Enzo Speed at 1:03 AM 9/20/2006
Here is the patent info describing what the washers do:
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Patent Office »</TD></TR><TR><TD CLASS="quote">Differential with preload spring
Document Type and Number: United States Patent 5524509
Abstract: An improved differential mechanism of the holdout ring type, characterized by the provision of a pair of annular thrust blocks engaged by sets of Belleville disc-spring washers which bias a pair of side gears axially outwardly apart against a pair of annular thrust washers, respectively, non-rotatably supported by the differential housing. By loading the side gears in the axial direction, the side gear radial freedom of movement is restricted, whereby the differential chatter and noise level during operation are significantly reduced. </TD></TR></TABLE>
Furthermore, I found this link which kicks ***. Notice his chosen washer configuration, which provides maximum preload:
http://rbryant.freeshell.org/obx_washers
He also advocates replacing the washers with higher quality ones, which is something I might look into. Especially after seeing the broken washer in this thread:
https://honda-tech.com/zerothread/1381146
This link explains how the LSD works:
http://www.sportcompactcarweb....rt_4/
General info on Belleville washers:
http://www.raymondasia.com/cat_belleville.htm
Modified by Enzo Speed at 1:03 AM 9/20/2006
09-15-2006, 03:13 PM
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Re: (Enzo Speed)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Enzo Speed »</TD></TR><TR><TD CLASS="quote">
It is IMPERATIVE that you install the washers as I have shown in the write-up. </TD></TR></TABLE>
alright thanks for clearing that up. I'm about to tear mine down and was just double checking about it before i reassemble it.
It is IMPERATIVE that you install the washers as I have shown in the write-up. </TD></TR></TABLE>
alright thanks for clearing that up. I'm about to tear mine down and was just double checking about it before i reassemble it.
09-15-2006, 03:21 PM
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Re: (Chris22215)
Here is a neat pic. Remember how everyone was getting their axles stuck inside the axle gears? Here is OBX's remedy - they partially machined out some of the splines and chamfered the inside edges. You can see in the pic where the extra spline material used to be:
09-16-2006, 06:43 PM
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Re: (Bense)
Big props for all the work. The design is simple. I don't think anyone here can appreciate the time you took to take pics, go over each part, & then have the patience to post photos & sort through everything.
Were any of the gears edges messed up? Had to deburr any?
Also, you go to your nearest fastener store & get new bolts or just said screw it & put those stripped ones back in?
Were any of the gears edges messed up? Had to deburr any?
Also, you go to your nearest fastener store & get new bolts or just said screw it & put those stripped ones back in?
