eBay LSD sandwich plate locker kits?

E28 technical advice asked and given! Troubleshooting, modifications and more.
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Comfyboyz
Posts: 27
Joined: Aug 08, 2022 9:21 PM
Location: Maine

eBay LSD sandwich plate locker kits?

Post by Comfyboyz »

Anyone have any experience with this type of system? With the prices of used LSDs with 200k+ miles going through the roof I’m exploring different avenues. For the money it doesn’t sound too bad and installation looks fairly straightforward.

https://www.ebay.com/itm/264499010855
Germz
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Re: eBay LSD sandwich plate locker kits?

Post by Germz »

I've seen these too, but havent seen any reviews either. I'm also curious.
Panici
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Re: eBay LSD sandwich plate locker kits?

Post by Panici »

Check out the "hardcore friction shims" (and this is a direct quote) from the ad photos.
They advertise "No metal shavings" because I'm sure previous versions of these "lockers" did exactly that and subsequently destroyed the diff.

Ask yourself if these tiny friction shims can take the place of a normal LSD clutch pack for any length of time.
If the answer is no then you'll be back to metal-on-metal in no time.

After a brief google, there seems to be some concern about on/off throttle characteristics and it locking/unlocking mid-corner. Even if the thing is by some miracle reliable I would stay away for the negative driving characteristics alone.
gadget73
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Re: eBay LSD sandwich plate locker kits?

Post by gadget73 »

Kind of in agreement with above, just based on looking at it and not from any direct experience.


The clutch-type LSD I'm familiar with have a much larger contact area, and a stack of clutches and steels to give a significantly larger amount of friction material. Coupling on the face of the bevel gear like this, you don't have a whole lot of area for the clutch to work against, and with just one disc per side I wouldn't expect it to last a whole lot of miles before its either just an open diff again or worn through the clutch and sitting metal on metal.
Comfyboyz
Posts: 27
Joined: Aug 08, 2022 9:21 PM
Location: Maine

Re: eBay LSD sandwich plate locker kits?

Post by Comfyboyz »

I have definitely been skeptical since I stumbled upon this type of wacky “upgrade”. I’ve always been in favor of using OEM style clutch type setups. I’ll have to just keep my eyes peeled for a decently priced one when the times right. I’m not surprised there isn’t much out there for reviews, at least stateside.
ilovemycat
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Re: eBay LSD sandwich plate locker kits?

Post by ilovemycat »

Interesting , I'm no rear end expert but it looks like it is a richmond style locker not a clutch type LSD . It says clutch type but it shows no clutches anywhere in those pics . Mechanical lockers are pretty common in old drag cars and 4x4s , I think the 65 shelby came with one . I am putting a Richmond Lockright in my 69' ford wagon currently.
gadget73
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Re: eBay LSD sandwich plate locker kits?

Post by gadget73 »

don't those engage on the axle splines though? Doesn't appear this one does. I just see a large clearance hole in the middle for the ends of the axle shafts. I was thinking the "connection" was using that disc that sits between the face of the bevel gear and the center block, and the springs in the middle of the two blocks are what produce the load on the discs to couple the shafts together.

but I'm also not exactly a diff expert.
Shawn D.
Beamter
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Re: eBay LSD sandwich plate locker kits?

Post by Shawn D. »

This looks like a terrible "solution" to the problem. All these ramps are doing is jamming the blocks into the side gears so hard the friction goes up between the side gears and these blocks that replace the spider gear assembly. I can see this ruining the side bearings due to excessive sideways loading they were never intended to encounter.
gadget73
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Re: eBay LSD sandwich plate locker kits?

Post by gadget73 »

how do the axles retain in a BMW diff ? the types I'm familiar with wouldn't load on the side bearings but most of the ones I've fooled with are a C clip style or a full floater. On both of those the side gear can move relative to the splined end of the axle, so any load between the gears would just transfer to the carrier housing itself. That actually could be a concern though, the ones I know of just have a machined surface on the back of the gear and inside the carrier. Jam the gears out to the carrier and that surface becomes a thrust bearing. I doubt it would lubricate well since there probably aren't any slots milled in there to make sure there is oil between the carrier and the back side of the gear. Steel on steel makes for itty bitty sparkly parts after a while.
Shawn D.
Beamter
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Re: eBay LSD sandwich plate locker kits?

Post by Shawn D. »

gadget73 wrote: Jan 24, 2023 12:03 PM how do the axles retain in a BMW diff ? the types I'm familiar with wouldn't load on the side bearings but most of the ones I've fooled with are a C clip style or a full floater.
The axle stubs are retained by a round-profile c-clip that mates with a groove on the axle. The axles can easily be popped out with a screwdriver and back in with a tap (or rotating while tapping to mate with the LSD plates). So, it's not a positive retention, but that's not really necessary since there are no notable side loads.
gadget73 wrote: Jan 24, 2023 12:03 PMOn both of those the side gear can move relative to the splined end of the axle, so any load between the gears would just transfer to the carrier housing itself.
This is the same here.
gadget73
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Re: eBay LSD sandwich plate locker kits?

Post by gadget73 »

so basically like the Ford setups I know. Those have a solid axle but no retainer other than the C clip sitting in a pocket in the side gear to keep it from falling off, and the pin that holds the spiders that is in the way of the axle shaft from sliding inward far enough for the clip to clear the pocket.

Those are sort of fun because if the axle snaps for whatever reason, the back wheel just comes out of the diff unless its got disc brakes. I was in my friend's car when that happened. The outer bearing failed and snapped the axle off. I was driving, smelled burning oil and then the engine revved as the cruise control tried to accelerate it. The diff was so hot it sounded like someone had dropped a basket of fries in a deep fryer.
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