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Post by chris71 on Dec 6, 2016 19:58:50 GMT
Evening people,
The question is per title. In the middle of stripping a donor car for parts. It is a original US BBR Turbo'd MK1 car so should have a LSD from what I can gather.
My understanding is that an LSD diff if you rotate either wheel in a forward motion the other side should do the same, but the rotate in opposite directions.
Just to be clear, there is no drive shafts or prop shaft connected just the diff still on the car. Is the any kind of markings of the diff that signifies if open diff or LSD ?
Help and advice would be gratefully received.
Thanks
Chris
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Post by Horney on Dec 6, 2016 20:52:25 GMT
The only way to 100% be sure is to take the flags shafts out of the diff. If you can see through the diff it's open. If you can't it's an LSD.
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Post by moro on Dec 6, 2016 21:43:21 GMT
The rotation test only applies to plate LSDs, Torsens and similar will rotate in opposite directions like an open diff would. Only way to be sure is what Horney said.
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Post by martiny on Dec 7, 2016 12:41:38 GMT
The only way to 100% be sure is to take the flags shafts out of the diff. If you can see through the diff it's open. If you can't it's an LSD. Other way around I think: An open diff has a solid bar through the middle joining the two planet (or spider) gears together. A VLSD doesn't. With the early 1.6 diffs you can also check the pattern of the 'ears' on the stub flanges. If it's a 1.8 diff then an open one again has a bar crossing the middle, Type 1 torsen has an open hole right through, Type 2 torsen has similar but it's a small hole and Tochigi Fuji Super diff has a hexagonal bar through the middle. It's just about possible to work out what type it is if you take the fill plug out and peer in or stick a finger in to discover what's there. See the diff spotter's guide on miata.net for internals pics and the 1.6 stub axle 'ears': www.miata.net/garage/diffguide/index.html |
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Post by chris71 on Dec 7, 2016 18:40:55 GMT
The only way to 100% be sure is to take the flags shafts out of the diff. If you can see through the diff it's open. If you can't it's an LSD. Thanks for the info but don't know what you mean by "flags shafts". Sorry for the ignorance. |
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Post by martiny on Dec 7, 2016 22:04:02 GMT
I think autocorrect stuck its oar in there. That would either have been 'flanged shafts' or 'halfshafts'. Same thing either way: you can't differentiate 1.8 differentials from the outside of the case. You can tell the smaller 1.6 diffs apart though, due to the pattern of little lobes on the halfshaft flanges as described in that miata.net link.
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Post by Vindi (Russell) on Dec 10, 2016 1:03:11 GMT
As above, the one where you can see straight through in between the driveshaft holes is a Torsen LSD, the one with a bar is an open one.
I'm not sure that's definitive though, if it was an early car (89 to 93?) it could have had a Viscous LSD and I'm not sure you can see through those?
Plus some cars will have aftermarket plated diffs from Kaaz, Cusco, Mazdaspeed etc. Not that common, but if they are fitted to anything it's usually FI cars so can't be ruled out.
Russell
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le sigh