Detecting a limited slip diff in a Seven
Discussion
Hello,
a friend of mine purchased a Seven some days ago - it's a 2000 my Caterham Roadsport, engine is a 1.8 liter Rover K-series, although upgraded to Supersport spec, and 6-speed.
So the car was sold to him with a limited slip diff, although during the first test drives it seems that it will only barely or won't lock at all. The suspicion is that the car does either have a fully worn-out or no LSD at all.
He already put it up on jackstands and turned the rear wheels. That resulted in one wheel turning into the opposite direction of the one that got turned by hand. I once had an old Ford Sierra with a limited slip diff in it, that did the exact same thing, but that diff did it's job perfecty and locked all the time when I wanted it to.
I know that depending on the type of LSD, the way the other wheel turns in the situation of hoisting the car and turning one wheel can differ. Researching online wasn't really that helpful at all, sadly, which is why I'm trying to get info here in PH.
Is there maybe some kind of overview available online with the types of differentials fitted to Caterhams? Or should the diff (especially together with the 6-speed box) have a certain number for it to be able to verify it's an LSD?
I know quite some Sevens run Ford and BMW diffs, so it should not be that difficult to find out what's installed, should it?
Anyway, we're glad for any help we can get!
a friend of mine purchased a Seven some days ago - it's a 2000 my Caterham Roadsport, engine is a 1.8 liter Rover K-series, although upgraded to Supersport spec, and 6-speed.
So the car was sold to him with a limited slip diff, although during the first test drives it seems that it will only barely or won't lock at all. The suspicion is that the car does either have a fully worn-out or no LSD at all.
He already put it up on jackstands and turned the rear wheels. That resulted in one wheel turning into the opposite direction of the one that got turned by hand. I once had an old Ford Sierra with a limited slip diff in it, that did the exact same thing, but that diff did it's job perfecty and locked all the time when I wanted it to.
I know that depending on the type of LSD, the way the other wheel turns in the situation of hoisting the car and turning one wheel can differ. Researching online wasn't really that helpful at all, sadly, which is why I'm trying to get info here in PH.
Is there maybe some kind of overview available online with the types of differentials fitted to Caterhams? Or should the diff (especially together with the 6-speed box) have a certain number for it to be able to verify it's an LSD?
I know quite some Sevens run Ford and BMW diffs, so it should not be that difficult to find out what's installed, should it?
Anyway, we're glad for any help we can get!
With the engine off and gearbox in gear, turning one wheel should be very difficult if there is a working LSD fitted, and the opposing wheel should try to turn in the opposite direction. If there is little resistance to turning the wheel then there is either an open diff fitted or an LSD without any preload (likely due to wear or clutch plate failure).
Trying to test by turning a wheel with the gearbox out of gear may be inconclusive as any resistance inside the diff could lead to both wheels turning the same way and spinning the prop shaft and output side of the gearbox.
Trying to test by turning a wheel with the gearbox out of gear may be inconclusive as any resistance inside the diff could lead to both wheels turning the same way and spinning the prop shaft and output side of the gearbox.
normalbloke said:
One wheel turning the opposite direction is an open diff, or completely shagged lsd. You can also try one wheel on grass, one on tarmac and try an emergency start...
Not always, Torsens do that when both wheels are off the ground and will spin an unloaded wheel.I would be asking on a Caterham forum.
Hey everyone,
so my dad and me bought this caterham a week ago. Now I ask myself if there really is a LSD fitted. I found that the differential is leaking oil on the left drive shaft.
Unfortunately the tank blocks the view onto the whole differential casing but i could find some tags/numbers on the casing.
Looks like a Ford Differential. Now can anybody tell me what they mean and how i can find out which differential it is?
so my dad and me bought this caterham a week ago. Now I ask myself if there really is a LSD fitted. I found that the differential is leaking oil on the left drive shaft.
Unfortunately the tank blocks the view onto the whole differential casing but i could find some tags/numbers on the casing.
Looks like a Ford Differential. Now can anybody tell me what they mean and how i can find out which differential it is?
Take a half shaft out and look down the axle tube...
from here :
http://www.mycaterham.com/66828/117416.html
from here :
http://www.mycaterham.com/66828/117416.html
You’ll not be able to tell by the casing, as it’s just a stock Sierra case.
You’ll have to pop a shaft out to see.
Seal’s leaking anyway.
Or dump the clutch as see if you leave the number 11.
If it doesn’t, you have an open diff, or your LSD, or Torque Biasing diff ( if it’s a quaife) is shagged.
If you take the diff out, note the number of spacing washers, as they are used to center the diff in the chassis.
Or better still, measure it yourself when you put it back.
You’ll have to pop a shaft out to see.
Seal’s leaking anyway.
Or dump the clutch as see if you leave the number 11.
If it doesn’t, you have an open diff, or your LSD, or Torque Biasing diff ( if it’s a quaife) is shagged.
If you take the diff out, note the number of spacing washers, as they are used to center the diff in the chassis.
Or better still, measure it yourself when you put it back.
Diff tag says No from a Ford fitment point of view. The Sierra fitted LSD was a viscous fluid LSD and relatively mild but adequate for a light car.
If it had a plate or Torque biasing diff you would feel it, yes giving beans off the line would prove it as would jacking it up and turning one wheel looking for the other to turn the same way. If it has a torque biasing diff there is a situation when no drive goes to the wheels when one wheel has no resistance such as one on ice the other on the road, a very light application of the hand brake is enough to start the torque biasing action
If it had a plate or Torque biasing diff you would feel it, yes giving beans off the line would prove it as would jacking it up and turning one wheel looking for the other to turn the same way. If it has a torque biasing diff there is a situation when no drive goes to the wheels when one wheel has no resistance such as one on ice the other on the road, a very light application of the hand brake is enough to start the torque biasing action
A Caterham won't have a viscous diff, it'll be a plate diff (Titan or ZF) or a Quaife ATB
Good resource here
A plate diff will chatter and knock like f
k at low speed in tight corners
Good resource here
A plate diff will chatter and knock like f
k at low speed in tight cornersDefinitive test of plate diffs
Get a torque wrench and a hub nut socket- 36mm I think. Or fashion some other method of attaching a torque wrench to the wheel / hub.
Put car in gear, jack one rear tyre off the ground leaving the other in firm contact.
Set the torque wrench to about 50ft/lb and attempt to turn the wheel / hub. If it’s an open diff it won’t turn without the other tyre turning. If it’s a plate diff it will turn with resistance.
If it’s a plate diff you can then reduce the torque on the wrench to find out how much torque it takes to beat the clutch plates. This will give you an idea how worn they are. Mid 20s to mid 40s are in the bracket, less and it is probably due a rebuild. I can’t imagine they get a tough life in a road car.
Get a torque wrench and a hub nut socket- 36mm I think. Or fashion some other method of attaching a torque wrench to the wheel / hub.
Put car in gear, jack one rear tyre off the ground leaving the other in firm contact.
Set the torque wrench to about 50ft/lb and attempt to turn the wheel / hub. If it’s an open diff it won’t turn without the other tyre turning. If it’s a plate diff it will turn with resistance.
If it’s a plate diff you can then reduce the torque on the wrench to find out how much torque it takes to beat the clutch plates. This will give you an idea how worn they are. Mid 20s to mid 40s are in the bracket, less and it is probably due a rebuild. I can’t imagine they get a tough life in a road car.
Olivera said:
HustleRussell said:
Put car in gear, jack one rear tyre off the ground leaving the other in firm contact.
Set the torque wrench to about 50ft/lb and attempt to turn the wheel / hub. If it’s an open diff it won’t turn without the other tyre turning.
Set the torque wrench to about 50ft/lb and attempt to turn the wheel / hub. If it’s an open diff it won’t turn without the other tyre turning.
Well it is a way to check an LSD. I unsuccessfully tried to connect some dots.
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