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Installing Quaife LSD

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darrellwalker Darrell Walker
Vancouver, Washington, USA   USA
1966 Triumph TR4A "Christy"
1981 Triumph TR8 "Kate"
I’d like to install a LSD on my TR8, and other than converting some other rear end, it looks like Quaife is the only real option. I’ve always had some issues with spinning a rear wheel even when my engine was stock, and now with some increased power, it is an even more frequent occurrence. To make it worse, one of the places it happens most is the intersection leaving my neighborhood, it is uphill, and a right hand turn where they always seems to be sand/gravel, even when it is dry out.

Besides the cost of the Quaife unit, the installation has alway put me off. But I’ve read the ROM over a few times, and I’m thinking the install isn’t as daunting as I had imagined. It looks like I just need to pull the axles out a bit (don’t need to complexity remove them), remove the rear cover, unbolt the bearing caps (after marking them to keep the placement and orientation), and then pull out the diff unit. After that, unbolt the crown wheel and transfer to the Quaife, and transfer the bearings (or probably install new ones). Then I would need to set the preload and backlash. That is where my first question comes up.

According to the ROM, you put the diff unit in the housing, with the pinion out, and measure the side clearance. Sounds easy enough, but I don’t want to remove the pinion, as the setup for that is more complicated, and I know the crush spacer isn’t available, But looking at the drawings, it looks like if I put the Quaife in without the crown wheel installed, it should have room to measure the clearance without hitting the pinion. Can anyone confirm that? Assuming that is the case, then I can install the crown wheel and take the second measurement. That brings up the second question. It appears the side shims are mostly unavailable. TRF does list the thickest one, I can’t find anyone else that seems to have them. Are these something would be available by size someplace? Or can I take the thick ones and sand them down (wet dry sandpaper on a flat surface)?

I’ve also been reading the setup instructions for some American rear ends, and some of those sent the backlash more directly (by measure the rotation of the crown wheel), but they of course don’t have that spec for our rear end. And some set the preload by just saying the shims should need to be tapped in.

A few more random questions for anyone that has done this (either just a rebuild, or installing a Quaife):

1. How tight are the axle shafts in the carrier? Do they just slide out, or do I need a puller?

2. Is there a SKF or Timken part number for the bearings? Doesn’t seem like a place to pinch any pennies!

3. The ROM says to use Loctite 601 on the crown wheel bolts. The only reference I can find to 601 is a data sheet from 2004, and in that 601 appears to be a bearing/sleeve lock, not a thread locker. Just considering the consumer products, should I used blue or red? I would probably opt for the stronger (red), but that says it needs heat to disassemble, and heating up the gear doesn’t sound like a good thing to do. And the ROM doesn’t mention anything like that when disassembling.

4. In theory, I think all of this could be done with the axle still on the car. But I suspect it is fiddly enough (especially for the first attempt) that removing the axle is probably easier overall. Especially without al lift.

5. After computing the new shim sizes, the ROM says to use a case spreader to reinstall. Is that needed? Has anyone built their own? Or is there one that can be adapted?

Anything else that I haven’t considered?

Thanks!
-Darrell



Darrell Walker
66 TR4A IRS-SC CTC67956L
81 TR8 SATPZ458XBA406206
Vancouver, WA, USA

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TR8todd Avatar
TR8todd Todd Kishbach
Mass, USA   USA
1977 Triumph TR7 "Rally Fraud"
1978 Triumph TR8
1979 Triumph TR7
1980 Triumph TR8    & more
Don't need a case spreader, or at least I never had. You are going to have to replace the pinion bearing. If you can't reuse the existing crush sleeve, make a solid one. You can sand down a side shim, but may not have to. I have a few of them laying around if you need to swap them. Axles slide out easy, bearings come off with heat and an impact driver or you can rig something up in a press. I have never used locktite in there, but that sounds like a good idea. A rear end is a rear end. Nothing fancy in there. All comes down to backlash and contact pattern. Set it up as if its a Ford 7.5. Think the specs are something like .014 to .018 You are going to need calipers, a dial indicator with a magnetic base, and an inch pound torque wrench. The torque wrench is to check the force required to spin just the pinion once its installed. Too much or not enough resistance and you will smoke the bearing. Pick up some contact paint as well. Use the best bearings you can find.



Edited 1 time(s). Last edit at 2017-01-25 06:57 AM by TR8todd.

darrellwalker Darrell Walker
Vancouver, Washington, USA   USA
1966 Triumph TR4A "Christy"
1981 Triumph TR8 "Kate"
Hi Todd,

Thanks for the reply. Just curious, why do you say that I'll need to replace the pinion bearing?

BTW, I found some Timken part numbers for the bearings here:

http://www.team.net/TR8/tr8cca/crossref/02_Data/DriveTrain.html


TR part# Bearing Outer Race
Carrier UKC981 LM29749 LM29711
Pinion front 539707 M88046 M88010
Pinion rear UKC978 HM88649 HM88610

Edit:

The TR part numbers for the pinion bearings don't match what the parts book says, it has them as 607181 and UKC977. But the Timken numbers mostly matches what Rock auto lists, but I'm not quite sure on the naming they use. They have Timken M88010 as "fits rear outer or inner", National HM88610 as rear outer, Timken M88046 as the rear outer bearing, and Timken M88040 as the rear inner. They also have National HM88649 as rear outer. For the carrier bearings, they list Timken Set16 for an "integral carrier", and Timken Set13 for "removable carrier", which I don't understand.



Darrell Walker
66 TR4A IRS-SC CTC67956L
81 TR8 SATPZ458XBA406206
Vancouver, WA, USA



Edited 1 time(s). Last edit at 2017-01-25 10:28 AM by darrellwalker.

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tirebiter Jeff Garber
Dighton, MA, USA   USA
I use a local prototype machine shop when I need a shim reduced in thickness. The guy uses a precision grinder that keeps both surfaces 100% parallel to within 0.0001" (one ten thousandths of an inch) tolerance. Maybe 0.0002" but unusually fine.

Start with the largest shim/spacer available and have it reduced as needed.

Crush collars can be hammered back to usable by putting them on a vice mounted round mandrel or large diameter screwdriver shaft. The shims under the large pinion bearing is what sets it's depth, not the crush collar.

Doing this work for the first time I highly recommend taking the entire rear axle assembly out of the car.

Agreeing with Todd. It's possible to get the correct inteference fitting carrier bearing shims back into the case by careful prying on both sides a tiny amount at a time. Get the thin ones in first and then put in the last thick one so it won't wrinkle up as you force it in. A spreader does not look hard to make but I've never needed one either.

Freeplay between ring and pinion and pinion height should be marked in the ring gear to be sued with the pinion as a matched set. Gear marking compound is the best way to determine yo uhave the correct contact patch. Sometiems the shims have to be swapped several times.

It is not imperative to get all preloads exactly right when deciding which shims to use. Close but at least snug with no freeplay is good enough. Save that misery for when it's going back together for the final time ... after you get a good contact pattern.

I've never installed a Quaife but I understand setting the bias between spinning the unloaded wheel or spinning the loaded wheel is extremely touchy and can cause some interesting results if you get it wrong.

One way to reduce rear wheel unloading is to stiffen the front suspension or running a stiffer anti-sway bar, which introduces some more understeer. Soemtimes the best result is from knowing how much you can push on the gas pedal with the steering wheel turned.

There are other limited slip devices available you may want to do a search on.

TR8todd Avatar
TR8todd Todd Kishbach
Mass, USA   USA
1977 Triumph TR7 "Rally Fraud"
1978 Triumph TR8
1979 Triumph TR7
1980 Triumph TR8    & more
You don't want to go to all that trouble and leave a 40 year old bearing in there. Especially since that is the one that goes bad first and is the main reason why so many TR8s are now running around with 3.45s. All those bearings are splash lubricated and the pinion bearing doesn't see that much splash.

darrellwalker Darrell Walker
Vancouver, Washington, USA   USA
1966 Triumph TR4A "Christy"
1981 Triumph TR8 "Kate"
Hi Todd & Jeff,

Thanks for your comments.

FYI for anyone else thinking about getting a Quaife, it used to be they wouldn't sell directly to the US. But they apparently do now, and with the current exchange rate, even including shipping, the unit is several hundred bucks cheaper than any US supplier is offering.

-Darrell



Darrell Walker
66 TR4A IRS-SC CTC67956L
81 TR8 SATPZ458XBA406206
Vancouver, WA, USA

Darth V8R Avatar
Darth V8R Vance Navarrette
Beaverton, Oregon, USA   USA
1980 Triumph TR8 "Wedgie"
In reply to # 1429996 by darrellwalker I’d like to install a LSD on my TR8, and other than converting some other rear end, it looks like Quaife is the only real option. I’ve always had some issues with spinning a rear wheel even when my engine was stock, and now with some increased power, it is an even more frequent occurrence. To make it worse, one of the places it happens most is the intersection leaving my neighborhood, it is uphill, and a right hand turn where they always seems to be sand/gravel, even when it is dry out.

Darrell:

Interesting project you have taken on there. I have worked with Limited Slip rear ends in just two cars: My corvette and my Z28 Camaro, and learned some interesting things along the way.

1. Limited Slip differentials are of little use in a situation where one wheel is lacking traction. They in effect multiply the torque being applied to the spinning wheel, and apply that much torque to the non-spinning wheel. A typical multiplication factor is 2.5-4 depending on the type of differential being used. So imagine your right rear wheel on polished ice. It takes a near zero amount of torque to spin that wheel. Now multiply that number by 3, and imagine that amount of torque applied to the non-slipping wheel. Doesn't get you moving very fast, does it?
2. There is always a preferred wheel that will slip first, even with an LSD. It is the right rear wheel in our cars because the right side of the car is lightly loaded (no driver on that side), and the engine torque tries to lift the right rear wheel off the ground during acceleration.
3. Body roll exacerbates the problem, because in a turn, the inside wheels want to unload due to cornering forces.
4. Under steer exacerbates the problem as well, since it results from weight transfer to the front wheels during a turn.

The only LSD that completely shunts all the torque to the non-slipping wheel (that I am aware of) is a so called "Detroit Locker". These are not used on the street because of their harshness and noise. The rest use the torque multiplication scheme I mentioned above. So the effectiveness of an LSD in preventing wheel spin while cornering will be disappointing unless you know what to expect.

My experience has been that money spent on balancing the suspension front to rear and limiting nose dive and body roll are much more productive (and cheaper) on an otherwise unmodified car than installing an LSD. Once all of the suspension tuning is done, then installing an LSD makes incremental and worthwhile improvements. The handling benefits are also legion, but we are talking wheel spin in this thread.

So, how to reduce wheel spin while cornering in our cars without an LSD?

1. Less body roll. This usually means a slightly larger REAR sway bar. This will keep the rear flatter during cornering and reduce under steer. Careful though, too large a rear bar will make the car over steer. Addco has a larger rear bar available, IIRC.
2. Less compliant bushings in the rear suspension. Urethane is an obvious choice here. The radius arms would be the most important items to rebush. The idea here is to reduce the tendency for the rear axle to move and thereby unload the inside wheel.
3. Stiffer, shorter rear springs. Keep the ride height the same unless you have other reasons for changing the ride height. Once again, you don't want the inside rear wheel to unload - this will reduce the amount of roll.
4. Anti-dive kit for the front end. Less rear to front weight transfer during hard cornering/braking.

So I would work on the suspension first, THEN if things were not good enough I would try an LSD.

Food for thought. I certainly would love to hear how a Quaife LSD works for you. So no matter what you do, keep us posted.

Vance



1980 Platinum Metallic TR8, navy blue interior
Bare metal respray, Crower cam, raised compression
ported heads, modified Zenith carbs, 0.060" overbore

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darrellwalker Darrell Walker
Vancouver, Washington, USA   USA
1966 Triumph TR4A "Christy"
1981 Triumph TR8 "Kate"
Hi Vance,

Thanks for your thoughts.

I've made all of the suspension mods that you listed, though I've also uprated the front sway bar, which may mitigate the larger rear bar in this particular case.

One you didn't list was tires. I have high-performance all-season tires, so I could get something stickier. But I drive my car year round (though I did skip the recent snow and ice), so the all-season tires are a compromise.

In our recent weather, I saw plenty of examples of what an open diff does on ice. But ice is about the worst case. But let's get even worse, let's put one tire on that frictionless surface that they take about in physics class. In that case, the tire on the frictionless surface will take zero torque to turn, and with an open diff, the other tire will also see zero torque. Moving to a LSD (clutch or Torsen/Quaife) will give the other tire say 3 times zero, which of course is still zero. A locked diff will still send 50% of the available torque to the tire with traction, but doesn't work too well on the street otherwise.

But in the case I usually see, I'm still able to accelerate, so there must still be a reasonable amount of torque being applied to the slipping tire. So if that value is X, the open diff will put 2X on the road. But with the Quaife, if the torque bias ratio is 3:1 (they won't actually quote a ratio, but consensus is that it is between 2 and 3), it will put 4X on the road, twice the open diff.

Anyway, I pulled the trigger today, so I'll let everyone know how the installation goes, and the result.

-Darrell



Darrell Walker
66 TR4A IRS-SC CTC67956L
81 TR8 SATPZ458XBA406206
Vancouver, WA, USA

tirebiter Jeff Garber
Dighton, MA, USA   USA
Is the Quaife you ordered the one with a pre-loaded clutch or is it the one with just the worm and spur gears?

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darrellwalker Darrell Walker
Vancouver, Washington, USA   USA
1966 Triumph TR4A "Christy"
1981 Triumph TR8 "Kate"
In reply to # 1430568 by tirebiter Is the Quaife you ordered the one with a pre-loaded clutch or is it the one with just the worm and spur gears?

It is the gear type, same principle as the Torsen I belive, but a different layout of the gears.



Darrell Walker
66 TR4A IRS-SC CTC67956L
81 TR8 SATPZ458XBA406206
Vancouver, WA, USA


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Darth V8R Avatar
Darth V8R Vance Navarrette
Beaverton, Oregon, USA   USA
1980 Triumph TR8 "Wedgie"
In reply to # 1430529 by darrellwalker Hi Vance,

Thanks for your thoughts.

I've made all of the suspension mods that you listed, though I've also uprated the front sway bar, which may mitigate the larger rear bar in this particular case.

One you didn't list was tires. I have high-performance all-season tires, so I could get something stickier. But I drive my car year round (though I did skip the recent snow and ice), so the all-season tires are a compromise.

In our recent weather, I saw plenty of examples of what an open diff does on ice. But ice is about the worst case. But let's get even worse, let's put one tire on that frictionless surface that they take about in physics class. In that case, the tire on the frictionless surface will take zero torque to turn, and with an open diff, the other tire will also see zero torque. Moving to a LSD (clutch or Torsen/Quaife) will give the other tire say 3 times zero, which of course is still zero. A locked diff will still send 50% of the available torque to the tire with traction, but doesn't work too well on the street otherwise.

But in the case I usually see, I'm still able to accelerate, so there must still be a reasonable amount of torque being applied to the slipping tire. So if that value is X, the open diff will put 2X on the road. But with the Quaife, if the torque bias ratio is 3:1 (they won't actually quote a ratio, but consensus is that it is between 2 and 3), it will put 4X on the road, twice the open diff.

Anyway, I pulled the trigger today, so I'll let everyone know how the installation goes, and the result.

-Darrell

Darrell:

Sounds like your expectations are very realistic, and you have used the easy tricks already. So it sounds like you are in a good space to proceed with the project. Can't wait to hear what you think of the whole thing when you are done. Nothing is more satisfying than a smoky burnout with TWO tires. Hah!

BTW, who did you source the Quaife from?

Cheers,

Vance

PS, with my Z28 I had the exact problem you describe, and I had an LSD. Right turns, stepping on the gas the inner tire would always break loose, but not on left hand turns. I got a big improvement by upping the rear sway bar by 2mm (from 19mm to 21mm), but there was still a very pronounced difference in left and right hand turns. Handling was much better, as the factory set up under steered at the limit, while the fatter rear bar brought it much closer to neutral. The Z28 used a clutch pack style LSD. The Torsen style LSD may be a big improvement over the clutch pack, I know Audi favors that design, while the Japanese seem to prefer the viscous style LSD.



1980 Platinum Metallic TR8, navy blue interior
Bare metal respray, Crower cam, raised compression
ported heads, modified Zenith carbs, 0.060" overbore

darrellwalker Darrell Walker
Vancouver, Washington, USA   USA
1966 Triumph TR4A "Christy"
1981 Triumph TR8 "Kate"
In reply to # 1430653 by Darth V8R
BTW, who did you source the Quaife from?

Hi Vance,

I bought it directly from Quaife:

https://shop.quaife.co.uk/rover-sd1-quaife-atb-helical-lsd-differential

Including shipping, it came in around $400 less than any stateside source I could find. And it is supposed to be here Monday!

-Darrell



Darrell Walker
66 TR4A IRS-SC CTC67956L
81 TR8 SATPZ458XBA406206
Vancouver, WA, USA

darrellwalker Darrell Walker
Vancouver, Washington, USA   USA
1966 Triumph TR4A "Christy"
1981 Triumph TR8 "Kate"
My Quaife arrived earlier this week.

I'm collecting the rest of the parts to do the install. I got the big nut that controls the pre-load on the pinion. It looks like it takes a 1-7/8" socket (or maybe a 47 or 48 mm).

Can anyone confirm what size I need? I assume it will need to be a deep socket, since it has to clear the threads that attach the flange. Most sockets I'm finding that size are impact sockets, is there sufficient clearance in the housing for a impact socket?

Thanks!



Darrell Walker
66 TR4A IRS-SC CTC67956L
81 TR8 SATPZ458XBA406206
Vancouver, WA, USA


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Darth V8R Avatar
Darth V8R Vance Navarrette
Beaverton, Oregon, USA   USA
1980 Triumph TR8 "Wedgie"
Darrell:

Ohhh. Pretty. Now I have Quaife envy....

Vance



1980 Platinum Metallic TR8, navy blue interior
Bare metal respray, Crower cam, raised compression
ported heads, modified Zenith carbs, 0.060" overbore

diver Richard Crothers
NorthEast, Maryland, USA   USA
Hello Darrell,

I have had good luck putting in GM center sections. One thing to do before you take it apart is check and record
all clearances, need to use numbers when putting back together. I had a problem with crush spacer so I was
able to use an after market shim pack kit for pinion shaft. Check to see if kit will work for you. The Gm 7 1/2" is close in size to the TR8 rear. As for putting shims on the side check numbers above, and put bearings in tight with brass driver.

Richard C.

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