Make my Jag rear stronger? Help-Ideas-Advice

[67JET]

I can feel my rearend trying to come out from under my car during a hard launch. I am going to add trailing arms but is their anything out there that goes to the top of the hub? I need Pictures and advice but keep in mind my 4 kids still have to eat and im not rolling in dough. Thanks for any thoughts you can share.

[mickmate]

You need a Watts linkage!

[CHANMADD]

Check ot my gallety .I have rear facing track rods and antiswaybar, which really helps stabilise the whole rear end. The track bars make a huge difference to the axle tramp. Also you must have the plate between the two fulcrum rods.
John

[RICK LAKE]

67JET I am guessing you have in board brakes on your jag rearend? You also have the standard outter hub bearing assemblies. You don't have any pictures of the rear of the car underside. Decooney would be the first place to start with. He helped ERA make a Watts linkage for the SC cars. Mounting plate that bolts to the stock hub housing. You will need a welder friend to weld a bracket to the frame. The other thing will be getting the right length radius bar to connect the two togeather. It's not a big thing. If you can't find Duanes info, go back about 1-2 years and try under ERA threads. There where pictures of the setup. Contempary also made a Watt's linkage. They made a special hub for there setup. I run theirs but had to modify the links to work. I am sure there is someone else on here that makes special hubs for Jag rearends. Try looking in the CWI catalog for parts. The special GT-40 hubs on some cars would also work with a little help.
3 Things for advice, A stock Jag rearend is good for about 450/450 HP and torque. You didn't say what tires you are running on the back end. Are the tire pressures the same? Has the car been corner weighted with your wieght in the drivers seat? You didn't say which springs and shocks you are running in the rearend. A video of the car launching would help with see what the suspension is doing. The alignment of the car,(thrust angle) rear camber and toe of both wheels all effect how the car launches.
Jag rearends, Get a Support cover for the rearend, if you are going to keep going burnouts. It's a cover that acts like a girdle to put pressure on the main caps in the center section and stops cap walk of the carrier. If you keep this abuse up, the stub shafts in the carrier will start to twist. You said money is an issue at this time, Get your self another carrier ( center section ) with the same gearing if possible and have a 30 spline setup installed in the housing. CWI sells a 30 spline setup with either your carrier and changing the guts to 30 spline spidlers or going to a 30 spline carrier straight. This will also come with chromemoly stub shafts that are now good for 600ft of torque and HP. This is what I run in my car. 10 years and no failures after a defective hub bearing was replaced. You will need to have a breather for the Jag rearend if you switch the rear cover. Alot of heat builds up when driving.
If you are looking for more info,private e-mail me. Rick L. Ps 1 some suggestion, this car was never designed to doing burn out, road racing autocross, cruising. The amount of damage the drive train takes when you hole shot the car is brutal. I race, only do a small burnout in water to heat and clean tires for 1/4 mile racing. I walk the car out of the starting line and roll on the throttle. If you are going to keep doing this, you may want to look at a 9" solid rearend for the car. It's stronger with 31 to 40 spline axles, will take a ton more abuse, the parts are easier and cheaper to get. Without seeing a video of the car launching, the suspension and possibly the pinion angles may need to be checked and changed to help off set the wheel hop.

[67JET]

Chanmadd - The plate between the fulcrum rods? Is that the plate on the rear end or the plates on the lower arm near the hub that your trailing arm bolts to?
Mickmate - The watts linkage is just what i was looking for. The price for all new hubs and arms is not.
Rick Lake - The mounting plate that bolts to the stock sounds like it's in my price range and i can cut, weld, fabricate- you know make stuff work- so installation is not a problem. I will try Decooney and see if i can find the parts and instructions to get this going.
Thanks for the thoughts and any more ideas are welcome.
By the way Rick - I'm not drag racing i'm just seeing what my car can do and trying not to brake it in the process.

[mickmate]

Best low buck solution I have seen is radius rods from the inner lower dog bone mounts to the outer lower dog bone mounts. It's 4 heims and two radius rods. That should minimise rear/front movement at the lower arm but doesn't stop the twisting of the top of the hub like a Watts does.

[CHANMADD]

The Watts doen't stop the deflection what it does is keep the hub upright in the event that the axle beaks..because the axle is the upper control arm.
The radius arms keep the lower control arm from flexing under acceleration. The lower arm is a round pipe that can flex!
Without the radius arm, the rear wheel "shudders" from front to back,
With the radius arm it can't deflect at all....the car squatts and takes off!!!
The reason also that they need to face rearwards is that the metal tube that you use to manufacture these rods is stronger in tension than compression.
John

[mickmate]

The watts stops the forward back movement at the otherwise unsupported top of the hubs. If the axle breaks it is also the top arm for these rears and it collapses inwards. The watts does nothing for that. The radius rods are usually designed to work in tension. They don't have enough cross sectional area to work as a column. Your bike wheel hangs from the top spokes, if it was standing on the bottom ones they would collapse.

[67JET]

I can see how the watts works. It does stop the front to back movement but because it rotates on the pin it lets the wheel goes thru it's travel with out getting into any bind. But how can you apply that to a factor jag hub? Where would you mount the pin? If i had a pin on the hub then i could use any linkage rods ( maybe some from Jegs or Summit) any length even make them myself.

[strictlypersonl]

If your differential is solidly mounted to the chassis, the only way for trailing (or leading) arm to work properly is to anchor it in-line with the lower control arm pivot. Otherwise, you get bind as the suspension moves up and down. Some kit (I forget which) used a leading arm. But that still allows a little motion from the lower control arm twisting. That is one reason why the ERA reinforces their Jag LCA.

One possibility is to use a trailing or leading shock (like a Mustang Quad Shock) that attaches somehow to the hub carrier near or above its axle centerline to dampen out the front-to-rear motion of the system. Unfortunately I don't think anyone makes such a system.

[decooney]

67Jet, I got your message. Here is the kit I developed a few years back, it's also pictured in my gallery. I might have two kits left stored away, if I can find them. The final result eliminated about 70% of the violent hop, but not all hop. The rest of it I was able to smooth out more with other dampning tuning and rear ride height adjustments. The next step is to scale and re-align the car. This kit was developed to minimalize modification impact to the chassis and components. Requires a few special tools and integration with other mounts. With this, my car definitely plants the rear harder and launches better now but CAUTION: I don't launch from a dead start after breaking my differential gears and stub axles for my second 1/4 mile test. I ended upgrading to new hardened stub axles and spider gears after I put this kit in. Duane

[67JET]

What kind of price tag is on this set-up? I can fabricate everything but the shock and bushings. Is their a special shock brand or part # for the shock? Are the plates on the hub thru bolted or drilled and tapped? As you can tell i an very interested. Thanks for the pic's

[decooney]

Shocks are not available any longer, so you'd need to come up with a different set Everything is zert-sert fitted. To make them up is not hard, it's the R&D (trial & error) time of getting all the pieces and angles right and even then it's all a prototype.

If you can make up a set on your own, that's the way to go. I sent you a price in a PM. I have two sets left, and won't be developing these any more. Too much time involved... Duane

[parhen4]

mickmate
you replied a watts linkage would help with 67jet's problem with his Jag rear end.would you explain how this would help?
Thanks

[Sinjin]

See my gallery for a photo of the Watts Linkage I fabricated for my DRB Cobra. Bracket bolts straight to the gussett on the Swing Arm. Does a great job of locating the suspension Longitudinally

[67JET]

Sinjin - Only 1 picture? Your killing me. I can see where the watts on the bottom would be a benefit but i don't see where it would stop the twisting on the hub. Now - with that said - watts on the bottom and on the hub - that would be like a 4 link and i will give that alot of thought. Thanks for the input and some pictures of the back to see your point of attachment would be great.

[Sinjin]

Hi 67 Jet - Have now added a couple of photos, one more of the Watts Linkage to my newly created album

[mickmate]

That is a good place to hook a watts as it replaces the original radius arm but doesn't swing a radius on a mushy rubber bushing like the stock set up. I have seen several different ways of stopping that lower arm flex including gusseting the inner and outer of the stock dog bone, adding a radius rod across the back of the dog bone, tubular x braced lower arms and also billet lower arms. It's pretty much a case of getting what you pay for. Interesting that the stock set up controls the movement at the bottom with a radius rod where all the aftermarket upgrades are trying to control movement at the top of the hub?? A watts linkage works on a pivoting centre link on the hub or axle tied forward and rearwards (or side to side when replacing a panhard rod) to the chassis. This allows the suspension to move up and down in a straight line while the centre link pivots. The trick is to have it do this without it binding or breaking anything. I'll try and post a pic of it but don't hold your breath, I'm a car guy not a computer nerd.........

[mickmate]

[mickmate]

I might be stupid but I am determined.........http://www.clubcobra.com/photopost/s...=66830&cat=500