Rear sway bars on a '72 240Z?

[ktm]

These are not my pictures, they were sent to me so I appologize in advance for not giving credit where credit is due. In case anyone is interested, this is how the aftermarket setup looks installed.

Actually, that is how the ST setup looks installed. The MSA kit does not include the new transverse link mounts with provisions for the sway bar.

[byunique]

I have a 73, with the mounts built in. Just FYI, after having the Motorsport Sway bar in, I had a welder reinforce the weld, because the original weld (after all those years) couldn't take the stress and started cracking. I'd go for the Suspension Techniques setup because of the better adjustability in my opinion and don't have to worry about weak welds (if you have the mounts)

[biddljj]

I re-enforced the area of the frame above the front sway bar mounts due

to new sway bar + rust issue.

Not just a Z - Z Disease

[ChrisZ]

Can anyone then tell me what sway bar this is, it is bourght to fit a 240Z and also in what direction it is suppose to mount.

Thanks

Chris

Edited November 18, 2008 by ChrisZ

[240znz]

Chris, it looks like the factory rear sway bar that mounts forward of the diff.

A few words on using a larger sway bar on the front. Make sure to reinforce the frame rail somehow. The PO of my car didn't and cracked the extra brace which is fitted within the internal cavity of the frame rail. He ended up welding a 3mm plate onto the frame rail to support the new mounts. When that seciton was rebuilt, I had the panel shop install some beefy extra brackets to handle the extra stresses. I have heard that some people just drill right through the frame rail into the engine bay and install a extra top plate and sandwich the whole assembly. Not sure that this is a good idea as it would just squash the frame rail and cause more stress. I think the best method would be to (if you have the time and money to make a good job) build in a new stronger internal bracing that spreads the load better.

Do it once, do it right = good nights sleep

[ChrisZ]

Hmmm. i kind of forgot to mention that it should be a eibach, it just slipped in to my mind now, i do have a 25 mm one for the front and i will take your advice and look in to how to reinforce.

Chris

[soundmasterg]

What were the stock sizes for the 240Z sway bars? I was thinking of upgrading to a rear bar at some point, and possibly going to a larger bar in the front too, but it would help to know where I'm starting off at in regards to the front anti-sway bar size.

Thanks!

Greg

[ChrisZ]

IIRC the front is 19 millimeter stock, you can upgrade to 23 or 25, as far as i know, you have to upgrade in the front if you put one in the rear.

Chris

Black dragon have a good site with sway bars, there you can also see the gain in procentage.

[ktm]

A few words on using a larger sway bar on the front. Make sure to reinforce the frame rail somehow. The PO of my car didn't and cracked the extra brace which is fitted within the internal cavity of the frame rail. He ended up welding a 3mm plate onto the frame rail to support the new mounts. When that seciton was rebuilt, I had the panel shop install some beefy extra brackets to handle the extra stresses. I have heard that some people just drill right through the frame rail into the engine bay and install a extra top plate and sandwich the whole assembly. Not sure that this is a good idea as it would just squash the frame rail and cause more stress. I think the best method would be to (if you have the time and money to make a good job) build in a new stronger internal bracing that spreads the load better.

Do it once, do it right = good nights sleep

The frame rails are "paper" thin. Simply drilling through them and installing a plate on the top will crush the rails. I had a 1/8-in. C-channel welded over my rail as well as installed 3/4-in. steel tubing inside the rail (where the bolts run through) for crush resistance.

[John Coffey]

The frame rails are "paper" thin. Simply drilling through them and installing a plate on the top will crush the rails. I had a 1/8-in. C-channel welded over my rail as well as installed 3/4-in. steel tubing inside the rail (where the bolts run through) for crush resistance.

I gotta step in here. The front frame rails on the S30 are not paper thin and if you guys didn't torque everything to 100 ft. lbs. maybe you wouldn't be crushing things. There is almost no place on a S30 that needs 1/8" steel sheet.

.083" steel sheet is strong enough (per SCCA, NASA, and others) to support roll cage mounting points on any race car in the USA. .125" steel sheet to support an anti-roll bar is overkill.

A C-Channel of .063" steel sheet stich welded to the frame rail with holes drilled through allowing nuts and bolts to fasten the anti-roll bar mounting is plenty. Torque the M8 fasteners to 35 ft. lbs. using Nylocs and you'll have nothing to worry about.

EDIT: deleted a pejorative word. Sorry.

Edited November 19, 2008 by John Coffey

[ktm]

I gotta step in here. The front frame rails on the S30 are not paper thin and if you guys didn't torque everything to 100 ft. lbs. maybe you wouldn't be crushing things. There is almost no place on a S30 that needs 1/8" steel sheet.

John, I am speaking from my own experience. I had originally drilled through the rails and uses long bolts with a small plate. I could not even torque to spec without the rail deforming slightly. I did not "torque to 100-ft/lbs", I followed the FSM for the torque specs.

I purchased Bad Dog's frame rail stiffener for sway bars and asked him to modify it from a bracket to a C-channel. It is my understanding that Roostmonkey manufacturers these for John at Bad Dog. I am mistaken regarding the 1/8-in. thick plate. It was most likely approximately 1/16 or maybe even 0.083" plate.

I was simply providing an example of how I reinforced the frame rail area. I mistakenly overstated the steel plate thickness.

[NissanMaster]

I had a replacement frame rail in the project bin so I thought you may like to see what the reinforcement on the replacement unit looks like,I suspect the reinforcement is the same as original.:bulb:

Edited November 22, 2008 by NissanMaster