240Z Chassis prep / reinforcements

[NZeder]

Given I posted a pic - I will just state this - I did so for confirmation that what was written and how my mind was taking in this info to ensure I was on the same page aka learning/taking it in.

 

So back on topic on Chassis prep/reinforcement. I have seen/read about how some add braces to the back of the TC rods to reduce the movement/flex in this area - I am thinking of doing the same so it this a good idea? Or should I spend more time/effort elsewhere aka rear suspension and limit its movement.

 

One more question to those that have seen many 240z/260z/280z shells - we know there are big differences between them with changes that were made over the years.

 

So how much stiffer is the last S30 shell/chassis stock for stock?

 

I know for a pure race car it should not matter as you will be adding a good 10 point cage that should pick up the front strut towers etc will add a bucket load of chassis rigidity - I am asking for those of us that have a dual purpose car that will be street/track so like me I can drive to the track and do club events. I know dual purpose is always a compromise and I think the 10 points that have been posted/listed are excellent for those of us with such goals in mind. But would say a 280z shell be a better starting point for a dual purpose car due to the changes the factory made in the uni-body or does it not matter? (I guess off topic given the thread is about 240z chassis prep but related I think, as if the 280z shell is stronger would it not be a better place to start?)

Edited May 6, 2010 by NZeder

[bjhines]

The 280Z weighed hundreds of pounds more than the 240Z. You can remove a lot of this added weight, but some of it is welded into the chassis. There are hundreds of small details that chnaged from year to year. The 280Z chassis is DEFINITELY more reinforced than the 240Z chassis. There is also a lot of steel added for crash safety purposes. The crash reiforcements are not always adding stiffness or performance. They are just extra weight in places like the doors and bumper mounting areas.

 

You can bend a 240Z door shell over your knee and fold it twice over and smash it flat with your heel. It will fit into a 12-pack beer box in your recycle bin. The 280Z door shell would take a slegehammer to fold just once.

[johndaniel.b.coffin]

No need to apologize for any of this. Most of the folks on this site like to figure things out, otherwise why would they got through the pain and frustration of modifying these rusty old cars.

 

OK, I do agree sir. Sometimes I just feel the need to somewhat defend people that I don't know. I do my best to research, But even I have made some post that I could of researched more. Sometimes it is just easier to ask. Like now. I have to give up most of my free time to look for something when in all reality, I really don't get much free time due to this crappy war. All will be figured out eventually. I will rest. Thanks again. I say good day.

[johnc]

 

So how much stiffer is the last S30 shell/chassis stock for stock?

 

 

 

As BJ posted the 280Z has significant strengthening added to the chassis. I've cut a 280Z shell up and, compared to a 1971 240Z that I cut up earlier, there's double the sheet metal structure inside the "A" pillar, the "C" pillar also has significant reinforcement, there are additional gussets from the "C" pillar to the rear wheel well, thicker sheet metal on the strut towers, additional sheet metal reinforcements in the frame boxes at the TC rod area, additional sheet metal reinforcements at the seat mounts and seat belt mounts, the seat mounts themselves are a lot stronger then the 240Z mounts, the rear bulkhead has additional sheet metal and two additional gussets, the cowl has additional reinforcements, and the front upper frame rails have internal reinforcements and better attachment to the cowl and the firewall.

[olie05]

 

8. RT Diff Mount.

 

 

I don't see how the rt diff mount adds to chassis rigidity. Could you please explain?

 

Also, the canepa z is a great example of a "different" approach to #7 on the list:

 

http://www.canepacollection.com/detail-1974-datsun-240z_imsa_gtu-brad_frisselle_imsa_gt_u_championship-5124662.html

 

They just use a plate that holds the differential and the rear control arm bushings. It also provides a place to mount their oil cooler and other things.

Edited May 7, 2010 by olie05

[Kurai]

Only this crappy camera phone one. The rear stock mounts are still there, strengthened by seam welding them to the floor and we put a 1" wide x 1/4" thick flat stock bar across them welded & bolted to the stock mounts. You can kinda see the spreader plate on the tunnel of the front seat mount.

 

The rear flat bar is not welded and finished in this picture and the overhang area was trimmed off before welding. The rear mounts had to have the bar so that we could mount the seats inboard enough to clear the door since the Sparco seats we are running are 23.8" wide at the widest.

 

Edit: You can also see my frankenstein floor patches where the stock front mount is, reused most of the stock floors because there was only a few rust areas. They aren't restoration quality but they are in there very solid and have Bad Dogs underneath.

 

Thanks!!! Yeah that is completely way off of what I was imagining lol. Also glad you mentioned that about the Sparco seats I have been hearing that the Z Seats are narrow (looking at a Corbeau set myself) and was wondering how I would tackle that issue but this seems to be a great solution.

 

Hey but just to apologize to anyone I may off offended wasnt trying to piss anybody off or anything like that its just like johndaniel was saying I have very little knowledge on the S30 and am in Afghanistan hanging out for a year lol, so in that I own a Z I have never even seen or touched lol (bought it right after getting here from another member), so if I ask a dumb question its purely from lack of experiance not laziness or anything. Everything i googled came up as either not making much sense or was for a completely different platform and not sure if the same concept applied when refering to S30 reinforcement.

 

Sry for stirring anything up def wasnt my intent at all. and thanks for the great knowledge you guys are displaying here I have never looked into chassis modifications at all.

[heavy85]

I've done most of the list on my car. See my galery for pics. Feel free to post any of the pics but I'm not taking the time to do it.

 

Cameron

[heavy85]

I've done most of the list on my car. See my galery for pics. Feel free to post any of the pics but I'm not taking the time to do it.

 

Cameron

[Kurai]

Lotta nice builds and data....thanks for the input.

 

Have any of you guys out there played with the application of Polyurethane foam to stiff up the chassis, I have seen it discusses on some other cars very few actually employing it with first hand input but looks like a very effective tool to use here is a example from Autofoam.........

 

http://www.autofoam.com.my/autofoam/index.php?option=com_content&view=article&id=23&Itemid=73

 

More data......

 

http://www.autofoam.com.my/autofoam/index.php?option=com_content&view=article&id=53&Itemid=77

 

there is more data under the "Autofoam" tab at the top of the pages...but you get the idea.

 

I may actually give something like this a shot in certain areas after i gain more structural data on the S30 chassis.

 

What are your guys thoughts on this?

Edited May 13, 2010 by Kurai

[johnc]

Lotta nice builds and data....thanks for the input.

 

Have any of you guys out there played with the application of Polyurethane foam to stiff up the chassis, I have seen it discusses on some other cars very few actually employing it with first hand input but looks like a very effective tool to use here is a example from Autofoam.........

 

http://www.autofoam.com.my/autofoam/index.php?option=com_content&view=article&id=23&Itemid=73

 

More data......

 

http://www.autofoam.com.my/autofoam/index.php?option=com_content&view=article&id=53&Itemid=77

 

there is more data under the "Autofoam" tab at the top of the pages...but you get the idea.

 

I may actually give something like this a shot in certain areas after i gain more structural data on the S30 chassis.

 

What are your guys thoughts on this?

 

A couple issues with using these types of foams on our 40 year old cars:

 

1. To be effective the cavity to be foamed must be clean, dry, and free of rust. The foam needs to stick well to the inner surface of the cavity.

2. It makes repairs very difficult. The foam or its residue just screws up welds - it must be completely removed before welding a panel.

3. In some cases it can trap water and create a rusty area.

[proxlamus©]

Excellent point about the foam John!

 

I cut a chunk out of my frame rails and even though it was "sealed", there was still surface rust inside of the rails. It would be close to impossible to clean all that off INSIDE the rails to get the foam to stick.

[Kurai]

Good call no foam it is. You know its kinda crazy i dig all over the internet looking for answers to questions that are answered here very fast.....It seems alot of data on the S30 just isnt documented...or maybe im just searching for the wrong words/phrases.

I've gotten more knowledge in this thread then in a month of searching the net.

[bjhines]

We hashed out most of this in dozens of threads over the years. You put a bunch of people together searching for info, calling manufacturers, etc, and the info comes out. There is some intersting info on using this foam through factory frame repair guidlines for newer cars and SUVs. Foam-filled structural replacement is a complex process. Clealiness and rust-proofing the surfaces are described as critical to proper repair/replacement. You can imagine how this would play out on our cars. The structural foam is fairly heavy(for foam), dense, and hard as wood.

[EF Ian]

I have a late UK 260Z (same chassis rails as a 280Z) and I'm looking to stiffen it for running an RB26. I'll definitly be running subframe connectors but I'm not sure whether to add baddog chassis rails over my existing rails, my existing rails are straight and solid so I'm wondering if I would see much benifit by adding the extra metal to them, obvoiusly it will be stiffer, but how much difference will it make? worth the extra weight?

 

 

What are your opinions guys?

[gmac708]

The baddogs need to be welded to originals forward of the firewalls anyway. The only parts you would be removing would be aft of the firewall and those sections run back to the seat mounts only. If everything is in good shape, I would leave them alone. It would not be that much of a weight savings for the work involved.

 

Gord

[morbias]

My opinion would be the opposite.

 

What with the crappy weather we have in the UK having metal boxed inside more metal is an invitation for rust to start eating your car from the inside out. With the close fit of the baddog rails it would trap moisture easily and hold it between the layers.

 

btw. why not just get a local fabrication shop to fold you up some top hat sections to your own specifications? I literally just last week picked up two new frame rails made from 1.5mm zintec (3 ft long) and it only cost £30 for both of them.

Edited December 22, 2012 by morbias

[EF Ian]

What with the crappy weather we have in the UK having metal boxed inside more metal is an invitation for rust to start eating your car from the inside out. With the close fit of the baddog rails it would trap moisture easily and hold it between the layers.

Thats a good point, although I'd have thought if it was welded closely to the original rails and then had plenty of seam sealer aswell it would be alright.

 

 

 

 

btw. why not just get a local fabrication shop to fold you up some top hat sections to your own specifications? I literally just last week picked up two new frame rails made from 1.5mm zintec (3 ft long) and it only cost £30 for both of them.

Not that many fabrication shops near me, not sure if the one I use for random bits of metal would be able to make something like that..

 

 

Even if I don't add extra metal to the full length of the framerails it might be worth me adding extra to the forward area of the rails around the area where the tension rods are.

 

 

I reckon if I add extra metal I would be able to use the rails for jacking the car aswell which could be handy.

 

 

 

 

 

 

 

 

 

It just depends if the stock rails on there own are going to be stiff enouth to cope with 400hp.

[gnosez]

A word or two about the Bad Dog Parts frame rails:

 

1) they come in two styles -240 & 280 (the early 260s use the 240 version) both are over twice the thickness as stock OEM rails

2) they are made to fit over a clean/undented OEM rail and the fit is very tight (weld on, seam seal, coat with your choice of undercarriage sealer)

3) both rails start about 9-inches in front of the firewall (covers about 2/3 of the TC rod box

4) the 280 version ends in the same place as the OEM rails ended

5) the 240 version ends past the point where the OEM rails did

6) there is an optional rear 240 rail section that extends the rail into the rear wheel well area (can be modified to use with  280 rails)

7) these rails have been installed in more than 600 Zs since 2004

[gnosez]

 

http://s160.beta.photobucket.com/user/psanders240/library/BSR-260Z-IMSA

 

These pictures were from a roll of undeveloped 35mm B&W I discovered a year or so ago and Z-Ya put up in photobucket.

 

You can see how they went about prepping the car for structural concerns.

[johnc]

All the pictures anyone will ever need...