Guest butlersZ Posted June 30, 2004 Share Posted June 30, 2004 Hi Guys, Has anyone ever made thier own strut tower bars for front and back? Also, are they available from anyone? I want a brace between the front towers and between each tower to the firewall. In the back just a single one between the towers should be sufficient. Any suggestions??? The engine is producing about 375-425 HP and 350 TQ, so I'm a bit worried about twisting the unibody. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted June 30, 2004 Share Posted June 30, 2004 There have been several designs produced by our membership. Most encompass a plate on top of the tower, connected by tubes to the other side, and to the firewall, to triangulate the structure. These designs are mainly oriented toward keeping the towers rigid in relation to each other when faced with the side loading imparted by the suspension. They may well offer some support for engine and chassis torque as well, but without any empirical proof, I'd wonder if the towers would twist in unison (along with the frame rails), thus making them less effective for this purpose. This is not all doom and gloom though, because IMHO, the Z is a fairly stiff car considering its weight, what it was designed for in the first place, and the era that it was designed in. Here is my version of what I wanted in extra stiffness. The engine is solidly bolted to the unibody at 5 point (including the tranny), and then triangulated up to the strut tower, and the strut tower brace that connects to the firewall at 3 points: Quote Link to comment Share on other sites More sharing options...
Guest 77vegasz Posted June 30, 2004 Share Posted June 30, 2004 http://www.zcarparts.com is the Motorsport Automotive web site. They sell nice polished aluminum bars with powder coated mounts for front and rear for about 110.00 each. Jon Quote Link to comment Share on other sites More sharing options...
Guest butlersZ Posted June 30, 2004 Share Posted June 30, 2004 How hard are they make? And what material would be the best? Aluminum, steel??? Solid or hollow? I want my car to handle extremely well for those Sunday afternoon drives on the twisty back roads. I was considering getting ahold of some solid bar stock aluminum and some 1/4" thick sheet and trying to fab some up. I pretty good at fabricating, well so far anyway, It doesn't seem too hard to make them but then again... If I make some I'll be sure to post some pics. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 30, 2004 Share Posted June 30, 2004 I made some with aluminum tap tube from Coleman. Just bought the tube, tapped it, used 5/8" rod ends. On the mounts I used 1/8" plate, if you look for pics of John Coffey's car, mine looks very similar to that. His triangulate better in the center of the engine bay, my rear mounts are more spread apart than his. I hit the vertical braces under the cowl, he apparently braced the center of the cowl area and ran the bars to the firewall in the center, which should work better than what I did. I don't have any pics of mine, but I believe there are some pics of John's at http://www.betamotorsports.com look for Rusty Old Datsun for sale. Quote Link to comment Share on other sites More sharing options...
fastzcars Posted June 30, 2004 Share Posted June 30, 2004 "Top End Performance" makes a setup like that. Although I've heard some things about bad customer service from some of the member's here, But at least it will give you some ideas.[/img] Quote Link to comment Share on other sites More sharing options...
Guest butlersZ Posted June 30, 2004 Share Posted June 30, 2004 Well I guess I'll get the tape measure and start taking some measurements and attempt to make some. The MSA ones won't work due to the fact that I have the SBC. It looks like there would be some clearence issues. What about cutting out the stock radiator core support, mines rusting anyway, and welding or bolting in some square aluminum or steel tubing of a decent size and thickness to help with the chassis flex? Any opinions on this? Besides, it look cool too. Also what about some braces under the car going cross wise from frame rail to frame rail across the tranny tunnel? Perhaps that would help with some of the distortion the Z experiences. I know that when I had my old '74 260 I would notice the plastic rear trim panels creaking as my car turned around a corner be it slow or fast speeds, so the back of the car does flex quite a bit. Anyone have any ideas or opinions on bracing the Z? Oh, it's a '78 that I'm working on now and yep, it's on jackstands! Quote Link to comment Share on other sites More sharing options...
Guest butlersZ Posted June 30, 2004 Share Posted June 30, 2004 blueovalZ, Now correct me if I'm wrong but wouldn't bracing your engine to the strut tower braces you made kind of cancel out the purpose of strut tower braces? You would think that when the engine revs the torque from the engine itself would put stress on the strut towers causing them to flex, thats if your engine is not solid mounted. Am I wrong? In a way I could see that bracing your engine to the strut towers would add strength and the small amount of power/torque that would normally be lost when the engine revs and twists on it's mounts would go to the tranny and rear wheels instead. I think I just lost myself here... Quote Link to comment Share on other sites More sharing options...
blueovalz Posted June 30, 2004 Share Posted June 30, 2004 Your question about the engine and towers sounds correct... for a soft-mounted motor. Mine is solidly mounted to the rails at 4 points, tieing the rails and motor together as one. This would eliminate any ramp, or cam action, impressed onto the towers in the configuration I've used. I would never have done this had I used rubber motor mounts. Quote Link to comment Share on other sites More sharing options...
Phantom Posted June 30, 2004 Share Posted June 30, 2004 http://www.racetep.com They provide multi-point front and rear strut twoer braces. I have them in my car. They are a very snug fit and non-adjustable so your car better not be twisted in any way or it will be very difficult to install them. Quote Link to comment Share on other sites More sharing options...
Guest 77vegasz Posted June 30, 2004 Share Posted June 30, 2004 I have a small block in my Z and use the MSA bar without issue. Jon Quote Link to comment Share on other sites More sharing options...
johnc Posted June 30, 2004 Share Posted June 30, 2004 What about cutting out the stock radiator core support, mines rusting anyway, and welding or bolting in some square aluminum or steel tubing of a decent size and thickness to help with the chassis flex? Stop! Forget about the strut tower bars. If your radiator core support is rusted, fix that first. You're wasting your time building anything to strengthen the chassis if the chassis is not already in good condition. Also, there's no reason and no place anywhere on a 240Z where you would need to use 1/4" steel plate. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted June 30, 2004 Share Posted June 30, 2004 Aw come on John, 1/4 steel bellypan! Guarenteed to lower your center of gravity significantly. Use 1/8" plate on the strut towers for any type of strut bar and you'll be in good shape. Also there is little need for a solid bar for this, I'd suggest looking at 1" tubing, ~0.083" wall or something similar. (0.065 would be fine too) If you have clearance issues you might try 2 pieces of .625" or .75" tubing run next to each other and stitch welded along the way. Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted June 30, 2004 Share Posted June 30, 2004 Drax, I like that idea of stitch welding the two 5/8" bars together to gain alittle clearence. Great idea! Plus on the ends you could wrap them around the sides of the strut towers. That would look nice too. Of course that would require you to be able to form the tubing. I've been tossing around ideas for mine, but I'm waiting to get the engine in the bay before I make anything permanent. Great topic! Quote Link to comment Share on other sites More sharing options...
johnc Posted June 30, 2004 Share Posted June 30, 2004 Bends in round tubing create flex points and weaken the structure. Keep the strut tower bars as straight as possible. Also, try to run large OD and thin wall tubing. The strut tower bars on my 240Z are 4130 1" OD .049 wall. Here's a picture of a strut tower brace I built for a STX class BMW 325is. It planted the front so well the owner had to reduce his rear spring rates by 50 lb. in. to get the car back to neutral. It was all built with 4130: .085" sheet, 3/4" OD .055" wall tubing, 1/2" OD .063 wall tubing, and 3" OD .063 wall tubing. The strut tower loads go into the large 3" OD tubing instead of through the strut bolts (like so many off the shelf braces). Quote Link to comment Share on other sites More sharing options...
rc's240z Posted June 30, 2004 Share Posted June 30, 2004 Got to chime in here as well...there have been many posts regarding strut bars for a Datsun Z. We provide a solution as well... http://www.pdkfabrication.com Like John C, John Williams (car pictured above) had to change his rear swaybar set up because of the added strength of strut brace we added. Ron[/img] Quote Link to comment Share on other sites More sharing options...
preith Posted June 30, 2004 Share Posted June 30, 2004 I'm kind of leary about using rod ends for this application. Sure, if your builing a part for the masses it's great to have some adjustability, but for a custom one off for your car? In theory, the strut towers would remain at a constant distance, but they could both be pivoting in parallel? Just thought I'd throw it out there. Quote Link to comment Share on other sites More sharing options...
rc's240z Posted June 30, 2004 Share Posted June 30, 2004 No rod ends in our product... Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 30, 2004 Share Posted June 30, 2004 I don't think rod ends have any downsides as long as the strut bars control in more than one direction. The MSA bars with just a single bar could allow the left or right side to raise in relation to the other, but if you've got it triangulated I think that solves that problem or at least reduces it. Personally I like not having to disassemble a bunch of stuff to do a valve adjustment. The way mine are set up I can take off one bolt on the bar that goes across and "flip" it over and out of the way. Not sure how much work has to go into removal of the PDK setup to pull the valve cover, maybe that center bar comes off easily too, but when you look at something like the TEP setup it looks like a bit more work... I can also say that I'm sure the PDK setup does a better job than what I've rigged together, but when testing mine I went around a corner where the front always got loose prior to the installation, and it DID NOT get loose with my bars in place. In fact I got two wheels in the dirt. On the INSIDE of the corner. Big big difference. I used to think that strut bars were a ricey thing like a polished cold air intake, but I was WRONG. Way wrong. I'm happy with the performance increase that mine give, and it was a great confidence booster for me because that was the very first thing I ever fabbed on a car from scratch (or as close to scratch as I'll ever get--not going to melt the ore to make the metal for the parts). Quote Link to comment Share on other sites More sharing options...
rc's240z Posted June 30, 2004 Share Posted June 30, 2004 Hi Jon!! The PDK solution uses a single allen head bolt though the attachement points on each side adjacent to the strut towers. It is very simple to access the Valve Cover, only one bolt on one side needs to be removed. The mechanic's involved deal with the issues of the strut towers in the front of an early Z twisting so triangulation is a big deal for this application. Strut bars using a Rod end solution will move rendering the bar solution less effective... GO WCZR!! Ron Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.