B00STDZ Posted May 10, 2011 Share Posted May 10, 2011 Interesting... Curious to see pictures of how well it fits on the car after it has been installed. Quote Link to comment Share on other sites More sharing options...
wheelman Posted May 24, 2011 Share Posted May 24, 2011 Jon, When I did the Subaru rack install I started with a 280 cross member, they're beefier than the 240 units. I had to cut reliefs into the left side engine mount tower and the main beam of the cross member just to the left of the rack mount to clear the valve body. I braced these points by welding angle iron to the opposite side from the cut. Does that make sense? A few comments in relation to the statements you reported hearing about other power racks: 1. You wouldn't have been happy with an electric rack that adjusts the assist based on speed, the scrub you are going to run won't reduce enough at speed to eliminate the need for PS and auto-x speeds aren't that high. I run less scrub than that and would go home with arms that ached pretty bad after a day of auto-x. 2. I'm running a Forrester rack with a stock GM pump from a 95 Caprice. It feels light and quick but is in no way vague and the pump has no problem keeping up, even on an auto-x course. 3. The Forrester rack is 2.5 turns lock to lock which is quicker than the stock Datsun rack and has a longer movement, very nice for auto-x. 4. A good fluid reservoir with some baffling in it is essential, my current setup doesn't have baffling and I get aeration which causes the pump to whine after a run. I've reduced the problem by running a higher fluid level but it's time to get a new reservoir. The rack you bought looks very nice, I'm going to watch this thread to see how it turns out. BTW: Once you get the car running you should think hard about coming over to the Tri-Cities or Spokane to auto-x with us, help me beat up on all the Vette drivers we have over here. Quote Link to comment Share on other sites More sharing options...
rsicard Posted May 24, 2011 Share Posted May 24, 2011 Tony warned me that the rack would be so much more powerful that I should beef up the frame rails to deal with the additional strain. I had already done some strengthening of the frame rails, but the Z crossmember is not the strongest looking thing and I don't really see a good way to increase its rigidity. Just playing around with the rack and an old crossmember I figured out that the old 6 cylinder engine mount towers had to come off, so those got cut. No biggee as I need to fab mounts for the L33 V8 anyway. Then I realized that the horns that stick off the front that hold the stock rack had to get cut back just to get the rack in position, so I did that. At this point I was able to get the rack positioned essentially in the stock position, but about 1/4" higher. Moving the rack back to the stock position fore/aft negates the work I did to move the rack back, but after graphing it out on the Ackerman thread, the difference will be minimal, so I'm not worried about it. The rack mount is my biggest dilemma right now. I think the most logical way to mount the rack is to weld two pieces of angle iron to the front of the crossmember so that the flat part of the rack sits right on them. This may improve the rigidity a bit over the long unsupported saddles that the stock rack used, but they're not exactly what I would call "overbuilt". I thought of using a long piece of angle iron all the way across the front and I think that would be sturdier, but then there really wouldn't be a good way to put the bolts in, unless I drilled a big hole in the bottom of the crossmember, although that's sounding like it will be the best option at this point. About the only thing I can think to do with regards to the crossmember would be to add a folded sheet metal gusset like a taco gusset between the crossmember and the frame rail, so that the lateral loads imparted into the frame go through two sides of the frame rail, instead of just the bottom. If anyone has any other ideas or previous experience, I'm all ears. It's easy to see that fitting the rack to the front cross member will be difficult. I also want a good power steering rack such as that which you have purchased. I want to road race my V8 240Z and will need a sturdy rack. That is why I am interested in your efforts with this custom rack. Your approach seems to be on track by first removing the engine mounts from the stock rack. The rack mounting points and engine mounting points will have to be integrated into a custom mount which can be bolted or welded back to the original front cross member. This may be a project for a good CAD person to visualize the custom mounting point bracket. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted May 24, 2011 Author Share Posted May 24, 2011 Cary came up with a very good idea for rack mounting, which is basically 1.5" square tube with a 7/16" hole drilled in the top and a large hole in the bottom so the bolts can be inserted and a socket used to tighten them up. I checked it out on the crossmember and it looked like it was going to work pretty well, and the fab work actually looked pretty easy. Basically just cut the top of the crossmember so that the tubing rests on the bottom skid plate, and then weld it in across the top (presumably with a gusset. To follow Tony's recommendation, I'll double up the mount points so that they are 1/4" thick. I've been slammed with the differential business, which is now really up and running (still nothing for Z cars aside from a couple seals, oil and LSD additive). I did have to order 1.5" square tubing and I got it in a couple days ago, but just haven't been able to make it out to the shop. I think with the way I'm planning on tying in the tube to the crossmember it will be OK, but I guess I'll have to put it together to test it out and see how it holds up. I'm finally getting back to normal on the work side of things, so I'm going to try and get out to the shop maybe tomorrow. I don't think the mount will be that hard to fab up, so I might be able to get it at least on the crossmember in the next couple days. I did figure out that the rack mounting holes are not centered, so I probably didn't need to cut the engine mount towers off. Oops. I think I'll have to take a look and see whether I want to run the stock towers or make my own mounts from the motor to the frame rails, and that will determine whether I leave the crossmember that is in the car in it, or if I switch them out, which will be slightly more of a pain in the ass seeing as how I welded the crossmember in. When I get it running and have run a few local races under me just to make sure that I'm comfortable that I've worked out the bugs, then I'm going to run every autox I can, so I'll probably be headed out your way, wheelman. I think it's going to be next season. I was doing really good over the winter, but this spring I haven't really done anything at all due to the new business coming together. Unless something changes, I think it's going to be on and off like this for a while. Quote Link to comment Share on other sites More sharing options...
wheelman Posted May 24, 2011 Share Posted May 24, 2011 When I get it running and have run a few local races under me just to make sure that I'm comfortable that I've worked out the bugs, then I'm going to run every autox I can, so I'll probably be headed out your way, wheelman. I think it's going to be next season. I was doing really good over the winter, but this spring I haven't really done anything at all due to the new business coming together. Unless something changes, I think it's going to be on and off like this for a while. Looking forward to meeting you and seeing your car. I completely understand about not making it this season, I won't be making all our local events either, work is crazy busy and I'm working almost every weekend to keep up. It should slow down this fall once the new instrument we're releasing is finally on the market but until then it seems like one loooooooong week. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted May 25, 2011 Author Share Posted May 25, 2011 I made some progress and actually got the rack into the position the old rack was in after I moved it back, but now I'm at a point where I am a little worried about the position of the rack vs the crank pulley. I'm not using John's Cars mounts, but my main concern is whether I will be able to move the motor far enough back for the crank pulley to clear. I was planning on setting the motor back as far as possible, but I'm not sure how much room I have to work with. The top of the rack is exactly 1.5" taller than the crossmember with it sitting on 1/4" bumpsteer spacers. It will actually be 1/8" lower than that, so figure a total height from the crossmember to the top of the rack of 1 3/8". The stock crossmember has a raised section that is 2" wide from front to back. The rear part of my rack is 2 1/8" from the back of the raised portion of the rack. In retrospect, the engine mount towers really did need to come off, so that wasn't wasted motion... Quote Link to comment Share on other sites More sharing options...
zdlite Posted May 26, 2011 Share Posted May 26, 2011 (edited) Boy, hard to imagine how you will get an LS motor behind that. I am running vette accesories which means the pulley is running closer to the block than the F body or truck. I have my engine back with less than a half inch clearance between the passenger side head and the fire wall. Even with that you can see the front of the crank pulley sits a little more than half way over the stock 240 rack. The rim of the crank pulley is about a belt tickness above the rack. I have my motor down pretty far to get hood clearance for the carb. The trans sits pretty low in the tunnel, lots of up room. You could probably go as far back but you may need to raise the motor to put the crank pulley above the rack. I also have a 3/16 inch shim between the cross member and the body (ala JTR), so the motor is low. On the plus side the motor doesn't move the way it is mounted. I am using S&P bisquit mounts and a urethane trans mount. Even an eighth of an inch of clearance is good. Edited May 26, 2011 by zdlite Quote Link to comment Share on other sites More sharing options...
rsicard Posted May 26, 2011 Share Posted May 26, 2011 I made some progress and actually got the rack into the position the old rack was in after I moved it back, but now I'm at a point where I am a little worried about the position of the rack vs the crank pulley. I'm not using John's Cars mounts, but my main concern is whether I will be able to move the motor far enough back for the crank pulley to clear. I was planning on setting the motor back as far as possible, but I'm not sure how much room I have to work with. The top of the rack is exactly 1.5" taller than the crossmember with it sitting on 1/4" bumpsteer spacers. It will actually be 1/8" lower than that, so figure a total height from the crossmember to the top of the rack of 1 3/8". The stock crossmember has a raised section that is 2" wide from front to back. The rear part of my rack is 2 1/8" from the back of the raised portion of the rack. In retrospect, the engine mount towers really did need to come off, so that wasn't wasted motion... Jon: Trying to visualize what you are talking and showing in the photos. The cross-member is made up of a "C" channel and contoured flat plate spot welded together. Does the 1.5" square tub get welded to the forward portion of the bottom flange of the cross-member? If not, how does the square tube attach to the cross-member? Please advise. Thanks. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted May 26, 2011 Author Share Posted May 26, 2011 The C channel raised part of the crossmember has been cut and the plan is to weld the tube to it and the bottom of the crossmember. Sounds like it's going to be too far back though. I could start over with the other crossmember and move the rack forward again. A 1" change in the rack position forward really won't change steering angles much at all and would actually be 1/8" forward from stock. The problem is that the center tube on this rack is a lot thicker than the Datsun part, so I'll probably be RIGHT UP against the firewall if I do that. I guess the other option is cutting the firewall to clear the head. If you cut (or hammered) yours just enough to move the engine back 1" from where it currently sits, would you have to modify both sides, or just one? Can I get a pic of the firewall where the interference would likely be? Thanks. Quote Link to comment Share on other sites More sharing options...
kj280z Posted May 26, 2011 Share Posted May 26, 2011 The C channel raised part of the crossmember has been cut and the plan is to weld the tube to it and the bottom of the crossmember. Sounds like it's going to be too far back though. I could start over with the other crossmember and move the rack forward again. A 1" change in the rack position forward really won't change steering angles much at all and would actually be 1/8" forward from stock. The problem is that the center tube on this rack is a lot thicker than the Datsun part, so I'll probably be RIGHT UP against the firewall if I do that. I guess the other option is cutting the firewall to clear the head. If you cut (or hammered) yours just enough to move the engine back 1" from where it currently sits, would you have to modify both sides, or just one? Can I get a pic of the firewall where the interference would likely be? Thanks. Jon On the crank pulley clearance - I'm running a under drive crank pulley and it provides lot's more clearance... I didn't like the clearance of the stock pulley to the stock steering rack - too close for comfort if you ask me... The under drive pulley provided a perfect amount and it looks like it would solve your problem as well Quote Link to comment Share on other sites More sharing options...
rsicard Posted May 26, 2011 Share Posted May 26, 2011 The C channel raised part of the crossmember has been cut and the plan is to weld the tube to it and the bottom of the crossmember. Sounds like it's going to be too far back though. I could start over with the other crossmember and move the rack forward again. A 1" change in the rack position forward really won't change steering angles much at all and would actually be 1/8" forward from stock. The problem is that the center tube on this rack is a lot thicker than the Datsun part, so I'll probably be RIGHT UP against the firewall if I do that. I guess the other option is cutting the firewall to clear the head. If you cut (or hammered) yours just enough to move the engine back 1" from where it currently sits, would you have to modify both sides, or just one? Can I get a pic of the firewall where the interference would likely be? Thanks. How much of the "C" channel portion of the cross-member had to be cut to the rear of the member to fit the square mounting tube? The "C" section of the cross-member is spot welded at the factory to a formed and stamped plate which has a flange at the forward and rear portion of the cross-member. Would the mounting of the rack come out too far forward if the square tube was welded directly to the forward flange of an unmodified cross-member? Just wondering. Please advise. Thanks. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted May 26, 2011 Author Share Posted May 26, 2011 On the crank pulley clearance - I'm running a under drive crank pulley and it provides lot's more clearance... I didn't like the clearance of the stock pulley to the stock steering rack - too close for comfort if you ask me... The under drive pulley provided a perfect amount and it looks like it would solve your problem as well Do you have the diameter of your pulley handy? How much of the "C" channel portion of the cross-member had to be cut to the rear of the member to fit the square mounting tube? The "C" section of the cross-member is spot welded at the factory to a formed and stamped plate which has a flange at the forward and rear portion of the cross-member. Would the mounting of the rack come out too far forward if the square tube was welded directly to the forward flange of an unmodified cross-member? Just wondering. Please advise. Thanks. If I had to guess, I'd say I cut it about in half. I could move it forward an inch and that should be just about at the front of the C part. Part of the idea here was to get the rack more closely tied into the crossmember. If I move it way out, then it would need a lot of gusseting to be as strong as it would be if I welded in where it is now. I could do something in between though, it doesn't have to be one extreme or the other. Quote Link to comment Share on other sites More sharing options...
tube80z Posted May 26, 2011 Share Posted May 26, 2011 25% underdrive balancer is 6.25 inches in diameter. I got mine from Scoggin Dickey and it's an Australian powerbond brand. I needed the extra clearance this gave the the stocker was almost touching the datsun rack I used as a mockup. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted May 27, 2011 Author Share Posted May 27, 2011 This rack is taller due to the larger diameter tube in the middle, and I think my previous mod made it higher than stock. Sounds like I'm into the firewall... Quote Link to comment Share on other sites More sharing options...
zdlite Posted May 27, 2011 Share Posted May 27, 2011 You don't have to go into the fire wall. If you raise the motor a bit you should be able to get over the top of that rack. Going with an undersized damper will reduce how much you need to raise the front of the motor. Depending upon your rear pinion angle you can work some tilt into the motor. Titling the motor front to back will help lower the overall engine CG an extra 1/8 if that is what you are after. My motor sits pretty level. To get it that way I leveled the rear diff as much as I could. I did the JTR mod of drilling out the rear mustache bar bushings and lowered the front of the diff when I put in a Ron Tyler style diff mount. I even “clearanced†the front diff cross member to keep the driveshaft from hitting it. If your diff is anywhere near stock inclination than you will have a few degrees tilt on the motor anyway. If I were you I would mount the rack where you think it will do the most good then hang the motor in the bay and start looking at geometry. One idea I did have, the vette crank pulley has two belt grooves. The back one is for the AC on a stock vette. I wonder if there is some way to get a pulley with just the back grooves and fashion an alternator mount off of that. That would buy you a couple inches in length. Not sure if you could ever find a damper like that or if it would work to cut down a stocker. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 14, 2012 Author Share Posted November 14, 2012 (edited) Back on this one. If there is one part of my build that has held me up more than anything, this is it. Stared at the mount that I had been planning on using for about a day and then cut it in half and decided to make two posts that stick out off of the front of the crossmember like the stock horns. The Woodward rack isn't symmetrical, so there was much hemming and hawing getting the thing centered on the crossmember. Finally just tacked a couple of 3/4" by 1/8" straps to the crossmember just to get the positioning correct. Once that was done I took a couple 1.25" square tubes and tacked them on to see what it looks like when it is all done. Moved the rack forward to make more clearance for the crank pulley. After having an argument about Ackerman with Leon I charted out the Ackerman and found that at full lock moving the rack as far back as possible made about 1 degree of difference. Not worth the hassle. This position moves the rack to parallel with the steer knuckles, so gives parallel steer. I'll just run a buttload of toe out. After seeing how little difference it made, making room for the pulley was a bigger concern than maximizing the tiny amount of Ackerman I could get. I didn't think I was going to be able to use the attached servo on the rack, but detaching it and getting the rack situated it looks like it will fit, just barely. Might have to notch the frame rail for clearance for the steering shaft. Other option is to run the servo remote and have 2 shafts. Trying to avoid that as it is yet more fabrication. Looks like my pinion housing will be about 3/4" below the crossmember, and the front of the hyd cylinder will be at about the crossmember height. Question now is what to do about that. Thinking about building the crossmember lower and making a skid plate to protect the cylinder. I'd hate to ruin a rack because I drove over a curb at the track and smacked it on the ground, and this car will be low. Edited November 14, 2012 by JMortensen Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 16, 2012 Author Share Posted November 16, 2012 Got the rack mounting done, welded and gusseted and ready to rock. Still not sure about the skid plate idea. It looks like the aluminum housing that holds the hydraulic cylinder is also hanging down about 1/4", same as the rack mounting square tubing. That pinion housing is about 3/4" down. Still considering whether or not to do a skid plate. I have a bunch of 1" square tube, so I could build a little frame and then weld a 1/8" plate to it and that would give clearance. Biggest problem is that the plate is heavy. I could just weld a section of square tube to the bottom of the crossmember on each side and then hope that the hyd cyl doesn't get whacked before the crossmember bottoms. Or I could have the square tubes sticking out off of the front like a spear. At least that way I could have them extend under the cylinder to give more protection without gaining all that weight... Quote Link to comment Share on other sites More sharing options...
tube80z Posted November 16, 2012 Share Posted November 16, 2012 Let the splitter be the skid plate. Put a few tubes to capture the back of the splitter on the crossmember and then use this as the mount. Cary Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 16, 2012 Author Share Posted November 16, 2012 That's a damn good idea, as usual. Thanks! Quote Link to comment Share on other sites More sharing options...
SteveO Posted November 17, 2012 Share Posted November 17, 2012 Jon- Just tuning in to this thread now for the first time. I had been thinking about looking at the Woodward Steering MR or MRC series racks for my '77 280Z project w/ LS motor. Curious to know if there is any specific reason why you chose the HL model over these, and if you think the mounting issues would have been any less with an MR or MRC. Steve Quote Link to comment Share on other sites More sharing options...
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