JMortensen Posted May 27, 2006 Share Posted May 27, 2006 I've been thinking about this for the last couple years and I actually already have some parts and materials ready to go, just kind of have to figure out which way to go. 1. Drill the steer knuckle out to 5/8 (have the bit already) and then use a 5/8" bolt through the steer knuckle with spacers on bottom to adjust bumpsteer. 2. Have the hole in the steer knuckle reamed to fit 7 degree taper which Cary says is a "standard" bridge ream. If I went this way I'd have to find a local machinist with the proper ream. I've priced them out and it seems they go for $100+ dollars. Which is the better option and why? Also, I have the short steer knuckles. I'm considering going back to the standard length knuckles for better Ackerman, as my tires tend to drag a lot in slow speed corners. I had previously considered moving the rack back in addition to running the longer knuckles. Not really sure which way to go on this. I think the Ackerman will help at autox and probably on the big track too, but the more I look at moving the rack the bigger a hassle it seems to be. Advise here would be appreciated, preith and Cary, I know you guys have been down this road before... For the adjuster I have 1" hex aluminum that I'll need to drill and tap. I know that the outside is going to be 5/8-18 RH and LH threads. I have the 5/8" taps. The inside is 14 x 1.5 LH and RH I think, I'll have to double check. That's going to be TOUGH to find a tap for, and I'm sure expensive when it's found. I think it is possible to cut the threads using a lathe. Anyone know the specifics on that? Also I'm figuring it would be easier to have the hex drilled and tapped in a lathe just so that it is centered. If anyone knows of a place in Seattle that would do this kind of work I'd appreciate it. The last couple times I called around to machinists in the phone book nobody wanted to help me. They basically said "Is this going to be a run of 500 or 1000?" and I said "I'll need 4 total" and they said they weren't interested. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted May 29, 2006 Share Posted May 29, 2006 I am having difficulty visualizing the connection and adjustability between the tie-rod end, and the 5/8" bolt. Can you help me on this? Quote Link to comment Share on other sites More sharing options...
Guest iskone Posted May 29, 2006 Share Posted May 29, 2006 If you can't find any shops oout in Seattle I know a few on my side that will do it. Small shpps are the best for this sorta thing. TMF inc. Puget Sound Precision Isk Quote Link to comment Share on other sites More sharing options...
JMortensen Posted May 29, 2006 Author Share Posted May 29, 2006 I am having difficulty visualizing the connection and adjustability between the tie-rod end, and the 5/8" bolt. Can you help me on this? I think yours is actually set up like what I'm talking about. Drill out the taper in the steer knuckle, slide a bolt through, then use spacers below to correctly position a 5/8" rod end, then a nut on the bottom. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted May 30, 2006 Share Posted May 30, 2006 My final configuration was the use of the OEM steering arms using a 1/2" bolt (this was because the 5/8" bolt seemed to be a bit of overkill in regards to it as well as the rod end) BUT, I had a split tapered shim machined to clamp the 1/2" bolt into the tapered hole of the steering arm. It holds it so well that I must "pop" the end of the bolt with a hammer a couple of times in order to remove the bolt from the steering arm. I had it machined slightly longer than needed, and then ground the length down to where the shim was just slightly longer than the tapered hole so that the 1/2" bolt head and washers would squeeze (or crush) the spacer down into the gap between the bolt and the arm's tapered hole. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted May 30, 2006 Author Share Posted May 30, 2006 OK, I suppose that works too, I just don't have a lathe so its easier to drill it to 5/8". I have a friend with a 510 who is using the 5/8" stuff and it works for him, but he drilled it undersize then honed it out to an exact fit on the bolt. I don't have the hones either, so I'd prefer to just drill it and stick a bolt in the hole, I guess what I'm worried about is a little looseness in the hole, and I'm thinking that this is where the tapered pin would have an advantage. Quote Link to comment Share on other sites More sharing options...
tube80z Posted May 30, 2006 Share Posted May 30, 2006 I've been thinking about this for the last couple years and I actually already have some parts and materials ready to go' date=' just kind of have to figure out which way to go. 1. Drill the steer knuckle out to 5/8 (have the bit already) and then use a 5/8" bolt through the steer knuckle with spacers on bottom to adjust bumpsteer. 2. Have the hole in the steer knuckle reamed to fit 7 degree taper which Cary says is a "standard" bridge ream. If I went this way I'd have to find a local machinist with the proper ream. I've priced them out and it seems they go for $100+ dollars. Which is the better option and why? [/quote'] For a track/racing car the better option is to use a bolt and no tapers. Simple reason is that you can take it apart and put it back together in the same location quickly. And since you'll be using spacers it will make adjusting bumpsteer easier if you change caster. Also, I have the short steer knuckles. I'm considering going back to the standard length knuckles for better Ackerman, as my tires tend to drag a lot in slow speed corners. I had previously considered moving the rack back in addition to running the longer knuckles. Not really sure which way to go on this. I think the Ackerman will help at autox and probably on the big track too, but the more I look at moving the rack the bigger a hassle it seems to be. Advise here would be appreciated, preith and Cary, I know you guys have been down this road before... As it was explained to me ackerman is a function of the tire construction. In the case of the FA tires you are using they like ackerman. The swift uses 100% ackerman and I know a few teams have added more when they run on teh slower street courses. So I'd put on as much as you can get. I intended to build a new set of steering arms but never made it that far. I bent the stockers out a little and moved the rack closer to the crossmember. I don't have any detailed notes anymore but I seem to recall getting near 70% ackerman with this setup. I thought it worked better. I don't think you'll be able to get a lot more than than this simply because of the packaging. The only way I think you could get it to work would be to convert to rear steer. For the adjuster I have 1" hex aluminum that I'll need to drill and tap. I know that the outside is going to be 5/8-18 RH and LH threads. I have the 5/8" taps. The inside is 14 x 1.5 LH and RH I think, I'll have to double check. That's going to be TOUGH to find a tap for, and I'm sure expensive when it's found. I've made a few tie rod using swedged steel tubing (for 5/8) on the outer end for the rod end. On the inside I cut a slot in the swedged piece using my mill and then cut off the threaded section of the stock tie rod and welded this in. I saw this done at a hotrod shop I hang out at. The only trick was to preheat all the parts and then let cool in sand. Cary Quote Link to comment Share on other sites More sharing options...
JMortensen Posted May 30, 2006 Author Share Posted May 30, 2006 How about turning the threads? Is that a realistic option? That swedged tubing solution sounds a little messy. Quote Link to comment Share on other sites More sharing options...
preith Posted June 2, 2006 Share Posted June 2, 2006 Looks like the bases have been covered already, but just for the record, I have NOT been down this road yet. I talked it up a bit in the past, but I still haven't had a chance to do what I had in mind yet. If you modify the cross member, you can also allow for bumpsteer adjustment by playing with the height of the rack overall; maybe getting it more in the ball park and fine tuning with spacers on the ends. You can buy a variety of pre-cut aluminum hex tubing, already drilled from Coleman racing, and most importantly cheap, at about $10 each. http://www.colemanracing.com/catalog/index.php?cPath=2_1025 Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 2, 2006 Author Share Posted June 2, 2006 Yeah finding a threaded 5/8" tube is easy, the problem is threading it onto the 14 x 1.5mm rack. I think at this point I might try Cary's suggestion. I checked into the 14 x 1.5 LH tap and it seems fairly impossible to come by. Even if I found the tap I've tapped enough tubes to know that I can't get the hole straight, so I'd probably want a machinist to do that for me as well, and Cary convinced me via email that modifying the swedged tie rods isn't that hard a procedure. I took a look at my crossmember, and the thing that sticks out first and foremost is that if you move the rack more than about 1" back you start running into interference issues with the LCA bolt. They're already pretty close unfortunately. Plus it doesn't look terribly easy to do anyway you go about it. Looks like you can move the rack back about and inch or so, then bend the knuckles about 3/8" out, and then... ??? I'm even starting to wonder about lengthening the steer knuckles. Just not too many other options. Maybe the other option of running a buttload of toe out is better at that point. I'm not giving up yet but it doesn't look like it's going to be easy... Quote Link to comment Share on other sites More sharing options...
preith Posted June 3, 2006 Share Posted June 3, 2006 Cary is probably sick of hearing this, but I’m still of the opinion that a stock car steering rack is the only way to go: Heh, ignore the right crossed out in the pic... The expense is considerably more, but ditching the entire stock steering system - rack, cross member, and steering column from the get go makes your life so much easier in the long run. Everything is then available off the shelf and practically no machining is needed. The steering rack is much easier to mount. I’m not entirely sure how I’m going to do it, but I was thinking fabricating a plate similar to this, but incorporating a threaded ackerman adjustment into it at a 90 degree angle to it, on the cross member. The inner tie rod mounts are available threaded, all ready to go for 5/8 rod ends. The steering u-joints, which Borgeson for example sells, can be used. The steering column can then be a splined shaft (also off the shelf) suspendend by rod ends, simplifying things and shaving some weight off the car as well. Also, when fabricating the x-member, I plan on pretty much going straight across from the frame rails, instead of angling forward like the stock one, thereby creating loads of room for ackerman, and mounting the engine to the frame rails. I believe you can’t set the motor back in FP, so that may be a problem for some of you. The suspension pick-up points can also be much more narrow if you’re using rod ends for them too, and clearance isn’t as much of an issue then as well. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 3, 2006 Author Share Posted June 3, 2006 I always wondered how those racks work. Can you get extensions or something to make the inner tie rod line up with the control arm pivot, or do you just run a super long tie rod? And if you ran a super long tie rod, wouldn't that mess with the bump steer quite a bit? I do like the idea of going to all standard circle track components. Probably can get a bunch of different steering ratios, and I'm guessing that they're relatively inexpensive. Not sure I want to get into completely fabbing a new crossmember at this moment in time, but it's an interesting idea anyway. Quote Link to comment Share on other sites More sharing options...
tube80z Posted June 3, 2006 Share Posted June 3, 2006 The steering rack is much easier to mount. I’m not entirely sure how I’m going to do it' date=' but I was thinking fabricating a plate similar to this, but incorporating a threaded ackerman adjustment into it at a 90 degree angle to it, on the cross member.[img']http://www.colemanracing.com/catalog/images/pn43.jpg[/img] The mount you have above is basically what I've done to my nissan rack. I welded a mount to the rack tube and use that to attach. Very similar in the end. I only chose this route because I had the rack and I'm cheap. For your ackerman adjustment why not build it maxed and then put spacers under it as needed. Also, when fabricating the x-member, I plan on pretty much going straight across from the frame rails, instead of angling forward like the stock one, thereby creating loads of room for ackerman, and mounting the engine to the frame rails. I believe you can’t set the motor back in FP, so that may be a problem for some of you. The suspension pick-up points can also be much more narrow if you’re using rod ends for them too, and clearance isn’t as much of an issue then as well. You'll have to watch the clearance to the oil pan but this should work fine. If you try and lower the car a lot you may have interference issues if you raise the crossmember/inner pickups too much. I still like the idea of doing something like this and have spacers that would allow one to move the crossmember to adjust the roll center. You'd need adjustment like Jon has on for the TC rods but it seems like it would work. For racks you might also take a look at a number of the sand rail companies. They have some low cost options that might work as well. Cary Quote Link to comment Share on other sites More sharing options...
tube80z Posted June 3, 2006 Share Posted June 3, 2006 I always wondered how those racks work. Can you get extensions or something to make the inner tie rod line up with the control arm pivot, or do you just run a super long tie rod? And if you ran a super long tie rod, wouldn't that mess with the bump steer quite a bit? Coleman lists them in their catalog. I believe they are set for the some of the basic chasis that might be bought. So some custom fab would beed to be done for a datsun version. Cary Quote Link to comment Share on other sites More sharing options...
preith Posted June 3, 2006 Share Posted June 3, 2006 The racks are also available in custom center to center lengths. I believe the typical rack pictured is about 18”. I measured up the stock one at about 24”. I’m not sure about the steering ratios. The racks are available in different ratios, but I was under the impression they weren’t changeable, or not without considerable effort. Another benefit of having the rod ends for inners as well is you can also space that side for bumpsteer. Cary, the cross member would still be U-shaped of sorts, but if you look at the stock one from the side it jogs forward a bit; this would be eliminated. There would still be oil pan clearance issue though without the engine set back a few inches. Quote Link to comment Share on other sites More sharing options...
johnc Posted June 4, 2006 Share Posted June 4, 2006 This thread is really cool, but I can't do anything with it! Its frustrating... The Street Mod 2 240Z I'm building for a customer is rule limited to the stock stuff as far as the crossmember and steering rack. I guess I'll try the tie rod spacers. Quote Link to comment Share on other sites More sharing options...
tube80z Posted June 4, 2006 Share Posted June 4, 2006 For a street mod car I'm not sure you can do much with the rack. I guess you could eliminate the bushings and move the rack and possibly pour in some new ones but I'm not sure how much, if anything that would gain. I had thought SM allowed liberal creativity on the outside, as in tubular control arms, custom fabricated strut housings, etc. I would think you could take some advantage with the steering arms and if you used a two piece strut you should be able to set the pin lead on the strut. This would let you experiment with much larger caster angles. I don't know if this will work with low profile street radials or not. Cary Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 4, 2006 Author Share Posted June 4, 2006 I found the tap here just now: http://www.icscuttingtools.com/catalog/page_211.pdf. I was trying to search on the net for 14mm turnbuckles. I figured if I could find the turnbuckle then maybe I could fairly easily find a metric rod end for the outer end. Didn't find the turnbuckle, but I did find the tap... So maybe that will help you with your customer's car John. Now I gotta figure out which way I want to go. Looks like the cost for the tap is about the same as the cost for the Coleman swedged turnbuckles, and I'd still have to buy the RH tap, although it seems to be readily available and cheap by comparison. It's under $10 here: http://www.use-enco.com/CGI/INLMK32?PARTPG=INSRAR2 EDIT--Just checked and the place that has the LH tap has a "general purpose" 14 x 1.5 RH for $6 something. If one could get a 14mm turnbuckle in the right length that seems like it would be really easy, just have to get a 14mm drill bit for the steer knuckle. Seems like it should be available, but I wasn't able to find it though... EDIT AGAIN- Also got curious and checked the drill size required for the 14mm tap hole. Turns out its .4921" so looks like a 1/2" drill would work just peachy. So that's good news. Still if someone wanted to do the outer 14mm rod end, would need a 14mm or .551" drill bit for that end. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 16, 2006 Author Share Posted June 16, 2006 Pulled out a spare steering rack and cleaned it up, actually has good bushings in it and feels nice and tight so I think I'm going to use it. Only issue is that the hole for the zerk is stripped. It didn't have a Zerk in it when I pulled it out of my parts stash so I put a Zerk fitting in there and greased the rack. When I pulled the grease gun off, the Zerk came with it. I've got some larger Zerks that I could use but I'd have to drill the hole larger, which I imagine would mean pulling the rack apart. Also considered cleaning the hole really good and JB Welding the Zerk in there. It only has to withstand the grease gun abuse, so that might be good enough. I've been thinking of different ways to mount the rack further back on the crossmember, and I was looking at the clamped on snubber thingy that is on the rack to prevent it from rotating. This clamp is a U bolt type, and both of the racks that I own have them. So I'm thinking it would be pretty easy to make a plate, drill holes in it, and weld it to the crossmember and then use the U bolts to attach the rack to the plate. Might be that the bottom half of the clamp could just be welded straight to the flat center section of the crossmember. If I ground the stock mounts off, and clearanced the rack, I think this would work and allow the rack to be moved back about 7/8" to 1". The question is would the U bolts be strong enough to prevent the rack from moving laterally? I'm thinking they would, I know that U-bolts are stronger than straps for securing U-joints. Anyone have a yea or a nay on this idea, suggestions, or a better idea for me? Quote Link to comment Share on other sites More sharing options...
Wiisass Posted June 19, 2006 Share Posted June 19, 2006 For the inside, have you considered having clevises made? If wouldn't be a hard piece to have machined. And then you could use a simple rod with right and left threads on each end with rod ends for your turnbuckle/adjuster. Then you would be able to use the 5/8 rod ends, which would help out a lot with cost because metric rod ends in the us are not anywhere near worth the price. And then you could do what you had planned for outboard bumpsteer adjustment. Also depending on how you do the inboard clevis, you could use that for bumpsteer adjustment as well. Another thing to be concerned about. Depending on how much your spacing the rod from the steering arm, you're going to have to account for the bending in the connecting bolt. If you space it enough the moment can be great and will bend that bolt. Depending on how you design the spacers, most of the load can be taken by them and you shouldn't have any problems, but it is something to keep in mind if you don't want this thing breaking at the track. Now I'm guessing the talk about moving the rack around is just for ackerman. What is the stock ackerman setting? How much are you planning on going or is it just a guess and test method? If you can't move the rack much, you could consider moving the outboard point laterally which will also adjust the ackerman. This is probably something that needs to be done graphically to make sure you're getting what you've planned on. 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.