Guest Anonymous Posted November 1, 2000 Share Posted November 1, 2000 I have a 71' 5 spd,r200,280 half shafts and I'm haveing problems with brakeing half shafts at launch. I'm about to install r200 lsd and I would like to solve this problem. I have seen your posts scottie-gnz with your reg. u-joints. How are they holding up? I'm thinking about changeing to 280zxt half shafts and flanges but the only juck yard I could find wants 175 bucks and it looks like a pain to replace shaft. What breakaway should I have the lsd set to. Any help would be great. billy Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted November 1, 2000 Share Posted November 1, 2000 BillyZ, I continue to be amazed at the varied results using halfshafts. I did not use regular u-joints but Derek Grubb does and he is running mid-10s with small slicks. I used solid u-joints in my halfshafts on both the L28T and GNZ and had no problems with banzai launches and mid-11 second ETs. I switch to CVs and Myron installs my halfshafts in his monster and snaps them with street tires. Go figure. $175 is way too much. If the halfshafts were not damaged, invest $60 in a set of solid u-joints or consider the CV swap if the interested parties on the forum can agree on the best adaptor solution and do a group purchase. ------------------ Scottie 71 240GN-Z http://www.mindspring.com/~vscott911/gnz.html Quote Link to comment Share on other sites More sharing options...
pparaska Posted November 1, 2000 Share Posted November 1, 2000 I paid $100 for the 280ZXT halfshafts from Clark Z cars of Arizona. I'd think the companion flanges would be on the order of $50 to $75 more. Not bad, IMO. Two new R200 pinion seals, a little grinding around the outside diameter, swapping the dust sheilds between the 240Z and 280ZXT companion flanges and you're good to go. Less than $250 if you paid someone to weld the dust sheilds on. Pretty cheap upgrade. But I know some have run into endplay problems with this swap. I don't know how, but it has happened. Greg Kring is one of those that this happened to and he shyed away from it (according to his web page). I'd say that Scottie's method of welding a plate onto the 240Z companion flanges and drilling 6 holes is worth considering to try to alleviate the endplay issue. From looking at the length difference in the 240Z companion flange and the 280ZXT on, adding a 3/8" steel plate to the 240Z companion flange ought to give about 1/4" more endplay in the shaft. ------------------ Pete Paraska - 73 540Z - Marathon Z Project - pparaska@home.com">pparaska@home.com - Quote Link to comment Share on other sites More sharing options...
MYRON Posted November 1, 2000 Share Posted November 1, 2000 I got lucky at the auto parts store this weekend and scored some "brute force" solid ujoints for a whole 12.99! I am begining to wonder if the problem that i am having is because of the original struts being pretty much worn out. The car is very soft in the rear end and may the more rapid angle change when i launch is causing the premature failure of the ujoints. What do you guys think: A supersoft rear suspension letting the car "squat" to rapidly and killing the ujoints?? Myron Quote Link to comment Share on other sites More sharing options...
pparaska Posted November 1, 2000 Share Posted November 1, 2000 I know that Paul Ruschman went after this issue by raising his differential. After lowering the car, he put in full bump in the rear and determined that the u-joint angle was too extreme, so he raised the back of the diff. Seeing as raising the back of the diff also helps the driveshaft u-joint angle issue with most V8 swaps, I think it's a good idea to raise to back of the diff for both reasons. I used a modified version of the JTR method for doing this - I cut about 0.3" out of the length of the top urethane mustache bar bushing above the end of the M-bar, and a like amount out of the center sleeve. I also left out the top large washer that comes with that kit. These two changes raised the rear of the diff by about 0.45". It was enought to really help bring my driveshaft u-joint angles closer to being the same (and smaller at the rear u-joint) and it made the halfshaft angle less severe at full bump. I have the CV shafts, so that was less of an issue for me. Oh yeah, an added benefit was to allow more room under the back of the diff for exhaust clearance. I could raise the exhaust a bit and run it more to the center of the diff because of this mod. ------------------ Pete Paraska - 73 540Z - Marathon Z Project - pparaska@home.com">pparaska@home.com - Quote Link to comment Share on other sites More sharing options...
jeromio Posted November 1, 2000 Share Posted November 1, 2000 I am slowly acquiring the parts do to my rear rebuild. My question is, if the solid U's are $30 each (?) then that's $120 (4 joints) vs. $100 for the ZXt CV shafts (assuming this Clark place has more)! It's a 240, so I already have 240 stubs. (I also have the shafts from a 280, but not the stubs). Are the joints even easy to replace? I mean, should I factor in having a shop replace them (I have no press for instance)? That would bump the Ujoint cost up some more. Seems like the CV swap is going to obe cheaper and possibly even easier than rebuilding my existing shafts. Certainly more reliable and robust (I have a stock L28 now, but I'm looking for an L28t). Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted November 1, 2000 Share Posted November 1, 2000 quote: Originally posted by MYRON: What do you guys think: A supersoft rear suspension letting the car "squat" to rapidly and killing the ujoints?? Myron I can't see how your 'rate of squat' kills them. They're killed by either shock load or angularity. Many (not neccessarily on this list) setup suspension so it looks/measures perfect sitting flat w/ no driver under no load. For 1/4 mile/hard launches it should be idealized so on full load/squat the joints see as little angularity as possible. (ie. if they have 4 degrees rolling/minimal load big deal, it's under load at 0-1 degree we'd like to see). For the shock load I have no experience but two cars same setup and one can blow joints due to driver induced shock loads while other driver can bring it on 'smoother' and prolong the life of these shock-prone items, that's from feedback via serious drag racing friends I occasionally benchrace with. Raising or lowering the diff/xmember seems to be the easiest way or in combination with changing rear ride height as well to achieve this correct geometry. Same applies to roadracing, setting up for best geometry sitting flat with no load won't help on full kick corner exit where you want max tread planted/traction etc.... Now if only I had all the tools to accomplish this easily on my own:-(O) Good luck and keep us posted, I'm doing school 100% now and NEED to have some stories to live vicariously thru right now! Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted November 1, 2000 Share Posted November 1, 2000 Jeromio, that would $30/pair. I paid $16/ea for Neapcos and Myron paid $12.99/ea for Brute Force. ------------------ Scottie 71 240GN-Z http://www.mindspring.com/~vscott911/gnz.html Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 2, 2000 Share Posted November 2, 2000 Jeromio, I've just put new u-joints thru my half shafts just using a vice, hammer and drift. It's a slow fiddly job but not that bad if you don't rush it. I'd like to do the CV shafts but I either can't find any or you get screwed for crap by them that has them..... And I was up against a time constraint as I'm heading for the track this weekend. I like the welded plate/6 holes idea onto a 240Z companion though, if I ever do find some CV shafts for a fair price. My stubs are the larger 260/280Z ones so I'd retain those and use the existing companions. Can anyone see why that wouldn't work? As far as I can see it'd be the same as the 240 approach, just slightly different dimensions/splines on the parts. [This message has been edited by zedskid (edited November 01, 2000).] Quote Link to comment Share on other sites More sharing options...
jeromio Posted November 2, 2000 Share Posted November 2, 2000 Oh, $60 for the set. Dumb = me. So, it's cheaper to do the solid Us than CVs. But, when you say fiddling, is that like 2 hours of fiddling, or is it interminable? There's another Pick&Pull about an hour away that I need to check out. Hrm, new shafts from Carparts.com are $90 each..... Funny though, they've got unique entries for left and right, but identical part numbers. Seeing as how my total expenditure will be over $1000 for this rebuild (bushings, springs, shocks, diff, etc), I may as well kick in the extra scratch to do the CVs. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 2, 2000 Share Posted November 2, 2000 I guess the best way to solve my problem is the cv conversion. I've broken two now and I am affraid to launch it now. I will look into raiseing the back end of the diff. to. Would 75 lb. brakeaway for the lsd be good? Or should I leave it alone? Thanks for your replies. billy Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 2, 2000 Share Posted November 2, 2000 If you wanted to shorten the cv shaft. Why don't you take the shaft apart, cut the rod and then weld the rod to the joint or have it resplined? billy Quote Link to comment Share on other sites More sharing options...
pparaska Posted November 2, 2000 Share Posted November 2, 2000 Billyz, Breakaway torque: I asked the same question a while ago. Most people said to leave it in the stock range (~25-35 ft-lbs). Supposedly this is much better than having it snap in and out in a turn with more torque running through it with a higher breakaway. If you're dragging only, I guess it wouldn't matter much. Cutting/welding halfshafts: Not advisable. At that small a diameter, a weld has to deal with very high shear loads. A weld out at the diameter of the outside of a 280Z companion flange is less stressed, and it is longer to take the load. If you wanted to shorten the "stick" in a CV shaft, the way to do it would be to cut it and have it resplined. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 2, 2000 Share Posted November 2, 2000 O.K. I'll leave the brakeaway alone. Because I want to autocross it. I'll raise the backend of the diff. as much as I can and do the cv conversion. Should I cut 3 in's off? Or ? And have them resplined. Will I need a slide hammer to remove the axle flange or will it come right off after I remove the nut? Thanks again,billy Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 2, 2000 Share Posted November 2, 2000 Jeromio, it took me about 5 hrs. approx. to go from shafts out of car to shafts back in car, including hammering out/in the UJs. I'm not a pro mechanic, BTW, just a keen hacker... But I think that it'd be wise to do the CV shafts while you've got it all apart. By all accounts it's the strongest/smoothest way to go. I'd think the extra expense would be worth it. And not having to hammer UJs again, hell that'd be worth it alone.... Quote Link to comment Share on other sites More sharing options...
pparaska Posted November 3, 2000 Share Posted November 3, 2000 Just a half inch on the left shaft would be plenty. Actually, that and use the "stick" and outer joint from another left CV shaft and the inner joint from a right shaft in the right side of the car and you'd gain 1/2" of endplay there as well. ------------------ Pete Paraska - 73 540Z - Marathon Z Project - pparaska@home.com">pparaska@home.com - Quote Link to comment Share on other sites More sharing options...
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