Scottie-GNZ Posted July 25, 2000 Share Posted July 25, 2000 Any high-powered Z-car will eventually rip the diff off the stock mounts. Solid mounts is one fix and using a chain or plastic-covered steel rope is another. Both have their drawbacks. I recently swapped out my diff and finally got around to taking some pics of my solution that I pretty much took for granted because it is working so well. I think the pics are self-explanatory but I can answer any questions if there are any. I use a strip of 1/8" steel and it required 4 holes to be drilled and some minor welding which my welder refused to charge me for. Dont know about all the diff x-members but the bolts that hold the strap to my x-member were screwed into pre-drilled and tapped holes. What is nice about this solution is that the stock mount is still in place, cannot be ripped, the strap does not generate any harmonics and it has held up to rigorous strip duty. Hope someone finds this useful. Scottie Quote Link to comment Share on other sites More sharing options...
Guest Fast Frog Posted July 26, 2000 Share Posted July 26, 2000 Thanks, Scottie-GNZ!! I've been hearing some strange noises that are not characteristic of the normal Diff and mustache bar sounds. I've looked under where the strap is located and can see recent wear from Diff movement. I'm going to check out your solution!! [This message has been edited by Fast Frog (edited July 25, 2000).] Quote Link to comment Share on other sites More sharing options...
Andrew Bayley Posted July 26, 2000 Share Posted July 26, 2000 Just out of curiosity, What have the “normal†diff and moustache bar sounds been? I finally switched over to the Motorsport solid diff mount (something I should have done long ago) and I picked up a lot of old noises that I USED to contribute to bearing and gear wear. I’m really going to kick myself if it was the old rubber mount the whole time. On the old mount the rubber eventually split apart, and I think the upper metal (diff) part of the mount was rubbing on the cross member. Either that or I’ve just blown through a THIRD R200. Has anyone experienced a “grinding†noise while cruising at higher speeds (+60 mph) with the driveline slacked (not loaded or unloaded). This noise is driving me crazy. It seems to get worse as the car warms up, especially worse after a ¼ mile run. Feel free to shout out any ideas or suggestions. -Andy P.S. Way to improve the stock diff mount Scottie! Now if you could only improve the actual diff itself… Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted July 26, 2000 Author Share Posted July 26, 2000 Andrew, with that solid mount in place it will be difficult to determine what noises you are hearing as every noise is being transmitted through the chassis. What I might suggest is replacing the solid mount with a standard rubber mount just to help you determine what the problem is. As for the diff itself, it just seems like you have bad luck. The diff itself is a very strong unit and as I have stated several times, the 10-sec GNZ has over 200 passes on his and 700hp 300ZXT had problems with the stub axles but never the diff. It is very likely that when we pick up a 20+yr diff, the damn thing could have the original lube in it. ------------------ Scottie 71 240GN-Z http://www.mindspring.com/~vscott911/gnz.html Quote Link to comment Share on other sites More sharing options...
Guest Fast Frog Posted July 26, 2000 Share Posted July 26, 2000 AB: I attribute "normal" Diff noises to aging Diff mount and old run down mustache bar bushings; plus any other squeeks and noises coming from the rearend. My '76 383Z is in super shape for a 25 yr old car and it's been garaged all of its life, but time and use still erode stock rubber bushings and mount rubber. I've not changed any of the rearend rubber since buying the car new in late '75. I've grown intimately familiar with all of its squeeks, thumps, and groans. When I accelerate hard, I can hear a slaping/clunking sound which I attribute to the aging and probable weakness of the whole Diff mounting sys. I had the same kinds of sounds but less intensive when restoring my son's '76Z with a stock engine. While changing out the stock springs and rotting brake hoses, we also installed new a Diff mount, both mustache bar bushings, and Diff strap. Now, all is quiet at the rearend!! I probably need to do the same thing to my '76 considering that I'm running 3 to 4 times the HP. Quote Link to comment Share on other sites More sharing options...
Guest needwaymorespeed Posted July 27, 2000 Share Posted July 27, 2000 Ive heard several times of the stub axles or half shafts breaking and the rearend is still great. does anyone know what the stub axles are made out of-metalurgically-wondering because im going to instll the cv joint hafshafts"thanks pete great tech article" and want to have the stub axles magnafluxed and heat treated first was going to run the stock 240 z stub axles dont want to run an adapter- but if the 280s are realy that much stronger maybee ill have to- andy how bout the r230 rear end its 9 in diamet ring gear-super strong-found in the q 45s and 90-96 300 z-they both have posi-viscous-just have to figure out the half shafts- Curtis Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted July 28, 2000 Author Share Posted July 28, 2000 Curtis, the stub axles and halfshafts are the main problem. What I am about to say is my opinion only and I am sure some folks will refute it. As stated in several articles, you want to use the 280Z stub axle and companion flange. All the stubs axles have the same dimensions except the splined area, the weak point. You can fit a 280Z companion flange over the 240Z stub axle splines without the parts touching. If the 280Z stub axle is magnafluxed and certified OK, it can take a lot of abuse. The standard halfshaft is also a very strong unit (I use the 280ZX units) and just about every one I have seen broken has been the result of the u-joint letting go and destroying the u-joint holders. I made my own CV adaptor and have the CVs ready to go but I am currently running the halfshafts with solid u-joints. I plan on seeing how far these can take me. They may break tomorrow but I fully expect to get into the low-11s or even hi-10s with them. Having said all of that, if you are starting from scratch and have the scratch , then follow Pete's advice and get the 280Z stub axle set, the 280ZXT CVs and some sort of adaptor. Unless you are running a monster SBC with slicks, I just do not think you need anything bigger than the R-200. Derek Grubb has proved that. ------------------ 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 July 28, 2000 Share Posted July 28, 2000 I like the diff strap idea Scottie. But a qu. on CV 1/2 shafts - I know its been asked before but it still doesn't click for me. I'm planning the CV mod, without an adaptor, but then my HP is a lot lower than a lot of you guys (I'm @ about 300 h.p., no slicks). When you run the "no adaptor" setup, 240Z stubs, the CVs are heavily compressed, and I'm told there's adequate (but not a huge amount) of travel left. When you run an adaptor setup, you're obviously using even more of this travel in the CV. My question is, I gather there's more room in the CV joints to slide than you might otherwise think? Must be so, otherwise them that's done it wouldn't be able to get it to work.... [This message has been edited by zedskid (edited July 27, 2000).] Quote Link to comment Share on other sites More sharing options...
pparaska Posted July 28, 2000 Share Posted July 28, 2000 zedskid, let me try to clarify this. Hit the links on the tech article page to see pictures of the companion flanges to help see what's going on. The 280Z (and 240Z) companion flanges are the short ones that bolt to the u-joint half shafts. The 280ZX Turbo companion flange is much longer. If you have but 300 hp, I'd think the 240 stub axles and 280ZX Turbo companion flanges would be fine. Then you don't need an adapter, but need to modify the 280ZX Turbo companion flanges (dust seal swap as noted on my tech article) and machine the outer rubber off of two R200 pinion seals to use as inner stub axles seals. Hope this helps, ------------------ Pete Paraska - 73 540Z - Marathon Z Project - pparaska@tidalwave.net">pparaska@tidalwave.net - Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 28, 2000 Share Posted July 28, 2000 Click!! (sound of light going on....) That's the bit that I hadn't latched onto - the comparative length of the 280Z & 280ZX companions..... Now I see why there's room for the adaptor w. the 280Z... d'oh!!! The rest of it I'd appreciated but not that... now all I have to do is to find some shafts - not an easy task; not a lot of the ZXs came to our humble shores.... Thanks again Pete. Quote Link to comment Share on other sites More sharing options...
clint78z Posted August 9, 2000 Share Posted August 9, 2000 Simple yet effective I like it, sounds like the new motor is showing you all the weak links . PS I just got my intercooler modified, they TIG welded and blended the tanks, it looks awesome !! Quote Link to comment Share on other sites More sharing options...
Guest Fast Frog Posted August 9, 2000 Share Posted August 9, 2000 Welcome to the forum Clint!! I think you're the one I sent my Calmap 30lb injector floppy disc too a few weeks ago. Is that right? If so, I hope the info on the disc was helpful!! Rick Quote Link to comment Share on other sites More sharing options...
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