rossman Posted January 29, 2011 Share Posted January 29, 2011 (edited) Is it me or does the RT mount bolts on dsommer's 240 look higher than on Woj's 280? If it's true then that could be the difference. Edited January 29, 2011 by rossman Quote Link to comment Share on other sites More sharing options...
NewZed Posted January 29, 2011 Share Posted January 29, 2011 Thoughts and questions - did you make the mount yourself or buy it? And to confirm, you have a 280? And you're running the stock L6 and transmission? Just wondering, I'm not even sure what car you have. Might be some good feedback to the builder, maybe 280s are slightly different. The original RT mount design was for the V8 conversion, I believe, and it was designed to lower the front of the diff to get the pinion shaft on the same plane as the transmission shaft, if I recall correctly. So the comments about getting your angles right are pointed at avoiding vibration when you're done, your shafts won't be on the same plane anymore. What some people have done (quite a few over on Classiczcars.com) is to keep the lower mount,then use a pinion snubber on the RT mount instead of the ES 3-1108. Typically they trim the snubber so that it barely touches or has a slight gap. This avoids tying the diff in too tight and getting vibration. It seems to work for those that have used it, and lets you keep the original pinion shaft angle, but accomplishes the goal of holding the nose of the diff down. Plus you you don't have to worry about grinding your cross member. Quote Link to comment Share on other sites More sharing options...
The Woj Posted January 29, 2011 Author Share Posted January 29, 2011 (edited) Is it me or does the RT mount bolts on dsommer's 240 look higher than on Woj's 280? If it's true then that could be the difference. I don't know about that, but what I did just notice is that his diff crossmember is different than mine. It does not appear to have a hump in the tranny tunnel area (that sounded really weird). This is on my 240Z, it's a late '73 though. Edited January 29, 2011 by The Woj Quote Link to comment Share on other sites More sharing options...
The Woj Posted January 29, 2011 Author Share Posted January 29, 2011 Thoughts and questions - did you make the mount yourself or buy it? And to confirm, you have a 280? And you're running the stock L6 and transmission? Just wondering, I'm not even sure what car you have. Might be some good feedback to the builder, maybe 280s are slightly different. The original RT mount design was for the V8 conversion, I believe, and it was designed to lower the front of the diff to get the pinion shaft on the same plane as the transmission shaft, if I recall correctly. So the comments about getting your angles right are pointed at avoiding vibration when you're done, your shafts won't be on the same plane anymore. What some people have done (quite a few over on Classiczcars.com) is to keep the lower mount,then use a pinion snubber on the RT mount instead of the ES 3-1108. Typically they trim the snubber so that it barely touches or has a slight gap. This avoids tying the diff in too tight and getting vibration. It seems to work for those that have used it, and lets you keep the original pinion shaft angle, but accomplishes the goal of holding the nose of the diff down. Plus you you don't have to worry about grinding your cross member. This is Roostmonkey's mount, which I purchased about a year ago. It is a '73 240Z which is going to be running a Ford 5.0 with a T5 someday. I have not even mocked the engine or tranny, though the mounts have already been fabricated (by the infamous JohnC no less!) - so I am not sure what the angles are going to look like. Perhaps I will look into this pinion snubber, I was actually looking at the first picture I posted and it appears that the diff in that one is also touching the mount. Quote Link to comment Share on other sites More sharing options...
NewZed Posted January 29, 2011 Share Posted January 29, 2011 Thanks for the info on the car. Looks interesting. I had a faint memory about an old Roostmonkey post so searched and found his Vendor's Forum thread. A lot of what's been discussed here was talked about then. Worth a browse - http://forums.hybridz.org/index.php/topic/85384-rt-mounts-are-ready-for-shipping/ Quote Link to comment Share on other sites More sharing options...
The Woj Posted January 29, 2011 Author Share Posted January 29, 2011 (edited) Thanks for the info on the car. Looks interesting. I had a faint memory about an old Roostmonkey post so searched and found his Vendor's Forum thread. A lot of what's been discussed here was talked about then. Worth a browse - http://forums.hybridz.org/index.php/topic/85384-rt-mounts-are-ready-for-shipping/ After reading this thread, I have realized that the pinion snubber is not going to accomplish what I want it to - which is doing away with the stock rubber mount. But, he does mention that the ES mount needs to be sanded in order to contour it to the top of the diff, which I did not do. This seems to be inline with what dsommer did also, though I still hold that dsommer's crossmember (from an earlier 240z?) is lower than mine - perhaps finding an earlier crossmember might help? Dsommer: any idea what year your crossmember was from and whether or not it was flat across the top or had the ridge that is circled here: Edited January 29, 2011 by The Woj Quote Link to comment Share on other sites More sharing options...
Nigel Posted January 29, 2011 Share Posted January 29, 2011 I have an RT mount in my '73 240Z L28 Turbo. It fit with no problems. I did not use the stock lower mount (complete waste of time IMHO). All I did was to install the bolts from the bottom up, with no washers under the bolt heads, and no washers or spacers between the poly mount brackets and the diff. I did notched the poly bushing for the correct pre-load. My crossmember looks just like the one in the picture above, and I did not have to notch the crossmember. The bolts heads have never hit the crossmember under deceleration. I've had it in the car for several years now. Nigel '73 240ZT Quote Link to comment Share on other sites More sharing options...
dsommer Posted January 30, 2011 Share Posted January 30, 2011 (edited) The dif mount is from a 280z, I used it during the R-200 swap years ago. The car is a 72 year model. When you do an R200 swap you should get all the parts, I heard that so many times (insert broken record) so that's what I did. As we move toward modifications and custom parts we must remember what was initially published on this site (member since 2000 and before when it was v8zcars or something like that) Edited January 30, 2011 by dsommer Quote Link to comment Share on other sites More sharing options...
zgeezer Posted January 31, 2011 Share Posted January 31, 2011 The dif mount is from a 280z, I used it during the R-200 swap years ago. The car is a 72 year model. When you do an R200 swap you should get all the parts, I heard that so many times (insert broken record) so that's what I did. As we move toward modifications and custom parts we must remember what was initially published on this site (member since 2000 and before when it was v8zcars or something like that) I have the RT mount in my Series 1 240z, Mounted it with the bolt head on the bottom, washers on both ends of the bolt and no clearance problem with the stock xmember. I also ground down the poly to fit the R200 nose as was described above. G Quote Link to comment Share on other sites More sharing options...
The Woj Posted January 31, 2011 Author Share Posted January 31, 2011 I have the RT mount in my Series 1 240z, Mounted it with the bolt head on the bottom, washers on both ends of the bolt and no clearance problem with the stock xmember. I also ground down the poly to fit the R200 nose as was described above. G It sounds like the solution to my problems is to drop the diff and grind the center out of my ES mount, then. I guess I need to line up my drivetrain first though. Quote Link to comment Share on other sites More sharing options...
wrcbonk Posted January 31, 2011 Share Posted January 31, 2011 I just got done going through the same issue. I installed a R200 using the R/T mount into my 1971 240. I ended up notching my cross member as well. I ended up with a gap between the bottom of the diff and the top of the cross member of about 1/2-inch. I did as others and filed down the bottom of the poly isolator to conform to the shape of the front of the diff. I will be installing a RB25 transmission, hopefully my angles are good. If not I will have to space things differently. Bonk Quote Link to comment Share on other sites More sharing options...
The Woj Posted February 4, 2011 Author Share Posted February 4, 2011 (edited) As a followup on the above issue. I removed my ES mount: Pulled out my trusty orange HF angle grinder and did this: And, I have lifted the nose of my diff this much: Edited February 4, 2011 by The Woj Quote Link to comment Share on other sites More sharing options...
sweetride2go Posted February 5, 2011 Share Posted February 5, 2011 That's what I did to mine too Woj, and I don't have a clearance issue... I used a grinder, and it wasn't near as messy as I thought it was going to be... Cheers Quote Link to comment Share on other sites More sharing options...
duragg Posted July 25, 2012 Share Posted July 25, 2012 Aaaah Geez that was a job. Installed my Technoversions RT Diff Mount and Energy (interlocking) mount. Beautiful product, superb response to all my questions from the proprietor. My 240 was about .125" more narrow than the top part of this mount so the install took a lot lot lot of BEATING to get that sucker in. Nothing more than sheer will and crashing hammer blows got all the holes lined up. I should have just taken it out and beat on the tunnel~ but once I got it up in there I couldn't get it out and I was in a hurry and I am a hack anyways, so. I also chose to relieve a little of the rubber from the mount to fit the shape of the thing a little better: Based on my historical averave, this will probably turn out to be a big mistake. But for now... its done. New driveshaft comes back tomorrow and I can finally burn that solid mount into a pile of molten... Quote Link to comment Share on other sites More sharing options...
duragg Posted July 29, 2012 Share Posted July 29, 2012 While I did not have to notch the lower mount (yet), I did have to adjust the sway bar mounting. My sway bar comes forward from the A-arms and winds around right under the rear driveshaft u-joint and it was hitting with suspension at full droop. Due to the geometry it probably wouldn't have hit while driving, but I raised the rear mount arm points which lowered the very front part and gave extra clearance. My car still shakes like a mo-fo above 60 so I will continue the hunt... Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted July 29, 2012 Share Posted July 29, 2012 duragg-is there an aligment shop that you can use to have your tires "true-ed?" It takes a special machine and not all shops have it. I had same problem on my daughter's jeep and truing her tires solved her speed-related shaking. I had replaced the shocks, had wheels rotated and balanced, replaced one rim, had alignment done, and replaced the steering dampner. It was a simple fix and was like magic-smooth as silk now. Quote Link to comment Share on other sites More sharing options...
duragg Posted July 29, 2012 Share Posted July 29, 2012 Yes. A good digital shop. But I don't remember it this bad before the 4.375 r200 swap. Granted the driveshaft is spinning faster now. My 15x10 rims will be here soon so I hate to invest money now. Tempted to put car on my beefy stands with rear tires removed and lug nuts tightened back on drums. Start car and let clutch out in 5th and raise rpm to 4000 and if it still buzzes the tires are ok. Quote Link to comment Share on other sites More sharing options...
SUNNY Z Posted August 16, 2012 Share Posted August 16, 2012 But I don't remember it this bad before the 4.375 r200 swap. Granted the driveshaft is spinning faster now.... How? The input speed to the diff will not change unless your transmission ratio changes. The only thing that will change is that your driveshaft might have more rpm at say, 60 mph, than it did at 60 mph with your numerically lower gears. If you're getting a vibration, I would look at the pinion angle of your diff, and the working angles of your driveshaft. That can cause a whole bundle of headaches. Quote Link to comment Share on other sites More sharing options...
Leon Posted August 16, 2012 Share Posted August 16, 2012 The only thing that will change is that your driveshaft might have more rpm at say, 60 mph, than it did at 60 mph with your numerically lower gears. Right, I think that's what he's getting at. Quote Link to comment Share on other sites More sharing options...
nissun1 Posted January 30, 2013 Share Posted January 30, 2013 Solutions? Quote Link to comment Share on other sites More sharing options...
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