I'm so relieved.

[GrayZ]

Originally Posted by rhipsher

I've had a vibration problem coming from the rear of my 90 Z for the past 1 1/2 or so and it's bugged the hell outta me as some of you already know. I've tried swapping the tires. No luck. I've replaced the rear wheel bearings. No luck. I've had a four point aligment done. No luck. Checked all of my bushings. Nothing loose. No luck. It's been bad enough that I couldn't even look out my rear view mirror because it shook so bad. I don't care how fast the car is it got to the point where it was no longer fun to drive anymore because above 60mph it felt unsafe. So I decided thats it I'm going to find and fix this problem if it kills me. I've taken this car to 179mph many times and now I can't even take it above 60mph? F that. And I found it and fixed it today damn it. It was my fault all along. A total rookie mistake that I can't believe I made. But it was something I had suspected all along. The last time I replaced my throwout bearing/fidanza and clutch disk I installed my drive shaft 180 degrees out. And let me tell you something! That makes all the difference in the world. When I spun the wheel by hand and watched the drive shaft I swear it looked like it had 1/8 in run out. When I rotated it 180 and bolted it back together and spun it by hand again it ran totally true. The shaft and the ujoint rear diff already had white paint on them to mark proper orientation and I swore I installed it right. I must have been in a rush. But it runs totally smooth now. No vibration or roaring noise. I felt like slapping myself over that one.

Glad to hear you found you're problem. I was wondering, What mods have you done to your car?? I'm assuming it's a 415 ?? Not to many of our Z's are able to leg out, much over 166, unless highly modded. Always good to compare notes.

[WVZR-1]

You might need to explain exactly your "rotation"! If you only changed the relationship of the rear joint to the pinion flange you changed "nothing" in relation to the drive-shaft and that seems to be what you imply here.

The only explanation in this case would be that the balance of the pinion flange isn't correct. If your pinion flange is an original it would have a sheetmetal deflector that would have a weight on it. I've heard of the pinion flange being balanced with a drive-shaft assembly but I've never done it or actually seen it done.

NOW if you removed the slip-yoke from the drive-shaft and rotated it 180* you certainly would have effected balance.

It would seem to me that there was more likely an install error the previous install or maybe one of the tangs on the pinion flange has been compromised and allowed the u-joint to be secured off center!

There's one simple remaining fact though, if you "saw what you explain here" the drive-shaft needs to be removed one more time and checked for balance and the run-out you explained.

It certainly shouldn't see "speed" until it's verified!

[rhipsher]

I don't want to over anylize it because it makes perfect sense to me. Its pretty simple. It works one way and not the other. When I ran top speeds in it, it was aligned just like I have it now. As far as ZR-1 not going past 166mph I have to laugh because even the data on this site shows them going between 175 to near 180 factory. My car dyneod at 342rwhp@336ft lbs tq at Coreys. Nothing special and I hit 179mph pretty easily. I have the video to prove it. I posted the video on here a couple of years ago. I thought everbody had seen it but I guess not. My car is no where near a 415. I guess not many guys on this site have tried it.

[Paul Workman]

Originally Posted by rhipsher

My car dyneod at 342rwhp@336ft lbs tq at Coreys. Nothing special and I hit 179mph pretty easily. I have the video to prove it. I posted the video on here a couple of years ago. I thought everbody had seen it but I guess not. My car is no where near a 415. I guess not many guys on this site have tried it.

I got up to 145 before vibration caused my dash and gear shift to "buzz". (Had to "180" my driveshaft and reinstall it to fix it!)

So, my friend...I think we're in "violent agreement". Come shoot some competition rifle matches w/ me and we can talk about concentricity, runout, and match case preparation.

Dayam! Is it spring yet??

P.

[rhipsher]

I would love to do that Paul. You'd probably kick my but at it.

[GrayZ]

Originally Posted by rhipsher

I don't want to over anylize it because it makes perfect sense to me. Its pretty simple. It works one way and not the other. When I ran top speeds in it, it was aligned just like I have it now. As far as ZR-1 not going past 166mph I have to laugh because even the data on this site shows them going between 175 to near 180 factory. My car dyneod at 342rwhp@336ft lbs tq at Coreys. Nothing special and I hit 179mph pretty easily. I have the video to prove it. I posted the video on here a couple of years ago. I thought everbody had seen it but I guess not. My car is no where near a 415. I guess not many guys on this site have tried it.

Rhipsher, to anwser you're question, No, i did not see the video, and i'm not calling you out, although the nonchalant way you stated you've been to 179 mph many times, did make me smile so now that we both have had a nice giggle, WOULD You mind, reposting the video of you going 179mph..cause i'd like to show my friends that make comments at the bar, a video to back up my proud ZR1 boasts,
At the Nellis mile shootout, I went to, most 350 ci ZR1/s ran around 155/160 mph top speed, Demps yellow car, modded exactly like mine at the time, ran 166, ergo the number, my car was modded by m. Haibeck, it dyno'd 424 rwhp. (I have the dyno sheet to prove it).lol.. I have had "Oprah" to 162 mph, Ted Feder's lightly modded car ran 162, all i'm saying is you must of had plenty of room, to get you're car to 179.... in my neck of the woods we don't have the place, to allow us to stretch her legs so to speak. The Morrison world record run, also ran In Texas, was on a test track in Stockton, under controlled environment, with plenty of road to get up to speed. I know that anyone that has a video of themselves running that fast would cherish it forever, I would, so please re-post it, I would really appreciate it.

[rhipsher]

Originally Posted by ITLGO2

Rhipsher, to anwser you're question, No, i did not see the video, and i'm not calling you out, although the nonchalant way you stated you've been to 179 mph many times, did make me smile so now that we both have had a nice giggle, WOULD You mind, reposting the video of you going 179mph..cause i'd like to show my friends that make comments at the bar, a video to back up my proud ZR1 boasts,
At the Nellis mile shootout, I went to, most 350 ci ZR1/s ran around 155/160 mph top speed, Demps yellow car, modded exactly like mine at the time, ran 166, ergo the number, my car was modded by m. Haibeck, it dyno'd 424 rwhp. (I have the dyno sheet to prove it).lol.. I have had "Oprah" to 162 mph, Ted Feder's lightly modded car ran 162, all i'm saying is you must of had plenty of room, to get you're car to 179.... in my neck of the woods we don't have the place, to allow us to stretch her legs so to speak. The Morrison world record run, also ran In Texas, was on a test track in Stockton, under controlled environment, with plenty of road to get up to speed. I know that anyone that has a video of themselves running that fast would cherish it forever, I would, so please re-post it, I would really appreciate it.

No problem. Here you go.http://s301.photobucket.com/albums/n...llyfast005.flv

Freakin AWESOME..........you are da man!

[Dynomite]

Originally Posted by Paul Workman

Come shoot some competition rifle matches w/ me and we can talk about concentricity, runout, and match case preparation.

Dayam! Is it spring yet??

P.

You sound serious....I am just a jack of all and master of none when it comes to the Z mechanics or loading ammuniton. I do get 3/8 inch groups shooting 55 gr sp with 35 grains of 748 in my 22-250 Savage model 12

Chronographed at 3,500 fps

[USAFPILOT]

It does take more than a mile to get to 180!