8 posts
1986 300ZX 2D Coupe
Centennial CO
4-30-2008
Vibration!!!
11:06 PM 4/30/2008
New guy to NICO, new guy to the 300Z! I recently purchased an '86 2door coupe with ~116K miles on it. Body's in great shape, interiors in great shape, a couple nit noid issues but one possible biggie! At highway speeds of 60-85mph I get this real bad vibration that seems to be coming from the rear diff area. Just so you know...theres brand new tires with balancing, wheels are NOT bent, 4 wheel alignment just done yesterday and camber was out very minimally. However, none of those things have gotten rid of the vibration. I'd heard that the older Z's sometimes suffered from rear end issues but what are the causes? I've looked at the CV boots for breakage to see if contaminants may have gotten to the CV joints but everything is rock solid and no leaks or wholes...can anyone help me out? evildky...you seem to be everywhere in this forum and appear to be very knowledgable...got any clues for this first time Z owner?
how are the U-joints in the driveshaft? could also be a balance issue with the driveshaft, but I'd start with the mounts, the front diff mount (pinion mount) is more prone to failure than the rear mount
"if I had all the money I ever spent on cars........I'd spend it all on cars" 12.378 in a rusty datsun with a sliping clutch "The Rusty Mistress" 299.3 whp and 305 lbft TQ, 2105 lbs I'm cleaning out my garage, lots fo Z parts, S30, Z31 and Z32 here is my ebay listing http://motors.search.ebay.com/_W0QQsassZevildky if you're looking for something shoot me an e-mail, evildky@bellsouth.net
The Ujoints "seem" solid/sound but now that you mention it I have notice a slight squeak in first gear that increases as speed increases but does go away after the revs get up...could be. I've already ruled out the rear wheel bearings as there is no play at the hub with the wheel on and under no load...I think I'll start with the Ujoints and go from there. Thanks for the input!
evildky: I've been doing some reading on the drive shaft/u-joints type work and came across a statement in Chiltons that states that 1975 and later models u-joints can NOT be replaced and that if the u-joints are bad, the entire drive shaft has to be replaced? Is that right?
actually it applies to all 70-78's. they are press fit, a good driveshaft shop or machine shop cna still replace them but it's very labor intensive and likely cheaper to replace the driveshaft
"if I had all the money I ever spent on cars........I'd spend it all on cars" 12.378 in a rusty datsun with a sliping clutch "The Rusty Mistress" 299.3 whp and 305 lbft TQ, 2105 lbs I'm cleaning out my garage, lots fo Z parts, S30, Z31 and Z32 here is my ebay listing http://motors.search.ebay.com/_W0QQsassZevildky if you're looking for something shoot me an e-mail, evildky@bellsouth.net
Delayed revisit to this post...I've had my car checked out (professionally) by a couple different shops and they all tell me the rear wheel bearings are good, drive shaft/ujoints are good and balanced, etc. I've had the wheels and tires (tires are new with very little weight) balanced 2x and the wheels independently spun without tires to look for bent wheels...nothing bent. Oh yah, I had a 4 wheel adjustment done as well and the rear wheels are within camber allowances. I'm at a loss here as I honestly cant figure out what may be going on. I've changed all the fluids to fully synthetic as well and cleaned the diff and tranny of any and all metal shavings (there was very little) with no affect. I dont get any vibration in my feet or in the gear shift. The vibration is most notable in 5th gear when speed is =or> 70mph. However, I have also noticed that there is a slight vibration in 3rd gear around 2500-3200 rpm. The car has 120k on it but it really drives like its near new and I would like it to be at its best, e.g. more than just a daily driver.
evildky...do you have any, any ideas? For that matter, has anyone else out there run into this type of problem? Any and all possibilities considered so please feel to respond!
front and rear diff mount might let the diff set at an off angle causing vibration? rear crossmsmber bushings can allow the whole rear to move whihc could cause vibration, it everyhing is solid and balanced then I guess the next items to check would be the trans outut shaft bearing, diff input and output bearings
"if I had all the money I ever spent on cars........I'd spend it all on cars" 12.378 in a rusty datsun with a sliping clutch "The Rusty Mistress" 299.3 whp and 305 lbft TQ, 2105 lbs I'm cleaning out my garage, lots fo Z parts, S30, Z31 and Z32 here is my ebay listing http://motors.search.ebay.com/_W0QQsassZevildky if you're looking for something shoot me an e-mail, evildky@bellsouth.net
lol, sorry, closest I an think of would be Ultimate Z in IL, have you check with your local Z club? (zcca.org) I must say I don nto recomend dealers for older cars, chances are the tech working on your car has never worked on one before, any good import chop will be as good or better than the dealer
"if I had all the money I ever spent on cars........I'd spend it all on cars" 12.378 in a rusty datsun with a sliping clutch "The Rusty Mistress" 299.3 whp and 305 lbft TQ, 2105 lbs I'm cleaning out my garage, lots fo Z parts, S30, Z31 and Z32 here is my ebay listing http://motors.search.ebay.com/_W0QQsassZevildky if you're looking for something shoot me an e-mail, evildky@bellsouth.net
okay, I've really got no idea what would do it, have you looked at your shocks? The Struts could be worn perhaps allowing for wheel hop at higher speed. I dunno just a guess. Are there any problems with your half shafts or hubs? Perhaps they one time lost a wheel and hit the hub hard enough to bend it. Again just a guess.
EvilDKY probably has the best guess in the Diff mount, or driveshaft out of balance.
tks for the feedback. The shocks are new and I've had the tires pulled off the wheels and had the wheels spun to see if they're bent...no bent wheels. Hubs are in great shape...no scuff marks anywhere on the circumference of the hub's either. All 4 tires are new and each wheel/tire took less than 1.5 ounces to balance them. I did get lucky today though. One of the Nissan dealers here in Denver that I hadnt ever done business with actually has an older technician in their shop that was on a local race team that ran 300z's. He went on a test drive with me today and told me that he needed to get it on the lift, but thought I had a combination of a driveshaft/ujoint issue and a bearing issue in the diff. We'll see...I have an appointment with them and we'll go from there. I also found out today, through evildky's link to the zcca.org website that the local Z club still has racing events here in Denver. They have an arrangement with the Colorado State Patrol to use their training track for club members to race on. Not sure I'd put my girl through it, but it might be worth exploring!
awesome, your local clubs are a great resource for parts, information and socializing, I'm going bowling with my local club this weekend
"if I had all the money I ever spent on cars........I'd spend it all on cars" 12.378 in a rusty datsun with a sliping clutch "The Rusty Mistress" 299.3 whp and 305 lbft TQ, 2105 lbs I'm cleaning out my garage, lots fo Z parts, S30, Z31 and Z32 here is my ebay listing http://motors.search.ebay.com/_W0QQsassZevildky if you're looking for something shoot me an e-mail, evildky@bellsouth.net
I have that same vibration in my car. I say the problem is in the diff. Because I broke whatever is causing the vibration when I was drag racing. I launched really hard, and I could feel the diff getting pissy behind me. After that run, I had the vibration. Strongest for me in 3rd and 5th gears for some reason... I didn't get above 3rd though (1/8th mile tack).
I haven't bothered to take everything out to try fixing it since I'm planning to get a drivetrain from a Shiro and swap it all out. But when that happens, if you still are having the problems, I'll take the diff apart to see if I can figure out what I broke.
sorry for the delayed response...was out of town for the 4th weekend!
Its funny you mention 3rd and 5th gears...thats exactly when I notice the vibration is worse or at least more noticeable! However, I was just tooling down the interstate when it all started.
bigred240sx...tks for the input...all bolts are there and tightness is to spec (torque setting). I pulled the rear hubs/wheel bearings this weekend...thats a job!...races, bearings, and grease were all in great shape.
Does anyone out there have a service manual for the 86 Coupe (na)? I would be interested in knowing if there were any such problems noted "back-in-the-day"...that they wouldnt mind looking for any related problems?
3rd and 5th gear vibration is most ikely in the trans, they share a shaft and bearing
"if I had all the money I ever spent on cars........I'd spend it all on cars" 12.378 in a rusty datsun with a sliping clutch "The Rusty Mistress" 299.3 whp and 305 lbft TQ, 2105 lbs I'm cleaning out my garage, lots fo Z parts, S30, Z31 and Z32 here is my ebay listing http://motors.search.ebay.com/_W0QQsassZevildky if you're looking for something shoot me an e-mail, evildky@bellsouth.net
Turns out the vibration was happening as a result of a bent driveshaft. I finally got the car on a lift and they spun her up in speed while up in the air. Shaft was visibly non-concentric in its rev's! I guess I need to buy and build my own lift...
So, I managed to get a new "steel" shaft with replaceable and serviceable u-joints for $219.00, shipping included...from wholesaleimportparts.com. Of course Nissan had an OEM for $685! (There are only two left in the entire Nissan inventory for an 86 Coupe N/A). The shaft weighs in at 12lbs...which is really light for steel, shaving approximately 17lbs from the original. Thats actual as I weighed it once it was pulled)! You can definitely tell the difference as the car seems to get speed much easier...an has no vibration whatsoever!
Thanks to all for the ideas and help...especially evildky...your knowledge is obvious!
gald you got it worked out, I've sufferend abotu every known failure, so I know lots of places to look
"if I had all the money I ever spent on cars........I'd spend it all on cars" 12.378 in a rusty datsun with a sliping clutch "The Rusty Mistress" 299.3 whp and 305 lbft TQ, 2105 lbs I'm cleaning out my garage, lots fo Z parts, S30, Z31 and Z32 here is my ebay listing http://motors.search.ebay.com/_W0QQsassZevildky if you're looking for something shoot me an e-mail, evildky@bellsouth.net
