1977, 280z with FS5W71B transmission

[240zadmire]

Took the rear wheels off.  Adjust the drum brakes a bit tighter.  Wire brush the inside stubs where they meet the drums as well as the wheel where they meet the drums.  Took for spins and still have that vibration around 80mph

I also checked all nuts on the joints for play and everything are tight.

 

the nuts I’m using look like below 

 For sure the old turbine wheels, the the holes for the nuts are a hair tighter/smaller.

 

what else can there be?

[Yarb]

Have you rotated the tires to the front?

[240zadmire]

1 hour ago, Yarb said:

Have you rotated the tires to the front?

Ah, will try that next.

[Zed Head]

That rim looks a bit used.  Aluminum wheels can bend also even though they often break.  I'd lift each wheel, set up a runout indicator next to it and give it a spin.  A runout indicator can be just a screwdriver sitting on a cinder block.

The guy that balanced them should have noticed something but might have had old equipment.

[240zadmire]

Took your suggestions…. The run off from center tread is about 1/32nd uneven on all wheels.  Rotate front/back, left/right still have vibration.  I narrow down to the right rear wheel case the most vibration.  
 

one note, I didn’t replace the wheel bearings when I restore the car.  I tried to shake the wheel by hand, kicking the tires and seem very sturdy.

 

another note is that no vibration when accelerating.   I’m able to accelerate to 90mph in the morning when traffic was really light and no vibration while accelerating.  As soon as I put in neutral or decelerating, the vibration begins until below 70mph.

 

I did check all nuts, halfshafts, drive shaft, all bushing, basically all bolt and nuts under the suspension and all are tight.  
What’s the deal?

[Zed Head]

On 5/23/2022 at 3:16 PM, 240zadmire said:

I've put about 400 miles on the new re-built close-ratio transmission.

 

On 5/23/2022 at 3:16 PM, 240zadmire said:

couldn't pass on a good deal on the set of mag wheel.

 

On 5/23/2022 at 3:16 PM, 240zadmire said:

I swapped fairly new tires set.  About maybe 4000 miles on it.

Did you do these three things at the same time?  Maybe there's a problem with the transmission, not the rims or tires.

Or maybe something got bent when the car was lifted to put the wheels on.  If you used the rebuilt transmission with the old wheels and didn't have the problem then you can narrow it down to what happened when the wheels were put on. 

Since it worked well before it is most likely a problem that was created when the recent work was done.  Don't get distracted by other things.  Look at the work that was just done.

[240zadmire]

When I swapped the transmission, the car was on wood blocks and the head of the pressed 😉. Basically it was on high evenly with the wheels intact.  I don’t think i bent anything, but who knows I might screw up somewhere. 
 

Granted I didn’t have a lot of miles on the new transmission with the old wheels, but I didn’t notice anything so vibrating like this.  You can say I’m one of the guys noticing weird stuff.  I’m very sensitive about/around my surrounding area. 😉. It’s a gift/curse some might say. 
 

last night I craw under the car again, trying to shake the driveshaft, check all bolts/nuts and they all seem sturdy.  No play.  What I notice is the transmission mount under the shifter is a bit “movable”  I think it should be like that to compensate the engine vibrating.  Unless the rubber is weak and about to give out, I think it’s should be like that.

 

another thing I read that the trap for the differential might be too loose… mine is about 1/4” gap, so I tried hard to put a spare rubber hose between the differential nose and the strap to tighten it for added measure. 
 

2 things I think might go the issues.

1. The wheel weren’t balance properly. 
2. the driveshaft is on its way out

3. possibly the drums warped.

 

I’ll will take the car for rebalancing once more time and see 

stay tune 

[240zadmire]

Not all shops or technicians created equal !

 

the shop that I bought the tires mounted, balanced and aligned the wheels/tires, were decent.  At lease I was happy for a year until I took the new mag wheels to swapped out the tires and balanced on the new wheels. 
needless to say, same shop, different technician have different results.  Reason I went for this same shop because Costco do not carry the tires size of the stock rims, 14”.

 

I took the car to Costco for balance.  The technician was cautious as he didn’t want to mess up the “classic” car as there’s no place to jack up the car.  I had to convince him the location where he can put the lifters in.  However, he still hesitated and the manager need to approve.  Manager didn’t want it either and insist to lift the car at the frame rails… fortunately, I did reenforce the frame rails so I ageed.

Low and behold, 90 minutes pass and it’s done.  Drove the car home, though short distance and NO VIBRATION at all.  I will have to do more driving tomorrow to confirm the result, but so far I'm happy with the result.

 

 

stay tune folks 

[Patcon]

Do you know what they call the guy who graduates last in his medical class?

 

 

Doctor... 😉

No offense to conedoger 🙂

[siteunseen]

I ask my nephew if he was a starter for his baseball team. He didn't know what that meant, said he was a player.

[240zadmire]

23 minutes ago, siteunseen said:

I ask my nephew if he was a starter for his baseball team. He didn't know what that meant, said he was a player.

Though I’m not that old… but this generation is so confused! 🙂

 

well, nothing beat a morning cruise where there’s practically no traffic on freeway… and that’s a rare sight in Southern California.  Did a 40 miles varying from 60-80mph and boy, so glad there’s no more unwanted massage vibrating feeling in the car.  Was really smooth.  Kudos to the Costco team.  They really did a great job and I’ve never spent this little money at Costco with such pleasant.  Go Costco!

 

I think we can put this thread to rest.  Thanks everyone for guidance and keep up my rants .