Weak 240Z U-joint resolutions?

[Nismo37]

Hey guys. I've got a series 1 240Z that I'm slowly restoring as I drive it. I've developed an intermittent grinding noise from the rear that I'm fairly certain is the U-joint... possibly wheel bearings. Either way, I know the early Z's have u-joint issues due to the drive shaft length and a popular fix is changing to a 280z drive shaft. What other parts need to be replaced in addition? Are the u-joints on the Z's overly difficult?

[Zed Head]

Either way, I know the early Z's have u-joint issues due to the drive shaft length and a popular fix is changing to a 280z drive shaft.

I've never heard this at all. Can you give a source for that information?

Wheel bearings and u-joints don't really make the same noise when they fail. U-joints get clunky during gear shifts, and can cause a vibration. Wheel bearings, at least the rear ones with big ball bearings, tend to get loose before making lots of noise, allowing the wheel to move side-to-side and up and down and clunk a little bit, I believe. You can jack the back up and lift and tug on the wheel to test the wheel bearings. Crawl underneath and visually examine and pry on the u-joints. There should be zero play.

[Nismo37]

I've never heard this at all. Can you give a source for that information?

Wheel bearings and u-joints don't really make the same noise when they fail. U-joints get clunky during gear shifts, and can cause a vibration. Wheel bearings, at least the rear ones with big ball bearings, tend to get loose before making lots of noise, allowing the wheel to move side-to-side and up and down and clunk a little bit, I believe. You can jack the back up and lift and tug on the wheel to test the wheel bearings. Crawl underneath and visually examine and pry on the u-joints. There should be zero play.

There is a local Z guru near my home that has hundreds of old Z cars and a couple barns full of parts. He's the one that pointed out the difference. If you google "240Z drive shaft lenght" you'll see some information on it as well. My u-joints do clunk a little going into gear but there is an annoying growling noise coming from the rear at 30 mph and above.

[Zed Head]

Actually, I've done a lot of driveshaft (propeller shaft) Googling and not seen that. There is an early short propeller shaft, used with the forward mounted diff. Then the longer 240Z shaft, same length as the 280Z shaft, with replaceable u-joints. Then the 280Z shaft with staked in, non-replaceable u-joints.

There is a problem with the side "drive shafts" (not the center propeller shaft) being too long on one side, if you convert to an R200 diff. That problem is described here and there.

And the diffs themselves have an annoying growling noise, independent of u-joints or wheel bearings. Could be the bearings though, but they can be checked. How long have you had the car and what have you done to it?

BUT, back to your direct question - if you have the forward mounted rear diff, then you have to use the short propeller shaft or remount the diff to the later rearward position to use the 280Z length shaft. Do you have the early diff position? You did not give the year of your car.

[zKars]

I remember a very old thread about some character near Boise that had a rather large stash of Z's and parts, but never did pin him or the exact location down. I think 'mystery solved" is appropriate. He should make himself known and get some action on that pile of apparently un-loved and un-wanted Z-bits.

Now on topic, I believe you have a slight mix up on the drive shaft verses the half shafts to each wheel. The issue revolves around the early and late diff location, which would change the required drive shaft length. Half shafts are all the same on all S30's.

[Nismo37]

BUT, back to your direct question - if you have the forward mounted rear diff, then you have to use the short propeller shaft or remount the diff to the later rearward position to use the 280Z length shaft. Do you have the early diff position? You did not give the year of your car.

My car was built in 1970, the original owner whom I bought it from stated it has the R180 differential so I'm assuming it's the forward mounted diff. The original L24 w/E31 head gave out on me a few months back. I've had the car since May. A loose cam bolt walked a pin loose and bent my valves. I had the clutch replaced and got a used L26 from the guy with all the Z stuff that I'm running until I can get the original engine rebuilt.

[Nismo37]

I remember a very old thread about some character near Boise that had a rather large stash of Z's and parts, but never did pin him or the exact location down. I think 'mystery solved" is appropriate. He should make himself known and get some action on that pile of apparently un-loved and un-wanted Z-bits.

Yes he exists. I've been there personally and have bought several items from him including an engine. I upgraded my cooling system to that of a 280z, mine still had the old metal fan shroud and fan. I have pictures too. Probably 250 z's of various models and years, mostly 240's - 300zx. Lots of 280's. He also has a couple of barns full of parts from body panels to drive train stuff. He doesn't appear to have a website but his name is Kim Blough (208)466-0004. Located in Nampa Idaho. He's mostly retired but if you can pin him down he's a wealth of knowledge. His business is called Idaho Z Car.

[rossiz]

interesting... any of those z's in running condition or good restoration projects?

are they stored under cover or rusting away out in a field?

map says he's less than 500 miles from me...

[Mikes Z car]

I have been inside one of the barns, I think there is just one. The barn is packed with Zs and there were many Zs outside as I recall from being there 5 years ago. The barn roof appeared to have a few holes but the cars seemed to be holding up well from what I saw. Most of them had some kind of damage from a wreck if I remember right but not sure that is true for all of them.

[Patcon]

From the aerial pictures on Google he appears to 100-125 cars outside and 3-5 buildings. three are quite large

C

[zKars]

Oh my...

I might have a new best friend!

[EuroDat]

There is a local Z guru near my home that has hundreds of old Z cars and a couple barns full of parts. He's the one that pointed out the difference. If you google "240Z drive shaft lenght" you'll see some information on it as well. My u-joints do clunk a little going into gear but there is an annoying growling noise coming from the rear at 30 mph and above.

Apart from the very interesting Z guru. Dam thats a lot of Zeds.

Your noises sound more like diff related. I would look at changing the oil and checking for metal depsoits in the oil. A bit more difficult would be checking the back lash in the diff. Excessive backlash can cause clunking noises during gear change and poor toe/heel paterns which cause whine and sometimes growling noises.

Chas

Edited September 21, 2014 by EuroDat