Lower Control Arm Bushing? Steering Knuckle difference?

[70z4fun]

Howdy,
Looking at redoing some of the front end of my '70 240z.

A few questions have come up. 
Should I replace the bushing in the lower control arm? A 49yr old car, it seems like a smart idea.

Should I use the stock one, or use a urethane version? Advantage or disadvantage?
Also, what is the the difference in the steering knuckle between an early 240 and later 240? I have seen a different ball joint offered, but not sure how to tell the difference between the two?

Thanks
Bob

[jfa.series1]

OE-style rubber bushings are generally best for street cars, poly-type bushings are best for track cars.  Rubber bushings provide compliance in the suspension so that harsh impacts are absorbed and  not transmitted directly into the body.  They also provide a small amount of flex that is not wanted in a track car where the suspension must respond immediately and consistently to driver inputs.  With poly bushings the ride is very tightly controlled and more harsh.  I initially installed poly bushings with my resto, did not like the ride quality and immediately swapped everything out to rubber.  Some OE/OEM rubber bushings are NLA so poly is the only choice - the steering rack is a typical example.

The online catalog shows a change in the steering knuckle and ball joint beginning with build date 7007.  I think the ball joint size was increased for durability.  If your car is prior to this date, you'll need to locate a pair of steering knuckles from a later car to fit the currently available ball joints.  Here's the link to the catalog reference:

http://www.carpartsmanual.com/datsun/Z-1969-1978/axle/front-axle

Hope this helps.

[timZ]

I'm restoring a 73 240 and interested to know how important it is to replace that lower control arm bushing? Or what's the best way to determine if it needs replacing?

 

Thanks

[grannyknot]

It needs replacing, unless the car has been restored at some time it will be worn.

[jfa.series1]

56 minutes ago, timZ said:

I'm restoring a 73 240 and interested to know how important it is to replace that lower control arm bushing? Or what's the best way to determine if it needs replacing?

 

Thanks

At $12.14 each from Courtesy (plus shipping to you) how can you not do it?  Aftermarket is even less at Rockauto.

https://www.courtesyparts.com/oem-parts/nissan-bushing-link-54535e4100

[timZ]

21 hours ago, jfa.series1 said:

At $12.14 each from Courtesy (plus shipping to you) how can you not do it?  Aftermarket is even less at Rockauto.

https://www.courtesyparts.com/oem-parts/nissan-bushing-link-54535e4100

Thanks for the advice and link!