My two swiss S30Z Fairlady Restoration build thread

[Captain Obvious]

Yes, the front bushing would (typically) be in compression, but I'm not sure that means it would make sense to put the rubber in the front.

The general belief (as I understand it) is that with the poly up front, you get the better handling benefits of the poly. but the softer rubber bushing in the rear gives the rod some compliance to pivot at that rear mounting point as the wheel goes up and down (when the suspension compresses and extends).

From the standpoint of not wanting to damage the rod, it doesn't matter which side gets poly and which side gets rubber. But to take advantage of the handling characteristics of the poly bushings, you want the poly up front.

And of course, the problem with putting the hard poly on both front and rear is that when the rod tries to pivot to change angle, the stiff poly resists the change and over-stresses the rod.

I'm not a suspension guy, but that's my interpretation.   

[JDMjunkies.ch]

In this thread, someone recommands to put the rubber in front:
http://community.ratsun.net/topic/26238-my-swiss-1972-s30-240z-rebuild-project/page-33#entry1544974

question is if it breaks due to Compression (and the rod bending) or due to the movement / angle, as you say.

not sure yet which is the correct route. both explanations seem plausible...

[Captain Obvious]

Actually, I believe he and I are saying the exact same thing. I think we are both recommending using poly on the compression side.

If I'm understanding his info correctly, the confusion may come from differences between the suspension geometries of the 510 and the Z?  I'm not a 510 guy, but it sounds like the 510 T/C rods run the opposite direction to those on the Z?

But I believe we are both saying the same thing?

 

[Zed Head]

22 hours ago, JDMjunkies.ch said:

question is if it breaks due to Compression (and the rod bending) or due to the movement / angle,

The tip breaks off at the base of the threads.  The hard polyurethane on the back puts a bending force on the tip of the rod.  It seems to fatigue it until it breaks.  Mine moaned and groaned until finally it broke when I backed the wheel in to a curb while parking.

If you install two PU bushings and then install the rod in its spot you'll find that it locates the rod very firmly in one position.  Grab the other end and try to move it and you'll see how it loads the tip.

[JDMjunkies.ch]

On 13.2.2018 at 4:09 PM, Captain Obvious said:

Actually, I believe he and I are saying the exact same thing. I think we are both recommending using poly on the compression side.

If I'm understanding his info correctly, the confusion may come from differences between the suspension geometries of the 510 and the Z?  I'm not a 510 guy, but it sounds like the 510 T/C rods run the opposite direction to those on the Z?

But I believe we are both saying the same thing?

 

 

On 13.2.2018 at 6:57 PM, Zed Head said:

The tip breaks off at the base of the threads.  The hard polyurethane on the back puts a bending force on the tip of the rod.  It seems to fatigue it until it breaks.  Mine moaned and groaned until finally it broke when I backed the wheel in to a curb while parking.

If you install two PU bushings and then install the rod in its spot you'll find that it locates the rod very firmly in one position.  Grab the other end and try to move it and you'll see how it loads the tip.

The more i read, the more confused i get. Nevertheless, i try to order a set of OEM rubber bushings and try to figure it out Thanks for all your advice, guys!

[Zed Head]

I was serious about installing the TC rod alone, with the bushings, then grabbing the end and pulling it through the motion it would see as the suspension moves.  The problem will become more clear, and the reason that Nissan designed that groove in the middle of the rubber bushings.

New rubber bushings would probably work great.  The PU craze has gone a little too far, I think, sometimes.  The PU on the TC rods makes the wheels a little less squirrely under hard braking but doesn't offer much beside that.  I have them on my car but also have a full set of MOOG rubber that I might put back on some day.  A lot of the things I have on my car are there just to see what the fuss is about.  That's how I broke a TC rod.

[240260280]

Stiff TC rod makes cornering over bumps horrible.  I went to the ball and socket...what a nice upgrade.

[JDMjunkies.ch]

Time for a little more knowledge today After i posted pictures from my T/C rod bushings in various forum-threads, people replied that i should swap to rubber in the back. After discussing a few topics i figoured out that original rubber bushings are still available new from Nissan and ordered a set, which i was able to pick up today:

 

The problem: According to many people, the T/C rod tends to brake at the yellow area, when PU-bushings are used both in front and rear of the Frame-rail mount. This due to much counterstrength whith the hard PU-bushings.

 

For sciences' sake i decided to compare both setups with an original NOS 240Z frame rail i have in my shop.
Top: Front PU / rear Rubber
Bottom: Front PU / rear PU

 

1st: Both PU. Fits perfect, but it's very stiff, both compression and angle-movement wise.

 

Second: Front PU / rear rubber.
You still have the advantage of PU-front (less rearwards movement during compression, red arrow), while having more freedom of angle-movement (yellow arrow) and therefore minimized the chance that the T/C rod will brake.

 

So thanks all for the inputs and advice and i'll definitely stick with the PU / Rubber combination for best performance and with least failure rate

 

[JDMjunkies.ch]

Time for another update. I lately stumbled on the Nissan / Datsun USA Technical service bulletin about the change of the hatch window rear defroster lines from Vertical to horizontal:

 

Since i had been wondering why my cars (which were built close together) came with two different types of windows, which i figoured out lately, it cought my interest and i started to look closer.
Car 1. SNR:  HLS30-56801 came with horizontal lines. Registered in March 1972

 

Car 2. SNR: HLS30-59660 came with Vertical lines.Registered in May 1972

 

Strange enough, the SNR of my (European spec) cars are one Digit shorter than the ones mentioned in (American) Service bulletin. Both my cars were built in late 1971, but i assume the date in the Service bulletin is not the production date of change, but the release date of the document. Given the lead time of the cars from production to first registration in switzerland, and the lead time from Production change to the release of the Service bulletin. i guess my two cars, built close together just happend to be around the change. Also it is a prove that there is nothing like a "Series 1" car mentioned often. My "older" car doesn't have the vented hatch / side emblems, but it still came with "old" type window.
Service bulletin 231 (1975 introduction of the Datsun 280Z, America) also mentions a 6-digit VIN (HLS30-6digits). So i guess we just got a different vin-Block for european cars? I checked both my stamped serials as well as the VIN-plate. Both my cars only have HLS30-5digits

 

Oh and then got some interesting read from the UK. Race & Rally Magazine, Jan. 1993

 

It features 16 Pages intresting background information about the Works 240Z rallye cars.

 

 

Including a variety of side-stories around them. Still have to read through it, but it seems very promising

Edited March 23, 2018 by JDMjunkies.ch
typo correction

[HS30-H]

7 hours ago, JDMjunkies.ch said:

h and then got some interesting read from the UK. Race & Rallye magazine Jan. 1993

 

It features 15 Pages intresting background information about the Works 240Z rallye cars.

 

 

Including a variety of side-stories around them. Still have to read through it, but it seems very promising

Don't take it all as gospel fact though. It's a nice article but it's chock full of the usual mistakes, misapprehensions, assumptions and received wisdoms. Better to use it as a base for further research and a lot of cross-referencing.

[JDMjunkies.ch]

3 hours ago, HS30-H said:

Don't take it all as gospel fact though. It's a nice article but it's chock full of the usual mistakes, misapprehensions, assumptions and received wisdoms. Better to use it as a base for further research and a lot of cross-referencing.

Thanks for your Input. I'll take it with a grain of salt. Meanwhile i've learned that many (especially older) documents are full of mistakes. Even the factory documentation is not 100% correct in some cases but it seemed like it includes a lot of Background Information, normally not found in the official (technical) documents.

[HS30-H]

22 minutes ago, JDMjunkies.ch said:

Thanks for your Input. I'll take it with a grain of salt. Meanwhile i've learned that many (especially older) documents are full of mistakes. Even the factory documentation is not 100% correct in some cases but it seemed like it includes a lot of Background Information, normally not found in the official (technical) documents.

There's really no input from the Japanese side of the story, so it is naturally skewed to the point of view of the people who have been interviewed. The people who built the cars and who took them half way around the world to compete with them are - in my opinion - probably the most reliable witnesses, certainly so in the specs and details of the cars themselves. You can witness drivers and navigators who actually used the cars in period apparently knowing relatively little about them. Comments like "they were relatively stock/standard", when they were far, far from that - especially so in the case of the early lightweight bodied versions.

In extreme cases it's akin to a sort of cargo cult scenario where a television falls into the hands of a culture that's never seen one before. When the Works rally cars turned up the UK for the 1970 RAC Rally, almost nobody had seen a 240Z before. They didn't know what was standard equipment and what wasn't. It's little wonder that the journalists of the time had a hard time understanding the full details of the cars thus setting in stone their mistakes to be followed ever since...