4 link rear.

[Ed]

Hello,


im planning to fit up a 4 link rear, and have a few questions... im sure im not the only one who has ever thought about the suspension change so.....

initially i was planning to use the front leaf spring eye for the front lower bar mount.. this would appear now to be too close to the axle. (approx 400mm)

the resultant short lower rod length would probably lead to bind and also the arc of travel would cause too much change on the pinion angle as well.

to over come this i thought about moving the front mount to a position along the 3/4 chassis. so the lower rod would be about (650 - 700 mm long).

i know its a question for an engineer, but would mounting on the 3/4 chassis be cause for concern?

this idea doesnt seem to contravene anything in the code of Practice either?

the top bars may run to fabricated brackets under the rear seat, but im trying to work this out, to provide the required strength and allow seats to fold down still etc.

i was trying to trinagulate the top bars too to avoid lateral movement of the axle housing since a panhard rod would be difficult to fit in the space, but this may still be an option.

this job would probably be more adept to fitting to a panel van or ute body for that reason.

I know Frank Micalef's "PRO 056" sedan had a 4 bar rear, so it is possible any ideas??

Cheers

Ed

[mcl1959]

A 4 link is good but all mounting points MUST replicate the original positions in the donor car or suspension characteristics are compromised.
Also a panhard bar or Watts link should be used to provide stability, it was there on the original car for a reason.


Ken

[FE_225]

Hi Ed
I've got a demo program that supossedly does all the calcs for setting up a 4 link rear end

The 4-Link Calculator lets you input, view, save, analyze and compare your 4-Link rear suspension geometry. You enter measurements for all 4 brackets for your car, or any number of cars. You can also enter other measurements like Wheelbase, Pinion Angle, etc. for more detailed calculations performed by the program. Once entered, the program will calculate Instant Center Length and Height, Anti-Squat %, and changes in Pinion Angle, Driveshaft Angle and Yoke Movement.
Making changes is just 1 click of the mouse. Click on a bracket hole to change the attachment point, or click on an Instant Center and the program draws the 4-Link setup which produces that instant center.

I haven't had a chance to have a play with it yet, but if your keen let me know and I'll send it to you.
Cheers
Tony

Have you got that beast fired up yet???

[Ed]

Hi guys,

Ken,
there is no donor vehicle for the 4 link apparently, but from my research and thinking about it, Im after a fairly long bar lenght to reduce bind and chainge in pinion angle in any height variation.

the triangulated 4 bars negate the use of a panhard rod, as the top bars prevent lateral movement, I may have to go to the parallel 4 bar set up for space confinements tho, and this will require the said bar.

springs are going to be set as far outboard as possible to pbtain the greatest mecahnical advantage, and the shocks will need to sit forward of the axle housing due to space confinements..

Hi Tony,

How have u been?

id be keen to see the programme you have, I ve done alittle research in this dept too, and if space and design permits, may place different settings for lower bars and top bars.

I have thought about fabbing a suitable crossmember which spans the 3/4 chassis rails.

normally bars angled up will give good anti squat, however at the expense of  forwward drive and roll steer.  my research has tlod me a level lower bar and 5 - 15 degree angle on top bars give the most ideal set up?

umm back to the motor...

still not going.. im a slacker, have u seen Glen m's progress!!

anyway, the motor is detailed, polished looks a million bucks, am going to slot her in after I have painted the interior as there is acres of associated wiring.

hows Stormin norman?

Cheers

Ed

[julius]

Hi

I love your idea of a 4 link in your FC, as I have had one fitted by TCR Restorations in our FJ ute show car where building they look sexy.

It is also my understanding that a 4 link rear is a good thing to keep the ass on the ground and stubility at the cost off a good ride. Depending on the sort off car your building is it a streeter, show car or drag car.

My suggestion to you is to talk to profesionals that fit them into cars everyday, Give Ray from True colour restorations  a call on 03 97203006. or John Taverna Chassis a call on 03 9359 5500 and see what they have to say.

Julius

[Ed]

HI Julius,

your FJ sounds sweet!.

I think the FJ has an advantage as its full chassis'd and the bed would allow the bars to sit higher up, of course there are no other considerations such as  passengers sitting in the rear on top of a suspension link!

I want to nut out most of what im doing then pay my engineer a visit.

A mate of mine used to build monster trucks for Macquarie 4x4 and he's going to give a little advice here and there, but I reckon with thought I can get the ground work done before submitting to the engineer for his thoughts.

Cheers

Ed

[FE_225]

Hi Ed
Haven't been too bad.
The Norman project has stalled again, just don't have the time to do anything these days, too busy with work and stuff.
No, haven't seen the progress of Glens, how's it coming along?
Program is on it's way, it's about a 3meg file.
Cheers
Tony

[Rusty13]

hi guys - did anyone get the 4 link system finished and working, if so can you share some photos or info on how you installed it as I'm keen to install on my FC rebuild

[Ed]

Hi Rusty13,

In the decade that has passed since starting this thread I have arrived at some conclusions based on recent experiences installing a 4 link on another project.

If and one when one day I get back to building another FE or FC which I probably will, i would run a parallel bar 4 link with watts link using a BW diff and Falcon link pin.

go for the longest bar lengths you can…

Alternatively, if you take the entire rear end out of an EF Falcon you could utilise that factory 4 link and just fab up chassis mounts.. this would give you a cheap alternative but you will need to accept the factory design (compromises) built into that design.

In any case expect some floor modifications plus more thought for locating items in the area like springs, or coil overs, maybe  airbags, shocks, bump stops, exhaust, fuel lines etc etc.

I have photos but not relevant to FE/FC.

there are some 4 links out there that have been installed.. it will also depend on the level of complexity you are comfortable of tackling.

Cheers

Ed

[FCRB26]

I have had 3 different set ups in my sedan the latest being the most complex.

But my earlier version worked ok the only change I would make is running the shocks up thru the floor to a crossmeber so you get more travel and I would do a crossmember for the upper arms. I would modify the rear floor section as well as my upper arms were too short.

Unless your tubbing the car I wouldn't bother.
But it made heaps of difference getting my sedan off the line no axle tramp. Just squatted down and launched.

Pete

[Rusty13]

Thanks Ed and Pete you have both given some great advice
Funny thing about this car restoring land we live in - for every question there is an answer and for every answer there begs another question or three but your message is understood, it can be done but its not straight fwd and requires a bit of (sorry a fare bit of) mucking around but you get a great result if done properly.

Thanks

[FCRB26]

This is my set up

[JB]

Here is mine... First time go at one, and if I can do it then anyone can. Untested as yet though.

[FCRB26]

We both might have a pile of bolts laying under our cars yet both untested..

[GMB-58FC]

I'm hoping to take inspiration from Pete's set up to aid in mock up of mine.

[Rusty13]

This is great stuff guys well done and thanks for sharing the knowledge

[fcv85l]

I run 4link with lower arms mounted into original front spring mounts with fabricated upper which are reasonably short,my car cops a hiding and the rear end has been spot on,it runs jag coil overs

[NES304]

I'm hoping to take inspiration from Pete's set up to aid in mock up of mine.

Pete is bored out of his brains and has nothing on at the moment and so is going into production of these real cheap !!!

[Ol_Girl_58]

Pete is bored out of his brains and has nothing on at the moment and so is going into production of these real cheap !!!

Cool, I'll have one.

I'll swap you a louvered bonnet, Pete.

[JB]

Have heard he needs more FE FC work.  :-*