Suspension question

[shrike]

So Im moving to Melbourne next month and have been looking at getting a classic Toyota

 

Specificly a MS55 crown sedan (so sexy (however sheepers MS51 is hot)

 

Ive come from Macpherson and live axle diffs (only dealing with double wishbone is the front of an r32 skyline)

 

So from what I can tell the MS55 has double wishbone suspension at the front

 

And 4 Link rear with springs on the solid axle and shocks seperate ?

 

Now coming from Mac struts ive been spoilt and can buy coilovers off the rack for the application

 

With the crown its alittle harder

 

So im going to want to lower it Safely and I want to be able to adjust the height depending on the wheels Im running (adjustable dampner settings would be a bonus)

 

(car will get mod plated)

 

So at the front the bottom of the shock bolts onto the bottom arm which the spring also perchs on and then the top arm bolts to the top of the shock and the spring pushes against it?

 

so if I want to go say 30mm lower do I need to reduce the max extension of the shock by 30mm? and reduce the spring height?

 

I mean if I remove the factory setup can I run a short shock with the spring incorporated onto it? with an adjustable shock body to control height ?

 

And for the rear can I do the same and remove the springs off the diff ?

 

probably really explaining this badly

 

 

Was thinking 6kg spring rates at the front and 4kg at the rear with a street style shock valving to match

[Frosty]

"I mean if I remove the factory setup can I run a short shock with the spring incorporated onto it?"   This is called a coil over.

 

Realistically with the Crown the only simple way to get an adjustable height is to bag it.

The stock shock mounts are no where near strong enough to take a coil over system without some serious reinforcement.

 

You can still run an adjustable shock with bags and I think the bags them selves are available in various rates just like a normal spring.

 

Another way is to get a set of springs that match the lowest you will want the car and then use a urethane spacer between the spring and it's perch, stock these are rubber and only thin but you can get them in various thickness and by running them top and bottom and using different combos you can achieve a whole lot of different ride heights to suit the wheel and tire combo.

 

It will mean taking the spring out to change the height but that's not a major on the Crowns after all you only have to take the shock out and the rears are free and the front is take the shock out and undo the inner lower mounts for the lower A arm, job done in about and hour.

 

Don't forget the front springs are about twice the strength of ones used in a strut because they are positioned 1/2 way along the arm so if you are trying to get the effect of a 6kg spring it will need to be a 12kg one to get it right, this also means the amount you trim or adjust the spring length is roughly doubled so be very careful if you plan on cutting the springs, it's very easy to trim to much off.

I think the Falcon (XR - XF) front springs are a good fit for the Crowns? They where a perfect match for my GS126 and are available in a huge range of heights and spring rates along with a Bilstien from a HQ Holden.

Can't be much help at the back as all the Crowns I have worked on are IRS or Elliptic sprung.

Good luck.