Step-By-Step Coilover Conversion...

[Norman V]

Hey Guys. I have a 71 240Z and I was wondering if this guide works for my car? Also I understand you use the  Bilstein P30-0032 shocks for the front but What do you run for the rear? Thanks in advance. 

 

I noticed in the parts list that only 2 shock need to be purchased here:

From MJMAutoHaus: (http://www.mjmautoha...roducts_id=1995)

- Bilstein P30-0032 shocks: 2 x P30.0032.SET @ USD199.95 ea

[thehelix112]

The dampers come in pairs.  I used the same shocks front and back.

 

Dave

[aarc240]

NormanV - check your strut diameters and lengths.

The standard 240z has smaller strut tubes at 50mm OD so everything is different including the coilover tubes and dampers.

On top of that, the rear struts are shorter by about 41mm.

If you have a source (like a rusted out 280z) you can change to the larger struts but you MUST shorten the rear tubes to at least the 240z length.

[tamo3]

Hi Dave,

 

Do you remember the length of the spacer for front and rear?

 

Thanks,

tamo3

 

Step 27. Install the alu tube spacer and damper, ensuring the spacer is sitting correctly vertical. I was a little worried about the strut being supported at the bottom, so I drilled a couple of holes in the solid alu spacer the same diameter/spacing as the holes in the bottom of the strut; and put some small dowels between the two. Hopefully this will make the strut less likely to wobble around during cornering.

[tamo3]

Oh, well, I figure it out.

It's about 4" in rear and 23mm in front.

 

Finally, I completed my coilover installation with Grand Control CG kit.

Mine is for 280z, but I exchange with 10" spring also, the hat is exchanged to VW hat which has wider diameter hole in the that fit to the Bilstein shock.

 

 

Thanks Dave for the great write up!!!

[deuce8ernerozero]

Could you draw a simple picture of how to make this work with illuminas and camber plates? I dont quite understand how to keep the steering light. Should I use a different spring top with the different shocks?  Thanks

[m1ghtymaxXx]

I'm getting close to ordering the parts to replicate the OP's build. first, 2 questions:

 

1)   Can anyone who has sectioned coilovers on a 280Z share how much they removed and what the resulting ride height range of adjustment was like? Please specify spring length and top mount/camber plate setup. The car is currently on Eibach Street springs and I figure that's a good maximum ride height to shoot for. I figure if I can go 3" lower than that, that's plenty. 

 

2)   Are there any top hats out their that would fit the Bilstein shafts? Doesn't look like a big deal to modify them as shown, but if there's something that would fit out the box, it would be good to know. 

 

 

 

Could you draw a simple picture of how to make this work with illuminas and camber plates? I dont quite understand how to keep the steering light. Should I use a different spring top with the different shocks?  Thanks

 

It sounds like your camber plates may not have thrust bearings in the assembly so that that weight of the car and steering loads are both being handled by the pillow ball mount. Details/pics of your setup would better show what's going on. 

[NewZed]

After reading all of these "coilover" conversions discussions (which really should be called adustability and/or lowering modifications since the cars already have coil-over-strut suspension), you realize that separating damping (the shock absorber) from springs is the key to understanding what to do.  Where the spring perch is attached determines ride height and adjustability range, and has essentially nothing to do with damping.  And the strut tube is cut only to make the shock absorber body fit correctly, clamped down to the bottom of the tube from the gland nut at the top.  With those two concepts, you don't really need any numbers, you could do the whole job with a Sharpie.  You do need numbers to determine which parts to get, but once you have them, no numbers needed.  In other words, you can't determine how much to cut until you have the shock body decided.

 

Just simplifying, for those that like simple.

[m1ghtymaxXx]

After reading all of these "coilover" conversions discussions (which really should be called adustability and/or lowering modifications since the cars already have coil-over-strut suspension), you realize that separating damping (the shock absorber) from springs is the key to understanding what to do.  Where the spring perch is attached determines ride height and adjustability range, and has essentially nothing to do with damping.  And the strut tube is cut only to make the shock absorber body fit correctly, clamped down to the bottom of the tube from the gland nut at the top.  With those two concepts, you don't really need any numbers, you could do the whole job with a Sharpie.  You do need numbers to determine which parts to get, but once you have them, no numbers needed.  In other words, you can't determine how much to cut until you have the shock body decided.

 

Just simplifying, for those that like simple.

 

 

Well there's a lot of misinformation in this post that may only further confuse people. The exact definition of a coilover could and has been argued to death, and I won't call you wrong, but the widely accepted definition is a height adjustable spring and damper assembly. 

 

The sectioning of the strut tube is not necessarily to make the damper cartridge fit. A stock sized cartridge will fine with no modification, and a shorter than stock cartridge will fit with only the addition of a spacer. The reason for sectioning the strut tube is to lower the ride height without affecting the travel or preload of the suspension. and this is often done in combination with a spacer to get within a  desired range of height adjustability. How much you cut has everything to do with what your minimum and and maximum ride heights will be, and any adjustments to height from there out (ei: moving the threaded spring perch up and down) will affect whether your available spring travel is in droop or compression. 

 

Careful how you try and "simplify" things for people.

[tamo3]

1) It depend on where your bottom of the coil located and spring rate. I cut about 1.5" and I can make it really low and really high too with 10" spring.

2) GC has it for VW Rabitt. I asked them to change the hats with my 280z GC coilover kit.

 

 

I'm getting close to ordering the parts to replicate the OP's build. first, 2 questions:

 

1)   Can anyone who has sectioned coilovers on a 280Z share how much they removed and what the resulting ride height range of adjustment was like? Please specify spring length and top mount/camber plate setup. The car is currently on Eibach Street springs and I figure that's a good maximum ride height to shoot for. I figure if I can go 3" lower than that, that's plenty. 

 

2)   Are there any top hats out their that would fit the Bilstein shafts? Doesn't look like a big deal to modify them as shown, but if there's something that would fit out the box, it would be good to know. 

 

 

 

 

It sounds like your camber plates may not have thrust bearings in the assembly so that that weight of the car and steering loads are both being handled by the pillow ball mount. Details/pics of your setup would better show what's going on. 

[m1ghtymaxXx]

1) It depend on where your bottom of the coil located and spring rate. I cut about 1.5" and I can make it really low and really high too with 10" spring.

2) GC has it for VW Rabitt. I asked them to change the hats with my 280z GC coilover kit.

 

 

Thanks! So is the shaft diameter is standard for that model Rabbit? Honestly that never occured to me, I just figured it was a Bilstein thing as they often have overly large pistons, shafts, etc. 

 

My concern about sectioning the struts was that I'm not sure I'll be able to do the work within proximity of the car, otherwise I'm sure I could figure out where I need to be with some careful measurements once I have all the parts on hand. 

[tamo3]

The Bilstein shock I used is for VW Rabbit. GC has kit for VW Rabbit. So, I request my 280z GC kit to swap hats with VW Rabbit. Also, I requested to swap spring from 8" to 10".  280z kit comes with 8" and 240z kit comes with 10".

[eaglez]

I just bought a '72 240, the guy took the 240 struts off and replaced with 280 structs springs etc.  Can those 280 struts be converted to coil overs and then be compatible with the 240 suspension?

[ladams17]

Did anyone ever mount these to the TTT tops like mentioned in the previous posts?