Guide: Coilover Conversion

[45aken]

Due to a lot of questions being brought up about coilovers, I’ve decided to create this guide. i just converted my struts to short stroke coilovers, and it was one of the best things I’ve done to the sprinter. I’m using some photo’s from the club 4ag website, which I’m insure if I’m allowed to use, so Mods please tell me.

Pro's:
1) height adjustability
2) interchange spring rates with relative ease
3) short stroke shock (wont loose travel)
4) pretension adjustments etc

Con's
1) cost
2) ...

OK basically this diagram will help out a lot of people with the whole 'short stroke concept'


Items needed:

• Shock
• Coilover Sleeve Kit
• Coilover style spring (63mm and 65mm ID are the most common)

with the front shock, i chose a celica ST204 KYB AGX shock, which is 70mm shorter than the ae86 standard.
I bought a Noltec coilover sleeve kit, which come with the threaded sleeve, 63mm spring seat, lock ring (which is also a spring seat for 65mm dia), top hat and adjustment spanners. used some 7kg apexi springs i had lying around.

step 1) Removal of struts.
to remove your standard struts from your ae86, first jack the car up and use some stands.
now this is the procedure:

1. remove wheel
2. remove the two 17mm bolts at the bottom of the strut. i'll get photo's of this soon
3. remove the two bolts which hold the brake caliper on and remove the caliper.
4. open the bonnet and remove the 3 nuts holding the strut's at the top.
5. i used a bar sitting on the sway and the body then pushed down to pry the bottom mount so i could get the strut out.
6. repeat for the other side

you can continue stripping the strut by removing the 'cap' in the middle of the rotor, removing the split pin and the 23(?)mm nut. this will allow you to take off the rotor and bearings etc.

now that you have the struts out, you can begin to disassemble them. here's how:

1. clamp the springs down with a spring compressor
2. remove the bolt in the middle of the strut top (bearing plate or whatever you want to call it)
3. remove the spring
4. remove the large nut that hold the shock into the strut (i used a vice).
5. remove the shock, if its an after market insert, just pull it out. if its still the stock shock, take it out very carefully as there is pressure inside!

Now you are left with an empty strut, which needs the spring seat removed. I used a vice and an angle grinder, some people use a lathe or a cutting torch. it doesn’t really matter what you use, as this is where the cut will be made to shorten the strut.

Once you finished grinding, it should look something like this.



Now it’s time to shorten the strut. Remember that however much you cut out of the strut, you car will now be lowered this much. Since my shock is 70mm shorter that the standard shock, I chose to cut out 50mm of strut and then use a 20mm spacer. Once you have decided how much you want to, and marked it out, cut the strut using a drop saw (or take it to any exhaust or fab shop to get it cut). Remember to cut so that you still retain the thread on the top of the strut, as it is hard to rethread this. (make the cut so that it removes the old spring seat).

Once you have made the cut, it is time to weld the 2 pieces back together. I got mine TIG welded at a local fab shop. This weld required no grinding to make it flush with the strut.

Because I used an alloy sleeve, I had to make a ‘ring’ out of some steel pipe that was also welded to the strut so that the sleeve could sit on it. (alloy does not weld to steel very well).

Now that you have the shortened strut, it is time to reassemble the suspension.

1. Sand off paint etc (the 51mm ID sleeve has to go over a 50.8mm ID strut)
2. ”Slide” the sleeve onto the strut (it wont be easy, mine was a real press fit, if it is not going to happen, throw the strut in the freezer and the tube in the oven at say 60 deg)
3. Screw the spring seat and lock nut onto the thread
4. Put the spacer in the strut, put the shock in the strut and screw the shock retaining screw down tight.
5. Sit the spring onto the seat, but the top hat on top of the spring (mine required drilling to get it to fit over the thread at the top of the shock)
6. put the strut top (bearing plate) on, and use the new bolt you got with the shock to tighten it down (this requires a vice grip or similar to sto the shock from turning while you screw the bolt on)
7. Repeat on other side.

This is what you should have:



Now throw the back in your car coilovers in your car, adjust them to the height you want, remember to LOCK THE LOCK NUT, and then go and reap the rewards of a race coilover setup!

PS. I don’t take any responsibility for whatever anyone does to their car after reading this guide. After all, this is just a guide. There is a lot of people out there with different ideas regarding what to use (steel sleeves etc), I’m not saying that this is the perfect way to do this (everyone has their own idea) I’m just showing you what worked for me. (this suspension has been checked by an automotive engineer and made by me (an engineer).

The total cost for this project was around $600 including the coilover kit and a pair or AGX shocks (I had the springs), this is not retail price either.

Hope this helps.

(im at work now, i'll update this if anyone notices i forgot anything)

[The Witzl]

I've only got one problem with your guide so far......

When you go to remove the factory strut from the car, it is actually a VERY GOOD IDEA to loosen (not completely undo) the nut in the middle of the strut top when the car is resting on the ground.

I've found on a number of occasions that the bastard strut top nut simply wont farken undo with the strut out of the car, especially if you have non-captive springs. You try to undo it, but the shock arm just spins with your attempts to undo it

This is the point where you abuse Mr Toyoda for using nylon lock nuts over the next 2 hours whilst you bolt the struts back in....

It's about 100000% easier to undo those nuts when the weight of the car is resting on the suspension (ie car on the ground)

[45aken]

no worries, chief. we had that problem. so we just pulled out vice grips and then we lost the vice grips so we had to use the super dodgey pilers and a vice method

but yeah, you method makes alot of sense.

[phrostbyte]

A rattle gun takes that top of strut nut out in one quick movement. Something to do with the sudden torque a rattle gun gives off and the nut takes the torque before the shock body has time to move.

Anyway a very nice guide, rep+ to you sir

Kev.

[psychofox]

For the springs, what is the free (uncompressed) height of them. I'm just about to do the conversion myself and was interested in finding out what others ahve done.

[MWP]

For the springs, what is the free (uncompressed) height of them. I'm just about to do the conversion myself and was interested in finding out what others ahve done.

What car?
What spring rate?
What insert and how long is it and its travel?
How much are you shortening the strut?
What ride height are you after?

I spent a few days working out this kinda stuff for my RA28 conversion... its not quite as easy as the guide above makes it out to be.

[45aken]

mate im not too sure, but i'll take a ball park guess and say 180mm would be the way to go. just measure the stroke length of the shock(top of the body to the bottom of the top hat), and then add the distance from about 3/4 the way up the sleeve (so you have a good height adjustment). this will give you a rough measurement of the spring size you require. i'll measure mine tonight though.

yes rattle guns work very very very good, but i just didnt have one. thanks for the rep

[45aken]

nearly forgot people. i used the noltec kit with the RAISED TOP HAT. this has it's advantages and disadvantages though. it acts like a normal top hat but it is raised at the top to act like a spacer between your bearing plate and the tophat. this allows you to run excessive camber without the tophat fouling on the plate, but it raises the car by about 1" (but thats why you have height adjustment )

[xolent]

can i have pics of the noltec spring hat?

[45aken]

not really because there on my car right now, but this might give you a better idea:



it's the same price too.

[The Witzl]

this thread is awesome btw

MWP, did you end up working everything out for the RA28? I want to do something similar with mine, but using an XT130 or RT132 strut (for brake upgrade reasons)..... but of course ive never sat down and measured / worked things out properly

[45aken]

Witzl<- no worries, i've always though toymods needed something like this, so i did it. it's a shame i didnt have my camera when we were actullay doing it to get some more detail.

[MWP]

MWP, did you end up working everything out for the RA28? I want to do something similar with mine, but using an XT130 or RT132 strut (for brake upgrade reasons)..... but of course ive never sat down and measured / worked things out properly

I did, but so far nothing is tested and as im currently OS (Canada).

A couple of photos of it all (almost) setup:
http://www.overclockers.com.au/~mwp/...0and%20Springs

Ill get the coilover sleeve welded up when ive got an engine, etc in the car so i can work out the ride height and adjustement i want.

The list of gear in those photos:
MS65 Hubs
RT132 Struts
LN106 Calipers
Caliper Rebuild Kit
Pug 604 Disks + Machining + Slotting + Redrilled
Noltec Coilover Kit
Koni Yellow Inserts & Koni Racing Bumpstops
King Springs + Spring Spacers
Whiteline Tender Coils
Greenstuff Front Brake Pads
T3 Adj Camber Tops

[Stefan]

My little tip for removing the bolts that attach the bottom of the strut to the steering arms - turn the steering wheel to find the position for each bolt where it is easy to access. Didn't occur to me the first time I removed struts.

[45aken]

if you go onto full lock when removing the nuts then it's much easier, or just get a mate to hold the wheel. i pulled air at the front of my car last night and the coilover's held up, if thats any intication of strength.

[BradW]

This may be a dumb question or it may have been answered in another thread so if it has I apoligise but here goes.
Instead of cutting the struts to shorten them, is it feasible to leave the struts the standard length and take up the space left by the short stroke shocks with spacers. Now I realise if you use steel spacers you are adding to the unsprung weight so would alloy spacers be suitable. Would there be a huge amount of force on them from the shock ( I don't think there would as the spring is taking all the weight of the car and the spacer would be there to just keep the shock from moving up and down in the strut). Are there advantages to having shorter struts over standard length ( I'm talking strut bodies not shock stroke) or are they cut to help reduce ride height as well as accomodate the shorter shocks.

Sorry for all the questions but it is something I have been thinking of for a while.

[roadsailing]

if you just use spacers, the shocks will bottom out and the springs will not be captive. if you weren't going to shorten the strut then you wouldn't use short stroke shocks.

a spring might take all of the "weight" of a car, but a shock takes all of the "speed" of a bump.

[c2888]

If you don't go short in the strut body when you use a shorter cartridge, then you will loose shock travel. Imagine that you've put a 60mm spacer in a oem length strut housing and now lower the car, If you go really low (wheels tucked under the guards) you will be sitting on bumpstops, and the cartridge will only ever move in the lower part of it's travel.

You really need some diagrams to illustrate the point, there's a pic floating around the internet showing how this phenomenon works. google up short stroke club4ag.

And if you don't have a friend/family member to hold the steering wheel, pull the key out again, the steering locking is actually useful for once.

dan

[takai]

Just thought it might be interesting to add some more pictures.
Here is my simple setup, i did exactly the same thing as 45aken, except im using XT130 struts and a Fulcrum collar/nut kit rather than the Noltec one. Also im using T3 upper hats and camber tops.

Here is the strut as it sits with just the tender (helper) spring there:

Now, helper or tender springs can be useful to keep the spring captive. In my case im using 180mm high springs, so they wont normally be captive, as such the tender spring just holds the spring in place when not compressed. Doesnt change suspension geometry or rates at all, due to being 100% compressed when the car is sitting on the wheels.

And this is what is meant by a "normal" upper hat.

Maybe the entire debate about T3 hats and tops should be kept out of this thread for now.

And then completed:


Im using the Tokico HTS102s and using a 50mm shortened strut with a 20mm spacer. Works brilliantly.

Also if you have two rattleguns, or even just one and you want to have some fun with stock struts, you can play the "launching" game when you are removing the springs. *note* i take no responsiblity if you hurt yourself doing that.

[BradW]

Thanks for the replies guys.
I googled and read the club4ag article. From how I understand it the struts are cut to give the lower ride height without compromising shock travel ( when used with short stroke shocks of course). If the lower ride height was achieved without cutting the strut the shocks can bottom out.
The amount that the struts are shortened is then determined by the ride height you are trying to achieve and the shock travel needs to be matched to the spring travel, correct?