Project to divert KK coil to KJ

[ikuo78]

This project started by acquiring a used KK strut for $20.

At first, I was thinking of just checking the structure or reusing the clevis.

However, the free length of the spring attached to it was 25mm shorter than that of the KJ.

The wire diameter is also thick.

The number of turns is also small.

That means the rate is high.

KK coil has short free length and high rate.

The set length is probably the same as KJ.

The 1G length is probably the same as KJ.

When I roughly estimated the set load for KK, it was 770N lower than KJ.

Set load is easier to feel than rate and has a greater effect on ride comfort.

Maybe I can get about 2.5 inches of lift without increasing the set load as much as the OME927, and without increasing the strut length as much as the top spacer.

to be continued.

 

[ikuo78]

To begin with, I was considering rebuilding the front struts.
This is because the shock absorber is the same as when shipped from the factory.

In Japan, there are distributors such as ARB, Teraflex, Bilstein, RC, Rancho and H&R.
KYB is a Japanese company.

However, they do not carry KJ parts.
The order price is the order price.

High-pressure gas products are dangerous goods, so Amazon will not ship them overseas.
eBay's shipping costs are too high.
Two Bilsteins cost $450 including shipping.

With Bilstein, the saucer is a separate part, so I might be able to change it to ID65 or 70.
But shocks are consumables, so the cheaper the better.

Once, I was able to get two Monroe shocks for $128 from a private importer.
Inside the package was an Amazon slip from when the importer obtained it in the USA.
Two for $114.
Did he import it for $14?
Apparently he quoted the wrong price, seeing as I only received one at first.

Lucky brings misfortune.
The welding where the clevis is attached was rough, so I smoothed it out with a file.
It was too rough, I shaved about 2mm.

Next, how do I lift it?

to be continued.

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[ikuo78]

From the coil length at 1G,
The force to compress the coil was calculated to be 3350N for the wheel and 6700N for the coil.
A 1G load of about 5050N is applied to the front wheel, so
A force of 10100N is applied to the coil.
The missing part probably depends on the angle.
To avoid complicating matters, the loss was kept constant.

The set load and rate is
KK Stock : 2652N 68N/mm
KJ Stock : 3421N 54.3N/mm
KJ RC Spacer : 5321N 54.3N/mm (As stock length.)
OME926 : 3859N 61.25N/mm
OME927 : 6160N 70N/mm

I would like to attach a top spacer to the KK strut, but
I would like to avoid increasing the strut length by 25mmor30mm.
Re-bump limits will die.
It wouldn't be a Jeep if I couldn't jump off the curb.

Currently I am lifting with a 35mm clevis spacer, but it makes a terrible noise when the tire is floating in the air.
That's the only thing I don't like.
I drive so that my tires never leave the ground.
The shock has also deteriorated sufficiently, so the speed at which it stretches is probably fast.

To obtain lift within the limited suspension stroke, the set load must be increased.
If it is a coil with liner characteristics.
As a compromise, I would like the set load to be at most 60% of 6700N = 4020N.

If I insert a 31.75mm spacer, I can lift it 2.5 inches.

When I try to calculate,
If I insert a 30mm spacer into the KK coil,
The set load will be 4692N.

It's a bit big, so I extended the set length by 10mm,
4012N.

KK coil with 30mm spacer and 10mm set length extension.
Even if I extend the set length, will it hit the suspension limit?

how?

I'll attach the calculations, but don't rely on them.

to be continued.

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[ikuo78]

Daystar.
Is it alright?

Daystar has a spacer for 1.5 inch UP.
Probably a 20mm spacer.

Amazon.com says it does not ship internationally.

How about Daystar2.5UP?
It would be a 31.75mm spacer.
Apparently it can be shipped overseas, so I bought it.

First, the instruction manual is difficult to understand.
The HOW TO introduced in Lost has the washer removed from the rod cover in the wrong direction.
Because the meaning of "bevel down" is not understood,
Most likely everyone has the tip of their shock boot stuck in the stock rod cover washer.
Over time, as the tip of the shock boot creeps, the rod nut loosens.

This is uncertain because it is just an imagination based on seeing the shape, not an experience.
I feel a little sorry for the fact that this is left unexamined.

The spacer was 40mm.
Since it's urethane, it probably dents and shrinks under load.

The same kit is offered with a 2 inch lift for KK.
I'm a little worried, but
KK is a little heavier.

I don't use the kit's mounting plate.
It increases the set length by 30 mm.

How about a 10mm extension?
The suspension won't stretch that much.
Let's measure it.

to be continued.

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[ikuo78]

When I measured it,
The strut extends to a coil length of 333mm.
In the photo, 290 - Isolator 10 + Spacer 53 - Clevis mounting position 10.
The RC spacer was 53mm. I mistakenly thought it was 35mm.
Since the clevis and RC spacer are in close contact, the installation position difference from the stock was set at 10mm.
In any case, it exceeds the stock set length of 296mm.
The stock re-bump limiter is a shock absorber in its stock condition.
That's obvious.
At 333mm, the knuckle was hitting the strut.
306mm would be fine.

When compared with similar lift specifications.

KK 30mm Spacer+Set10mmUP : 4012N 68.00N/mm 2.43in
KJ RC Spacer : 5759N 54.30N/mm 3.38in
KJ 30mm Spacer : 5049N 54.30N/mm 2.36in
OME926 17mm TopSpacer : 3859N 61.25N/mm 2.44in
OME927 22mm Cut : 4620N 70.00N/mm 2.42in

RC spacers have a high load.
It is 1747N lighter than the current KJ+RC spacer, so I will lift it with this.
Considering urethane as an elastic body, the rate when placed in series with the KK coil is 56.5N/mm.
Placing springs in series always reduces the rate.
It's pretty good, isn't it?

This is somewhat contradictory to the difficulty of assembling that can be seen from the HOW TO regarding strut assembly.
I wonder if it can be extended if assembled.
Is it just that the bushing is hard and difficult to assemble?

I have to buy a 10mm spacer.

to be continued.

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[ikuo78]

Oops, I miscalculated.
290-10-10+53-10=313

The rebump limit listed as 333mm in the post above is actually 313mm.


By the way, Daystar 2.5 has a re-bump stopper.
If it works, it will be revolutionary.

The knuckle hits the spacer and stops.
At that time, the spacer tries to push the knuckle outward, applying thrust load to the upper and lower ball joints.
The shock rod is also pushed inward through the spacer.

Is it correct?
I don't really understand.
I feel like the direction to accept it is bad.
There won't be any strange sounds at first.
It's not worse than hitting the strut directly.

I hope it doesn't reach there with a set length of 306mm.

I will wait a while for KJ's stock mount plates and isolators to cross the Pacific Ocean.

to be continued.

 

[ikuo78]

Think about the full stroke.

By inserting a 30mm spacer, the spring reaches its full stroke 30mm before the shock's full stroke.

Daystar probably lowered the top plate to put a bump stop there.
It looks like the mount bush is used as a bump stop.
There is no bump stop in the kit.

I won't be using the Daystar top plate, so I'll have to find a replacement.
I don't think the coil will bite, but it is likely that the stress will exceed the allowable stress.

I'm going to put a bump stop on the shock rod.
50mm soft one.
It says that the hardness is shore A65.
Hits from 30mm up stroke.

Is it a little early?
It should be enough to stop with an upstroke of 50mm.

It's good because it's soft.
It says that the allowable load is 2200N.
There will be no excessive load.
The concern is whether the shocks are made to take such loads.
Monroe's shock doesn't stroke to the point where it hits the mount bush.
Stock shocks move that far.
The Monroe has a catch on the bottom to prevent it from stretching during transportation.
The one you turn to release.
This may cause the catch to hit depending on the rotation position.

Monroe also has an unnecessary protrusion where the Daystar spacer is set.
There is a bulge around the drain hole where the plate and cylinder are welded.
I have to cut it down.

Terafrex's bump stop is short for my strut specs.
Shipping costs are also high.
130 dollars for 2 pieces including shipping.
Higher than shocks.

Currently, the bump stops are stock size, but the tires have probably never rubbed against the fender.
But I don't know if I pushed the stock coil past the minimum height.
The rear gets rubbed a lot on the mogul terrain though.


to be continued.