Michael's 180B Sedan Z18ET

[Bartman]

On the 1200's, the top hat has a flat on one side of the hole that prevents the shock absorber shaft from rotating. I don't know about on your struts though.
Also is that 100mm free length, or with the weight of the car on it? Either way thats heaps of bump travel.

[Mikewazowski]

Yeah I noticed that the insert had a flat side on the threaded section, didn't appear to be one on the top hat. I will investigate it more thoroughly next time

That was my best guess at the travel I'll have with the weight of the car on it. Free travel at the moment is about 140 mm. Just thought I'd double check before I welded it all up.

[gingofthesouth]

Good shit. Nothing beats nice new shocks. Makes the car feel 200x better on the road!

2 - When doing up the nylock nut (at the top of the strut) that holds the spring top hat on, how do you stop the insert rod (the part with the thread) from spinning around? It seems to me that it will just spin around instead of the nylock doing up. I know it mustn't somehow as I've done it before but I can't remember

Rattle gun

[Mikewazowski]

Alright so I had a measure up last night and it looks like the KYB R31 inserts might have 10 mm more extension than the inserts I took out of my R31 struts. Ideally I want something that is shorter to make damn sure my springs are captive now that I've moved the lower cup down the strut.
I thought that I'd just go with KYB Z31 inserts P/N 365056 but apparently these aren't made anymore so I can't get them.

Ideally I'd like to get a shorter (~35 mm) insert than the R31 ones to put into my struts. Does anyone have any ideas of common short insert swaps that work well? (Have good damping etc?)

I had a look on the net and some possibilities might be:

Toyota MR2
Toyota GT4

Not sure though...

[Mikewazowski]

Ok well after some investigating the MR2 inserts look like they could be the go.

Nissan R31 Part number #365073
Length: 373mm
Extended: 560mm
Compressed: 380mm
Diameter: 43.5mm
Shaft: 22mm

Toyota SW20 P# 365099
Housing: 355mm
Shaft: 170mm
Extended: 525mm
tube diameter: 43mm

Looks like the MR2 inserts should be 35 mm shorter than the R31 inserts at full extension
Only downside is I'll have to cut an 18 mm section out of the strut tube to fit the inserts in since they are shorter, but that shouldn't be a big deal.

I'm assuming that a 0.5 mm difference in the housing diameter won't matter/I can pack it somehow?

[MR1200]

pack it with a bitta oil bud

[Mikewazowski]

pack it with a bitta oil bud

Pack between the insert and the casing with oil?

Also, just had a bit of a brain wave, the inserts I have sizes for are for the front of an MR2, whereas the engine is in the back. I wonder if that will be an issue if I use them in the front of my car?

[Mikewazowski]

Ok I just measured up the inserts that have come out of my R31 struts, and it turns out that they don't match the R31 dimensions provided by KYB. So I had another look at the stuff written on the strut.
There weren't any brand names or anything, but I did find two numbers...
73229 and CF13MA1A

I had a look and it looks like 73229 is a Monroe part number for a Z31 front insert. So perhaps my front struts had Z31 inserts installed at some stage? Would be pretty tempting to get the same things again as then I'd know they should fit.

One question that I've been wondering about...Is there any advantage to having your springs held under more compression by the insert?
For instance, if your springs are captive, but only by a little bit, will that make any real difference to anything compared with if you had a shorter insert that held them more compressed (by say 30 mm) at full extension?
Is either one better than the other or is it all going to be the same once the weight of the car is on it?

[Mikewazowski]

One question that I've been wondering about...Is there any advantage to having your springs held under more compression by the insert?
For instance, if your springs are captive, but only by a little bit, will that make any real difference to anything compared with if you had a shorter insert that held them more compressed (by say 30 mm) at full extension?
Is either one better than the other or is it all going to be the same once the weight of the car is on it?

A chance to answer my own quesion

I was thinking about this and since the front springs are progressive, once the car is lowered down and the "softer" coils touch they will become dead, which will mean they no longer contribute to the force exerted by the spring. So it shouldn't really matter if they are compressed before or after the car is lowered as far as ride height is concerned. Also, even if the coils are held in a compressed state, the weight needed to move the coil down further would need to exceed the reaction force that the coils are exerting on the top hat. So again it shouldn't make any difference to ride height.

So the short version is essentially: I should buy some Z31 inserts since it looks as though they will fit straight in and it should all work out

[gingofthesouth]

One question that I've been wondering about...Is there any advantage to having your springs held under more compression by the insert?
For instance, if your springs are captive, but only by a little bit, will that make any real difference to anything compared with if you had a shorter insert that held them more compressed (by say 30 mm) at full extension?
Is either one better than the other or is it all going to be the same once the weight of the car is on it?[/quote

A chance to answer my own quesion

I was thinking about this and since the front springs are progressive, once the car is lowered down and the "softer" coils touch they will become dead, which will mean they no longer contribute to the force exerted by the spring. So it shouldn't really matter if they are compressed before or after the car is lowered as far as ride height is concerned. Also, even if the coils are held in a compressed state, the weight needed to move the coil down further would need to exceed the reaction force that the coils are exerting on the top hat. So again it shouldn't make any difference to ride height.

So the short version is essentially: I should buy some Z31 inserts since it looks as though they will fit straight in and it should all work out

The down force would have to be greater than the captive force for it to make a difference. Looking forward to pics