f6sk
f6sk Reader
12/8/14 6:38 p.m.

I want to replace the shocks on my 2,000 lbs Isuzu I-mark. I'm looking for something with a shorter operating range, so when I lower it the springs wont fall out.
I found several shocks that approximately fit, but are for heavier vehicles. (A 1978 ford bronco for example)

Must I find one for my size vehicle? Would a beefier shock work better, or would it extend my spring and increase my ride height?

I know nothing about shocks. learn me.

Dusterbd13
Dusterbd13 SuperDork
12/8/14 7:22 p.m.

A shock should never extend a spring. I read this often on different forums, but cannot see how it would except for different stops for the rod, etc. Struts could have a different spring mount location.

I often use shocka from heavier cars, as I believe that they have stiffer valving. No way to know for sure as I dont have a shock dyno.

Im currently running blazer bilsteins on my elcamino.

Opti
Opti Reader
12/8/14 8:43 p.m.

You can find fitment guides that list mounting type, extended and compressed lengths.

Info from tenneco's catalog.

Front Strut: Body Type B10 Body Length 13.219" Compressed Length 14.417" Extended Length 21.051" Travel Length 6.634"

Which when equipped with lotus suspension are apparently the same as Saturn SC coupe SL sedan and SW wagon (thats from SACHs fitment info)

You could get a bilstein insert valved for your fitment and install in your strut housings, have only seen this done, never attempted so I dont know how difficult it is.

On some cars when you lower them you can cut the mount to move the pistons resting place when at ride height and effectively recenter it (regain compression stroke lost when lowering) but from pictures of your strut mounts I dont think its possible, but I dont have one in my hands to look at, but since they mount with two studs, it MAY be possible to just find a mount for a different vehicle that is a little taller.

I have no idea how to look up different struts that will also fit, there are too many variables for my brain to consider.

On the rear I cant find any fitments for the lotus suspension shocks, so no measurements, they all say w/o lotus susp, and I have no idea what the differences are.

Brett_Murphy
Brett_Murphy GRM+ Memberand UberDork
12/8/14 11:27 p.m.

This is of interest to me.

chada75
chada75 New Reader
12/9/14 5:21 a.m.

Don't hold me to this but I was always told that "Gas" Shocks/Dampers will raise a car.

foxtrapper
foxtrapper UltimaDork
12/9/14 5:22 a.m.

Download the monroe catalog. It will list all the shocks and their dimensions and ends so you can figure out what off the shelf unit will fit your needs. If one does indeed exist.

Zip ties work very well at holding springs in place. Just do one end.

dean1484
dean1484 GRM+ Memberand UltimaDork
12/9/14 7:25 a.m.

We had similar issues with springs in our MR2 years back and fixed it by zip tying the springs to the top and bottom mounts. Solved the problem

f6sk
f6sk Reader
12/9/14 8:07 a.m.

Right. I downloaded the Monroe catalog. There are zero perfect fits for the rear. However with minor modification (change the lower through bolt form 10m to 12 mm) I can use a 78 Bronco shock. So, will that be too beefy? Or is this an awesome cool great idea to get a better/track appropriate shock?

Dusterbd13
Dusterbd13 SuperDork
12/9/14 8:52 a.m.

Do it. Should work well.

iceracer
iceracer PowerDork
12/9/14 10:35 a.m.

You could always put a chain on it to limit droop.

f6sk
f6sk Reader
12/9/14 7:29 p.m.

For those looking to modify their setup, the Monroe site has a list of shocks/struts and their lengths.

http://www.monroe.com/assets/downloads/english/MonroeMountingLengthSpecifications.pdf

Kenny_McCormic
Kenny_McCormic PowerDork
12/10/14 12:17 a.m.

Look up the spring rates for the bronco, compare them to your own.

f6sk
f6sk Reader
1/22/15 11:57 a.m.

And I found something! A koni off of a saab 9-3. It is a bit shorter, a bit wider and the through bolt is bigger. But I can work with that. Koni adjustability FTW!

Kramer
Kramer Dork
1/22/15 1:08 p.m.

Gas shocks differ from hydraulic shocks by having a gas-filled bag stuffed into the fluid reservoir. If the fluid is agitated, the gas bag slightly expands and prevents the fluid from foaming. There isn't a huge amount of gas, nor is there a large psi pressure.

chiodos
chiodos New Reader
1/22/15 3:01 p.m.
Kramer wrote: nor is there a large psi pressure.

Pressure ranges from 100-300psi. Id call that a "large psi pressure"

tuna55
tuna55 UltimaDork
1/22/15 3:15 p.m.

I had this thought a while ago. Not only is he asking "what will fit" but also "will it be valved correctly"? I don't know the answer to the last one.

pres589
pres589 UltraDork
1/22/15 3:37 p.m.

I'm betting the average Saab 9-3 convertible runs a much stiffer rear spring than a sub-ton Isuzu I-Mark. These might be awfully stiff for the application.

I recently worked a set of Koni SRT.R rear shocks meant for the early-2000's VW Jetta onto the back of my Suzuki SX4. The SX4 has really soft rear springs and honestly I wish I had gone with something else as far as a shock upgrade. The Koni's are too stiff, in my estimation, and I'm left with a somewhat nervous, stiff ride. There's also some issues with differences in the mount and they're noisy over bumps. Just a word of warning.

f6sk
f6sk Reader
1/22/15 9:00 p.m.
pres589 wrote: I'm betting the average Saab 9-3 convertible runs a much stiffer rear spring than a sub-ton Isuzu I-Mark. These might be awfully stiff for the application. I recently worked a set of Koni SRT.R rear shocks meant for the early-2000's VW Jetta onto the back of my Suzuki SX4. The SX4 has really soft rear springs and honestly I wish I had gone with something else as far as a shock upgrade. The Koni's are too stiff, in my estimation, and I'm left with a somewhat nervous, stiff ride. There's also some issues with differences in the mount and they're noisy over bumps. Just a word of warning.

Great this is exactly the kind of info I was looking for. I'm hoping that the adjustability part of the konis will allow me a tolerable ride.

wlkelley3
wlkelley3 SuperDork
1/22/15 9:13 p.m.
chiodos wrote:
Kramer wrote: nor is there a large psi pressure.
Pressure ranges from 100-300psi. Id call that a "large psi pressure"

Nah, 1,000 psi or more is "large psi pressure".

But then I deal with aircraft hydraulics.

Opti
Opti Reader
1/22/15 9:43 p.m.

Congrats. I loved the konis on the Z28, ran them at full soft and a few sweeps off full soft and they rode and handled great.

If they are too stiff, see if revalving is an option, if not at least you have a fitment and can find some billies which pretty much everyone revalves.

ebonyandivory
ebonyandivory SuperDork
1/23/15 6:23 a.m.

I used Crown Vic shocks on my Samurai.

Not sure if that's a similar situation but you can see why it's a good idea in theory.

dean1484
dean1484 GRM+ Memberand UltimaDork
1/23/15 6:44 a.m.

The biggest thing with shocks and struts is when you lower a car you don't want to crash the piston in to the bottom of the housing. Koni makes stops that go on the piston to prevent this. They are sold separately. On a side note if you crash a shock you void the warranty.

pjbgravely
pjbgravely Reader
1/23/15 11:51 a.m.

Why don't you use a limit strap? Topping out a shock seems like a poor way to hold a spring in.

f6sk
f6sk Reader
1/23/15 12:14 p.m.

made a bushing for the bottom

f6sk
f6sk Reader
1/23/15 6:55 p.m.
pjbgravely wrote: Why don't you use a limit strap? Topping out a shock seems like a poor way to hold a spring in.

Yes!, but the future goal is a lowering spring, and perhaps a helper spring to keep things in place.

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