Trying To Understand Lifting a KJ/CRD

woodtick · **Posted:** Sun Apr 15, 2012 6:40 pm

OK, I've always been told the only stupid question is the one not asked, :roll:

and I've never put on a lift. And I also understand that people such as Mr Mudd are fonts of knowledge. :SOMBRERO:

So, here it goes.

When talking about the different lifts for a CRD or gas KJ I see numbers to identify different springs (927's are rated @ 400#, 790's @500#). Are these numbers supplier specific or industry standard?

Are they stock length or longer?

The struts in these lifts, are they longer or just new, or top plate spacer?

Can I achieve a 2" lift in the front with stock coil and strut replacement and a spacer plate over the top, possibly also clevis shimming?

In the rear is a coil spacer OK with longer shocks?

How much clevis and spacer is safe?

See what I mean? I need help understanding. Buying a frankenlift etc. isn't in the cards so I'm looking for "maintenance items" that will achieve most of what I want under the watchful eye of the family CFO (wife). :wink:

Thanks,
Doug

cgass · **Posted:** Sun Apr 15, 2012 7:11 pm

Well I can help with some of the questions.
The springs are longer both front and rear.
The front shocks are the same size as stock, most people opt for a firmer "heavy duty" shock since the spring is firmer.
I don't believe it's possible to get 2" out of a top plate and clevis lift alone.
You could run spacers in the rear with longer shocks, but the ride will be worse and the springs will sag faster.

tommudd · **Posted:** Sun Apr 15, 2012 7:16 pm

Doug,
Where oh where do we start?
:wink:

Yes your stock CRD sprongs are rated at 410 lbs, 927 OMEs are 400 and OME 790s are 500. These are the rates of the OME springs, other companies may have different spring rates
The front"shock" is the same length as stock, don't need longer ones BUT OME seem to work best on the CRD
Now if you install a 1/4 inch top plate you will acheive 1/2 inch of lift, a 3/8 inch clevis will net you 3/4 of an inch so in theory if you did both you would of course get 1.25 inches of lift.
Oh and what works best is 3/8 inch clevis you can go to a 3/8 inch top plate to gain a small amount more.
You could install a rear puck/spacer to gain lift but ride would be the same and just gaining height is all
The best way of course is a full spring lift which you can do in the 700-750 range 4 springs/4 shocks ride and handling are so much improved over stock both on and off the road
Keep asking those questions, its the only way to learn :wink:

woodtick · **Posted:** Sun Apr 15, 2012 8:22 pm

Thanks Tom and cgass!

Is 3/8" top spacer and 3/8" clevis the max? or can I get 5/8" on both and get 2 1/2" total lift?

Just replacing the original springs ought to net me something compared to what I have now. I bought this CRD in January and even though it was never off-roaded, I'd assume the original stock springs have lost a bunch of the original height from the factory.

What do I use to hoist the rear evenly?

audiboy86 · **Posted:** Sun Apr 15, 2012 9:19 pm

3/8's is your max out any higher and you take the risk of the two going thier seperate ways while going down the road. And if it was me i would just buy it in pieces you know front spring then rear then shocks in the same order. The top plates and extra Isos for the rear can be had for about 200. I have a feeling if you do it this was the wife wont really even notice until the jeep is lifted. And then all you have to do is let her ride in it one good time and you probably wont be able to get it back. :ROTFL:

Randy B · **Posted:** Sat Apr 21, 2012 9:22 pm

Thanks Guy's this thread helped me understand more about lifting the KJ

At The Helm · **Posted:** Sun Apr 22, 2012 7:45 pm

If you were looking for an explaination of spring rates, they are just weight ratings. For a 500# spring, it takes 500 lbs to compress ot one inch, 1000 pounds to compress it two inches, and so forth.
Those 3/8" top plates are about $50 for two and rear isolators are like $6 each, usually four total are added.
If i were you i'd take the above advice and just collect parts, it wont seem that expensive and you'll be way better off in the long run. Thats pretty much what i've been doing anyway.

woodtick · **Posted:** Sun Apr 22, 2012 8:46 pm

Atthehelm wrote:

If you were looking for an explaination of spring rates, they are just weight ratings. For a 500# spring, it takes 500 lbs to compress ot one inch, 1000 pounds to compress it two inches, and so forth.
Those 3/8" top plates are about $50 for two and rear isolators are like $6 each, usually four total are added.
If i were you i'd take the above advice and just collect parts, it wont seem that expensive and you'll be way better off in the long run. Thats pretty much what i've been doing anyway.

Yeah, I'm going to have to squirrel away some $$. Lift, timing belt job, and I'd love to get a new Euro TC. Lifts are all new to me though, and this thread is teaching me.

DarbyWalters · **Posted:** Thu Apr 26, 2012 12:40 pm

Well in the mean time a set of 235/75/16s will fit on a stock CRD and don't look bad after a lift. You could go really cheap and just do the clevis lift in the front...235/75/16s...and a rear spacer and get pretty good results.

woodtick · **Posted:** Sun Jan 13, 2013 9:57 am

tommudd wrote:

Doug,
Where oh where do we start?
:wink:

The best way of course is a full spring lift which you can do in the 700-750 range 4 springs/4 shocks ride and handling are so much improved over stock both on and off the road

Keep asking those questions, its the only way to learn :wink:

OK time to learn more.
How much lift is ok before losing mpg or having alignment/ binding issues? Do I need a spring compressor for install? Is there a how to write up with pics? I am hoping to be able to do this in summer.

tommudd · **Posted:** Sun Jan 13, 2013 10:03 am

Woodtick
To start anytime you install a lift along with larger tires you will lose some MPGs
Nature of the beast, more wind resistance, heavier tires in most cases, changes to the overall gear ratio etc
You have a CRD so you can't lift as much as a gasser the regular way.
If I had one, go with the OME kit for CRds which includes the 790 front springs, OME shocks seem to work better from what i have heard with the CRD.
Spring compressor, I'd take them somewhere and have them done. The 927s takes quite a bit with those cheap hand compressors, at 500 lb the 790s are a bear to do.

woodtick · **Posted:** Sun Jan 13, 2013 10:13 am

So just take front shocks/ struts and springs to a local shop to have assembled? Can this be done prior to starting the job?

tommudd · **Posted:** Sun Jan 13, 2013 10:21 am

It can be done beforehand BUT you'll need a pair of top mounts and isolators

woodtick · **Posted:** Sun Jan 13, 2013 10:27 am

How much are those? Are the isolators the parts that squeak in the cold when the front suspension cycles like going over speed bumps or in and out of alleys? If so, shouldn't they be replaced any way?

tommudd · **Posted:** Sun Jan 13, 2013 11:03 am

NAPA Part Number: NS 905902
IMPORTANT INFO: Front Right Hand,Right
56.99 each

and no that is not what squeaks, its the sway bar bushings which get dirt and grime in there, spray them out good at the car wash

mikey1273 · **Posted:** Mon Jan 14, 2013 12:46 am

I will say that the OME Kit is what I got and it was just installed today on my CRD. I got the 790 springs and all OME shock/struts mine has not been measured yet after but it looks 2 or maybe even 2 1/2 inch taller. I did not use the 3/8" top plate Jeff the mechanic Friend that mostly did it for me tried on one side and there were not enough treads on the bolts to get thing together that he felt ok with it so we left that out. I did not do any Clevis either. The 790 springs did fit his compressor ok but compressing them to get the strut in you could see was visibly challenging the thing but it worked.

I want to take and post pics of my jeep but it was starting to get dark and I only had my cell phone camera with wimpy flash so the pic was low quality.

I also need to take it for an alignment this week. I have yet to decide where to take to.

Edit: I have pics of mine in the Jeep pics section now :JEEPIN:

tommudd · **Posted:** Tue Jan 15, 2013 11:17 am

mikey1273 wrote:

I did not use the 3/8" top plate Jeff the mechanic Friend that mostly did it for me tried on one side and there were not enough treads on the bolts to get thing together that he felt ok with it so we left that out.

Not to start anything but to clarify, there is plenty of room for 3/8 inch plates if anyone wants to run them. Of course only Boiler and RRO had them.
I've installed 8-10 sets plus ran them on mine for several thousand miles with no issues.

TheBlueKJ · **Posted:** Tue Jan 15, 2013 11:41 am

tommudd wrote:

mikey1273 wrote:

I did not use the 3/8" top plate Jeff the mechanic Friend that mostly did it for me tried on one side and there were not enough treads on the bolts to get thing together that he felt ok with it so we left that out.

Not to start anything but to clarify, there is plenty of room for 3/8 inch plates if anyone wants to run them. Of course only Boiler and RRO had them.
I've installed 8-10 sets plus ran them on mine for several thousand miles with no issues.

JBA has them I saw them the other day on his listings for parts for the KJ when I was browsing.

tommudd · **Posted:** Tue Jan 15, 2013 12:04 pm

1/4 inch unless he just started making 3/8 inch
haven't looked at all of the "extras" for a while :wink:

TheBlueKJ · **Posted:** Tue Jan 15, 2013 5:06 pm

Well then I guess he just started the 3/8" then :lol:

Trying To Understand Lifting a KJ/CRD

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