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Unread 08-20-2014, 02:25 PM   #1
json1123
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1979 CJ7 
 
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Location: Corona, Ca
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Lifts, why are they so confusing?

One small word, lift, so many questions. The more I read, so many differing of opinions, I'm having a hard time keeping track of it all.

For starters I'm still a noob, this will be my first lift purchase/install for context. I don't have a problem with doing work, but the
more challenging the work (e.g. welding,etc) I am hoping to avoid in the short run, but not entirely against it.

As far as stance/looks go, I prefer a 4" lift on 33's. I will be doing mostly fire roads with an occasional trip somewhere more aggressive.

My set up: 1979 Jeep CJ7, 258 with T-150, Dana 30 and AMC 20 running 33's, and stock gearing which I know will require a change)


Lift Options under consideration are 2.5" lift, 2.5" + 1" body lift, or 4"lift:

From what I understand the impacts of each are:

2.5" lift:
required:
- install
- enjoy
possible/optional:
- tie rod flip or drop pitman arm (and is 1 better than the other? I have read that the drop pitman arm is a tad shorter than the stock one. This will result in a slight loss of turning radius and a bit of play in the steering wheel.)
- alignment (+ camber & castor corrections)
- extended brake lines


2.5" + 1" body lift:
- same as above + I have read as long as you go with, for example a Daystar 1" kit you should be ok with no extra mods, but the following I have seen mentioned.
- Extend the clutch linkaget? What about longer radiator hoses, relocating fan shroud, etc....?
- Also need to uncollapse/adjust the steering shaft from the firewall to the Box

4" lift:
First, start with a kit that comes with:
- drop pitman arm (still not sure about this as the more I read looks like I'm better off with a Tie rod flip, and that this kit works well http://ok4wd.com/featured-products/r...-flip-kit.html) OR does the 4" require both?
- shocks
- longer U bolts
- springs obviously

Here I'm not sure which is required vs optional, here is what I have seen mentioned in both contexts:
- alignment (+ camber & castor corrections) - this will be required, just here to be comprehensive
- extended break lines
- T-Case drop
- extended drive shafts or cv shaft
- pinion shims
- drop pitman arm/TR flip


I think any lift will also exaggerate any existing steering wear/tear/issues.


All of the difference of opinion is based on what? Preference? The age of the jeeps and the difference in wear/tear and previous done work? I"m
surprised that some people get away with so little mods and others seem to require such a comprehensive set of them.


What exactly is required/optional for these? Or is the answer the dreaded "it depends?"


Lastly, brand. It seems the ranking on JF is OME, RE, BDS, the rest. They also seem to decrease in price in the same order. Because of that, and the warranty I would lean towards BDS. I do wonder what the difference is between BDS and Skyjacker because BDS is still almost 1k.


Sorry for the novel. Any assistance here is greatly appreciated.

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Unread 08-20-2014, 02:38 PM   #2
CSP
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Camber will not change as a result of a spring lift. Caster shouldn't either as long as it's a CJ lift spring and you stick with stock length shackles.

A tcase drop is a band-aid repair for driveshaft vibrations, IMO. Leave the clearance gained where it should be and install a CV type rear driveshaft as the proper repair if you have driveshaft vibes. Many don't. With either of these alternatives you do one or the other as they are mutually exclusive to each other.

Longer shocks will be necessary with either 2.5" or 4". YOu only have them on your 4" list. Longer ubolts are only needed if the spring pack is thicker. Longer brake lines are required with either as well.
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Unread 08-20-2014, 03:01 PM   #3
json1123
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Quote:
Originally Posted by CSP View Post
Camber will not change as a result of a spring lift. Caster shouldn't either as long as it's a CJ lift spring and you stick with stock length shackles.

A tcase drop is a band-aid repair for driveshaft vibrations, IMO. Leave the clearance gained where it should be and install a CV type rear driveshaft as the proper repair if you have driveshaft vibes. Many don't. With either of these alternatives you do one or the other as they are mutually exclusive to each other.

Longer shocks will be necessary with either 2.5" or 4". YOu only have them on your 4" list. Longer ubolts are only needed if the spring pack is thicker. Longer brake lines are required with either as well.

Thanks CSP, so even with the 4", there is a chance I may not get driveshaft vibe and therefore not need a cv shaft?
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Unread 08-20-2014, 03:36 PM   #4
CSP
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Yes there is a chance. You never know until you drive it.
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Unread 08-20-2014, 08:07 PM   #5
delirious1
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Do a search. I made comments about the daystar mods needed
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Unread 08-20-2014, 11:00 PM   #6
BagusJeep
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Quote:
Originally Posted by json1123 View Post
All of the difference of opinion is based on what? Preference? The age of the jeeps and the difference in wear/tear and previous done work? I"m surprised that some people get away with so little mods and others seem to require such a comprehensive set of them.

What exactly is required/optional for these? Or is the answer the dreaded "it depends?"
Some owners are more willing to accept compromises than others.

Say you lift the suspension 2.5" and do not drop the pitman arm. The steering linkage is now no longer parallel, it is forming a <.

It is not a large < but it exists and your steering is compromised. What if you decide that is fine, within your limits, and do nothing?

Maybe the next guy decides that $30 on a pitman arm is fine and he lowers the arm.

It is the same with extended brake hoses. Some are willing to leave them as they look OK. Others wil realise the suspension is hanging up on the brake hose on every jump.

Vibration is all in the teeth of the beholder.

Standards in the modification department vary tremendously. If they did not we would not have the dreaded "PO" whose mistakes we are fixing.
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Unread 08-20-2014, 11:30 PM   #7
rixcj
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When I swapped in a set of YJ leaf springs, it gave me about a 3" lift. I had to adjust the caster, rear pinion angle, get new driveshafts, add a dropped pitman arm, adjust my clutch linkage, change all my tub mounts ('glass tub...different than a steel tub, as far as mounts go), and I'm sure there were a few more things I'm forgetting.

It seemed like it took forever, as I had to do several of the steps more than once to achieve satisfactory results.

So, in a nutshell, I'm one of those guys that had to do everything that CAN be done after a leaf spring swap.

Rich
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Unread 08-21-2014, 06:48 AM   #8
Megaram
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Quote:
Originally Posted by rixcj
When I swapped in a set of YJ leaf springs, it gave me about a 3" lift. I had to adjust the caster, rear pinion angle, get new driveshafts, add a dropped pitman arm, adjust my clutch linkage, change all my tub mounts ('glass tub...different than a steel tub, as far as mounts go), and I'm sure there were a few more things I'm forgetting. It seemed like it took forever, as I had to do several of the steps more than once to achieve satisfactory results. So, in a nutshell, I'm one of those guys that had to do everything that CAN be done after a leaf spring swap. Rich
I'm in your boat, driveline mods and all. Guess we were some of the unlucky ones.
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Unread 08-21-2014, 07:21 AM   #9
rixcj
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That may well be, but hopefully all our fine tuning will pay dividends as time goes on...

Rich
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There's a fine line between "hobby" and "mental illness".
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Unread 08-21-2014, 07:58 AM   #10
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Rick,
I'm assuming those weren't stock YJ leafs.
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Unread 08-21-2014, 08:10 AM   #11
Myren
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I've got pretty much the same Jeep as you, '79 CJ7 258. I needed new springs, u-bolts, U-bolt plates, shackles, bushings and more that I'm forgetting. Since I needed so many replacement parts I went with RE 4.5 lift. It has the extended brake lines, new pitman arm, shocks, greasable shackles & t-case drop kit. I haven't done the tie rod flip yet so I'm not sure if you'd need it or not.

Since you're mostly going to be on road I'd say it depends on the look you want and what parts you may need/want to replace. And regardless of the lift you get I'd go ahead and get an alignment any way. I got a lifetime for $200 or so.
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Unread 08-21-2014, 08:31 AM   #12
DFWRusty
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Buy what you feel is needed because you can always go back later and buy the drop pitman arm or cv drive shaft...etc... etc... I would highly recommend new brake lines and u-bolts. Your brake lines will be stretched just with a lift then you start flexing it's double duty on those old things. Your original u-bolts will probably get some sort of damage during the removal process and it will be easier to just have some new ones sitting on your bench ready to go.
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Unread 08-21-2014, 09:00 AM   #13
JeepHammer
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Quote:
Lifts, why are they so confusing?
Because you are screwing with the ENTIRE suspension & steering geometry.

------------

You are messing with the drive shaft & 'U' Joint angles in two planes.

You are messing with the pinion angle.

You are messing with steering link angles in 3 planes.

'Spring Lifts' mean deeper 'U' or bend in the springs,
Since your connection points didn't change that means longer springs to have the ends come out at the same points for connection as stock.
That means the spring gets LONGER that stock as you compress it...

It also means the axle MOVES forward and backward as you compress, decompress the spring...

--------------

Then there are the considerations for what you intend to do with the vehicle...

If you street drive very much, you will want a stiffer spring rate, less soggy bushings so the vehicle doesn't heel over and sway around at highway speeds...

If you are doing mostly low speed off roading,
Then you want SOGGIER springs, soggy bushings so the suspension/axle can move around where it gets the best traction...

If you are going to do both, then you want something that works reasonably for BOTH applications, which by common sense are mutually exclusive... Everything becomes a trade off from that perspective.

---------------------

If you intend to street drive, keep the firmer HARD RUBBER inserts at the frame/spring 'Eye' connections.
If you want 'Soggy' to absorb odd angle and jolts on the trail, then use the most soggy bushings you can find.

If you want good street handling then use a STIFF spring that doesn't let the frame/body sway around over the axles.
If you want the axles to get a good bite off road, then use a SOGGY spring that will allow for better weight distribution over the axle ends/tires.

If you want good road handling, then use a 50/50 or 60/40 shock rate so when you hit small bumps on the pavement the shock can compress and rebound quickly...
If you want good off road shocks, then you want a shock that is quick to Droop and get weight/traction in a hole, and give you reasonable compression when you hit a rock or off center bump...

Shock bushings are even a consideration...
Again, with highway driving, you want a reasonably hard bushing so the shock gets into the game faster,
While off road you want a reasonably soggy bushing to take up the 'Small' bumps you might encounter without getting the shock fully involved...

With a lift, you have COMPLETELY screwed up the steering link angle.
That means a lowered steering box or lowered 'Pitman' arm on the box to get that steering link horizontal again.
The more angle off horizontal the steering link is, the more 'Bump Steer' you are going to encounter, and the more leverage you are going to put on the Pitman arm and steering box, and the steering box mounting to the frame.

With road driven vehicles, you want a shorter sidewall tire, with more plies in the side wall.
This keeps the 'SWAY' induced between contact patch and vehicle rim down to a minimum.
When you off road, you want a TALL, SOGGY sidewall on the tire so the tire can deform to the terrain and get traction.

Lifts usually come with wider rims and wider tires.
This aggravates the CAMBER problems, especially when the rims don't have the proper backspacing.
Moving the wider tire out and away from the frame moves the CENTER of the tire/road surface contact patch, and that screws with alignment and scrub radius.
(scrub radius is comes from both tires NOT being turned the same amount when you turn the wheels, one tire 'Scrubs' sideways somewhat, and moving the contact patch around can cause too much scrubbing, steering problems around turns)

Lets not forget things like longer shocks to make up for the increased distance between frame mount and axle,
And longer brake lines, if you use rubber lines, the more rubber, the more swelling, and the more swelling the lower the pressure and slower responding brakes,

When you put on taller tires you are adding leverage to the wheel/tire (Distance between wheel center and road contact patch increases, like putting a 'Breaker Bar' on a socket/bolt)
And the brakes are less efficient since the leverage is working directly against the brakes...

And you raise the center of gravity up which gives that weight leverage over the suspension and contact patch at the road surface...
The suspension being what gives you control over the vehicle and all the stuff that is going on while driving...

-----------

It's not as simple as whipping on some lift shackles and some longer, more bowed springs and taking off down the road...
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Unread 08-21-2014, 09:36 AM   #14
CSP
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Holy cow......
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Unread 08-21-2014, 10:09 AM   #15
JeepHammer
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The gist of it is, short lifts require less modifications, while taller lifts require major modifications if you do the job correctly.
Unless you are going full off road, a short lift will clear reasonable tires and the vehicle will still be safe on the highway.

Just trying to explain why guys get into trouble with lifts, there is no short answer to that one.
The 'One Size Fits Nothing' kits screw you on both ends, highway and off road...
So know what is involved and know what you are talking about and you can make an educated decision on what parts you want.
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