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General Forums => The Mess Hall => Topic started by: drunkencityworker on December 14, 2009, 07:53:18 PM
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OK...since I made the mistake of buying new in box cj springs for my YJ off CL. I am hopefully soon going to be purchasing ranger pauls yj springs. I have already altered the mounts on rear when the 8.8 went in by making the lower mounts parallel to axle and installed the more upper shock mount relocation bracket. So I am going to measure droop and compression to try and get the correct shocks for my set up.
I have seen write ups on the pre '88 f250 upper shock towers for the front.
Questions
1. Has anyone done this mod
2. Did It make a difference
3. Should I take this opportunity to maybe add boomarangs in back and straight shackles for the front with a little bit of lift to give a better ride and articulation
Here is a link but its for a cj
http://www.in2jeep.com/fordshockmt.htm
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I installed the F250 towers on the front of my YJ and they worked out great, allowed me to install some crazy long Bilsteins to get the most droop possible.
Boomerang shackles work great in the rear to clear the crossmember when the suspension compresses, and they work good in the front to help prevent the shackle from folding under against the frame.
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I am sua. Is it still worth the work for shock towers
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It's a cheap easy mod, with minimal welding required. They're only $15 each at the ford dealer.
What is it you're trying to accomplish? For me, I came across some very long Bilstein 5125 shocks at a bottom dollar price, brand new. Using the Ford towers allowed me to push the shock further up towards the fender to allow for more shock travel, and it does away with that hokey post mount at the top of the shock, allowing for the more common eye mount.
If you want more shock travel and can't move the lower mount down, then up is the only way to go. My Bilstein's have about 14" of travel.
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Based on my inspection of my YJ with 4.5 inches of SUA lift, the lower shock mounts should be raised a bit (or the upper mounting point lowered) to allow more droop. The YJ seems to end up with the shocks pretty extended on level ground, allowing for limited droop. In my case it does not seem to limit droop with the Jeep lifted from the front bumper with a hi lift jack but it might limit forced droop a bit. This is with the 30.46" / 17.42" Skyjacker shocks (13 inches of travel, which should be plenty if correctly positioned). If you end up shortening the distance between the shock mounting points, be very careful you don't limit compression with the shock.
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I am sua. Is it still worth the work for shock towers
Can you benefit from the added travel SUA? Maybe a little but not much. But raising the top mount several inches will enable you to then raise the bottom mounts on the axle the same amount if they hang lower, so they are parallel to axle tube. One less thing to hang up on crap then. Every little bit helps and this is a cheap effective mod if you weld or have a buddy that does.
I don't recall exactly where those end up on a stock axle because I cut those off my D30 a long time ago, so I could be way off here, but IIRC they hung down several inches.
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This is a pretty common swap. It's almost routine on Pirate4x4 and other hardcore sites. Not only Jeeps buy Sami's as well as anything else that needs longer shock mounts. With longer shocks, I doubt they will be your limiter any longer. If you've extended or relocated your brake lines then all that would really be limiting your suspension would be the leafs.
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Based on my inspection of my YJ with 4.5 inches of SUA lift, the lower shock mounts should be raised a bit (or the upper mounting point lowered) to allow more droop. The YJ seems to end up with the shocks pretty extended on level ground, allowing for limited droop. In my case it does not seem to limit droop with the Jeep lifted from the front bumper with a hi lift jack but it might limit forced droop a bit. This is with the 30.46" / 17.42" Skyjacker shocks (13 inches of travel, which should be plenty if correctly positioned). If you end up shortening the distance between the shock mounting points, be very careful you don't limit compression with the shock.
Sounds like you could benefit from longer shocks, and if they come close to bottoming out, you may need to extend your bumpstops. It's all about the droop anyway.
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I'm doing these when I three link the front.
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Sounds like you could benefit from longer shocks, and if they come close to bottoming out, you may need to extend your bumpstops. It's all about the droop anyway.
The thing I've noticed is that they are not even close to bottming out because the tire hits the fender way before (before the axle hits the bumpstop too). On the other hand they may be pretty close to limiting droop. So it looks like what is wrong is the positioning. The lower mount should be raised a bit so that droop is not limited and it can be raised without getting into compression limiting. I think shock mounting points should be studied carefully before modding. Some suspension types will not benefit from longer shocks if they are not positioned right.
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The thing I've noticed is that they are not even close to bottming out because the tire hits the fender way before (before the axle hits the bumpstop too). On the other hand they may be pretty close to limiting droop. So it looks like what is wrong is the positioning. The lower mount should be raised a bit so that droop is not limited and it can be raised without getting into compression limiting. I think shock mounting points should be studied carefully before modding. Some suspension types will not benefit from longer shocks if they are not positioned right.
i think the idea is that longer shocks have more travel so that's why he wants taller shock towers (if i got it right) - but from what you are saying it sounds like the problem is not the upper mount for the shock - i haven not research it or check to see how much it allows to go up/down in front so i can't really tell if that is the case there, but i did look at the rear and in my case the up-travel was limited by the shock absorber and not the bumpstop (that's even with the low hanging mounts on the D35) so in that case an upper mount shock relocation would be beneficial. Also, i think he's got the tube fenders so probably an extra couple of inches of room before his tire hits the fender (or flare)
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Yup, it depends on the specific setup. That's why I recommend that the situation be studied a bit before modding. If I were to raise my front upper mount by one inch or more and then go with 14" travel shocks instead of my current 13" travel shocks, I would get no additional droop. If I just installed 14" travel shocks with the existing mounts, I would get 1" more droop but I would need to be careful of limiting the compression with the longer shock body. I've looked at a CJ7 and they run shorter shocks in the front (compared to YJs) and seem to get about the same range of suspension movement. It seems to be because on the CJ7 the shock is better positioned relative to the movement that the leaf springs and tire size allow. The stock YJ seems to me to have a particularly borderline configuration of shock mounting points (too far apart) which tends to limit droop.
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trust me there is very little movement in the cj leaf springs.
1 shorter
2 narrower which means thicker leaves
3 thicker leaves means less flex
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If I was my choice, I would do it. You will need three different measurements for any shock. A extended length, a compressed length and a neutral length. Typically stock shocks are shorter then what you'd need. If you take the track bar off and disconnect the swaybar the shocks or the brake line will be you're limiting strap. This is a good way to damage either.
One reason for going to a longer/larger size shock is to keep it cool. Smaller shocks will heat up faster. A larger shock body should dissipate heat better as there is more surface area as well as fluid. The stock shocks were were also not chosen for their optimum travel since they really where not thinking about articulation, especially with a YJ.
The normal set for a 2.5L was 4/5 packs. There was also 5/5 as well as 5/6. Also, keep in mind that the YJ was 1" lower then the CJ. The main reason for the YJ being the way it was was because of the roll-over claims from the 60 Minute piece back in the 80's. AMC designed a Jeep that was less prone to rolling over and what they did was to lower the CG and lock up the suspension.
Some other considerations; the suspension is basically a lever. As you move away from the fulcrum you there will be more travel. Conversely, as you move closer to the fulcrum you will have less travel. The CJ-7's axles are not only narrower but the frame is as well. This is also why, if you triangulate a shock, you will use less travel. If you triangulate a shock 45* you will only use about 50% of the shock's travel. Although front shocks are usually mounted vertically while the rears are usually at an angle of some sort.
So, do the swap, measure and buy the appropriate shock.
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Triangulating shocks lowers teh effective valving rate as well, essentially making them seem "softer" I find the response is smother an the small bumps knock out fewer fillings.
Dave
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If you want more droop: If you raise the upper mount say 4 inches, make sure you can get a shock that is at least 5 inches longer extended than the ones you have now. In my case, the current shocks are about 30.5 extended with 13 inches of travel. I found some Teraflex shocks that are 33 inches extended with 14 inches of travel and are supposed to be used with the revolver shackles. If I were to install the extended mounts 4 inches higher I would actually lose 1.5 inches of droop. Oops! So a better plan would be to extend the upper mounts only about 1 inch and gain 1.5 inches of droop. 0.5 inches of compression would also be lost so I would have to be careful about bottoming out the shock. If your tires are limiting the compression, it would be cheaper to extend the bump stops and lower the upper mount (or raise the lower mount) to get the extra droop you want.
Here are some examples of Rancho long travel shocks:
34“ extended length shocks offer 14” of travel
36“ extended length shocks offer 15” of travel
Bilstein offers several with about 14 to 14.5 inches of travel with from about 33" to 35" extended length. Then they jump to 17" but those are over $300.
So about 14" is about all you can reasonable expect to get. As you can see the extended length grows more than the travel and the travel does not increase all that much. You have to be very careful to position the shock exactly right to get the full benefit. A lack of analysis could make you end up with the opposite of what you wanted to achieve.
The point is to be careful, think about your budget. What shock will you be able to afford? Make sure you don't end up having to buy some really expensive specialty shock. Will your springs actually allow you to take advantage of the added shock travel?
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If you go for longer shocks to get more droop make sure the rear drive shaft CV joint does not bind at full drop, the centering ball is very short lived if the CV joint binds at full droop