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83 CJ7 350 tbi, TH350, D300 twin sticked & clocked, narrowed Chief D44 Eaton Elocker & Moser shafts, Explorer 8.8 Detroit locker, 410's, RE 4.5" spring lift 1" body lift, 35" Claws, cage tied to frame, Corbeau baja seats, HD tie rod and draglink, u-bolts flipped, custom skid plate and sliders, Warn 9.5ti winch with Amsteel synthetic line
First complication: the spring perches I ordered may not work out as well as I had hoped.
you will notice that they are quite a bit longer and "taller" than the originals. I think these would be just right for a SOA but that is not the plan. If I were to use them they will drop the rear axle 7/16" and I don't know what problems the added length will cause in spring stress in a SUA arrangement.
Other than that they are very well made and fit perfectly. Any thoughts?
yup you got the wrong perches for the SUA. take a sharpie to them and figure out what size you want them to be, trace the right dimensions and take them to a welding/metal fab shop and they should be able to cut them to the right size with a plasma cutter. I would say hit em with the cut off wheel but the inside curve for the axle tube will be a PITA. or cut the extra length off them and get a new set of shackles that will lift the rear 1/2".
FWIW I installed the same set of perch's under the other CJ I built with no noticeable side effects from it.
1978 CJ7
Silver paint with black hard top on 33" radials & eagle alumium rims. Good looking ride and have done lots of work to make it look and run great.
Stock equipment is 258 carb, power brakes, power steering, hard top & hard doors (per vehicle gross weight) tilt steering wheel, big brake package with large rotars & drums, T18 Trans with low 6.4 granny gear, Dana 20 transfer, Dana 30 front axle, Dana 44HD rear axle with 3.73 gears. True Trac ft & rear.
I was around jeeps in the 70's and drove a 1973 Jeep Truck. My family had 4 jeeps at the time. We also joined a jeep club back then too. So about 6 years ago looked for a Jeep CJ and found the vehicle above.
First complication: the spring perches I ordered may not work out as well as I had hoped.
you will notice that they are quite a bit longer and "taller" than the originals. I think these would be just right for a SOA but that is not the plan. If I were to use them they will drop the rear axle 7/16" and I don't know what problems the added length will cause in spring stress in a SUA arrangement.
Other than that they are very well made and fit perfectly. Any thoughts?
I have the same RuffStuff Specialties Replacment Spring Perches.... and I installed a Dana 44 rear for my CJ7 . I also saw some of the same points you did. I do have a few thoughts for you...
These are HD spring perches , lazer cut, no hesitation to say good stuff
Longer perches will lower and stiffen spring a bit, because its on the curved side of spring and with the U bolts will squeezed down the longer perch on the inside/top of the CJ spring. Mine rear end did get a bit stiffer..... a side affect did not need.... my CJ was very stiff already.
Dana 44 pumpkin has 1/2" more clearnace than the AMC20 , I saw you mention the longer spring perch is also about 1/2 taller..... I noticed this and the perch height with a STD CJ spring mount will lower the rear end about 1/2" and will also flatten the spring curve a bit. So you gain 1/2" below the Dana 44 pumpking vs the AMC20 axle.... The CJ will squat a bit more with a flattened spring.
AXLE WRAP.... The longer spring perch will cut down axle wrap. As the rear will bit/traction and unload/spin the axle will/can put torque on the axle springs and allow the pinion to push up (forward launch) and can bind the drive shaft on high torque low gear situation.... SO the longer spring perch does have a benifit with high HP or high torque gears will control the rear end better...
Guys with high Hp engines may like the longer perches mech advantage to cut down on axle wrap. Axle wrap will hurt your traction and as the pinion moves up/down can also bind the drive shaft causing failures and vibrations...... This could be good solution for lots of CJs also...
Shorten Perch...... The longer perch can be cut down by inch or so on each side, remove 2" or so from each perch. This will cut down on the "flatening" of the spring arch. Will Allow for a softer spring and more arch. GUESS on my part but the more LIFT on the spring the more the longer preches will remove more of the arch. So I have a 2.5" spring lift and saw the spring was flattened a bit. 4" lift.... guess will have more spring flatening and thus more affect with the longer perch....
My suggestion and actions?
MY CJ7 springs are very stiff..... I put in Dana 44 rear HD, regeared, and locked front and rear. The CJ springs have been pushed more with the lockers/ flexed more and have loosened up compaired to the first 4 yrs of use. So, yes USE can soften up the spring ride... ON the rear now I have NO AXLE WRAP and a smooth double track when I try to break loose on gravel.... so doing its job. IF i do work back on axle for some reason I would remove about 1" from each end of the longer perches to maybe the stock AMC20 lenght.... the AMC20 was longer & wider than the Dana 44 spring perches. I would use the old perches as a guide to lenght... EAsy to cut long perch shorter when in hand but harder once welded on axle. Also that Dana 44 has 1/2 axle tubes.... will need a good welder to attach properly..... I paid ot have mine welded on since the welder I use is smaller.... cost me $20 bucks to do axle perches and few other pcs too.
The Three holes on replacement perch...
The extra holes can be used with lift to keep the stock drive shaft. Taller springs and can use the closer hole on perch and the drive shaft may stillhave the lenght to be used with the lift spring and still have a proper lenght.... Move it back to the furhter hole if lowering spring lift and drive shaft might be too long in that case....
During a wheeling 4 day wk end.... I collasped my AMC20 rust spring perches.... Prev Owner put angle shims under the rear axle perches and they were a bit rusty after 35 yrs. From torque and the axle shims being a bit narrow.... the rear of perch collasped. My axle could now wrap and turn / rotate with the extra room on a damaged collasped NON flat perch.... When pushed up I had a drive shaft vibration... I was 220 miles from home and was able to drive it home.
Been there, saw many of the same considerations, thought this would help you.
If you want that 1/2 height back... could always have a machine shop take out the extra height.... Hard to do at home but a machine shop could do it for you. Just a thought.
I think they are the best spring perches on the market.
Ruffstuff and - Barnes4WD.com - Off Road Fabrication Parts rock. You can use Pirate10 to get a discount at Ruffstuff but Barnes is still usually a bit cheaper. Both have great products and service
I am kind of thinking of going with 1" over sized rear shackles and shortening the perches about an inch on each end.
I could re cut the 2 2/4 radius to drop it but, damn, they fit so sweet.
Now that I am getting into this can anybody tell me if the Dana 44 is the same length as the AMC20 from axle center to u-joint? This will have a lot to do with which hole the spring is set in and how the perch is shortened.
I bought the complete Ruff stuff kit with the plates and U bolts but to be honest, I have not taken them out of the wrapping paper yet to look at them.
I think i have just about decided to pick up a hole saw on the way home and lower these perches as far as possible, just have to leave enough room for the spring stud to fit. I can't talk myself into the 1.5 inch lift shackles.
I bought the complete Ruff stuff kit with the plates and U bolts but to be honest, I have not taken them out of the wrapping paper yet to look at them.
I think i have just about decided to pick up a hole saw on the way home and lower these perches as far as possible, just have to leave enough room for the spring stud to fit. I can't talk myself into the 1.5 inch lift shackles.
IO,
Might be interesting trying to cut that with a hole saw an keep it level on both sides.
Know someone with a Bridgeport?
If it was me I would clamped that on the table and to a right angle fixture and make sure to put a piece of aluminum for table protection between the the bottom flange and the table.
I would put a large fly cutter or boring bar in the mill and bore it out from the top down. Make sure your spring flange is at 0 degrees vertical & horizontal so that both your perch flanges are cut to the same height.
Also make sure since that was a burned plate that your grind off the area near where the burned cut & slag is to take some of the temper away so you don't damage the tool on the way in.
Just a thought!
You are right on all points and I thank you for this input.
Actually I do have an antique horizontal mill that I can set up to carry a hole saw. You would be impressed how well it works when you can secure the work and the saw has a true and solid center.
I have put a 2" half hole through 1" plate and was amazed at how fast I could feed it. With this set up I should be able to clamp the spring surface to the table and cut both radius down 1/2"+ both sides at one set up and dead square.
IO,
Might be interesting trying to cut that with a hole saw an keep it level on both sides.
Know someone with a Bridgeport?
If it was me I would clamped that on the table and to a right angle fixture and make sure to put a piece of aluminum for table protection between the the bottom flange and the table.
I would put a large fly cutter or boring bar in the mill and bore it out from the top down. Make sure your spring flange is at 0 degrees vertical & horizontal so that both your perch flanges are cut to the same height.
Also make sure since that was a burned plate that your grind off the area near where the burned cut & slag is to take some of the temper away so you don't damage the tool on the way in.
Just a thought!
You are right on all points and I thank you for this input.
Actually I do have an antique horizontal mill that I can set up to carry a hole saw. You would be impressed how well it works when you can secure the work and the saw has a true and solid center.
I have put a 2" half hole through 1" plate and was amazed at how fast I could feed it. With this set up I should be able to clamp the spring surface to the table and cut both radius down 1/2"+ both sides at one set up and dead square.
IO
Sounds good , sometimes those hole saws have a tendency to wonder a little, just keep your feed and speed down a little and use plenty of coolant...........no reason to rush, you should be fine.
OK tonights project was successful. lowered/raised the perch radius by 1/2". This should put me to within 1/8' of where I once was if you don't count the bigger axle tube diameter.
I may be over thinking this but I paid good money and put a lot of work into what Limited lift I have. I don't want to give up a 16th without a fight.
