How do I raise the rear with Jag IRS?

[Young1]

My Unique with Jag IRS looks great empty. With 2 people, full tank and stuff in the trunk she quats low and gives me even less oil pan clearance. It has two non adjustable coilover shocks per side. Will the coil spring boosters/spacers sold at JEGS fit? will they work to get me up 1 1/2 inches? How many are needed per spring? Are they a good idea?

[mickmate]

1 1/2" is too much for a spacer as you have to compress them to get them together. Sounds like you need stiffer springs. Measure the diameter of the wire in the springs and see if it's 7/16". If it is look for 1/2" springs. There are several height adjustable coil overs available for the Jag applications too.

[Dwight]

how old are the shocks and springs?
A few weeks ago I helped my buddy replace the shocks and springs on his 92 Unique. His was hanging low in the rear end and the new parts helped.

Dwight

[Young1]

Kit was purchased fall 2007 and was titled a year later. Car has 3200 miles. I am looking for an inexpensive solution since I experienced a 55% salary cut this summer.

[sllib]

Have you talked to Unique? They probably know more about their car than anyone on this forum. I sympathize with you on the pay cut. I got a 100% cut this year and my car is sitting, unfinished, until I get back to work.
Bill

[Dwight]

I'm with you on the pay cut, I retired in Jan.

The Weavers told us to buy adjustable coil overs for $1000. Jeff bought stock aftermarket Jag replacement shocks for $400 delivered.

We found the rubber bushings in the mounting hole had rotted. Sometimes it would make a metal to metal noise when he was driving and the car drooped on one side. The new shocks have a hard plastic bushing not the soft rubber.

Dwight

[Snake2998]

I would guess that a half inch spacer at the bottom of each spring will make all the difference. Don't forget that you have almost a 2:1 leverage effect and a half inch will add almost 200lbs of pre-load on each side or 100 lb per spring assuming the springs are 200lbs per inch each so given the approximate 2:1 spring ratio (a wild guess) the spacers will cancel a 200lb passengers weight.

[Dwight]

I have a lot of pictures that I took when we replaced Jeff's shocks.

I did not see any way to raise or lower without major rework. I had to make a "tool" to install the springs onto the shocks with my 30 ton press. That's the hard part of the whole job. We had replace Ron's Jag front shocks on his Shamrock a few years ago and had worked out a system then.

I don't think you can install a spacer under the spring but if you did I don't think it will change the length of the shock.

Jeff's springs looked used, more rust pits than the years and mileage of his Cobra would have caused.

Dwight
If you need more pictures of the rear end email me at algunruner@aol.com

[CHANMADD]

The jag stock shocks had two mounting positions on the shock for the spring retainers. Also in th e rear they offered two different springs, one taller with more coils.Also my shocks are Gabriel 3 way adjustables, that have been on the car since 1989...
I have two replacements on the shelf, unfortunatley not adjustable by Gabriel mde in South Africa. So one should be able to get it right with stock Jag stuff.....I did.....

[Grubby]

Out of the ERA manual for the Jag based rear - "The ride height will change roughly equal to the collar height change."

So if you put a 1/2" spacer in all 4 shocks, you should get a 1/2" ride height increase.

I don't see any reason a small spacer would not fit if you used a proper spring compressor. 1/2" is pretty thick.

John

[Young1]

Dwight you are right. My springs look like they have rust pits too. Do you think I can use those rubber spacers that jam between the spring coils? Rather than compressing and removing the spring?

[Dwight]

I don't know. The last time I tried them was 30 years ago and it did not work. But today they may have better rubber spacers.

I looked at more of the pictures that I took and you can add a spacer between the upper shock mounting plate and the frame.
It may be 4 or 4 1/2" square with four holes, 1/4" or 5/16". Aluminum or steel would work. Easy to make and easy to install.

Dwight

[Dwight]

I think you can buy just the springs, maybe $40 each.

I found the picture of the upper spring mount.

You have to remove at least three of the bolts so you can remove the upper shock mounting bolt. Then you can put both shocks on.

You could cut four spacers out of pipe or heavy wall pipe to fit between the plate and frame. You'll need longer bolts. The electrical suppy houses sell 1 5/8" x 1 5/8" 1/4" thick square washers in what ever hole size you need. Lowes and Home Depot should have them.

If your springs have rust pits I would buy new springs. I think that would solve your problem.

Dwight

[Young1]

I will get the car jacked up and look at that more closely this week. I have noticed the spacers are aluminum on my car and different thickness on each side. I suppose to compensate for differences in weight and body alignment of each rear corner?

[Young1]

Today I added 7/8 inch thick flat aluminum spacer above the shock mount plate. Cut it, drilled it and bolted it in. It raised the rear 1 3/8 inch just like I wanted. Thanks Dwight for the insight. Car sits with just a slight tilt to the rear. Will be so much better with full tank, stuff in the "boot " and two people. This forum is awesome.

[Dwight]

Your welcome Young1,
it's nice that I can contribute something. I have received so much information from this site.

Dwight