When I rebuilt the rear end some years ago in my restoration, I used Boge shocks. Not sure why, probably because they were cheaper. I got distracted by another resto, so now, 10 years later, I am working the front and bought a pair of SPAX. The four Boges cost the same as one Spax, but I guess at this point in the restoration I don’t care about money anymore. So will mixing the front SPAX and rear Boges have nasty consequences? I could buy Boges at Terrys if I need to. I just want to be sure everything will work well and be safe.
The car doesn’t care what brand of damper you have, just that the damping rate is appropriate, front and rear.
When I was way into classic Minis about 20 years ago, Spax had a reputation with those “in the know” for taking wild stabs at their damping rates, and having a pretty narrow window of adjustability. I understand they’ve got much better in recent years, but I’d start with them on their softest setting, and if they feel stiff compared to the rear, you might want to consider another brand.
For what it’s worth, I have Spax strut inserts on the front of one of my Cortinas, and they are fine. I also have Konis on the rear
Also John, you may wanna check Terry’s again - I don’t think Boge front or rear shocks are available anymore, at least not for S1 and S2 E’s. I’ve been looking for a set of front ones for my S1.5 and coming up empty!
I’ve used just about them all over 50 years, multiple E Types, racing and slaloms etc. The best I think are Spaxx adjustable but I’ve had mine for 25 years and can’t obviously comment on any changes made to them since then. They just seem to work better. They need better bushings than they used (again 25 years ago) - I replaced the stock bushings which had completely deformed 5 years ago with poly from an aftermarket source.
I don’t care for Gaz - two things - the fronts are real wimpy in size, and I’ve long been told that size matters in shocks, but the backs are ok -bigger than the front even though there are 4 in the back. Causes me to believe the fronts are an afterthought to the company. Also mine came plated and have corroded badly - bimetallic action it seems.
When I bought my fhc 5 years ago. It came with Koni Classics - a black painted shock, on the front. They are very impressive - adjustable by the usual Koni method (at least doable on the front as opposed to the rear). Years ago I put orange Koni’s on my '68 ots, front and back, but they were unacceptably hard at the softest settings. That’s an experience others have reported.
So today my coupe has Classic Koni’s up front and Spaxx in the back., and my 68 ots has Spaxx up front and Gaz in the back. I autocross the 68 and the Gaz are easier to adjust than the Spaax - that’s why they are there.
Whatever you buy you need to make sure the rear shocks when fully extended are at least the length of the stock Jaguar shocks.
I first replaced my rear Konis with Gaz because I wanted the adjustable perch, and for several years I drove with the front Konis on. I finally swapped them too just because they were harsh feeling and a pain to adjust because they have to be removed to do so. You can only tell by driving it, if yours feel “balanced” or not.
I’ve got the rear back on the car and noticed that the springs look too short on my new Gaz shock/springs. The shock overall length matches the old ones but springs are only 9” long. I realize the perches are there to snug them up but I’m worried that I may have gotten the wrong springs. In the photo, the adjustable perches aren’t putting any pressure on the springs.
It looks like you’ve still got loads and LOADS of adjustment on the spring perches, so you should be able to bring the car up to where it needs to sit.
How did you select these springs? Did you match the spring rates to the originals?
With adjustable spring perches the spring length isn’t terribly important as long as you can get to your desired ride height. What is important is spring rate. It needs to be close to stock if you are looking for a stock ride.
9" length should be fine, btw. I’ve run 8", 9", and 10" on my E types over the years (with adjustable perches) trying out different rates and ride heights.
Try to have the shocks settle (from full extension) about a third of their of their full travel with just the weight of the car.
Start there and fine tune for ride height, ground clearance and bottoming.
My 2 cents.
Jaguar specs for the rear springs were: Early cars: Free Length 10.1", number of coils 9 3/8, Late cars 10.5" and 10. Wire diameter for both is .432". E Type springs have “Finished Ends” which is meaningful in determining the number of coils. See: Counting Coils - The Spring Store
A coil spring is a coiled torsion bar, it works the same way, as the wire in both twists, it does not bend - the critical things are wire diameter, and number of coils. The number of coils determines the length of the wire in the spring - the more wire the softer the spring. The wire diameter also determines the spring rate of the coil. Surprising to most is that the type of steel used in the wire doesn’t make all that much of a difference. An important part of the design is not having the coils so close together that they bind on compression.
Your springs are too short, and appear to have about 9 coils. Don’t know the wire diameter. They will be stiffer than stock, all other things being equal - again I don’t know if that’s the case as wire diameter impacts this. They may work fine with the adjustable perch.
Just that the springs are shorter than the originals. That’s got to make the ride a bit harsher. Since I’ve never driven the car with the original springs and the time I drove an E-type was 30 years ago, I’ll probably be okay with it.
