Last week, I built a spring compressor to disassemble the used set of Spax adjustable shocks and springs that I’d bought for my Lotus Europa. The shocks tested out fine: They were neither blown nor seized, and the adjusters firmed and loosened the damping.
So, just reassemble them and install them, right? Not so fast.
As I’ve said, in addition to replacing broken or worn-out parts, one of the goals of the front-end refresh was that, while I had things disassembled, I wanted to try to lower the nose of the car slightly. U.S.-spec Europas like mine had the nose artificially high in comparison to the European versions to comply with federal headlight height standards. Yeah, I know; people laugh when you say that you want to lower a Europa whose roof is already only 42 inches above the ground, but if you see a stock S2 or a Twin-Cam Special like mine, your eye will immediately be drawn to the inappropriately large amount of space above the front wheels as compared to the rears.
These days, to lower the nose of a Europa, most people would buy a full set of shocks and springs with adjustable spring perches, thus allowing the height of both the front and the rear to be tweaked, but the $1300 cost was outside my budget. In contrast, I bought the used set of Spax shocks for $225. They’re easily 30 years old and, with adjustable shock damping but with fixed spring perches, were the trick thing to install in the 1980s. It was my hope that, since these were an aftermarket performance modification, someone had already outfitted them with lowering springs, but the fellow I bought them from had no idea. It turned out he’d found them and some other Europa parts in a storage area he was cleaning out. So a secondary reason for taking both the original coil-overs and the Spax set apart was so I could measure the uncompressed length of all the springs, see what they actually were, and decide which, if any, to put back on the car. After all, I assumed that both the shocks and the springs that were in the car were original, but I didn’t really know.
The front springs that were originally on the car had a 2.5-inch inner diameter and were about 12 inches long, but to my surprise the springs from the Spax shocks turned out to be two inches taller (14 inches). The coil thickness was also slightly larger. I did some reading of spec sheets reproduced from original Europa shop manuals and learned that they were probably the stock springs from an earlier Series 2 Europa. Obviously, I was glad I’d gone to the work to disassemble and measure them.
So, if I wanted to lower the nose of the car, I needed shorter front springs. I could get those either by buying new ones or cutting a few coils off the ones I had.
Now, lowering a car simply by using shorter springs and making no other changes has limits. The springs and shocks should work as a system. When they’re mounted on the car, you want the weight of the car to partially compress the spring, giving it and the shock room to compress and rebound without hitting either the lower or the upper extension limits. If the springs are mounted on the shocks, as they are on the Lotus, the maximum height is limited by the extended length of the shock, and the minimum height by the compressed length of the shock, possibly minus the height of the fully compressed spring. Regardless of whether the springs are shorter than stock, if they’re very stiff (have a very high spring rate), they’ll hardly compress even under the weight of the car, and the car will feel like it’s up on its tippy-toes. If the springs are very soft (very low spring rate), they’ll sink under the weight of the car, and the car will settle closer to the bottom end of the shock. If the springs are soft and too short, the suspension is likely to easily bottom out over bumps. For these reasons, it’s a little risky making willy-nilly individual changes yourself, and it generally is best to buy a shock and spring package that has been vetted as working well as a system. If you do make changes yourself, small ones are generally best.
If you read up on cutting springs, you’ll find you’re told that A) Cutting coils changes the spring rate (makes them effectively stiffer); B) Cutting one or two coils doesn’t really change the stiffness that much; and C) You need to pay attention to how the cut end of the coil fits the spring perch both before and after cutting. On the vintage BMWs on which I’ve cut springs, the perches have an indentation to receive the tip of the spring, so cut springs still fit nicely in the perches. However, on the coil-overs on the Lotus, both the ends of the springs and the perches they sit against are flat (as you can see in the photo above), so to make a cut spring sit flush with the perch as it needs to, you need to heat the tip of the last coil with a torch, mush it downward to bend it, then grind it flat like the coil you cut off. It’s not that I can’t do this—I have an oxy-acetylene torch and a grinder—but, even though I now had a spare set of springs I could experiment on, it wasn’t something I wanted to spend my time doing, especially considering the iterative process of cutting, installing, and testing to see how much lowering effect it has.
Instead, I pored over Europa forums, reading up on available choices for lowering springs. As I said, many people buy a shocks/springs package that both stiffens and lowers, but in addition to the expense, the last thing I wanted to do was overly stiffen the suspension. Stiff springs may be an ingredient in go-cart-like handling, but, particularly on old cars, it’s common for them to exacerbate rattles. The idea of stiffer springs on that fragile fiberglass body was not appealing. Plus, the Europa already has go-cart-like handling.
There appeared to be some consensus from people on the forums who’d bought a la carte springs that 11-inch front springs (one inch shorter than stock) barely lowered the nose, 9-inch springs were too short for street driving, and 10-inchers were just about right.
But there was also the question of spring rate. The stock Twin-Cam 12-inch front springs are 116 pounds per inch (interestingly, those 14-inch S2 springs had a softer 100 lbs-in rate). People reported installing 10-inch front springs with 250 lbs-in rates and more. That sounded really stiff to me. And, since I was planning on replacing only the front springs, I didn’t want to unbalance the car front-to-rear. I set out to find some 10-inch front springs with a spring rate slightly higher than the stock 116 lbs-in.
I found that one of the Lotus parts houses I order from sold lowering springs with specs that sounded appealing; the fronts were 10 inch, 125 lbs-in, for about $180 shipped, which wasn’t too bad. I wondered, however, if I couldn’t do better on my own. After all, the odds are that parts houses aren’t commissioning custom spring designs, and instead are simply reselling off-the-shelf springs.
There are several reputable companies, such as D. Faulkner, Hyperco, HR, Eibach, QA1, and others, who sell a great variety of springs that you specify by the diameter, length, and spring rate. There are also vendors such as Apex, Jegs, and Summit Racing who sell springs from those manufacturers. In the end, I went with a set of 10-inch-long springs with a 125 lb-in spring rate made by QA1, sold by Amazon for $39.95 each, shipped. They were, in theory, returnable, but I knew that, due to the slow pace of my work in the garage during winter, that the odds were slim of getting them installed and tested within 30 days. This made the low price all the more appealing in case I needed to eat them.
The coil spacing on the QA1 springs was much wider than on the original springs, as you’ll see in the photo below, so much so that it would’ve been possible to install them using a standard spring compressor. However, the little home-built compressor I described last week worked so well for disassembling the coil-overs that I employed it for reassembly.
When I mounted the new QA1 springs on one of the Spax shocks, and compared it to one of the original front coil-over setups, I noticed something: The geometry of the two shocks was slightly different, with the bottom spring perch on the Spax shock being about a half inch lower down, and the fully-extended length of the shock also being slightly less. This alone, irrespective of the springs, would have a slight lowering effect on the nose.
I installed the front coil-overs in the car, threading the long bolt through the upper wishbones and their bushings, and putting the lower wishbones back on their threaded pins. This was all really just a test fit, as there were still new ball joints, tie rods, and trunnions to install, but it was still a pretty good milestone.
I also reassembled the rear coil-overs on the newly-procured Spax adjustable shocks. Unlike the fronts, the difference between the S2 and TCS rear springs was minor in height, appearance, and specifications, but I used the original TCS springs. If, after testing the car, I find that the rears need to be shorter, or stiffer, or both, removing the rear coil-over assemblies is much less work than re-doing the fronts.
Before assembly and installation of both the fronts and the rears, I carefully confirmed that each Spax shock was set exactly halfway between the stiffest and softest setting, and that, at least by feel, their stiffness appeared to be about equal, so they all had the same baseline for further adjustment.
It’ll be a while before it’s all back together and I find out if my front spring selection drops the nose a little like I’d hoped—and if the adjustable dampers firm things up without shaking the fiberglass to death. Still, it feels great to check off another thing on my winter project list.
Rob Siegel has been writing the column The Hack Mechanic™ for BMW CCA Roundel magazine for 33 years and is the author of five automotive books. His new book, Resurrecting Bertha: Buying back our wedding car after 26 years in storage, is available on Amazon, as are his other books, likeRan When Parked. You can order personally inscribed copies here.