Showing posts with label coilover. Show all posts
Showing posts with label coilover. Show all posts

Saturday, 21 September 2013

E21 316: Burst shock-absorber woes...

SPAX adjustable - like hen's teeth.
Well, I've had a bit of a nightmare week. As I was replacing the front n/s shock-absorber with the new spring, ready for the MOT on Saturday, the strut-insert burst in my face. To get an extra couple of inches clearance at the top and get it under the wing I'd been pushing the damper down into the insert. I figured they sit quite far down with the short-springs anyway, but eventually, probably after doing it several times, I must have plunged it further than its full operating depth and it popped, sinking the insert completely into the strut.

You wouldn't think pushing it down would pop it, considering the forces on it under load, but once its down far enough the top seal just fails under the pressure of the oil. You can have SPAX, as with most adjustable-inserts, re-filled and the seal replaced if you can be bothered to send it back to the manufacturer and pay the cost, but with time of the essence I just bought a new one.

Larkspeed in Leeds were the cheapest, though the price had gone up from £90 to £112 [and £118 now for the shortened!] for a single insert, but they claimed to have the part in stock and would have it to me by Tuesday the latest. Today I rang them to say it'd been a full week since they rang to confirm the order and still no insert. After half an hour they rang me back to say the insert had been specially ordered from SPAX, who were now lacking correct parts and can't build them until the end of October. I wish they had told me that last week as I'm now waiting on a refund...

Bilstein - fixed damping-rate and pricey,
nothing but good reviews.
I rang DC Performance.co.uk, who also claimed to have the part in stock and it would take 2 or 3 days. Before parting with any money this time I asked if they could check the insert is definitely in stock, which they are not, so it's not looking hopeful for any existing stock anywhere. I will be contacting SPAX directly from now on.

Monroe Gas-Matic - strong, but ride too soft.
So what are the short-term options? There are no ride-adjustable inserts in stock and available now, so it looks like i'm now bound to non-adjustable inserts. Stiffened Bilstein inserts are £62 each, where OEM-replacement ones can be had for as little as £20. With the springs this low, I have no idea what would work best. The sportier, better-brand damper might last longer under the stress and be a better match for the adjustable SPAX on the other side. Alternatively, the cheap, softer damper might compress better under the load and a pair will only cost £40 should the o/s one need swapping too. Another option is to replace both with Monroe gas-filled dampers for £123. The blurb says they are a heavy-duty design for trucks and vans, but according to this thread they are just too soft and will cause me to bottom out. So, £60 for one Bilstein it is, or take a chance on a cheap KYB. Hmmm, stress.

Sunday, 15 September 2013

E21 316: Taller springs for MOT.

Well my MOT, the UK roadworthiness test, has come round and the E21 is just too low to get into my local testing station, let alone up onto the ramps. This is where height-adjustble coilovers would be worth their £650, as even if I can get the car onto the ramps, an attempt to raise the wheels off the ground will cause the short springs to become loose in the pans. The solution to this problem is still cheaper than coilovers - shortened strut-inserts from this post at ~£400, but I'll still have to find somewhere with ramps low enough to take her.

Seems to me the easiest and cheapest overall solution is to just swap longer springs in for the test and put the chopped ones back on later. Seems like quite a lot of effort just for a 30-minute inspection, but that's motoring in the UK, we're at the mercy of the MOT and it sees more cool cars off our overcrowded roads than insurance write-offs ever would.

Slight length difference. The red SPAX was a -40mm too.
A nice set of yellow APEX -40mm springs set me back just £80 from eBay. They are a lot longer than I remember though, which heralded me finally buying some spring-compressors, £17.99 and bringing the grand total of this years test to a ton before I've even had it inspected... not good.

Fitting the rear springs was a doddle, but the fronts threw up a few problems. Getting the cut spring off was easy enough, but even under compression the longer one was never going to fit in the space available. After damaging my newly filled wheel-arch and bursting one of my strut-inserts - nightmare - I started looking for a better guide on replacing springs and find out if it can ever be done with the strut and brake-line still attached, but one doesn't seem to exist - a good validation for this and other blogs! I did, however, find a Youtube video of some guys fitting H&R springs without removing the shock, which did give some clues from about 3min30 onwards:


PROCESS:

Rear Springs - 

1. Follow the steps in THIS POST to remove and re-fit the rear shock-absorbers, swapping the cut-spring for the new ones, obviously.

Front Springs [without removing strut, steering or brake-line] -

1. Raise the car and remove the corresponding front wheel. [It makes life easier to drop the front on axle-stands and remove both wheels, doing both springs together.]

2. Undo the top-nut from the shock-absorber, located on the suspension turret under the bonnet, using a 19mm wrench and 8mm open-end spanner at the top of the strut-insert to stop it from rotating.

3. Disconnect the brake-pad sensor wire by simply pulling it apart at the join behind the disc and sliding the rubber-mount free of the bracket.

4. Remove the earth-lead from the strut by undoing the bolt with a 10mm wrench.

5. Remove the bracket holding the brake-line to the strut using a 10mm wrench and open-end spanner. [This is essential to free the brake-line enough for it to tilt forward without having to remove the hose and drain the brakes. Without freeing the bracket, the brake-line will be stretched to breaking.]

** If the spring is still under compression without the weight of the car on it, use spring-compressors to hold it short enough to loosen the top spring-pan away from the turret.

*** The strut can be tilted out far easier with the track-rods unbolted, using a 17mm wrench and moved out of the way, but mine wasn't budging easily and there is enough room if you can push the steering-arm down enough.

6. Remove the four nuts holding the anti-roll bar brackets to the sub-frame using a 17mm wrench and open-end spanner. The anti-roll bar should drop down and remove tension from the two struts.

7. Tilt the shock-absorber strut out of the wheel-arch, remove the top spring-pan and spring.

8. Drop the new spring onto the bottom pan and reverse the above steps, using spring compressors if necessary.

Wheel-arch gap a little more prominent. Was it really that much before?!

Sunday, 2 June 2013

E21 316: More negative-camber on the front? Adjustable Top Mounts.

They had to be ordered from Poland so took a couple of weeks to arrive, but it was worth it for the £105 delivered as they are very nicely machined and finished. They are an easy straight swap with the stock top-mounts, I've covered the process at the bottom, and I only encountered one snag where the silver steel bush, in the centre of the top-mount bearing, wouldn't quite fit over the top of the strut-insert. Using a bolt as a drift I managed to gently tap the bush down onto the strut-insert with a hammer. This mushroomed the top of the bush, so once it was very tightly fitted to the strut it would no longer fit into the bearing! A lot of reaming later using an old file and the bush would just about fit enough into the bearing to get the top-nut on and draw the bush up as it was tightened on. If it wasn't for that one snag, the plates would have been fitted in 20 minutes per side, so a good bit of advice would be to use a bit of oil or WD40 when fitting the bush to the strut-insert, or heat it first to get it on and allow it to cool again before slotting it into the bearing.

Now fitted, they're a doddle to adjust with the allen-head bolt setup, even with the wheel on and without lifting the car. As the new plates don't have a rubber shock-mounts like the stock items, I figured there would be a lot more road-noise with just metal on metal and there is, but not nearly as much as I expected. There's a bit of a knock going over big bumps, but I don't know if this is just a louder transmission to the body than the stock mounts, or if the giant spring-pan of my stock struts is hitting the body when it flexes enough. The big spring-pans mean I can't run the camber-plates fully over to the negative side and to get the amount I have now they are sitting awfully close to the body while the car is stationary, so I can imagine them contacting with enough rotation in the suspension. The only solution to this problem is smaller diameter spring-pans, i.e GAZ coilovers and another £700... watch this space, probably for some time.

Silver Project are an independent engineering company in Poland and make these along with a lot of other cool bits for different cars, check them out on Facebook [] or their store on eBay [http://myworld.ebay.co.uk/silver-project-pl/].


Quick video of the plates in action and showing the amount of tilt:

FITTING PROCESS:

1. Lift the front of the car, remove the corresponding wheel.
2. Grip the strut-insert to stop it from turning and remove the top-nut using a 19mm deep-socket.

3. Push the wheel-hub down using your foot so the top of the strut-insert drops out of the top-mount and can be moved to one side.

4. Support the top-mount from below, undo the three nuts holding it in place using a 13mm wrench and lower the top-mount out of the wheel-arch.


5. Fit the camber-adjustable top-mount from below and replace the 13mm nuts and washers.

6. Undo the four allen-head bolts on the adjusting-slider of the top-mount so it moves freely from side to side, using an M4 allen-key/socket.

7. Apply grease or a little oil to the smooth part of the strut-insert just below the top-thread so it can be easily drawn into the bearing.


8. Pressing the hub down with your foot again to allow the strut to be moved around, locate the top of the strut-insert into the silver bush of the top-mount.

9. Once the strut-insert is about 1mm into the bush, there should be enough of the threaded part poking out of the top to get the top-nut on and draw the strut up into the bush as the nut is tightened with a 19mm deep-socket. [The strut-insert will likely need gripping further down to stop the whole thing turning with the wrench.]


10. With the wheel either on or off, slide the camber-adjuster to gauge the angle and make sure the spring-pans on the shock aren't contacting the body-turret, then tighten up the four allen-head bolts with an M4 allen-key/socket to hold it in the desired position. [There is not a lot of headroom in these smaller BMWs, especially if you're using larger stock struts.


11. Replace the wheel, drop the car and enjoy your new crazy-cambered or nicely straightened-up front wheels! There are a few steps to this one, but provided you don't hit any fitment snags, it's a quick and easy job if you know the suspension setup.

Sunday, 3 March 2013

E21 316: Spring Chop Chronicles 3 - Double Drop!

I was so keen to test out the o/s/r wheel-arch I rolled in last week that I left the locking wheel-nut key on the wheel and sped off. This is the one bit of kit you don't want to lose, as I couldn't get the wheels off to paint, chop, or even roll the n/s/r arch off the tyre [which has been smoking and squeaking all week] until my replacement key came on Friday. Needless to say it's been a busy weekend...


I started by taking 2 coils out of the uncut n/s front spring to compare it to the o/s with a single coil removed and it wasn't a lot lower and not sitting on the tyre thankfully, so I chopped the o/s down to match it. With 2 coils taken from each of the front springs that's slightly over 2kg off the chassis, which should in part make up for my heavy steel spacers.


Above shows the original height of the SPAX spring, a drop of 40mm from stock.


Now with a single coil removed, above, the car sits at about -55mm from stock, give or take. That's low! But not low enough...


2 coils removed and she's as low as she'll go on the normal-length strut inserts, but there's still just about enough clearance to get one finger into the arch. Don't seem to be getting any scrubbage off the tyres, which is good considering 


Now we're really scraping...


...but so is the sump! 2 inches ground clearance for this engine then - speed-bumped roads are out of the question! Let's hope someone doesn't leave a brick lying in the street!

E21 316: Spring Chop Chronicles 2 - Cutting E21 Springs Explained

Cutting car springs at home - a good idea? Well, no. We've all heard the story about that guy who chopped the springs on his Mum's Nova SR and ended up on his roof. Most modern springs are tapered at either end to hold them into the spring-pan and this means that cutting them changes the design and they won't fit. If they do they won't work properly holding up the weight of the car. Your average knowledgable bloke will say "Ah, yes, but they will work if you cut them right!". This is not the case. You can never cut tapered springs to work right, period.

If you own an E21, or one of most other classic cars, then you will likely have the old style 'pigtail' springs that do not taper at either end. They're just a coiled spring, which end in a point and sit in a groove in the spring-pan top and bottom [2 in the pic below]. These CAN be cut shorter and still work - as long as they are cut right.

Why do it?
You want to go lower with your car, but a spring-kit isn't available to go as low as you want. You don't want to fork out money for lowered springs. 

Front

Rear



Saturday, 23 February 2013

E21 316: The Spring Chop Chronicles: 1

Q: Is it possible to DIY-cut stiffened SPAX already lowered springs, by hand and without removing the shock from the car and without messing it all up?

A: Yes!


I've wanted to slam the front down so it matches or is lower than the rear since day one and with my recent splurge on the rear axle I thought it was about time. I had my heart set on a set of shortened SPAX strut-inserts, £200, assuming they were what was keeping the front end up, but it turns out I may have -40mm springs, not -60 as I thought, so the best bet is shorter coils. I would never in my wildest dreams have considered cutting the springs shorter and getting away with it, but it turns out the front springs on E21s are the 'pigtail' kind so can be cut and there are a lot of E21 guys doing this successfully on the forums, so considering a set of -60mm SPAX are £123, I thought I'd give it my best shot.

This page on E21Build.com on chopping stock springs was the most helpful with the process -  http://www.e21build.com/2012/12/cut-springs-and-other-things.html - but I thought I'd try and do a slightly more in depth guide, below.


First remove the top-nut using a 19mm deep-socket and yank the strut down a bit in the wheel-arch. This is so there is no tension left on the spring. Although the car's weight is taken off the spring by the jack it is still under a bit of tension, enough to cause harm, until the top-nut is undone.


Mark a line on whichever coil you are cutting directly above the natural bottom-end of the spring [where it fits to the notch in the baseplate]. This is the ONLY position at which the spring coils can be cut as the top-end of the spring fits into another notch in the top-mount and it won't line up if the spring is rotated.


I went with cutting one coil off for now to see how things go. *NB: The cable-ties I've used in the pic are NOT for compressing the spring. The spring was already under no tension, I was holding it up to cut.


Once the spring is cut the gap is too small to remove it from around the strut-body, so the only way to do so is to chop the off-cut in a second place and remove it in two pieces. Lowered-springs are made of some seriously tough sprung-steel and making one cut, let alone two, is hard work, particularly if you're only using hand tools as I was. Due to limited space I'd recommend the smallest profile whizzer-disc you can find, otherwise you'll wind up using a hacksaw blade by itself, as I did.


Seat the new bottom-end of the spring into the baseplate notch, make sure the top-end is still in the right place in it's notch and gently jack the strut back up through the hole in the top-mount. The tricky part is getting the strut-insert in the right position to get through the top-plate/mount enough to get the top-nut in place, without shifting the spring from either notch. I found the best way was to press the top-plate and washer down over the insert first, then guide it up through the top-mount and slide my hands out as the strut was jacked up by a pal. Once the threaded part of the insert can be reached by the nut from above the top-mount, even just a couple of turns, tightening the nut should be enough to raise the strut into the mount. Again, make sure the spring is seated correctly, as are the rubber boots - these can be seriously annoying to hold in place!


The spring position might look a bit jenky while the car is still raised, but fear not, as long as the spring is seated flush, with the first coil up from the cut end sitting snugly inside the rim of the baseplate, not proud of the edge, then all should be well and they'll settle nicely with the weight of the car on them. 

How much lower?
I am led to believe by the previous owner that my front SPAX SSX springs are -40mm [though they may be -60mm after all]. After cutting just the bottom coil out the car has dropped another 3/8 of an inch [~15mm]. If i'm right and they are the 40mm springs, I'm currently at about -55mm. If, fingers crossed, cutting a second coil will give me another 15-20mm, I'll be running at a 70-75mm drop, which is exactly what I want, given that the £700 GAZ coil-over setup, boasting the biggest off-the-shelf drop of all, only goes down to -65mm. On the other hand if I do end up having started with the 60mm springs, then I'm already at -75mm still with nearly two fingers of tyre to arch clearance and going any lower will probably wreck the springs - oh well, at least the full set of 4 SPAX SSX is only £123, [http://www.larkspeed.com/index.pl?p=60S003043&a=i]. 
An added worry is the strut-inserts bottoming out from the spring only having 4.5 coils of resistance rather than 6.5, but that's still a little over two-thirds of stock and my inserts are stiffened SPAX PSX anyway, so I don't see why they won't hold up in theory with the damper set quite stiff. There doesn't seem to be any bottoming out with one coil cut, but if they start doing it with two I guess I'll have to fork out for the shortened strut-inserts after all [http://www.larkspeed.com/index.pl?a=i&p=SPX112TAS155I&part=BMW-E21-3-Series-incl-M-Technik-45mm-strut-insert-Spax-Adjustable-Shock-Absorber-Insert-Shortened]. As for ground clearance, the metal bar that runs under the sump is currently just under 4 inches from the floor. It wasn't much more than that before, granted, but could cutting out one more coil be the tipping-point in losing all everyday drivability? We will find out tomorrow!

Monday, 23 July 2012

Suspension dreaming...

Ok, it's not the ideal time to be to looking at expensive suspension mods when I'm about to shell out a fair few hundred for the re-spray, but I've found the solution to getting the front down as low as it's going to need to be.

Check out these shortened struts from SPAX - http://www.larkspeed.com/index.pl?p=SPX116TAS156I&a=i - available from Larkspeed.

Why chop springs when you can chop struts? These are 40mm shorter than the stock SPAX struts I have and they're already a 60mm drop, so these would give a full 4 inches up front and that should be getting the front down something similar to the rear.

The website says they accept any spring of 45mm drop or more, so I'm guessing my SPAX will slot straight on,  but at least I have a few weeks to reel from the spray-job and save up as the only drawback is they're £99 each. Not a huge outlay on an already £650 setup, but a way off for now :(

** After a bit more research I decided to chop the SPAX springs first to get a bit more low and only buy the short-inserts if my current SPAX ones start to bottom out. Yes, it is possible to further chop lowered-springs - see how I got on here - The Spring Chop Chronicles: 1