Sunday, 24 February 2013

Bit more inspiration to spur us on...


Saturday, 23 February 2013

Arch Rolling - First Test.


ET Plus complete arch-rolling kit was about £100 on eBay and comes with a full set of spigot rings to fir anything.


Hard to see in the pic, but quite a bit of scrubbing on the tyre and a faint red line all the way around the sidewall from the sharp-edged lip, below.



Rolling-tool bolts on to the hub, winds out against the arch and you're away, rolling it back and forth, winding it out a little more each time. This was insanely easy compared to what I was expecting. 


I managed to roll the sharp lip up almost flush and gave the rim of the arch a slight flare in about 15 minutes flat. No more scrubbage for now, even if the look hasn't changed much.


It's best to use a heat-gun to warm the paint so it doesn't crack, but without one to hand I figured hot water would do the trick. A bit of loose paint still flaked off from under the arch, but it looks like I'm already beginning to get rusty bubbles under the rim of all four arches and they will probably have erupted by summer. The n/s arch also consists of a fair bit of primer, so it'll be interesting to see how neatly that rolls out and I'll ask my paint guy how much smoothing and spraying all the arches will be with my left over paint. 

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!

Wednesday, 20 February 2013

Rear Wheel Spacers + Arch Rolling Kit!

With the engine now back in fine fettle [we hope!], I couldn't wait to get back on-project and spend a bit on stance, so I've started with these 20mm spacers for the rear wheels. I'm not sure if it's an illusion of the E21 body-shape, but the rear wheels always look a bit tapered in from the front ones, so these spacers should primarily even up the front/rear track or even bring the back wheels a bit further out than the front, as it should look. They'll also help make my rather skinny 7J wheels look a bit fatter and get the arch-clearance a bit tighter - and, of course, will make fitting fatter wheels [which is going to have to happen at some point isn't it] easier in the future.

In fear of the spacers pushing the wheel out too far and causing the outside of the tyre to contact the wheel arch, I also bought a wheel-arch rolling kit. It's about £100 to have a pair of arches rolled professionally and, as mine is a work-in-progress and I'm not 100% on the setup I'll be using, I decided £97 for my own kit will definitely work out cheaper if I need to keep on rolling them out as I go lower and wider...


French made spacers are nicely machined, but billet steel and pretty heavy.


Deemed too wide for extra-long wheel-bolts, these babies have two sets of holes and bolt on to the hub by themselves.






Rear wheels slightly proud of front ones as they should be, but a slight loss of negative-camber.

Wheel Painting!

Thought I'd spruce up the ratty Melber alloys this week to try and get away from the touring-car look and back to the general stance car vibe by painting the rims in cream. Or beige really, Peugeot Panama Beige to be precise - I spotted a Mk2 Golf with the full wheels painted in it and it looked like a nice antiquey dark cream. It looks decidedly lighter on mine though, perhaps I should have gone for Antelope Beige after all.

The dish I have left in the dark metallic-grey for now, but as one has the paint polished off something will have to be done, maybe a matt dark-grey or just grey-primer, we'll see.












Saturday, 16 February 2013

More manifold gaskets...

Stuck the new and much better quality exhaust-manifold gaskets on today from Euro Car Parts. They're thicker than the eBay ones and have steel rings round the inner rim like a head-gasket, should make a better seal. It's got rid of the cracking noise from that dodgy one on cyl. 4 [this post] and the engine sounds sweeter than ever.

Surprisingly the manifold nuts all came off as they should this time and left all eight studs in the head... weird, but it certainly made fitting the gaskets a lot easier.



Sunday, 10 February 2013

Engine cured! - Culprit: manifold gasket...

After repeatedly timing the ignition perfectly to Z on the flywheel, [see this post], we decided there had to be something deftly wrong to be causing the loud noise and backfiring [in the vid below], rather than just the distributor being out of line.


The first hunch was the exhaust had broken while being twisted to get the cylinder-head out and was blowing like mad, but my initial inspections revealed no damage to the down-pipe or manifold and the four manifold gaskets looked all to be in position.

That is to say they LOOKED in position... Today, in the pouring rain, I got the car up on ramps to see what it was I'd missed and as soon as the torch flicked on I could see the answer at last - one of the exhaust-manifold gaskets had slipped off the stud and was only covering half the hole! Nightmare... Right at the back of the engine where we couldn't see and, ironically, the one for cylinder 4 that started all the trouble.



As you can see the gasket has been totally blown apart by the hot exhaust and has separated quite badly in the middle leaving only the metal. I checked the rest of the gaskets in my set for a spare, but can only find the same shape gasket with an oblong hole, perhaps for the E28, so tentatively decided to re-use the blasted one, correctly seated this time and caked in Holt's FireGum.

As soon as the engine fired up again it sounded like it used to. It's amazing the difference that gap in one single exhaust port made to the noise level. It was still idling low though and revving badly, so I grabbed the timing-light again to have another go, turning the distributor to line up Z on the flywheel - 25 degrees before TDC. Now the 30 year old M10 has really begun to purr once more. Awesome! Still some fettling to do on the carb. tuning, throttle/choke cables and checking to see if my damaged manifold-gasket is holding up, but at least she's back on the road after a tense month!

Saturday, 9 February 2013

HOW-TO - Stereo Head-Unit Retrofit

I had noticed a few electrical gremlins since fitting the modern stereo and have finally figured out the slight wiring difference between the 316 and the 320, the latter of which is shown in the E21 Wiring Diagrams available on the internet [download here]. Thought I'd throw up an updated diagram of how the wiring can be correctly adapted in the base model E21s.



Basically if the car had a stereo available as an option, which only the higher models did, then the two power wires necessary for a modern stereo are present. On base models [315, 316, 318], only a single aux. power wire is present. It can be made to run a stereo head-unit, but there are problems so if you're thinking of doing this it's worth reading my failsafe guide.

As in the diagram above, a modern radio/CD-player type head-unit will most likely require two power sources. A red wire connected directly to the battery that supplies a small amount of power to save settings and CD positions, and a yellow wire connected to the ignition switch that tells it to only turn on when the car is fired up. *Connecting both wires straight to the battery is an option so the unit can be used with the ignition off, but this will mean a higher drain to the battery and obviously has the potential to be left on by accident.

GUIDE:

At the back of the centre-console somewhere will be a chunky black wiring-connector, referred to as C40 in the diagram above, with 4 prongs and five wires joining either side. Two brown/violet wires from fuses 17 and 18 join at C40 and become a single wire - this is the best source for ignition power. The single brown/violet wire goes to a small 2-prong connector, which shouldn't have anything plugged into it, so connect the yellow wire here. The larger brown earth-wire on the connector goes back to C40 and grounds with the rest of the instruments and interior lights at G49, somewhere to the left hand side of the passenger side footwell. This is an ideal place to ground the black earth-wire from the head-unit, but modern stereos draw a lot of current and it might be worth running the black wire to a new earth-point on the centre-console bracket, as in the diagram above.

The only source in the dashboard connected directly to the battery is the cig. lighter circuit on Fuse 16 and has no spare connector so a wire must be spliced somehow into the red/yellow wire running through connector C40 - I just used a Scotch-block type crimp-connector. This new wire should be connected to the red wire on the head-unit.

To connect the relevant prongs on the head-unit wiring-connector I used short pieces of wire with female spade crimp-connectors. At the other ends are male spade-connectors to fit into the brown/violet wire-connector and similar connectors for the speakers, though I simply cut these off my speaker-wires and connected them straight to the head-unit connector with female spade-connectors.

Unlike the diagram above, 315/6/8 models should have green [pos.] + green/black [neg.] wires for the left-hand speaker and grey [pos.] + grey/black [neg.] wires for the right, to be attached to the corresponding prongs on the head-unit connector. These models should also have no rear speakers, unless they have been added on and will have a range of wiring colours.


Unless your planning on hiding your head-unit away somewhere, which I was originally, then you will need a fascia-adapter. They're not common, but can still be bought new from BMW or BMW Classic or one might come up on eBay, but I haven't found a spurious one yet. I was lucky to be given one with the car, still sealed in its bag. I intended not to use it and stash the head-unit in the glove-box or beneath a flap as security isn't great in the E21s, but I must admit it does look smart.


If a constant live connection to the battery is not something you want or your cig. lighter socket is already running a high-power device, then the simplest method is to just power both the red and yellow wires from the single brown/violet wire terminal [pic below]. This works just fine in powering up the head-unit, but the memory-power is turned off with the ignition and it won't save your settings or jump back to where a CD was previously playing. 

It will also be drawing the full amperage through the rev. counter circuit, Fuse 17. This shouldn't cause a problem in theory, as the same terminal on connector C40 has a more direct route to ign. power, the other brown/violet wire from Fuse 18, but it still caused a problem for me after a week or two when the rev. counter/clock unit began to trip out and stop power to the radio and instrument lights somehow. Neither fuse would blow, but power would not return to anything on that circuit until both fuse 17 and 18 had been pulled out and re-inserted with the ignition turned on. You may get away with an extra or shorter earth wire, rather than the radio/rev. counter circuit grounding at G49 with the rest of the dashboard etc., but run this setup with caution.

Sunday, 3 February 2013

Distributor/Ignition Timing: Strobe Light Ahoy!

So my adventures into re-timing the spark-plugs continue with the purchase of a Gunson Xenon timing strobe-light! I went for the cheapest kit in Halfords, but it was still a slight pain at £45, considering it's in addition to a new dizzy-cap and rotor-arm, set of spark-plugs, compression-test kit, gasket-set, oil, coolant and a 30mm socket to turn the engine from the crank, but as I just can't seem to get the old M10 engine running happily I guess it's just as vital and at least we can use it to time in our old MGA engine this summer (hopefully).

Before I start to moan again about the intricacies of re-timing the distributor I should say that I know there is no need to remove it in order to get the cylinder-head off and the dizzy should really be left in place to save all this trouble, but the diaphragm on mine was blocking one of the head-bolts so that wasn't an option for me.

The timing light works by flashing every time your 1st-cylinder spark-plug fires. There is a timing-mark on the spinning crank-pulley or flywheel that passes a stationary mark on the block at the exact point the 1st spark-plug should be firing. When the flashing light from plug 1 is aimed at the spinning pulley it shows the timing-mark in a fixed position in relation to the stationary mark and allows you to gauge how how many degrees before or after the correct point the spark is. Clever stuff.


On the BMW M10 engine, there are two timing-marks on the flywheel, one for top dead-centre [TDC] and another, called Z, that corresponds to the right point before TDC that the 1st spark-plug should be firing. The marks are visible with the flashing light through a small oblong hole at the back of the crankcase. It's easy enough to find the hole, but seeing into it with the timing-light is a challenge in itself, let alone trying to adjust it or move the dizzy-cap and I ended up having to stand over it with my feet on the strut-tops to steady myself enough without leaning in from the side and crushing the wheel arches. There is another TDC timing-mark on the rearmost rim of the front crank-pulley, which is a lot easier to see with the timing-strobe from the n/s of the engine-bay, but the mark is tiny so when you do find it it's best to file a larger notch across the whole pulley - mine had this done already and it makes things a lot clearer.

It's best to first time your engine to Z on the flywheel, at 2200rpm, using 0 degrees of advance on the timing-light gun - just shine it into the oblong hole and rotate the distributor-cap until the large pointer is lined up with the silver ball, not the TDC line. Now check the front crank-pulley for reference by shining the light at it with 0 degrees advance. The groove for TDC should appear around 25 degrees before the stud on the engine-block. Rotate the dial on the timing gun slowly to 25 degrees and the groove should move in line with the pin. Simples.

Ignition timing isn't too much of a fine art, so as long as the rotor-arm contact is roughly on point no.1 on the dizzy with the engine at top dead-centre then it should fire right up and not need much adjustment to find Z. Mine was still making the god awful noise after repeatedly timing to Z, but this turned out to be a badly positioned exhaust-manifold gasket [in this post] so, obviously, check everything else isn't amiss before starting to mess with ignition timing.