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Welcome

It took 2.5 years to build the car and pass SVA (now IVA) and a lot longer to get to where it is now! To see the Sportster out on the road have a look at one of the videos here.

During 2008 we rebuilt the BMW engine from 2.5 to a 2.8 creating an M20B28 stroker engine. It uses the crankshaft from the later BMW M52B28 and the conrods from the M20B20. Not much more work is needed other than a clean up, slotting those bits together and a crank spacer. To read about the engine build click here (very picture heavy!)

In March 2009 it was painted, a full set of images is here.

Maintenance

2019 MOT – handbrake failure and fix

So the MOT tester is a beast of a man and ripped both handbrake cables clean off the mounts! Better it failed here than in an emergancy though.

The orginal handbrake adjusters are bolts with the head of a bolt chopped, the end drilled with the lathe and a recess to capture the shorted handbrake cable with a spot of weld.

As the handbrake cables were now shorter than before the bolts were too short. These were extended by chopping the machines part off the old bolt and welded on to a new bolt making it longer. The recess needed drilling out again to remove old handbrake cable.

If this fails again it will need new handbrake cables.

The torn ends zipped tie down to make them easier to clean up for welding

Cables welded back on

Finally mounted back into the handbrake handle and adjusted. Hand brake retested with better results than the rear brakes!

The car was also failed on emission first time round as the machine was set wrong. HC limit for an 88 engine is 1200, it comes in around 650 – which as been the same for a numbr of years now. They incorrectly wanted to see less than 18 – keep an eye for that one, page 12 of this document is useful if you need paperwork: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/676700/in-service-exhaust-emission-standards-for-road-vehicles-19th-edition.pdf

Engine Work

Water leek, from back of the head

Another week, another new fluid all over the floor! Coolant this time from the rear port on the cylinder head. That’s the pipe that goes to the interior heater core:

Took it off and cleaned everything up on the head

New coolant flange gasket fresh from eBay!

Eveything fitted back together (after dropping the bolts…). It’s a little bit fiddly getting this back on with the battery tray in the way. The bolt seen in the follow photo on the left of the image is much higher up than you’d think.

The nice thing about the Sporters, more room to get behind the engine is just 4 bolts away!

Engine Work

Fuel pipe refresh, car pee’d all over the floor!

Car pee’d on the floor…

It’s a bit drippy here at the back, but also at the front on to the start motor – not overly safe and smelled pretty strongly of fuel.

The main leak is here at the back between the hardline and the hose. The hoses have gone quite hard with age. There is a flare on the copper pipe.

All the fuel hose is 12-14 years old, this was visually the worst – the main picked pipe which is most exposed to the elements. The rest hard gone hard but were not cracked yet.

Emptied 25ltrs of fuel out the car using the Power Probe – all power disconnected on the car, hooked the probe up to the battery and switched 12v on the the positive side of the pump. Drained the tank very quickly into fuel cans.

Brand new hose up front for both the feed and return. Although these pipes all looked OK it was worth changing everything while the fuel system was drained.

New pipe from the tank to the first filter, to the pump, the next filter and then down the copper pipe where it was leaking. Also replaced the return rubber line.

Here are the rest of the old pipes that when in the bin, these had gone pretty stiff especially when compared to the new pipes.

All back together again! Used the power probe to prime the whole fuel system and check for leaks before starting the engine – fired up instantly, no waiting for the fuel pressure to build up when you prime the systems.

If you’re going to do any work on rubber hose, this tool from Sealey is invaluable, cuts nice straight ends every time!

Engine Work

Coolant flush and refresh

This drain plug has been leaking forever, the drain part is reverse thread and normal thread into the radiator. The thread into the radiator needed more PTFE.

Due to topping up with water over the last couple years the coolant was starting to get hotter than normal when the engine was pushed. With the new coolant G48 with suitable BMW specification the needle stays steady on 80ºC when pushed hard. When testing on idle at a standstill the fan kits in at 88ºC and comes down again nicely to the low 80’s. 

Brightwork

Front indicator stalks refresh

The front indicators were starting to rot pretty badly, replacements are not very expensive so I decided to change them for new.

The new ones are little bit shorter than the originals:

Old indicator:

New indicator stalk – I like to proportions of the placement much better between the headlights, spots and indicators:

 

 

 

Interior

Seat Repair

The Cobra Roadster 7 look nice, but the construction quality is questionable at best. After 6500 miles the driver seat broke in two. I’m very happy the nice SVA man insisted on the seat belt bar as one of the major fail points on the first pass at the SVA test:

I took the vinyl and padding completely off the base, the back rest I only removed about 1/2 as it looked it was going to be difficult to get it all back in the orignal positions:

Just welding the pipe back together would likely have resulted in a failure quite quickly. Therefore I added extra metal inside the tubes for strengthening, here before being cut to length checking for fitment, the one other otherside as a bend due to the position in the break:

I then drilled some holes through the tube for welding the metal to the tube, the extra metal is visible through them: 

Time to fire up the welder:

I welded in the extra metal to the tube through the holes, and around the tube to join it back up again:

In addition to the metal in the tubes I also added plates either side of the seat over the whole bend:

Both sides completed with some paint over the top

Finally the seat needed reassembly, the vinyl stapled to the wood backing

Getting the vinyl back in place with the least amount of wrinkles was a bit of challenge

Next sides went on, these are connect with hog rings. I bought a specific set of pliers for installing the hot rings but it was still quite challenging to get them in place.

Finally I install the seat back in the car, this one will be the passenger seat for now:

Chassis

Upper wishbone refresh and wishbone mounting rod

I changed the upper bushes today. They were rally design ones, which I’ve now replaced with Powerflex. I thought the bushes had worn as things didn’t look straight anymore. Turns out it was actually the rod which was bent and the bushes are OK. I’m going to use two of them on the diff mount (still original rubber mounts) and keep the other two as spares:

It’s pretty clear this is not so good, both sides were bent:

As I don’t have replacement materials to hand as a temporary measure I’ve straightend out the rods. Here are some sizes for reference:

Installation of new bushes:

 

 

There are powerflex product number PFF19-10 – also available in the black series which is a higher shore hardness: PFF19-102BLK

Bodywork

Reassembly, paint, lighting, electrics

The rear wings, tub and spare cover are back from http://www.specialisedpaintwork.com/ for some touch up work and removal of all the stone chips on the wings! The wings were starting to look more stone chip hole than paint on the front. To protect the wings this time I purchased some 3M VentureShield from https://www.invisiblepatterns.co.uk/ – I made a pattern using paper first then cut out the 3M stone chip protection film and applied. It took a lot of soapy water and work with the squeegee to get everything stuck down.

After fitting the stone chip protection film, I installed the new 3D printed light covers:

Wiring updated for the new inner LED lights:

Stuck the rear tub back on, this time using A316 stainless ‘A4’ nuts and bolts, these shouldn’t go rusty as easily as the previous 304 stainless ones. Got the nuts and bolts from https://www.westfieldfasteners.co.uk/

Decided to use vinyl wing piping from https://www.woolies-trim.co.uk/ instead of the rubber trim that’s been on there since 2005 (that had started to go solid). The texture on the trim is very nice.

Next it was time to tackle some electrical, this tool from https://www.powerprobe.com/ (via https://www.summitracing.com/) is an invaluable tool for dealing with 12v car electrics. It will tell you if you have a ground, or a positive (and how many volts), plus you can use the switch to send a ground or 12 volts to the item your are connected to. A good way to test relays, bulbs, LED polarity etc.

Reconnected the 4 pin water proof connectors and tied up the excess cables out of the way of the tyres.

These are new two pole Lucas 403 bulb holders and a very cool set of LED lights that output both white and red light spending on which pins you connect up. They cover reverse and fog, which means I can run twin fog / twin reverse lights! The old Lucas 403 holders were starting to look a bit rusty so the new ones were good to get anyway.

Finally, an extra cross over cable is needed to bring the 12v+ fog/reverse to both sides of the car:

Reverse on!

Fog on!

Finally, due to the indicators now being LED they ran in super insane broken bulb mode. As such the flasher relay needed to be swapped out. I had gotten an LED flasher from S-V-C https://www.s-v-c.co.uk/product/led-flasher-relay-12v/ it’s pin out is reversed from the BMW flasher relay and the ground is on a wire from the top. The flasher relay comes with a polarity swapping attachment so it goes right into the same connector as the stock flasher. The ground I’ve attached to the same location as the horn and other steering wheel wiring grounds.

Finally, some assembled shots:

Chassis

3 point reel seat belt conversion

ziptie test, safety 3rd!

Hole cut for threaded belt insert

Test fit of new piece

Use the lathe to clean up these spacers

Reel mount

Reel mout welded in

Upper mount welded in and test with spacer

Reel mounted

Otherside done too

Works quite nicely, could do with a guide for the belt on the seat

And finally plugged into place!

Chassis

Rear rust clear up

Doing some clean up work, the Sportster has been on the road for a while now so it was time to check for rust and clear anything up

Little bit inside the shock tower area, most was on the metal upright towards the back of the car.

More from inside the shock tower

This part is covered by the tub down to where the E30 A arms mount.

Under and below the tub area in the rear

The good news is that it was all surface, no structural issue. The worst part was the end of square bar under the back runs along the tank.

Cleaned everything up with a wire brush on the angle grinder, treated with loctite rust remedy and painted with chassis and rollbar paint. Also to go on later some underseal with waxoil.