Project BMW 635 - Getting it sorted: Our shed

By: Guy Allen

Project BMW 635 Project BMW 635 Project BMW 635
Project BMW 635 Project BMW 635 Project BMW 635
Project BMW 635 Project BMW 635 Project BMW 635

Our Pet Bimmer is back in the workshop

Project BMW 635 - Getting it sorted: Our shed
Project BMW 635: Getting it sorted


Project BMW 635

April 2010

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Our rolling restoration project has made huge progress since the last update. Guy Allen reports on the trials and tribulations of sorting out his old Bimmer.

While we finally got Brunhild the 635 street legal (see part 2), there were still a number of issues on the must-do list.

The basics included:

The gearbox was fine but the shift action sucked;

Ignition system was flaky (still missing at times);

Fuel injection (still had a dud throttle and soft power-delivery);

The cracked dash looked like a war zone;

Minor electrical gremlins;

Door/window seals;

Grille trim needed replacing;

Air-conditioning not working.

In addition, the engine bay looks messy and the overall body needs a fair bit of cleaning up – it looks good from a distance but there are a lot of little chips and scratches that need attention.

So where to start? For me, the big priority was getting the car running properly, then move over to the cosmetics.

One thing I just couldn’t live with, though, was that dash. There’s something about facing a moonscape every time you get in the car that gets under your skin. In Melbourne, the logical place to go to was the Dashboard Doctor in Coburg, which has been around a couple of decades.

Alan, the owner of the company, says his services are very much in demand these days, as people discover that old family jalopy in the back shed is now worth restoring. Getting the dash in and out of the car is a substantial part of the cost, so you can save a fair bit if you’re able to tackle the job yourself. A warning from the experts, though: the older the car, the more likely it is that assorted ancillaries and fixings have become brittle over time, so treat the job with care and be aware you may end up looking for often hard to find replacement parts.

The restoration process includes stripping away the old vinyl, fixing the underlying foam back to its original shape, then vacuum-forming a new skin over the top. I got them to do the removal and installation, and Alan rates the Six-series as the toughest of the BMWs to do.

Having the dash done made a huge difference to the feel of the machine, as this video shows. There are still a bunch of issues inside that need work, but they’re relatively minor.


My next step was to get the car running right, as there had been an annoying miss from day one, plus a tendency to flame out at idle in hot weather. Both the ignition and fuel injection desperately needed sorting out. Having been through a similar process with a Holden Kingswood we did up some years ago, and more recently watching some excellent work on Project HG, we knew exactly who to talk to.

For ignition, we went to Dick at Performance Ignition Services, in Nunawading (Melbourne). His approach is straight-forward, which is to fit more reliable, modern parts where it suits, or restore the old for those who demand authenticity. His company does everything from complete vintage distributor rebuilds through to bespoke systems for race cars.

As with all too many jobs on this car, nothing was simple. Dick discovered the all too common problem that someone who was perhaps not as knowledgeable as they thought had, in trying to fix one problem, created a whole new set of dramas. For example, the vacuum advance was blocked, but not the retard, the fuel pressure regulator was hooked up to the wrong vacuum hose, the plugs were the wrong heat range and the advance curve was out. The factory hadn’t helped, as the ignition module was in the worst place possible – under the (now leaking) windscreen washer bottle – and was producing a very weak spark.

Repairs included replacing the module with a less expensive but more effective aftermarket unit, a Crane multispark, which was relocated out of harm’s way. The ignition coil (also looking tired and emotional) was replaced for a high-output unit, and the leads for low resistance items. With the timing reset, we now had a car which started easier and should, once the injection was done, stop guzzling fuel at such an alarming rate.

Next port of call was Tony at B&M Fuel Systems in Richmond, Melbourne. He is one of the few carburettor and injection specialists left in the country, so his workshop ends up being a fascinating parade of machinery varying from the pedestrian through to the exotic. Like the ignition folk, he found some entertaining sins from previous workshops, but his biggest challenge was simply tracking down the exact spec for this car. The L-Jetronic system fitted to this example is well enough known, but BMW was clearly making changes on the run during the late 1970s and very early examples like this are particularly tricky when it comes to tracking down the correct spec.

It’s hardly surprising that, at 32 years old and over 230,00km, the system needed a pretty big overhaul. While the core electronics were fine, much of the system from the injectors up needed refurbishment. Tony quietly chipped away at it, checking the results with his in-house dyno until he was satisfied.



With those two crucial systems – ignition and injection – fixed, the car was undeniably easier to start, more crisp on the throttle, more powerful and was consuming far, far, less juice. But I was still underwhelmed. In its heyday, this was supposed to be a 218 horsepower machine and, after all that work, it still didn’t feel like it. We were soon to discover why, at some expense.

There we were, winding the six up through the gears when it suddenly spat back at me, and then ran on four, maybe three-and-a-half, cylinders. Oh dear, I’d broken it.

A quick retreat to Ian at IDB Automotive (a Six series specialist in Richmond, Melbourne) soon saw it undergoing some major surgery. Not only had the head gasket gone to lunch, but we discovered a number of valves were leaking, hence the ‘soft’ performance. Ian announced the existing head could be refurbished – thank heaven, as replacement would have been a nasty hit on the wallet.

Copping yet another bill after all the expense so far was something I really could have lived without, but in a peculiar way I was glad it happened when it did. At least now we had a clear cause for the lack of grunt.

With everything sealed up I now had a wildly different car. A (probably unreliable) seat of the pants measurement suggests we’ve picked up 50 horses from when I first bought the machine. It now revs very willingly, and the performance is in a completely different class. So that gasket may have done me a favour by failing when it did. Now the 635 does feel like a 200-plus horse machine.

Somewhere along the way we got another little surprise with the centre bearing on the driveshaft going to lunch. It started with a light knocking noise each time I let out the clutch from a standstill, and quickly became more and more rambunctious. Fortunately, it was a straight-forward fix – one more thing crossed off the "what else could break?" list.


Since we were hanging around the workshop, now seemed as good a time as any to address a few more problems, namely the floppy gearshift and deceased air-conditioner. Oh, and the suspension still wasn’t quite right.

The gearshift was a common enough issue. Assorted bushes and joints wear over time, plus, of course, the 635 can develop its own little twist on the plot. Ian at IDB worked on this, bringing the action back to something more normal. The action is a good street set-up.

Another little trick this model 635 can develop is allowing the shifter to droop from its original mounts in the drive tunnel. What ends up happening is the base of the mechanism will end up just touching the driveshaft, in turn letting off an alarming tapping noise. At first I thought I’d trashed the normally bulletproof (and hugely expensive) dog-leg Getrag five speed gearbox. However some careful realignment with new mounts soon solved the problem at minimal cost.

Next was to revisit the suspension. We’d fitted new Bilstein dampers a few months before but, because I was getting grumpy about the amount of money going out the door, elected not to do the obvious and replace the springs at the same time. That was a mistake, as the originals were sagged and long past their use-by date. A new set has the car sitting up noticeably but more importantly riding the bumps far better with a lot less crashing and thumping.

A little aside here. I got the springs done at Pedders, with instructions to the workshop to do nothing else. The company’s franchises landed in the news that week, with Channel Nine’s A Current Affair exposing them for over-servicing, or trying to get unwitting punters to ‘fix’ things that didn’t necessarily need doing.

In my case, I was presented with a quote for further chassis work, adding up to around $2000. This was unimpressive, to say the least. The car’s underpinnings had only recently been checked and refurbished where needed. One of the recommended replacement items was new shock absorbers!

For once we had a repair which presented no challenges: the air-conditioner. The compressor unit was a generic part and the system was soon underway. It’s a little noisy and not overly powerful, which is common enough for this period, but is a necessity in an otherwise poorly ventilated cabin.


The next step was perhaps a little harder to justify on performance grounds, but let’s give it a go anyway: I went for new wheels on the basis we could then fit some nice current performance tyres. Convinced? Well, it was worth a try…

Wheels have turned out to be a saga. It came with BMW-branded BBS wheels, in a 14 x 6.5-inch size. We replaced the tyres some time ago with the existing size (225/60-14) in Bridgestone Turanza. I commented at the time the tyres were a temporary measure until I could sort out a more appealing long-term solution.

At first we rounded up a good set of the original TRX wheels, which are now stored in the shed. They are much too expensive to fit thanks to the peculiar metric rim size, with rubber costing $500 a corner for what is likely to be an outdated compound. I also kept the BBS wheels.

In the end, we went for a set of Superlites, which are Minilite look-alikes. Okay, they’re not original equipment, but they suit the car’s period and have really lifted the appearance of the machine. More importantly, we’re now able to fit current compound tyres, thanks to the 16 x 7-inch spec.

One lesson we learned was not to trust the sizes of the tyres on a used car, no matter how original it looks. Brunhild’s rubber had been rubbing on occasion, which I put down to sagged springs. However subsequent research revealed the wheels had a bigger than stock rolling diameter, which led to us changing the order on the new rims from 225/55-16 to 225/50-16. And the final choice? Toyo Proxes R1R which, so far, I’m a fan of. There’s no shortage of grip and they seem to have a substantially quieter ride. To me, good grippy rubber is relatively cheap and very effective insurance.

Last on the list was window tinting, something about which I used to be very ambivalent. The risk is your car ends up looking like it’s owned by the local drug runner. However my reservations faded away after trying a couple of other vehicles with the work done. Not only were they cooler inside, but there was a chance the interior would cop a lot less sun damage. In the 635’s case, you have a small cabin with a lot of glass, which can turn into a sauna. So, for a few hundred dollars, it was worth a shot. And I expect any day now to get hauled up for a narcotics search…


So where have we ended up? With a bit of luck, I can now relax a little. The car seems to be reliable, is performing as well as it’s ever likely to, and is comfortable. That’s a pretty good mix in a classic vehicle.

Now it’s time to turn our attention to the host of little but annoying things that need fixing – mostly cosmetic. While there’s no intention to turn it into a concours machine, it would be nice to get it as presentable as reasonably possible, without spending a fortune.

Wish me luck. We’ll bring you more updates as the project progresses.

(Look out for a couple of new videos, soon – one on doing the ignition and the other on fuel injection.)

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