Preamble:

Although I have many VWs in my fleet, up until the summer of 1997 I had not yet owned a Scirocco.  My wife and I were expecting our first baby, and it seemed that the last thing that we needed was a sportscar.  I was driving an 84 Jetta GLI, my wife was driving a 97 Golf TD.  A friend forwarded a posting in a local forsale newsgroup to me for a one-owner 84 Scirocco in a nearby city - price, $300 CDN.  I contacted the seller immediately, and arranged to view the car.  It had been sitting for a number of years, and brakes and exhaust were corroded beyond belief.  The passenger's side vent window had been smashed and was covered with a piece of plastic.  The rear quarters were very badly rusted and there was  a small hole under the back bumper cover on the driver's side.  Surprisingly, owing no doubt to the fact that it was a BC car and had not been winter driven since coming to Ontario, the underside of the car was factory clean and free of rust.  The interior was clean with the exception of torn seat upholstery.  I purchased the car for the advertised price and had it towed home with the intent of either using it for parts or perhaps fixing it up at a much later date.  The car was stored for a year in a shed at our recently acquired farm.

After the winter of 97/98 I retired my 84 GLI in favour of an 83 Jetta GL with a rather tired turbodiesel.  I swapped in a 1.6 NA and used the car on my daily 200km commute.  However I missed the performance and handling of the GLI, so I set about swapping the powertrain from the GLI into the Scirocco (although they used the same engine and transmission, my GLI engine was in excellent shape)  With some moderate exhaust, intake and cam modifications I drove the Scirocco as an alternate vehicle to my Jetta, enjoying decent mileage and performance.

In the fall of '00 I started rebuilding a Turbo Diesel motor to swap into a 92 Golf diesel I had acquired, with an eye to replacing the 83 Jetta, whose body was rusting badly.  Through the winter I worked on the Golf, all the while wondering how I could afford to keep driving my Scirocco as fuel costs continued to rise.  By the time spring rolled around I decided to install the Turbo Diesel into the Scirocco and sell the 92.  I had one last red-line drive with the JH motor, and parked the Scirocco in the shed.  I took a couple of days off work, and completed the conversion.  The Turbo Diesel Scirocco was born in May 2001.

The Swap:

Because VW likes to keep costs low by using a lot of common parts in their cars, the overall difficulty level of this swap was low - not much more than swapping any VW engine into a chassis that came with it from the factory.

Challenges I faced included:

airbox mounting - the CIS airbox on the Scirocco was on the left side - the A1/A2 turbo diesel airbox is on the right side.  I removed an TD airbox mounting bracket from an A1 Jetta TD, and mounted it on the right frame rail with self-tapping sheet metal screwes.

wiring -  although the diesel does not require much in the way of engine wiring (a hot wire for the stop solenoid is about it) I wanted a clean, factory looking swap.  I removed the Scirocco's CIS engine wiring harness, and replaced it with the engine wiring harness from an '89 Jetta TD.  Because these cars use the same fuse box/relay plate, this was not a challenge.   I simply unplugged one harness and plugged the other in.

glow plugs -  a necessity for starting the VW diesel engine, a provision had to be made for the glow plug circuit.  A few runs through the wiring diagrams for the donor (89 Jetta TD) and the Scirocco revealed that simply plugging glow plug relay in place of the fuel pump relay was all that was required.

cold start - VW's IDI diesels use a cable-controlled timing advance in the injection pump to aid cold starts.  In factory A1 Jetta and A2 diesels, this cable terminates on a formed plastic knob that's recessed into the dash below the left vents.  I knew that the Scirocco dash had a dummy plate immediately to the lower left of the steering column.  A little research in the parts fiche revealed that some European carburetted Sciroccos came with manual chokes, and the cable and knob were identical to those used on the A2 diesels.  I mounted the A2 diesel cold start cable in this location, and it looks factory, because it's using factory parts.

instrumentation - My Scirocco came from the factory with an MFA trip computer.  I was hoping to be able to retain the MFA while at the same time being able to install the tachometer from the 89 Jetta TD.  I was not able to convince myself that this would be worth the effort required, and I opted for swapping in the complete cluster from the Jetta (I did maintain the Scirocco's speedometer to preserve the car's actual mileage.)  Because the Mk2 Scirocco and the A2 Jetta through '90 share compatable cluster wring and housings, I was able to plug the Jetta cluster directly into the Scirocco's harness.  It was necessary to jumper a wire in the cluster harness at the relay plate to complete the glow plug warning lamp circuit, however.  In the Scirocco, this wire is used for the O2 sensor warning light, which was not available on Canadian models.  I also had to jumper the cluster wire for the tach signal at the back of the relay plate, as this signal comes in from the alternator's W terminal on the diesel.

exhaust - I started out with a factory KKK turbo from an A2, so all I had to do was use an A1 TD downpipe (of which I had a number.)  This adapted easily to the stock cat back exhaust of the Scirocco, as they are the same diameter.  The TD downpipe ends at the beginning of the centre resonator, which is right where the Cat ends off on the 8V Scirocco.  I welded 1 7/8 3-bolt flanges on both pipes and bolted them together.

fuel lines - The VW diesel's fuel system is pretty straightforward, with all pumping function being looked after by the injection pump itself.  All that is required are feed and return lines, and a fuel filter.  My Scirocco is an 84.5, which utilizes an in-tank transfer pump to supply the main CIS fuel pump.  I removed all of the CIS fuel parts - main pump, accumulator, resevoir, but left the in-take pump in place.  I then plumbed the supply line into the outlet of the transfer pump and the return line into the return line at the top of the tank.  The injection pump draws its fuel through the unpowered transfer pump (which acts as little more than a pickup screen, which it has built into it.)  This setup has worked well for me and given  me no problems, and has the added benefit of allowing me to prime the fuel system after a filter change simply by applying 12 volts to the transfer pump.

fuel filter - In the A2 (and up) diesels the fuel filter is mounted on the right shock tower.  In this location it does not interfere with the turbo diesel's air intake hose.  However, on the Scirocco (and the A1 platform in general) there isn't sufficient room to mount the filter in this location with the stock turbo air inlet.  VW chose to mount the turbo's fuel filter on the firewall in very close proximity to the downpipe.  The stock turbo diesel included a heat shield for the fuel filter as well because of its location.  I looked briefly at mounting in this location, but the Scirocco is sufficiently different from the A1 Jetta firewall to make this not feasable.  I opted to install the fuel filter behind the right headlights on the side of the rad support frame.  I was using the A3 fuel filter that I had previously in my 83 Jetta - this filter is a good deal because it includes a preheat valve (found on later A2 filters) when you buy it, making it a much better deal than buying the A2 filter and valve separately.  The filter is slightly longer than the A1/A2 filters, but it was not an issue for me in this location.  The filter worked fine in this location until I installed a 675mm radiator (see cooling, below)  Then the rad's end tank was right up against the filter and I started to have problems with heat soak in the filter causing low engine idle and longer starts.  In the summer of 2002 I relocated the filter inside the right front fender.  In this location it is protected from engine compartment heat, but is also protected from grime and road debris by the fender liner.

cooling - Initially I maintained the Scirocco's stock 525mm radiator, but started to notice the coolant temps would rise noticeably when under periods of high boost/load. I opted to install a 675mm rad in the car to increase the cooling system capacity. The initial install involved a used rad from an 86 Golf - once I had ironed out the details of the install I purchased a new rad from my VW dealer for $150 CDN (part no. 191 121 253 B) I used an A2 upper rad hose (191 121 101 Q) and Scirocco 16V lower rad hose (533 121 051 B.) I had to trim the engine side of the upper rad hose by about 1.5" in order to keep the bends from being stressed between the engine and the radiator. In order to provide clearance for the alternator, which is mounted low on the diesel engine, I installed the 675mm rad on an angle, moved forward on the passenger's side. I was able to use stock holes for the lowe rad pins (most likely A/C condenser hole on the right side) but I had to cut a hole in the upper rad support for the right-hand bracket. You can see a picture here. This is the same method used to mount the rad on an A2 platform, where the rad is mounted on an angle.

... to be continued

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