Here's a bit about my latest turbo-diesel conversion.
Personally I prefer driving vehicles with manual transmissions. The more direct control over the vehicle, better power transfer and better fuel economy have always been deciding factors for me. My wife, on the other hand, feels quite differently. She definitely prefers the ease and simplicity of having just the Stop pedal and the Go pedal. For the past few years I've kept one automatic vehicle for her to drive and the rest of them have been manuals. I've come to closely understand the the downside to that SOP. Whenever there is an issue with her automatic, I become the family chauffeur. This is especially inefficient as it consumes a lot of time that could otherwise be spent fixing whatever issue her car is experiencing. To that end, despite having a fairly nice 5-speed high top AHU mTDI camper, I decided to build an automatic mTDI and eventually sell the 5-speed. Having a vehicle that we will both drive happily is a lot more important to me than the fun of rowing through the gears.
About a year and a half ago I found a '91 automatic with a seized 2.1 WBX in Phoenix and hauled it up the hill. It sat while I addressed other priority projects all the while my mind was buzzing about which turbo-diesel engine to install. I really like the TDIs for their added fuel efficiency and low-end torque, but the rpm range of the earlier IDI engines much more closely matches that of the WBX engines meaning that an AAZ install could be done with the stock R+P whereas a TDI would really want a gearing change. While flip-flopping the added cost of gearing changes or the added benefit of increased fuel economy I came across an advert of a fellow selling the complete 15° ALH Automatic drive train from his van. Unfortunately he had had an electrical fire that started with the A/C wiring in the driver's side rear pillar and totally gutted his previously very nice van. The heat of the fire had melted the engine lid and some of the plastic components on the top of the engine but the metal components survived albeit crusty. As part of his initial swap he had regeared the automatic to the Euro 3.73 R+P. I purchased the swap and had it shipped to me.
Because I build and sell mTDI injection pumps, the damaged electronic components were not an issue. The mechanical pump is a distinct step up in reliability over the electronic engine management and certainly the way I was going to go regardless. The pumps I build are based on the Cummins 4BTA base pump which has a pump snout that fits the 1Z/AHU pump bracket. I figured I'd add a bushing in order to fit the ALH pump bracket (the snout of the ALH pump is larger with a corresponding larger opening in the bracket) but a Land Rover 300TDI mechanical injection pump fell on my lap for a great price. The Land Rover pump has the same larger snout as the ALH pump and so is more closely a bolt-in option. Because it was a used pump I decided to pull it to bits and make sure it was all good internally. I had to replace the camplate due to some pitting and the governor shaft and flyweight assembly due to some odd wear, but otherwise internally it was in very good condition. I made a rod that extended from the stock transmission rod up to the accelerator lever where I fastened it with a heim joint.
The engine is mated to the trans at 15° using the a Kennedy adapter plate and drive plate. It came with two mounting bars (one for each mount) but I do not know who initially produced them. If anyone has further info on that I'd appreciate it. It looks like a typical mk2 mounting bracket on the driver's side which has been modified to fit around the VNT15.
During the conversion I swapped the coolant pipes for stainless ones as the plastic pipe ends had the usual failure. I modified the fuel filler for the larger diesel nozzle and dropped the fuel tank for cleaning. I'm not sure how long the van had sat, but I believe it must have been for quite a while. There was a fairly thick layer of varnish sludge in the bottom of the tank. The fuel tank grommets had all turned to goo and the fuel sender was thoroughly gunked (constant open circuit). I dumped out as much of the varnish goo as I could, dumped in a gallon of acetone, sloshed that around, added a few gallons of diesel, sloshed that around and drained it. I then added a few gallons of diesel and called it good. I'll add the leftovers to the tank in a 10% mix until gone.
The cooling hoses were not hard to do. I re-mounted the expansion tank (with the base) from the rear heat shield to the passenger side of the engine bay where the air cleaner had previously been located. I did a hose routing that basically mimicked the ALH automatic using all hoses or hose sections from the bin of old coolant hoses I keep in the parts storage. Here's a flow path diagram (pardon the chicken scratch quality...):
I made an adapter for the end of the head so that I could use one of the early aluminum coolant flanges there along with the two early temperature senders. I probably could have used the stock ALH head flange, but I wasn't sure how the temp sender would behave with the stock vanagon gauge and the mk2 glow plug relay I was using.
I relocated the power steering reservoir as well and adapted it to the ALH. That adaptation was extremely easy. The high pressure banjo bolts right up. The low pressure hose just needed cut and clamped onto the lower nipple on the ALH pump.
I spent an afternoon making an engine wiring harness for the stop solenoid, coolant level, coolant temp, oil pressure and glow plugs. For the oil pressure warning system, I added a tee to the single oil pressure sender port and ran the high and low pressure senders. As mentioned, for the glow plugs I am using the mk2 fast glow plugs wired into the OXS light. Granted it will run the glow plugs much more often than necessary on the TDI, but I don't mind.
I made a block-off plate for the EGR on the VNT15 manifold. I also made a flange/pipe in order to run from the intake to the compressor scroll of the VNT15, temporarily bypassing any intercooling. I am also temporarily running the turbo vanes stationary in a mid range. For the air cleaner/intake I used a 1.6TD intake boot, sliced it and added one piece of bent tubing. It now clamps nicely onto the turbo compressor inlet and the air filter fits nicely in the Driver's side D-pillar.
I made up a dipstick tube from steel brake line and a dipstick from a low-B bass string and hardware store parts. I can check the level easily from the license plate door. I still need to lift the lid to add oil but will rectify that situation in the future.
The engine lid interference is pretty extreme. The engine pokes up about 3.25 above the top of the engine cover. I cut out that section of the engine lid and another smaller section that interfered slightly with the coolant expansion tank cap. The small opening for expansion tank clearance got a small thin piece of sheet metal over it. The larger section got a bumped up section made of 1/16" thick steel that I rivetted to the fiberglass cover. It is now quite solid and unfortunately about as heavy as the early metal lids.
While many people seem to see the raised lid as a downside, I don't. This weekend I will be installing a rear bench sofabed using the bay bus westy hinges. The bay hinges will raise the bed up about 6 inches and so to match the new bed height I will similarly raise the hatch platform area. That will give a significant amount of additional storage along with a flat fold-down bed.
After a bit of adjustment it is downright fun to drive. Performance is significantly better than a 2.1 WBX. Off-the-line it really scoots. It will squeal the tires on dry pavement if you floor it on a turn. I haven't done enough driving to have any fuel economy info. I do not yet have boost, EGT or tach gauges working yet and so don't have any feedback on those.
Next up is to make the rear sofabed and raised platform over the engine and welding in the passenger swivel base. The longer list will include a standalone programmable electronic vane control, EGT, boost, tach, air water intercooler system, turbo swap to a GT1852V, upgraded injectors, new exhaust, oil filler from license plate door, over-tranny battery tray for starting and aux batteries, get the A/C up and running and add a high top. The VNT vane control, air water intercooler, injectors and turbo swap should result in a truly massive increase in performance.
