'91 Vanagon Automatic mTDI ALH Conversion

[libbydiesel]

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.

[libbydiesel]

Here are some pics of the accelerator linkage.   As mentioned, I attached it to the injection pump lever with a heim joint.  I did weld a small extension onto the injection pump lever in order to achieve the proper throw to match the vanagon accelerator pedal range of motion.  The heim joint then fastens to a bolt that I welded onto the extra accelerator linkage rod that I fabricated.  That rod snakes down around the oil filter housing and then attaches to the stock linkage rod with another welded-on bolt and jam nut.







Here's a pic showing the easy dipstick access.  The dipstick tube snakes over the top of the pump/accessory bracket and then turns to enter the stock dipstick tube location in the block.


Here's the passenger side mounting bracket from above.  Again, I do not know who produced the bracket.


Another view from the side.


Here's the driver's side mount.  It also shows the simple way I have used to make the vanes stationary and yet adjustable until I have the standalone electronic vane control completed.


The mounts do have a VW part number on them but I haven't had a chance to cross-reference it for an application.

[8v-of-fury]

oooh me love.

Very nice work Andy-Roo!

[burn_your_money]

Now that looks like a fun vehicle.

Why did you use a solid rod for the pump to tranny instead of a cable?

[libbydiesel]

The main reason was just to make it easy.  The vanagon automatic has the accelerator cable attached to the trans linkage.  I left that attachment alone.  From there, on the stock gas engine, it attaches to the throttle body via linkage rod.  I removed the connection at the throttle body and made that second linkage rod to go to the pump lever.  It turned out to be no as easy as I thought, tho.  Here's a copy of a post about the van that I put on another forum.

My wife has been using the van as her only driver since I got it going and she LOVES it.  I keep telling her that it is detuned from what it will be with it intercooled and functional VNT control but she thinks it has plenty of power and that I should focus on something that actually needs to get done.  :-)  We both work from home, so we don't drive very many miles.  We have so far put less than 500 miles on the van but the exact number is a guess-more on that in a moment.  

I addressed a couple of minor issues (nothing with the actual engine install).  I installed the rear sofabed.  I used the bay bus hinges and so the seat is at the stock vanagon height and the bed is at the correct height to match the raised engine lid.

There was an excessive amount of vibration being transferred to the accelerator pedal and I believe it was due to the linkage rod vibrating.  I bent another rod to the same profile and welded the two together for added stiffness.  It reduced the vibration noticeably so that it is now what I would consider normal for a cable operated diesel.

The speedometer/odometer seemed to work alright when I first got the van going, but gradually over the first tank of fuel, it started reading noticeably low and the needle started doing the jump up and down dance.  It gradually got to the point where it would just sit at the stop pin and jump up a bit every few seconds and then just laid still on the pin.  While that whole degradation of the speedometer was occurring, I had a fuel supply issue.  When the odometer was reading 225 miles, I had a situation where the engine was a little harder to start a couple of times and then when driving it, it started getting a rhythmic hesitation.  I popped the engine lid and there was a fair amount of air in the lines.  I drove to the nearest fuel station and filled up.  It took 8.9 gallons and the problem went away entirely.  225/8.9 = 25.3 MPG which is about what I would expect for an automatic vanagon driven all in-city and when I was driving I wasn't been easy on it.  I hadn't had a chance to investigate odometer accuracy but I am running larger than stock tires and so I figured the MPG were in reality better.  More on that in a moment.  

Inside the tank, the fuel supply comes from a center baffled area and has a tube that connects over to the tank outlet.  I believe that fitting is sucking air and so the issue surfaced when the level dropped below the leak in the tube.  I figure a fuel tank replacement is in order.

I eventually got around to diagnosing the speedometer issue.  I found that the metal cable end that is supposed to be square and fit through the dust cap of the driver's side front tire had gradually worn itself down to round and so the cable was not spinning.  I purchased a replacement cable from GoWesty for $30 and the speedometer is now the most rock solid vanagon speedometer I've ever seen.  No perceptible wiggle at all.  The worn out speedo cable also means that the odometer was similarly reading low and erratically.  The 225 miles traversed is not only low for running large tires, it is also low for the missing turns of the cable.  I assume fuel economy is better than the aforementioned 25.3.  

I addressed the non-functioning power mirrors and got them working properly and cut down the little stop tabs for added motion.  I really like the power mirrors as the adjustment is very easy and they don't flop at highway speeds like the older mirrors.

[burn_your_money]

The main reason was just to make it easy.  The vanagon automatic has the accelerator cable attached to the trans linkage.  I left that attachment alone.  From there, on the stock gas engine, it attaches to the throttle body via linkage rod.  I removed the connection at the throttle body and made that second linkage rod to go to the pump lever.  It turned out to be no as easy as I thought, tho.  Here's a copy of a post about the van that I put on another forum.

Oh ok, that makes sense. I'm use to the 1.6d autos where it's a cable running from the tranny to the injection pump.

How are your MPGs?

[libbydiesel]

WRT MPG, all I can say at the moment is that it is better than 25.3 miles per US gallon with all in-city spirited driving.  I've got another 100+ miles on the next tank of fuel with GPS verified working odo.  I'll fill it back up in another 100 miles and report back.