The Reverse Spinning 1.8t Engine Project

(Not currently available for sale)

April 8, 2013

There seemed to be a lot of interest in this idea. In 2012 Syncroghia started a thread on the idea of turning a TDi engine backward on the Samba.  I also had been wondering if it was possible. The TDi would have needed a custom camshaft to work. I am working on running an AEB backward, the advantage of this engine is the intake and exhaust cams are separate and I’m hoping I can re-time the timing chain and belt to open the valves at the right time running reverse of the norm. I consider the AEB/ATW 1.8t and the ALH/1Z TDi engines a gift from VW. They allows us to mix a lot of old parts with much newer parts because they are based on the old engine blocks from the ’70s, ’80s, and ’90s, yet they have much more modern cyl heads and engine managements. You can bolt a 1975 rabbit oil pan and transmission to either of these engines.

April 12, 2013

I believe I have the oil pump sorted out.  The picture above is the 1.8t oil pump drive part. The first picture to the right are the diesel oil pump drive parts. What is pictured there is the bottom of f1.6 diesel vac pump I cut up. The smooth side of the timing belt is what drives the diesel intermediate shaft thus it is reverse the rotation of the crankshaft. Next picture are the Tdi and 1.8t oil pumps, 1.8t to the right.  The top view of the diesel oil pump through the bloc. The diesels have oil running up the oil pump shaft to lube the vacuum pump, I cut the shaft off just above the lower bearing in the vac pump base and welded the hole up so we don’t lose all the oil pressure. I just need to make a cap for the aluminum vac pump base and I believe it will be all set. I also pulled the gear off the diesel intermediate shaft and pressed it on the 1.8t one.

The transmission I have out on the floor happens to be from a V6 passat, code DVZ. I used the very cool gear chart on the TeammFactory site

This is what my speeds/rpm would be using that trans. (red) compared to the stock 2.1 trans. (blue)

April 12, 2013

Starters, on the right is the 1.8t Passat/Audi A4 starter, on the left is an ABA 5speed starter. I think I have got lucky here, it looks like I can use the ABA internals and steel housing with the Passat aluminum mounting piece to reverse the direction. Here is a look at the bell housing of the Passat transmission with the clutch and flywheel in. The neat thing about this transmission is it has two sets of bolt hole in the bell, it can bolt up to the V6 or 4cyl.

I’m adding a few pictures here just for reference. It looks to me like its all reversible with mostly taper roller bearings used to control axial alignment.

April 16, 2013

I believe the starter is done. The only 1.8t starter parts used are the solenoid and the aluminum housing. Bench tested and it spins backwards. Its getting hard to remember what is forward and what is backward now. The shaft sticks out about a 1/4″ into the bell housing, if it is a problem, it will meet the bench grinder.

April 17, 2013

The block is clean, painted, and ready.

April 20, 2013

The crankshaft sensor wheel needed to be indexed for the new rotation direction. The wheel is a 60 tooth minus 2 teeth. I turned the crank clockwise (normal direction) until the center of the missing teeth was centered with the crank sensor hole in the block. I then measured the top of #1 piston to the top of the block. Then took the screws out that hold the wheel to the crank and turned the crank counter clockwise until the measurement was the same, spun the wheel until the sensor hole again lined up with the missing teeth. Then I match-marked the crank to the wheel in its new location. In order to mark where to drill the new holes, I turned a 6mm bolt and cut the head off it. We then screwed it into the tapped hole until just the point was sticking out. Then lined up the marks I made on crank and wheel and tapped it into place so the points would leave a mark where I needed to drill the new holes.

April 21, 2015

 Here is the factory cam location marks for TDC #1

Here is the factory cam location marks for TDC #1

If we turn the exhaust cam 90* ccw, the mark lines up perfectly with top machined surface of the head.

If we turn the exhaust cam 90* ccw, the mark lines up perfectly with top machined surface of the head.

when those marks are lined up, #1 cam lobes look like this.

when those marks are lined up, #1 cam lobes look like this.

and we turn the intake 90* cw, the mark also lines up with the top of the head.

and we turn the intake 90* cw, the mark also lines up with the top of the head.

The new firing order will be 1-2-4-3. I'll have to swap the ignition coil plug and injector plug from 2 to 3 and 3 to 2.

April 21, 2013

Chain tensioners- Here is a diagram of the Audi/Passat 2.8 V6 (ATQ or AHA), if you look closely at them, they are basically the 1.8t head with one cylinder missing. Although all four cams are turning CW, one head has been turned around so all intakes are on the inside and exhaust are on the outside. The right (1,2,3) head is driven like a typical 1.8t and the left one (4,5,6) is driven by the opposite end of the exhaust cam. In other words, one turn backwards compared to the other one. I hope that makes sense! The left head of the 2.8 puts the tight side of the chain on the top like my 1.8t running backward will do.

April 22, 2013

Cam Position Sensor The 1.8t uses a cam sensor to tell the ECM what cyl is firing and to make sure the timing has not gotten out of place. It is a hall sensor identical to the 1.9 and 2.1 Vanagon distributor sensor.

When the gap is centered with the sensor....


The intake cam is in this position....


It is just before the #1 cyl is at top dead center.

There is a bent tab on the sensor wheel that lines up with a notch on the end of the cam to put it in the correct position.


I turned the cam in the opposite direction an equal amount, bent the tab flat and marked where the wheel was in relation to the notch. Then made a new indentation on the wheel to align it in the new position for reverse rotation.


April 25, 2013

Pistons The piston pin is offset .093″. To be able to put them in backward, I milled the small notch in the skirt to clear the piston squirter and a small notch on the top to clear the middle intake valve.

April 27, 2013

I got the V6 left side tensioner mentioned earlier and have it mounted in place. It fits exactly like the original, just made to have the tight side of the chain on the top.

May 1, 2013

As I’m slowly assembling the engine, I’m jumping into the wiring as that is my favorite part of any conversion. With these AEB engines, the wiring is very easy compared to the Subarus. The harness unplugs with these plugs, they are the only wires you need to deal withd

I powered up the ECU with a 9volt battery and hooked it up to VCDS (VAG-COM). Check out that voltage reading.

May 6, 2015

For the timing belt, I ended up using a 16v manual tensioner and the early AEB belt. With a new belt, and the tensioner at the loosest position, the tension is perfect and the with the crank set at TDC #1 the cam lines up exactly where it needs to be, with the mark lined up with the machined surface of the top of the head.

May 8, 2015

I used a ATQ V6 idler, made to be used on the tight side turning 4 cams, and the tdi small idler with a custom made bracket for the tensioner. (Thanks to Andrew Libby for ideas!)

May 10, 2013

First start.  Timing is off, but will be corrected shortly.

May 17, 2013

I made a bracket with a slot to hold an idler pulley and allow belt adjustment. I first tried using a V6 idler, it was just a used one I had and the bearing was a little wobbly, it proved not to work, it threw the belt at about 3.5-4k. I replaced it with a timing belt tensioner from a 1.8, that one seemed to do the trick. I used a serpentine belt from an AEG 2.0 that is dual sided, we had to cut off one groove to make the width right. I’ll check and see I am able to buy a new one that is made like this. We hooked up a Rabbit radiator, hoses, and a fan and ran the engine fro about an hour and a half today. I revved it up to 5k at one point and decided I would rather have it tucked in a van before going any higher. Results were very good, oil pressure was normal, temps were normal, idle smoothed out, it sounded great.

May 18, 2013



With the engine up and running well enough for me to move on, it is time to think about how I’m going to shift this transmission. It looks like there is not much I can do with that shifter. I thought about adapting the Vanagon shifter to the trans using custom made linkage adapters. It looked like a lot of work to do. I thought about making my own cable shifting set up. That also would have been a lot of work, custom brackets, levers, cables, etc. Then I remembered that the early Porsche Boxster used the identical transmission, exact same one just different gearing. The Boxster being a mid engine car has very long cables, they need to run from the shifter all the way up and over the engine, and all the way to the far end of the transmission. Also all the linkage is made for me to Porshe quality. 1062932

May 22, 2013

I have a hacked up, cut off rear section of a Vanagon that we use to mock up engine mounts in. It rolls around on the rear wheels like a wheel barrow and can be rolled totally upside down even with an engine bolted in it. It is very ugly but so nice to use. With the 012 transmission, the CV flanges are offset about 5/8″, I positioned the engine/trans assembly 5/8″ off center to center the hubs to allow for equal axle lengths. The engine and body section are each supported by 3 jacks to allow precise adjustments. It took about an hour using levels, straight edges, and tape measures to get things squared up.

May 23, 2015

Getting the supports figured out.


May 24, 2013

Adapting the axles The 012 transmission will have either the old style CV joint hub in 100mm or 108mm or it will have the newer tripod roller CV. If you have the 100mm then your all set, the vanagon is 100mm. I read that the 100 hubs will not interchange with the others because the spline is different. The trans I am using has the later stye hubs, I was planning on swapping them for 108s and just using 108 CVs on the van’s 33 spline shaft, I even bought a set and have not even received them and I had to abandon that idea. It seems Alika on The Samba went through the same thing with his project. Those CVs were only used on 93 Eurovans (as far as US cars go) and they are not to be found anywhere. Here is what I did.. This is the late style passat CV hub, that step is 100mm dia. The stock van CV sits in there perfect but there is no way to bolt it down. I know it’s not elegant. I built up the area where bolt holes were needed with a welder, machined it level with the step, and drilled/tapped holes.

June 14, 2013


It runs!

Picture above is taken in fifth gear at 60 mph.

It is running AWESOME!!!!!!

I had about ten minutes last night to road test it, it was way overwhelming when I first hit the road trying to wrap my head around what to concentrate on, the hubs I adapted, all the modified parts on the engine, the new reverse location, cooling system, new brakes, etc.

I did have to correct the location of the cam position sensor ring, but other than that, it went very well. It feels so much different than my other 1.8t van which is basically identical except the engine is tilted at 50* and the 4 speed transmission. I am not going to go any taller with the tires, in fact it may actually be geared a bit too high.

When I came back to the shop, my brother asked how the clutch felt, I had totally forgot about it because it felt normal.

June 15, 2015


With just a few hours of test driving, we leave for the Litchfield Bug-In…and actually make it there.


Our video-maker is Russian, but you get the idea…

July 7, 2013


This is on a full tank of 87 octane (I always fill vanagons until the pump firsts clicks off, I don’t keep forcing more in) just normal around town driving including a run just north of Manchester Vt. My tire diameter is stock.


July 26, 2013


I’m up to 2200 miles on the project, still no problems except the oil drip and too tall gears. I’ve gotten 22 MPGs on the last three fill ups.

This is the van at West River Westys

I finally found the time to swap the transmission.

Trans on the bottom is from a 2005 passat, top one is the one I just put in from a 1990 audi 80/9.

The transmission was very easy to swap, the engine balances itself on its mounts when the transmission was removed so there was no need to support it.

The new gears are much nicer, pretty much ideal. By using the older transmission, the hubs did not need any work, just bolt up the stock Vanagon CVs/axles. Pretty cool. I also put a new clutch kit in today, I had been using a used one with 265k miles on it, it worked fine but was getting thin.

Aug 8, 2013


Video of driving with the correctly geared transmission.

30 – 50 mph in 2nd gear @ 6.5 seconds


With tuned ECU

30 to 50 in about 4.5 seconds

The new ECM claims to add 45whp and 60Ftlbs tq, I don’t know if that is true or not nor do I care. It has made a big difference in driving this van, not just for rocketship launches, but for everyday driving. I am able to climb more hills without downshifting now, on a flat or down hill I can take off in second easily, low RPM pull has increased a lot. It has however added a lot of intake noise. I am using the Ford F-150 muffler on this van and have almost no exhaust noise, I’ll have to look into making the intake a little quieter.

Nov 9, 2013

Here is how the engine cover will look.  This is a client’s van I put the same engine in.


March 9, 2014

This is the van  (Mt. Greylock on the horizon) with 10,000 miles on this engine/transmission. I have never driven a Vanagon daily over a winter, I always made sure I had a Quattro or 4mot with 4 studded tires each winter for many years now. I wanted to put as many miles on this and test it in all different conditions. I have driven this at a low of about -15F to high of about 98F and through salt and very thick slush. I am glad I did, I learned that the serpentine belt idler I was using was intended to be inside a timing belt cover for a reason, it did not like being out in the weather. I replaced it with one from a TDi serp belt. I also found a way to use the factory spring loaded serp belt tensioner to maintain a good pressure on the belt, I had been using a manual tensioner.



June 23, 2014


I can now make 100% new shifter, shifter box, and linkage. No more collecting or working with rusted old worn out stock vanagon shifter linkage.

D Clymer (from The Samba) has run into the same issue in trying to collect cores for his Subaru 5 speeds, a lot of them are just worn out junk at this point, it is better to work with new material.

This entire shaft can be put in the van with out even removing the fuel tank. It gives a very nice shifter feel.

This whole project was originally posted on the Samba here.  There are tons of interesting comments and suggestions that were provided to me along the way.  Thanks!