Building a New Rabbit Heart - 1.9 TD

[Derekxj]

Hey gents!

So here I am again. I've been stalking these forums for a few years now - bouncing in and out as my life and interests in what i wanted to do with my car changed.

Little summery, its an 84 Rabbit 1.6D NA. 5 speed.
My goals have always been, to keep this car as my daily go-getter getting awesome fuel mileage. Its gotten to the point however where I dont really ENJOY driving it anymore. At first it was cool, and different. Now it just feels slow and boring. With this said, ive been on the hunt for a 1.9 TDI to make an MTDI for a while now. Finally found an engine at an amazing cost - Originally told it was a tdi, but owner knew literally nothing about the engine -  if it was good or bad. All i knew was i would be building something so i didnt care.

With all of this said, i know the engine came from canada and im REALLY beginning to suspect it might be an AAZ. Can some of you help identify? This will be my build thread. I'm striving to make my car FAST. I want to squeeze every last bit of power and torque out as possible. Machine work, and whatever else required is NOT an issue. I will be building this over - time. I want my car to spin tires through 3 gears. I want to have enough top end pull to put a passenger back into the seat, and hard at 50+ mph if i want to.

Internals? Head work? Intakes? Here's what im starting with!!!

[carrizog60]

you have a 1.9td.
the tdi head is not straight.

[Derekxj]

you have a 1.9td.
the tdi head is not straight.

Thanks!!! Okay so does that mean this engine IS an AAZ? 

[vanbcguy]

you have a 1.9td.
the tdi head is not straight.

Thanks!!! Okay so does that mean this engine IS an AAZ? 

AAZ or 1Y... I think they're essentially identical internally.

Note that it appears someone has forced an imperial bolt in to the oil pressure switch hole on the head; that's soft aluminum with a hard steel bolt of the wrong size threaded in to it. 

[libbydiesel]

The 1Y has the oil jets, but has different rods/pistons along with a different CR.  That looks like an AAZ to me as it has the turbo oil return line port.  It's easy enough for the OP to check, though.  Look at the block code. 

[Derekxj]

The 1Y has the oil jets, but has different rods/pistons along with a different CR.  That looks like an AAZ to me as it has the turbo oil return line port.  It's easy enough for the OP to check, though.  Look at the block code. 

I put a picture of what i think is the block code above. How do i reference this is there a website or something that i can figure this out? I need to know before i start ordering parts and whatnot.

And yes there is an imperial bolt in there. I'll be sending a tap through those threads just to make sure their clean once the head comes off. Complete dissasembly down to the block will be starting soon i hope!!!  Any comments from anyone on how i can make this thing an ANIMAL of an engine for my little rabbit?  Recommendations on how much to bore, what internals to use ( forged etc ? ), how to get the compression up, what internals on the head should i start looking into ?  Valves? bigger valves?  Im an internal engine newb here guys. This will be my first COMPLETE engine build myself. Mainly most important will be figuring what im going to be doing to the block so i can get pricing from the machine shop.

[RabbitJockey]

aftermarket rods for a 1.9tdi should work, and id use all arp hardware for the bottom end.  for the head, id recommend porting it, and for the valve train you will want to talk to techtonics tuning, i don't think larger valves are really necessary but you will want to make sure you have the 7mm valve stems, and use an aftermarket cam like the dr diesel cam that giles sells.  also inspect the precombustion chambers in the head, if there are any cracks or if they have been milled down to the head surface then you should replace them.   if you do all that you should have a pretty solid long block for making good power.  then you must decide on your turbo and manifold choices,and of course who will build your performance pump.

[Derekxj]

aftermarket rods for a 1.9tdi should work, and id use all arp hardware for the bottom end.  for the head, id recommend porting it, and for the valve train you will want to talk to techtonics tuning, i don't think larger valves are really necessary but you will want to make sure you have the 7mm valve stems, and use an aftermarket cam like the dr diesel cam that giles sells.  also inspect the precombustion chambers in the head, if there are any cracks or if they have been milled down to the head surface then you should replace them.   if you do all that you should have a pretty solid long block for making good power.  then you must decide on your turbo and manifold choices,and of course who will build your performance pump.

Thanks for all of this info. Im not quite ready for it yet.....but eventually I will really need to sit down and put together a parts list. I've heard of getting pistons coated in some new high tech coating in diesel engines to raise compression.....Is this something that can be done on these engines also? I've seen that pistons are sold for as much as .050 overbore.......That would be a serious increase in displacement...agreed? Thats certainly something i would be willing to look into.

This is going to be a slow build.......Order parts as i get money, and eventually hopefully hopefully wind up with a complete engine within a years time or so to drop into the old bunny.
As for the pump - I still need to ACQUIRE one - Any info on which pump would be ideal for making serious amounts of power? I will presume.....that i will be giving it to no other than Giles to build for me.

[vanbcguy]

The actual block code is the engine code, AAZ or 1Y. It's stamped on to a pad on the block rather than cast in like the picture you showed.

I'm sensing some gasser thoughts in your head that you're trying to apply to a diesel - you mention increasing compression for instance. There's actually a lot less to do on these engines to make decent power, most of the power potential is actually in the choice of turbo and intercooler. I would resist massively over boring too, there is only so much meat in these blocks. It isn't like an old school V8 where they were made so crudely you could often go wayyyy over safely.

I doubt you can find anything more than a 1mm (0.25ish") oversize piston. There may be 1.5 mm but that's pretty extreme. As mentioned though the exterior stuff is where the most potential lies on these engines.

Definitely use ARP bottom end hardware. Main studs and rod bolts. There's been a fair number of broken AAZ bottom ends due to failing hardware on here. I believe any rods that fit an AHU should work, rods designed for the ALH will have the right dimensions but may hit the intermediate shaft, this includes most H-beam style rods.

Any stock AAZ pump will be fine as a core. Giles will make it in to all it can be.

If you really want the maximum potential and you're buying rods, pistons and a custom pump already I'd stick an AHU head on there and make it in to an M-TDI instead. No prechamber to worry about and a nice increase in fuel economy while making big power a bit more easily.

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[RabbitJockey]

yeah if i was building for power and all i had was a long block id go tdi

[Derekxj]

yeah if i was building for power and all i had was a long block id go tdi

Do you mean MTDI? I really hate wiring. Not only do i hate wiring, but i REALLY love simplistic mechanical power in its purest form. If i put an AHU head on it, this will essentially make it a MTDI somehow? perhaps im not quite understanding.  Does anybody know where this plate on the block is with the engraved engine code? Back? front? side?  It came from canada, not that means much but i know the AAZ's are plentiful up there.

[libbydiesel]

I'm 99.9% sure what you have is an AAZ.  Any other code with similar components would be a 1/1000 oddity. 

The block/crank are essentially the same for the AAZ and AHU with the only difference being the hole in the block for the crank position sensor and the trigger wheel for it on the crank.  Rods are the correct dimensions for the AHU but a little different in design.  To turn it into an mTDI you would need the AHU pistons and head complete with valve cover and injectors.  I'd also swap the pump bracket and timing covers in order to use the added roller. 

[vanbcguy]

The physical block is virtually identical between the AAZ/1Y/1Z/AHU. Direct injection engines (1Z/AHU) have different pistons and rods and a different cylinder head but the AHU/1Z parts will go in the AAZ/1Y block and vice versa.

Yes, I meant MTDI. Rover injection pump, TDI head and pistons, upgraded rods, you're good to go. There's definitely a few other bits (injectors, injector lines, pump mount bracket) that need to be used too.

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[Derekxj]

Hello Gents'

Pushing forth with this build very soon and am now in the market for rods, pistons, and any head components such as double valve springs, big valves, titanium seats, etc etc etc. I dont want to get into modifying internal parts like rods but I DO want some sort of performance parts - forged if they make them or thats possible. My ultimate goal is to squeeze 200 hp ( roughly ) out of this thing. I've decided to just stick with the AAZ head and keep it a regular 1.9TD. Any input on which components i should be putting my money towards?   Block should be going out to the machine shop in the next month to get bored .030 over.

[libbydiesel]

200HP is more than I would want to make with an AAZ and a lot more than I would want for a Mk1.  You might want to start stocking up on transmissions.