Depends on the block. I'm pretty sure The first gen tdi blocks can use the aaz head but you would need to swap in aaz pistons as well.
So how do I tell if said block will work
Google? Ahu is the block you want. Going mtdi might be easier then rebuilding an ahu block to idi specs no?
I have never messed with 1.9s so I'm here to ask questions. Worked with other diesels just no VW. I'm going to do a 1.9 in my toyota pickup. Have access to a short block tdi 1.9 so where do I look at on the block to tell what block it is and besides swapping Pistons what else has to be changed to run idi head
It can be done (with a piston swap), but IMO that's a step in the wrong direction. I'd get a TDI head for the TDI block. If you don't want to deal with the electronics, you can get an mTDI injection pump. You'll end up with more low-end torque and better fuel economy at similar power levels. The engine codes that have the same block layout are the 1Z, AHU, and AFN. Nothing else would need to be changed from the short block to run an AAZ head other than the pistons.
So what year Jettas where no electronic s
Mechanically injected jettas were available until 98 in Canada I think? But that being said tdi were also available for a couple years before they were completely phased out. Aaz's were never in the states so sourcing parts can be difficult. On an assembled engine the easiest way to tell if it's a tdi by the injection pump and the injectors. I believe the 3rd injector has a wire coming off of it. And the cap on a tdi pump looks completely different and also had more wires coming off of it. By just the block you should be able to tell if it's a tdi if there is a crank position sensor.
When we say mtdi it means converting an electronically controlled tdi engine to be mechanical. Its not as simple as throwing in an older pump. There are a few options on pumps. I'm not 100% on the details of them but I think a land rover 300 pump is almost plug and play it a hybrid pump can be made but I believe it takes 3 pumps to get all the parts.
The reason with you would need aaz pistons is because the direct injection pistons have a bowl in them that's meant to focus the spray pattern from the injectors and ignite the charge where the older style use precups to mix the air/fuel so they are not compatible.