Friday, August 15, 2008

Conversion from Indirect Injection to Direct Injection

This will also work for the 1.6 TD engines.
I have been working to convert an Indirect Injection Engine(IDI) into a Direct Injection Engine (TDI) and fit it in the blue Syncro after the brown one is done.
As I had a few Audi 5 cyl 2.0 TD engines laying around I thought that it would be interesting to convert one of them into a TDI and see if it would run OK and how much improvement there would be in fuel consumption.
I bought a 2.5 TDI cylinder head on Ebay Germany with a set of injectors, injection lines and an TDI Injection pump.
I am using pistons from a Renault 1.5 Clio diesel and modified them to make them fit and compensate for the 6 mm longer stroke of the Audi.
As one of the engines had the last oversize pistons in there, I had a set of sleeves installed in the block and honed out to the 76 mm of the Renault piston.
I have modified the original Audi TD injection pump to accept the 20 mm TDI pump shaft and clearanced the timing advance piston, TDI's need lots of advance.
Also changed the pump internally so that it has four rollers on the camplate instead of the TD's original three.
I will keep you posted on the progress.


Tom said...

Glad to see you're still trying to keep it simple:-) If I had a nickel for everything I didn't understand I'd be a very wealthy man...

Just checking in to see if you got the laser tool back and in good shape.


Tom said...

Hey Herman, how is the build going? I am currently rebuilding my 1Z and looking for new 80mm pistons. There are two kinds, the original style and what I believe are called ASV pistons with extra oil cooling passages. I'd prefer the ASV style but can't find any, was wondering if you new of any sources?

Thanks, Tom (from Colorado)

Herman said...

Hi Tom,I installed 2 aux. tanks lately, replaced heater core and fan motor and putting the dashboard back together, on to body work next.

You can find the ASV pistons here:

I don't know if it is worth that much money unless you are racing it!

Cheers Herman

wildenbeast said...

Have you seen this? Someone else has successfully done what you are working towards, only it is on an AAZ engine;

Herman said...

Hey wildenbeast, yes I have seen those conversions.
They are easy to do because the stroke and bore are the same as the TDI.
It is just a matter of swapping pistons and cylinder head plus a mechanical injection pump.