Here's som info about the topic. I've taken this info from vwdiesel.net that was taken from brick-yard.co.uk. This is high valued information so I think it's worth saving here too!
Hi Folks, not been on here for a while...
Just thought I would drop you an update, Now clocked up just over 55,000 miles since the mTDI conversion on my 87 Caravelle. Mechanical failures in that time include Starter Motor & water pump.....thats it!
Actualy thats not true, the Gearbox gave way last week with a locked up diff..........Accelerating up a gentle hill and 'BANG', kicked out of gear and one back wheel locked......Ooops!
So, now on the hunt for another gearbox.
Anyone considering this budget conversion, (AHU 1.9 TDI, AZZ pump, GTD Boost Pin, Sharan Intercooler) go for it, it's been a joy to drive for the last 4 years. Has always given me 400+ miles on a tank of fuel.
(the box clocked up 205,000 miles before it let go.......so not too bad!)
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The internal's of the pump are not modified, however the fuel metering is.....its very easy, you shut down the idle screw on the trottle arm so the throttle arm is fully closed. This means you lose tick over speed, however you then adust the main fuel delivery screw on the back of the pump and set your idle with this instead. (you must also shut down/back off the residual fuel screw that compensate for Air Con. Dont worry, you will never overfuel it, even when using the boost pin to its most aggressive position, smoke is hardly visiable. But you must make sure the main delivery scew is worked with in 1/8 increments, it is very sensive, turn it too far out and you could risk diesel runaway. The golden rule is to make sure the engine returns to idle within 3 seconds of revving up high. I made my own boost pin for even more power and only then was I getting some black smoke, driving with the home made boost pin was amazing and I could Pull from 30mph to over 80mph in 5th!!! I lost MPG so reverted back to the adustable GTD boost pin( can pull 35mph to 80 in 5th, so only lost a tiny bit) I posted a massive page on here years ago in great detail how to do it (I have worked with Marine diesel engines most of my life, so I knew what I was doing.
You must then give the pump a touch more advance (timing) because the AAZ pump takes a lilttle longer to build up the required working pressure to lift the injecter needles.....
Providing you are not getting black smoke and you havent messed aroudn with the Turbo waste gate, you wont need to worry about exessive ehaust manifold temps either, its all very simple.
If anyting the TDI's run cooler than the AAZ engines because the greatly increased head efficiency and direct injection properties. Indirect (AAZ) engines, the combustion starts in the Howard chambers which greatly increases head temps. TDI's run much cooler, I have sat for hours in the nasty cornwall summer traffic jams, I have never once had the cooling fans kick in and Im still runnning the smaller petrol radiator!!!
I used to have a good 1.6TD crew cab, its every bit as powerful with more torque and stonks along the motorway (I held it at 70mph for over 7 hrs driving back from cornwall through the night, no problems. Flat out it does a smidge over 80mph, (94mph down hill is the most I have ever had) but this is the limitations of gearing and pure BHP.
Shame the box broke, it was a rare one, (8D) nice and high geared similer to the more desirable AAP BOX.
As for budget conversion, Home made left hand engine mount, exhaust and intercooler plumbing. Engine out of a 98 MK3 Golf Estate, AAZ pump of the shelf from the scrap yard and the intercooler.
Stock T3D flywheel and clutch, gearbox was £50 of ebay......so had my monies work out of the box LOL.......Never thought I would get 55,000 trouble free miles........amazing!
As for comparison to newer stuff, I drive a 57 plate 1.7Common Rail Astra van for my work everyday, the Velle feels more responsive with no Turbo lag and more torque. The Astra feels half asleep. I must be getting pretty good power becaue I can fly past all those bay window's climbing hills in Cornwall........LOL
The entire thread can be found here: http://www.brick-yard.co.uk/forum/mtdi-55000-mile-update_topic62248.html
