Author Topic: Differences in 1Z / AHU / AFN heads and blocks (Read 19337 times)

MikkiJayne · « **on:** January 14, 2008, 01:28:25 pm »

Hi All,

I'm after a bit of info on some specific mechanical differences between the 1Z / AHU and AFN engines please.

Is the head different between any of them?

Are the AFN block / crank / pistons any different to the AHU (I know the 1Z and AHU pistons are different)

I have a complete but stripped AHU, a running but shafted 1Z, and an AFN bottom end, and just weighing up my options for what to put back together.

Thanks

Mikki x

mdonau · « **Reply #1 on:** January 16, 2008, 09:55:59 am »

The pistons may look different, but function & size is the same,
the AFN has Sputter con-rod-bearings..110HP through bigger nozzles
and the VNT/VTG turbo instead of the Wastegated

jimfoo · « **Reply #2 on:** January 16, 2008, 11:46:40 am »

I thought I remember hearing the AFN is an inch longer, so neither crank nor head is compatible.

mdonau · « **Reply #3 on:** January 16, 2008, 12:02:22 pm »

Quote from: "jimfoo"

I thought I remember hearing the AFN is an inch longer, so neither crank nor head is compatible.

thats the difference between 1,6l and 1,9l..

all old 1,9l VW-Diesel have a 95,5mm crank an most have 144mm rods (the N/As have 150mm)

you can take every 1,9l block with that auxillary-axle and combine with IDI pistons and head or TDI pistons & head..

chassis-mounts, sensor-holes etc. are sometimes specific.

jimfoo · « **Reply #4 on:** January 16, 2008, 12:35:53 pm »

I was confusing ALH with AFN. I know nothing about the AFN.

Quote

Ok...

Head...no deal. ALH heads have a differently shaped oil return galley on the front of the head compared to the 1z/AHU heads. That is def. one difference right off the bat. I can't remember if the other oil passages and coolant passages are different...

Pistons... All TDI pistons for the 1.9 TDI will swap into each block. I have a 1z block that I'm running ALH pistons in (though modified combusion chambers, ceramic coated, etc.)

ALH and AHU pistons are the same. They are quite a bit stronger and less "crack prone" compared to the 1z TDI pistons which are single piece "cast" units.
ALH/AHU units are beefier in their construction, are made from a different alloy and also have brass triuons, and thicker ring lands without going to look at my measurements and pictures from the mTDI motor now in the Mk1.
There was a slight difference on the 1z motors, with the location of the top ring relative to the AHU variation and the later ALH motor. I believe the top ring on the 1z motors sits higher than the ALH ?
Off the top...can't remember.

Can the pistons be used? Yes...

ALH crank to AAZ?

No...the ALH block is slightly longer than the "traditional" external water pump VW blocks... this includes the 1z and AHU motors. The crank in turn is slightly longer to accomodate.

RabbitGTDguy · « **Reply #5 on:** January 16, 2008, 01:01:59 pm »

Quote from: "jimfoo"

I was confusing ALH with AFN. I know nothing about the AFN.
Quote
Ok...

Head...no deal. ALH heads have a differently shaped oil return galley on the front of the head compared to the 1z/AHU heads. That is def. one difference right off the bat. I can't remember if the other oil passages and coolant passages are different...

Pistons... All TDI pistons for the 1.9 TDI will swap into each block. I have a 1z block that I'm running ALH pistons in (though modified combusion chambers, ceramic coated, etc.)

ALH and AHU pistons are the same. They are quite a bit stronger and less "crack prone" compared to the 1z TDI pistons which are single piece "cast" units.
ALH/AHU units are beefier in their construction, are made from a different alloy and also have brass triuons, and thicker ring lands without going to look at my measurements and pictures from the mTDI motor now in the Mk1.
There was a slight difference on the 1z motors, with the location of the top ring relative to the AHU variation and the later ALH motor. I believe the top ring on the 1z motors sits higher than the ALH ?
Off the top...can't remember.

Can the pistons be used? Yes...

ALH crank to AAZ?

No...the ALH block is slightly longer than the "traditional" external water pump VW blocks... this includes the 1z and AHU motors. The crank in turn is slightly longer to accomodate.

Hey...all that info looks like one of my jumbly posts....I was scratching my head saying, "Hey, I have said that same exact thing somewhere before...and not too long ago!"

Joe

MikkiJayne · « **Reply #6 on:** January 18, 2008, 06:49:18 am »

Thanks guys.

So basically the AFN and AHU blocks are the same then, but with different bearings and slightly different pistons?

How about the heads between 1Z and AHU?

Thanks