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Author Topic: AHU ALH head/piston swap question  (Read 8428 times)

November 29, 2007, 01:16:41 pm

alphawerks

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AHU ALH head/piston swap question
« on: November 29, 2007, 01:16:41 pm »
Hi all,

I have an AHU which has had the valves have hit the pistons on two cylenders. Don't ask how, I don't know, I bought it that way. Can any pieces from an ALH fit to the AHU block, ie: head and pistons?
If not does anyone know if the ALH crank would fit in an AZZ that has dropped it's cambelt pulley?

Thanks, Ryan



Reply #1November 29, 2007, 02:26:15 pm

jimfoo

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AHU ALH head/piston swap question
« Reply #1 on: November 29, 2007, 02:26:15 pm »
No idea, but I'm looking for a bad piston for size comparison. Want to sell one of yours?
Jim
1966 Land-Rover 88" with 1.9 1Z which has been transformed to an M-TDI
TFO35 mechanically controlled VNT, IC , and 2.5" exhaust.
Driven daily

Reply #2November 29, 2007, 08:26:00 pm

RabbitGTDguy

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AHU ALH head/piston swap question
« Reply #2 on: November 29, 2007, 08:26:00 pm »
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.

There is a nice thread on here in the IDI forums about AAZ crank repair and how it has been successfully done.

Joe
1979 Rabbit mTDI crazy $*(\%& bunny...
1972 VW Westfalia
2009 VW Tiguan SE 2.0T (Wife's car)
2001 Audi TT 225 Quattro Roadster (something newer :) )

Reply #3November 30, 2007, 01:00:00 pm

A2TD

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AHU ALH head/piston swap question
« Reply #3 on: November 30, 2007, 01:00:00 pm »
Quote
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.


The pistons I took out of my 1Z were forged, I think the cast pistons were only in the very early 1Z blocks.

Reply #4November 30, 2007, 05:46:28 pm

RabbitGTDguy

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AHU ALH head/piston swap question
« Reply #4 on: November 30, 2007, 05:46:28 pm »
This was a 95/96 block that mine were pulled from...maybe they were cast. I can go back and look. The 1z pistons def. a different in construction, strength and composition than the AHU and ALH pistons from later motors. However, as mentioned...and per the question...they will interchange/fit.

:)
1979 Rabbit mTDI crazy $*(\%& bunny...
1972 VW Westfalia
2009 VW Tiguan SE 2.0T (Wife's car)
2001 Audi TT 225 Quattro Roadster (something newer :) )

Reply #5December 01, 2007, 03:51:58 pm

myke_w

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AHU ALH head/piston swap question
« Reply #5 on: December 01, 2007, 03:51:58 pm »
good luck finding tdi pistons... I've been looking for sets for the 2 months, all my suppliers are dry... if you find some new, let us know where..
Contact me for hard to find for idi and tdi parts


Reply #6December 01, 2007, 04:38:51 pm

RabbitGTDguy

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1979 Rabbit mTDI crazy $*(\%& bunny...
1972 VW Westfalia
2009 VW Tiguan SE 2.0T (Wife's car)
2001 Audi TT 225 Quattro Roadster (something newer :) )

Reply #7December 01, 2007, 06:12:15 pm

myke_w

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AHU ALH head/piston swap question
« Reply #7 on: December 01, 2007, 06:12:15 pm »
errr..  :( I meant Nural Brand, those are cheapie Chinese knock offs

 8)
Contact me for hard to find for idi and tdi parts


Reply #8December 01, 2007, 08:44:36 pm

RabbitGTDguy

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AHU ALH head/piston swap question
« Reply #8 on: December 01, 2007, 08:44:36 pm »
yah....unfortunately, thats all that has been up as of late :(

Joe
1979 Rabbit mTDI crazy $*(\%& bunny...
1972 VW Westfalia
2009 VW Tiguan SE 2.0T (Wife's car)
2001 Audi TT 225 Quattro Roadster (something newer :) )

Reply #9December 01, 2007, 10:55:02 pm

myke_w

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AHU ALH head/piston swap question
« Reply #9 on: December 01, 2007, 10:55:02 pm »
When my supplier has them I can do Nurals in std and .20 for 435 a set, but things are dry these days. I've occasionally seen the "HD" ones on ebay for 6xx something now and then, but can't really justify the expense because I know the Nural ones are tough as nails.   Too bad really..
Contact me for hard to find for idi and tdi parts


Reply #10December 02, 2007, 12:47:40 pm

jtanguay

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AHU ALH head/piston swap question
« Reply #10 on: December 02, 2007, 12:47:40 pm »
those pistons on the ebay link look like the ones from www.dieselvw.com hmmm......... chinese knock offs?!  would be nice to buy them and see at which point they melt/break/crack/pit.  :lol:


This is how we deal with porn spammers! You've been warned.

Reply #11December 03, 2007, 06:37:40 am

RabbitGTDguy

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AHU ALH head/piston swap question
« Reply #11 on: December 03, 2007, 06:37:40 am »
I didn't go to look on the site...I'm guessing since it is www.dieselvw.com that it must be the user "prothe" on ebay? It would be interesting to see "what" they do. I've asked him before when I was in a nozzle search about "who" produces his nozzles, just for general knowledge...and I could never get an answer.
That...I reported to Ebay. We do have the right to know (and I wanted to confirm)

Joe
1979 Rabbit mTDI crazy $*(\%& bunny...
1972 VW Westfalia
2009 VW Tiguan SE 2.0T (Wife's car)
2001 Audi TT 225 Quattro Roadster (something newer :) )

Reply #12December 18, 2007, 11:53:02 pm

Slave2School

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AHU ALH head/piston swap question
« Reply #12 on: December 18, 2007, 11:53:02 pm »
Do they have teflon or graphite coated skirts?
Waiting for a bigger better diesel to come along.
2002 ford focme wagon

Reply #13December 19, 2007, 12:09:40 am

jimfoo

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AHU ALH head/piston swap question
« Reply #13 on: December 19, 2007, 12:09:40 am »
That is what I bought. There is a pic of one here. http://vwdiesel.net/phpBB/viewtopic.php?t=11359&start=30
You can't see it in the pic, but the first ring land has some kind of reinforcement. It's not steel, but it is very slightly attracted to a magnet.
Jim
1966 Land-Rover 88" with 1.9 1Z which has been transformed to an M-TDI
TFO35 mechanically controlled VNT, IC , and 2.5" exhaust.
Driven daily