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Author Topic: 1Z/AHU vs ALH?  (Read 26737 times)

January 25, 2007, 08:11:18 pm

lord_verminaard

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1Z/AHU vs ALH?
« on: January 25, 2007, 08:11:18 pm »
Ok, keeping electronics and engine mounts out of the question, what are the differences?  Just because I see 1Z and AHU's a lot cheaper than ALH's and wondering if there is any real reason why one would be better than the other.  Thanks!

Brendan
84 Scirocco 8v
01 Jeep TJ 4.0


81 Scirocco 'S -->Soon to be m-TDI
93 Corrado SLC VR6
'86 Golf N/A Diesel  -->Wife's car
1990 Audi CQ
05 New Beetle PD TDI


"I am a man, I can change... if I have to.... I guess....."

-Red Green

Reply #1January 25, 2007, 09:35:51 pm

RabbitGTDguy

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1Z/AHU vs ALH?
« Reply #1 on: January 25, 2007, 09:35:51 pm »
Internally, they are hugely different. Some Def things are... 1z/AHU injectors are set at a lower pressure... ALH are set at 220bar if memory serves me correctly. Also...internally, the pistons of the 1z are 1piece, cast units similar to the IDI TD pistons... 1z pistons also have a top ring that sits higher up on the piston than on the AHU/ALH engines...
With the AHU engine introduction the TDI pistons saw a significantly strong alloy introduced, brass triuons and thicker rings lands compared to those pistons in the 1z.
The blocks of the 1z and AHU are the same... very similar to the blocks used by VW for almost 30 yrs... mounting bosses for MK1, MK2 MK3 apps, all exist on both 1z and AHU engines... the water pump is external from the motor and belt driven
The block of the ALH was changed and lost the MK1 mounting boss for all four bolting mounts. The block is slightly longer in the main run than the 1z/AHU units. The block is supposedly "reinforced" in the ribbing more but uses the same internals as the AHU (1z exception because it has the cast pistons).The vac. pump is relocated and no longer the traditional vac. pump that is driven off the int. shaft on the earlier 1z/AHU motors and the water pump is internal, driven off the timing belt.  The head is also different on the ALH motors, with the new block it has a wider "central galley" oil return in the head vs. the 1z/AHU built on the older style block that has a central relief galley and one that sits to the left on the front of the head as well. The valve cover on the 1z/AHU mounts similar to the AAZ cover (3 stud mount) whereas the ALH cover is all cast aluminum and mounts with several studs
Lets see...what else... well, 1z/AHU motors use a slightly different configuration for the injection pump.... a 7 pin pump vs. a 8pin (correct me if I'm wrong) on ALH pumps. Also, 1z/AHU motors use the traditional sprocket drive for the injection pump with a fixed sprocket . The ALH introduced the use of a pressed on hub to the pump and an adjustable sprocket that bolt to this up that allows for initial timing adjustments to be made WITHOUT having to take the pump loose at the front flange and back retaining bolt (like you do have to do on old IDI motors as well...)

The 1z/AHU was rated with 90hp and 150ft/lbs...the ALH 90hp and 155ft/lbs

1z/AHU used a wastegated Garrett turbo that was fairly small and with the ALH the movement was made to the use of the VNT 15.

As far as performance. Flat out...there is more programming options, etc. for the ALH just off the shelf...on the market. 1z/AHU programming for the electronics end of them....not so much.  Also, the ALH engines are supposedly able to support more hp/tq as well. However, several nice AHU and 1z's have been built up (in my case, I did a 1z, but I replaced the weakest link...the pistons with modified ALH units) and perform very well... in many ways, I think easier to maintain with the external water pump, etc. Read about stories of those with ALH's that have had the water pump go and take the timing belt with it and in turn, wrecking the head, pistons, bent valves, oye.... lots of stuff. Most cases of that though is owner neglect...not paying attention to maintenence.

I'll reread to see if I missed anything :) think i got most of it though..

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 #2January 25, 2007, 10:14:32 pm

wolfsburgnut

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1Z/AHU vs ALH?
« Reply #2 on: January 25, 2007, 10:14:32 pm »
What did you have to do to make the ALH pistons fit in the 1Z block?

Peter
1995 Golf 1.9
1994 Golf Marathon
1990 Golf 1.8
1986 Golf Wolfsburg Ed.

Reply #3January 26, 2007, 05:43:38 am

RabbitGTDguy

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1Z/AHU vs ALH?
« Reply #3 on: January 26, 2007, 05:43:38 am »
they fit without issues...same bore, same height, only different is in between how high the top rings sit on the two. I should have said modified for my own tastes as I had the lip machined on the combustion chamber bowl to lower compression w/o hurting squish and also it removed the most crack prone area of either piston...if cracks start to occur, it usually at the lip. I remember Kerma mentioned to me that when they looked at the injection spray pattern, part of the pattern distinctly hit the lip...with it removed...it does not. I also had mine thermal coated up by Swain Tech for some extra insurance...

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 #4January 26, 2007, 07:46:43 am

lord_verminaard

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1Z/AHU vs ALH?
« Reply #4 on: January 26, 2007, 07:46:43 am »
Thanks Joe, you rock, just what I was looking for!  :D

Brendan
84 Scirocco 8v
01 Jeep TJ 4.0
81 Scirocco 'S -->Soon to be m-TDI
93 Corrado SLC VR6
'86 Golf N/A Diesel  -->Wife's car
1990 Audi CQ
05 New Beetle PD TDI


"I am a man, I can change... if I have to.... I guess....."

-Red Green

Reply #5January 26, 2007, 08:48:48 am

Tintin

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1Z/AHU vs ALH?
« Reply #5 on: January 26, 2007, 08:48:48 am »
Quote from: "RabbitGTDguy"
I remember Kerma mentioned to me that when they looked at the injection spray pattern, part of the pattern distinctly hit the lip


Yes they is true, look in my post, I had  photo of my pistons, and have sees the inj. spray pattern very clearly which is hit the piston bowl
http://vwdiesel.net/phpBB/viewtopic.php?t=2848&postdays=0&postorder=asc&start=255

ALH have a larger end on the crank shaft for the sproket of timing belt, and the hollower sproket and the bolt are larger, the oil Pump is drive out by chains in the oil pan........  the ALH came plate is more aggressive, due to higher inj. open pressure. (220B)

In europe, exist a AFN motor, the same as the 1Z/AHU,  But with 110 HP, the set-up is a .205inj. , 190Bar open pressure, ALH came plate, and a VNT15 turbo.

For the remainder, I think that RabbitGTDguy said all.

Reply #6January 26, 2007, 08:57:25 am

Tintin

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1Z/AHU vs ALH?
« Reply #6 on: January 26, 2007, 08:57:25 am »
I had forgotten, for the ALH the max HP is 90HP @ 3750rpm.

The 1Z/AHU is 90HP @ 4000RPM  and the AFN is 110HP @ 4150.