ALH head on AHU block?

00013cave

Veteran Member
Joined
Oct 15, 2005
Location
island state of Montreal
TDI
1998 jetta TDI, 1997 GLX TDI
Like the title says. Not sure if this has been answered somewhere else but doing some research for a future project. Want to use a good AHU block but use an ALH head so i can have a VNT, unleaking valve cover etc
 

vanbcguy

Veteran Member
Joined
Feb 22, 2013
Location
Vancouver, BC
TDI
'93 Passat - AHU mTDI with GTB1756VK
They're quite different, definitely won't fit.

There's nothing about the head that gives you the ability to use a VNT. All 8V heads have the same exhaust ports.

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Windex

Top Post Dawg
Joined
Apr 1, 2006
Location
Cambridge
TDI
05 B5V 01E FRF
Ports and bolt spacing are different - just do an image search on ALH AHU head gasket, and you'll see that they don't match.

VNT on an AHU? many have converted. Generally requires fabrication work on the rear engine mount, and a tune of course.
 

libbybapa

Veteran Member
Joined
Nov 15, 2011
Location
Where?
TDI
'83 AHU mTDI high top Vanagon, '84 AHU mTDI pop top Vanagon, '85 Franken-mTDI Adventurewagen Vanagon, '91 Vanagon ALH mTDI tin top auto, '02 Jetta eTDI Wagon, '02 Jetta eTDI Sedan
Intake/exhaust port spacing is the same. Intake/exhaust bolt spacing is the same. Head bolt spacing is the same. Coolant port spacing is the same. Oil supply to the head is the same. Here is an image that has the differences highlighted in red and green. I believe all of the differences are oil drains that allow oil to drain from the head to the block. I feel unsure about the one with the blue arrow. Can someone confirm? I believe they could all be tig welded shut and then the head surfaced. The green area would need to be filled in as shown and machined to the correct AHU profile for the front center drain. It's probably doable and somewhat tempting due to the better availability of ALH heads and the much improved sealing of the ALH valve cover. It would be a lot of work and easy to trash a good head if it was messed up, though.

 

iluvmydiesels

Veteran Member
Joined
Nov 21, 2015
Location
phila area
TDI
AHU
due to the better availability of ALH heads and the much improved sealing of the ALH valve cover.
nice outline.
id have questions as to whats going together there, quite a few. but one of the only points you brought up, for all that work, youd need to do (most) yourself. you have a better sealing valve cover. heheh.
 
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