BHW/ALH VE Hybrid...

Ross

Member
Joined
Feb 18, 2017
Location
Maine
TDI
01 Beetle ALH 5speed
There's no provision on the cjaa or cbea crankshaft for the tone wheel. Also the ALH Pistons will not fit the tapered end rods. You could use BRM Pistons. Or just find a BHW short block.
Thanks for this information.
 

03Golfer

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Apr 8, 2020
Location
Canada
TDI
09 Jetta, 92 Toyota swap (ongoing), retired 03 golf
If I'm not mistaken, one could technically run tapered rods on ALH pistons, just without the benefits of increased load area on the piston? Of course, not ideal if you don't already have the parts laying around.
 

ecala001

Veteran Member
Joined
Aug 17, 2020
Location
California
TDI
03 golf
View attachment 112622
hole drilled....see the dimple deep in the hole? I ran into the water jacket and the dimple is the outside of cylinder #1 ...still enough material to tap

View attachment 112623
tapping the hole with a bottoming tap

View attachment 112624
because the stud wanted to bottom on the cylinder I had to grind off about 1 1/2 threads

View attachment 112625
using a feeler gauge throught the WP hole and checking between the stud and cylinder wall to make sure the tightened stud did not bind/deform the cylinder

View attachment 112626
installed with loctite and tightened :)

View attachment 112627
tapping the 7x1 holes for the ALH front seal holder

View attachment 112628
holes completed

View attachment 112629
ALH seal holder in place
if you can recall what tap sizes did you use?
 

jimbote

Certified Volkswagen Nut
Joined
Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
TDI
Tacoma 4x4 converted to TDI
I just realized I forgot that large roller hole 🥲 do you know the tap size for that?



If you look through my pics you can see the hole already drilled/tapped for the large idle roller. I had no idea that some BHWs did not have the hole there. Should not be a problem drilling/tapping but make sure the hole is precisely located as this can affect belt tension.
 

ecala001

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Aug 17, 2020
Location
California
TDI
03 golf
If you look through my pics you can see the hole already drilled/tapped for the large idle roller. I had no idea that some BHWs did not have the hole there. Should not be a problem drilling/tapping but make sure the hole is precisely located as this can affect belt tension.
yeah I was looking through the thread and couldn't find info on the large roller. I was bummed when there wasn't a hole lol
we looked at another bhw we had and we didn't see a hole at the bottom either. I wonder if 04 and 05 were different . unless the block we grabbed is not a tdi? it showed 2.0 on block and remember the head looked like a bew
 

Motohead1

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Joined
Jul 16, 2016
Location
charlotte
TDI
2002 bug+telephone pole
Jimbote I finally about to embark on this and my BHW shortblock is missing its original headgasket so I am unsure if it was a 1,2, or 3 hole headgasket. Any info on what to use or what quinch measurement to find out?
 

jimbote

Certified Volkswagen Nut
Joined
Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
TDI
Tacoma 4x4 converted to TDI
Jimbote I finally about to embark on this and my BHW shortblock is missing its original headgasket so I am unsure if it was a 1,2, or 3 hole headgasket. Any info on what to use or what quinch measurement to find out?
I don't have the Piston projection measurements on hand but any Bentley Passat b5.5 TDI manual should provide that spec.
 

Motohead1

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Jul 16, 2016
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charlotte
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2002 bug+telephone pole
I don't have the Piston projection measurements on hand but any Bentley Passat b5.5 TDI manual should provide that spec.
Thanks found it. Deck piston projection needs to fall between .91mm and 1.20mm. 1 hole gasket is 1.45mm. 2 hole is 1.53mm. and 3 hole is 1.61mm .
 

Motohead1

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Jul 16, 2016
Location
charlotte
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2002 bug+telephone pole
Ok, but aren't those just compressed gasket thicknesses? How does each correlate with different projections?
Im gonna assume the same methodology of other gas builds Ive done and look at what the protrusion spec is and what is available from the factory in this case.
I havent confirmed it exactly but I am going to assume undecked head that you want a min .41mm to max .54mm deck projection minus gasket thickness. Also those are BHW numbers and slapping an ALH head on there will lower the compression slightly. Ive got some more digging to do but its safe to say staying right around .50mm difference will be fine.
 

jimbote

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Joined
Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
TDI
Tacoma 4x4 converted to TDI
Im gonna assume the same methodology of other gas builds Ive done and look at what the protrusion spec is and what is available from the factory in this case.
I havent confirmed it exactly but I am going to assume undecked head that you want a min .41mm to max .54mm deck projection minus gasket thickness. Also those are BHW numbers and slapping an ALH head on there will lower the compression slightly. Ive got some more digging to do but its safe to say staying right around .50mm difference will be fine.
Looking at Elring gaskets on rockauto. One hole is from .91mm to 1mm. Three hole 1.11mm to 1.2mm ... No two hole listed (probably out of stock), so I'm assuming it's for projection of 1.01 to 1.10.
 

jimbote

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spiral arm, milky way (aka central NC)
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Tacoma 4x4 converted to TDI
Im gonna assume the same methodology of other gas builds Ive done and look at what the protrusion spec is and what is available from the factory in this case.
I havent confirmed it exactly but I am going to assume undecked head that you want a min .41mm to max .54mm deck projection minus gasket thickness. Also those are BHW numbers and slapping an ALH head on there will lower the compression slightly. Ive got some more digging to do but its safe to say staying right around .50mm difference will be fine.
Also ,iirc, the ALH head does not drop compression. The BHW piston's larger bowl lowers the number.
 

Motohead1

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Location
charlotte
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2002 bug+telephone pole
Also ,iirc, the ALH head does not drop compression. The BHW piston's larger bowl lowers the number.
You are correct the piston bowl drops the CR not the head. Assuming a undecked ALH head of course should be close to spec as a hybrid block can be.

So I did some measuring and found this unmolested BHW block has a piston protrusion peak of .98. Measured in line with the piston pins. So a 1 hole gasket is on its way.
 

jeeppatriot-alh

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May 7, 2023
Location
London
TDI
Alh
thanks! the BEW piston tops are flat, so you could if you cut valve reliefs as A5 stated or you could replace the BEW pistons with BRM units
Hy, you know if i can do this
thanks! the BEW piston tops are flat, so you could if you cut valve reliefs as A5 stated or you could replace the BEW pistons with BRM units
Hy, can i do this conversion, alh head in to a bwd 2.0 pd, jeep patriot 2008 fabrication ?
 

Cannedheat

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Joined
Mar 26, 2020
Location
Victoria, Canada
TDI
2002 ALH, 2003 ATD
Thank you for this detailed write up. I am curious about the head gasket. I am building a ALH with over sided BHW (0.5mm) pistons and haven't found enough supporting evidence to say if a BHW head gasket will match up to my ALH block. I did see you had mentioned using the BHW gasket for your application additionally how much interchangeability the TDI's have . My main reason for questioning the gasket issue in my build is due to Darkside Developments having a listing for "2.0 8v Head Gasket for 1.9 TDI with BHW Pistons". In said description they list BHW stock VW part numbers 03G 103 383 K which seems to be they're selling stock BHW gaskets under a different listing
 

oldpoopie

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May 14, 2001
Location
Portland Oregon
TDI
2001 golf gl, 2006 jetta, 1981 ALH swapped rabbit pickup, 1998 beetle
You have to use a BHW head gasket in order to accommodate the larger diameter BHW pistons. The basic architecture of that generation block allows the interchange of head gaskets Between ALH, BEW, BHW, ARL etc.
 

bigsexyTDI

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Sep 28, 2005
Location
Kentucky
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'98 NB, '04 Jetta
In my 20 years of TDI Clubbing, I have never built one of these... and now that I am I am eternally thankful for this wealth of knowledge. And yet, even so, there are still sometimes questions that I can't seem to find an answer to, or questions that arise because of new things learned.

Reading this thread taught me that BHW and ALH have different rod journal sizes. The old school hot rodder in me immediately wants to go the opposite of most in this thread and go to the smaller journal, but on the BHW crank.

So there is the question. Has anyone ever had a BHW crank offset ground to an ALH journal to get the extra stroke?
 

turbovan+tdi

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2003 TDI 2.0L ALH, auto, silver wagon, lowered, Colt stage 2 cam, ported head,205 injectors, 1756 turbo, Malone 2.0, 3" exhaust, 18" BBS RC GLI rims. 2004 blue GSW TDI, 5 speed, lowered, GLI BBS wheels painted black, Malone stage 2, Aerotur
There is no extra stroke, the size is due to the bore being bigger on the BHW.
Diesels make more than enough torque, if anything, you want to reduce rod length.
 

03Golfer

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Canada
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09 Jetta, 92 Toyota swap (ongoing), retired 03 golf
Interesting thought on the offset grind. I would think with a set of custom ALH journal rods it should work. Personally I'll take a stronger crank though. I believe with a good turbo/ injector/ tune setup any gains from the displacement increase would be slight. Where I have more commonly seen this done is on naturally aspirated engines that have no replacement for displacement.
 

bigsexyTDI

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Location
Kentucky
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'98 NB, '04 Jetta
Interesting thought on the offset grind. I would think with a set of custom ALH journal rods it should work. Personally I'll take a stronger crank though. I believe with a good turbo/ injector/ tune setup any gains from the displacement increase would be slight. Where I have more commonly seen this done is on naturally aspirated engines that have no replacement for displacement.
Yeah we did it on our pulling tractor engines and Big Block Mopars.

Here it would just be funny to say you had a 2.2 stroker :p
 

PakProtector

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Jan 5, 2014
Location
AnnArbor, MI
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Mk.4's and the Cummins
Run the numbers...you get the difference in journal size extra stroke, and rod needs to get half that shorter. It is another .1 liter or so, but I probably did it on an ALH bore...LOL

These don't spin fast enough for the smaller journal to be worth the strength cost.

Nice idea with the GTD/VRK...

Douglas
 

jimbote

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spiral arm, milky way (aka central NC)
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Tacoma 4x4 converted to TDI
Run the numbers...you get the difference in journal size extra stroke, and rod needs to get half that shorter. It is another .1 liter or so, but I probably did it on an ALH bore...LOL

These don't spin fast enough for the smaller journal to be worth the strength cost.

Nice idea with the GTD/VRK...

Douglas
Couldn't you just keep the stock length rod and move the pin position with custom piston?
 

PakProtector

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Mk.4's and the Cummins
Couldn't you just keep the stock length rod and move the pin position with custom piston?
I think/thought it a wee bit easier to get custom rods than custom pistons. For a stock or 0,25 overbore on an ALH, I think it hard to beat ARL pistons. Same basic conclusion for the OEM BHW pistons( either stock or standard overbore sizes ). I have not confirmed this, but I think getting galleried, steel ring land pistons would be lots worse than a set of rods of custom length. Taking a forging and cutting c-c length and journal ID's sure looks less complex in The Land of Small Production.

Aaaaand, on 81mm bore I make the displacement boost from 3mm stroke at 61cc.

Douglas
 
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