IZ/AHU Camshaft vs. AAZ Camshaft Question

[rich brennick]

Question for the experts:

Is the 1Z/AHU camshaft the exact same as the AAZ camshaft?
If not, is either one more preferred than the other?
For a 1Z rebuild of mine w/ mods for low end torque.
Thanks ahead,
Rich

[rallydiesel]

No the AAZ is definitely different from the 1Z/AHU/ALH (all the same).

Here's a table showing the specs:



Table put together by TDIMeister from TDIclub.

[rallydiesel]

Looks to me like the AAZ opens a bit sooner and stays open a bit longer. Unfortunately lift isn't included. jimfoo runs an AAZ cam on his mtdi. I think the AAZ might be a bit better of a performance cam on a 1Z than the oem cam.

[rich brennick]

Now THAT was FAST!  Thanks much.

[Hey]

I have an AAZ camshaft on my mtdi and it works really well!!

Injector 205, 20psi and the clutch doesn't hold at 1200F EGT

[ChopSauce]

OK, that works, but better ?
 - and how much better ?

[jtanguay]

I have an AAZ camshaft on my mtdi and it works really well!!

Injector 205, 20psi and the clutch doesn't hold at 1200F EGT

i think jimfoo is running the AAZ camshaft on his as well, and i haven't heard of any negatives of going that route. apparently he used all the parts from his AAZ head into a prothe 1Z/AHU head, and it worked.

[Hey]

Yeah you are right... everything seems compatible!

I used 4x tdi A3 connecting rod with 3x A4 pistons and 1x A3 piston. I used the lifter from a 1997 AAZ, camshaft from 1997 AAZ also.

I measured the piston protuberance (is that correct word?) and it was almost equal for all 4 pistons (very precise measurement). I had a 2 hole gasket on my 1.9td. The tdi spec are a little bit different, but it also gave me a 2 hole gasket, but a little bit closer to the 3 hole spec. So I use a 3 hole gasket... so I can put more boost.

The tdi pistons are a little bit taller... I measured it. Also the rings go a little bit higher on the chamber, that is obvious.

All the rest of the engine was from a 1996 AAZ. I also put new connecting rod bearings. The AAZ engine had 340 000km and you could still see the honing marks!!! All the bolts are the same. The connecting rod shape is different, but is compatible and seems to be the exact same length... not sure though.

I checked the oil today... 5000km since I put synthetic oil and it didn't take any!! wow!! my old AAZ would have take about 1/4 of a small bottle.

About the performance, I have m-tdi, 10mm head, 205 injectors, vnt17va at 20psi and at 1200F EGT (~¾ of pedal), the tdi A3 clutch slips a little bit in third and in 4th much more since I can't hold it.

[jtanguay]

About the performance, I have m-tdi, 10mm head, 205 injectors, vnt17va at 20psi and at 1200F EGT (~¾ of pedal), the tdi A3 clutch slips a little bit in third and in 4th much more since I can't hold it.

you should look into getting the VR6 clutch kit.  its about $200 or so, and will hold 300 ft/lbs which is more than your motor will make, unless you do some crazy mods  :lol: its a really cheap solution.

and i think when you say "piston protuberance" you mean piston protrusion.   :wink:

did you build your own mTDI pump?

[Hey]

and i think when you say "piston protuberance" you mean piston protrusion. Wink

lol! Yeah... that is what I meant.

did you build your own mTDI pump?

Yes, this is why I made a post to show how I did it.

[slowcaddydan]

bringing up this old topic again, i see a few people running the AAZ cam in the AHU head. are people successfully doing the opposite? the interwebz imply that they're compatible and some websites say it's even better. i need a new AAZ cam but can't really afford $250 or more for it.

said website that says AHU is better for AAZ: http://shopping.boraparts.com/product_info.php?cPath=21_27_83_128&products_id=700

[theman53]

That is the AAZ cam or so the add says in the years listed. There wasn't a TDI until 96 IIRC a passat, anyhow from what I gather the older 1.6 hydro cam *NOT MECHANICAL VALVE* is a better upgrade. Here is a link that shows some stuff from the cams, but not the TDI cam, sorry.
http://www.vwdiesel.net/forum/index.php?topic=25149.0

[RabbitJockey]

yeah i think 1.6td cam is a cheap upgrade, but u no how lots of non vwdiesel.net tdi guys think:that cam can't be better its from an ancient idi 

[slowcaddydan]

Thanks for the chart. I've seen it before and can sort of read it but I think I'm too stupid to fully grasp its contents. Forgive me if I misstate facts here, this is only my understanding:

I gather that there's 2 things i need to worry about in regard to damaging the engine: (1) duration valves are open, and (2) how much they open. If the lift is too high when the piston is on its way back up I'll have problems. If the valve isn't closed when the piston's at its top position I'll have problems.

The AHU cam has less lift than the AAZ, which is why people throw the AAZ in the AHU. If I use a cam with less lift, my performance may suffer due to lack of intake and exit of fuel/air. Since the AAZ/AHU crank/block is the same there shouldn't be collision issues with valves staying open, and lower lift means less chance of collision due to amount valves are open, but I'm still concerned about performance lost. I don't plan to race this car but will tune it some (1.9TD with K03, gov mod, fueling, prob intercooler)

I'm interested about the 1.6TD cam

[theman53]

Basically, from what I have read not first hand experience, the older cams were less concerned about emmisions. So they were more performance oriented by default and that makes sense. The lift will be similar and as long as you do not time it improperly it will be ok.
From looking at cam duration and ramps and what little knowledge I have of things, the older cam will have better performance as the duration @ 1/2 lift is more, so it "should" give more velocity to get the intake air to fill the cylinder better. It looks like it will stay open longer as well, so that means more air, more air is better for more fuel, more fuel better for better performance, etc. etc... Just my Hillbilly .02 that isn't scientific.