About to change AAZ 1.9D head, tips?

[Bladeserpent]

Hi all,

I am planning on changing the head on a AAZ 1.9 N/A swapped Vanagon and would like some help/advice before i start tearing everything down.

I was able to find a good youtube video of the teardown here https://youtu.be/NhmousPg8Ig and a replacement head here https://www.hansautoparts.com/AAZCompleteHead.aspx

In terms of parts, what should I need? I read the head studs are “torque to yield?” So i’m guessing i need to buy new head studs? Assuming those come with gaskets? Any real advantage to ARP head studs? (They are pretty pricey, but do you not need to do the torque sequence, eg stages + 90 degree). Any special tools that I will need to removal the head? (Can the camshaft oil seal be tapped in or special tool). Any other gaskets or “kits” that I need (other than head gasket ofcourse)

And lastly and probably most importantly, timing. Would it be possible to removal the head, change it, and keep the timing in place? I am a little confused on this. Is timing just for the injection pump or the head pulley and engine as well? Maybe set the engine to tdc? Where would the markings be if i wanted to do this? I’d assume there has to be some procedure here as a new head would be in a certain position.

Any help or advice would be greatly appreciated!

[MarkWard]

ARP studs have a specific torque value and it comes with the directions in the box. Good quality parts. You can also reuse them.

Can you change the cylinder head without retiming? Probably not. I'm assuming your replacement head has a camshaft? If you are reusing your camshaft and don't care about the cam shaft seal, in theory if you pump and cam timing are correct now, you could put the engine at TDC before you disassemble making your own timing marks and putting it all back together. Turn the engine through by hand 2 revoultions and verfiy your marks you made are still aligned. If no solid resistance is felt, you probably got it right.

Disclaimer, the above is not the correct way to do this job. If you own a diesel vanagon, you should purchase the cam and pump lock tools. They are not much money. You should also purchase the dial indicator setup for timing the injection pump. Learn how to do it correctly and put the tools in your arsenal. Good luck.

PS, if you go the ARP headstud route, you likely need to set the cylinder head on the block and then install the studs. I don't think there is enough room to fit the head with the engine installed and the studs in place.

[OlisGarage]

There is no way your repair will hold. You will be forever chasing issues if you use anything from hansautoparts.

If you have the money and motivation to do the job twice, go for the parts from prothe (“Hans”) the first time around. Then when it fails, you’ll have to source original ones. You will end up redoing the job.

You have been warned.


Good time to also do the timing belt and rollers. Again, do NOT buy parts from hansautoparts.
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1981 VW Vangagon TDI (in progress)
1984 VW Rabbit Convertible (daily)
2003 VW Jetta Wagon TDI (recovering from a hit and run)

[?Waldo?]

Indeed, Hans has a very bad reputation for selling low quality parts and having very poor customer service after the sale.

Timing applies to both the injection pump and the cylinder head. Both have their own fine timing procedures. You can remove and replace the cylinder head without affecting the injection pump timing (pump is bolted to the block) provided you get the timing belt off and back on so that the injection pump is sprocket is set at the same belt tooth relative to the crank that it was set to prior to removal.

The fine timing of the camshaft should definitely be redone. Even very slight differences in the machining of the new head casting vs. the old will change the timing of the cam. It would be pound foolish to replace the head without making sure to set the timing of the cam correctly.

[Gizmoman]

If your goal is a trouble-free long, running diesel, I highly recommend a new Kolbenschmidt head and ARP studs. I also did a port and polish on mine, which required the removal of the valves, but it's not really necessary if you are looking for stock output.
This forum has a wealth of information regarding the AAZ >https://vwdiesel.net/forum/index.php?board=6.0. Even a new head not installed properly will be trouble, so do your research and don't cut corners.

I also agree with the others - stay away from Hans Auto unless you are buying non-critical parts like window cranks.
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82 Vanagon Westy - AAZ 1.9 TD, HE200 Holset, WAIC, 27.75 dia tires, Electric power steering, 5-speed AAP w/.078 5th
Oversize spare carrier - stock location (no longer for sale).