AAZ rebuild for my '78 Rabbit

[RamcoNorris]

Wiggling the valves is the proper way of checking.  It is better if you have a dial gauge and measure the valve play from the head w/ the valve stem flush w/ the end of the guide.  Rock the valve back and forth to check clearance.  1.3mm is the Bentley manual's max spec for these engines, on both in and ex.  Pg 15a-16, Fig. 19.

Thanks for this, I'm still waiting for my Mk3 Bentley to arrive. The Mk1 says the same for tolerances but wasn't sure if it was the same for the AAZ.

I'll have an update later today.

[RamcoNorris]

Update

Started to tear down the head and see how bad things are in there.

Pulled the glow plugs. The one on the right is from cylinder #1 that has the suspect valve.


Compressing the valve springs to get the valve keepers off. This tool worked great, really easy to use. Found it on Amazon for only $45, not bad.


All the valves came out very easily, except for the #1 exhaust valve. It took a bit of force to get it out of the guide. Took a measurement to verify what I could see with my eye, it was bent.


The intake valves all had quite a bit of build up on them, but they seem to be cleaning up nicely.


Disassembled head.


Ordered the following parts for the head rebuild. They should arrive soon so I can keep going on this. I'll be ordering valve guides just incase they are shoot. I have a dial gauge coming so that I'll be able to measure first. If they're close at all to the acceptable, they'll just be replace. At least it will be an excuse to go buy a press.

8mm exhaust valve (074 109 611)
Lifters - (034 109 309AD)
8mm valve steam seals - (026 109 675)
8mm valve guides (056 103 419A)
Cylinder head gasket kit (028 198 012F)
Injector heat shields (068 130 219)

While waiting for parts I'm hoping to port/polish the head a little. At least clean up the casting marks.

[RamcoNorris]

I have found the root of my issue, the dreaded crank nose key. It used to be there but clearly is now missing.

[CrazyAndy]

/\ /\ /\

Called it. 

How does your crank nose look?  If it's not that bad then you can just get a D cut 180 degrees out on the nose from the keyway notch and run it like that.  If it IS that bad . . . well, then you may need some spray welding and turning done to the nose.  I was that unlucky; make sure you get a knowledgeable welder/machinist if you go that route.  Trust me on that last one, the last thing you want is a chip off the spray weld getting into seals and wallering out the nose further.

P.S.:  Search the forums for threads on head porting; there are some good pics and instructions on here.

[RamcoNorris]

Called it. 

How does your crank nose look?  If it's not that bad then you can just get a D cut 180 degrees out on the nose from the keyway notch and run it like that.

It's not too bad. Not too much damage to the nose.


I already picked up a TDi gear and went around to a couple machine shops. They just scratched their heads and directed me to other shops.

Do you think it could be done without welding the key way and just cut the nose 180 degrees from the key way? I'd really like to use something like one of these jigs.

http://www.vwdiesel.net/forum/index.php?topic=32768.msg303989#msg303989

Looks like it would be much easier than trying to find a shop to cut the nose.

[libbydiesel]

IMO, you could get away with not welding, but your old keyway looks hammered enough that you will need to clean up the crank nose.  I have done so in place by removing the cam and using the starter to spin the crank (glow plugs removed) while using a dremel mounted in a jig to grind the crank nose true again. 

[TylerDurden]

Some guys pin the pulley & crank.

http://www.brick-yard.co.uk/forum/fixing-loose-jx-bottom-pulley_topic31849.html

[RamcoNorris]

IMO, you could get away with not welding, but your old keyway looks hammered enough that you will need to clean up the crank nose.  I have done so in place by removing the cam and using the starter to spin the crank (glow plugs removed) while using a dremel mounted in a jig to grind the crank nose true again.  

Here's a better picture of the nose after a quick cleaning. It doesn't look to bad; think I'll try avoid welding.

[CrazyAndy]

Looks pretty good, but you do have a little bit of a lip on each of the keyway ends, especially on the one on the counterclockwise edge.  However, nothing a good turning down and check for nose flatness won't fix.  You might want to PM Fatmobile and Andrew to see if they will sell/loan/let you copy their nice tools so you can save some headache of having to go around to find a machinist that will do crank work.  Cut 180 out.  Dowelling might also be a good adition if you plan to run some big power, but that is up to you.  How's that crank nose oil seal groove feel?

How's the head work coming?  Found any more surprises?  Measured vale play yet?  How are you still feeling about porting?

You're making good progress on inspection so far; keep updating! 

[RamcoNorris]

Time for an update:

It is starting to look like the engine either recently had a complete overhaul or had very few miles on it. The valve guides were well within spec, they look and measured like they were new. Can't recall the actual reading I got but it was well under the 1.3mm allowed. Because of this I decided against porting, I didn't want to cause any damage to the guides. I'm sure I could have done something without damage but since I'm just looking to run it in stock form and not go for all out performance, it will be alright.

I got a new exhaust valve to replace the bent one; along with all new lifters. Now cylinder 1 looks like it should. Lifters sitting level again.


Cleaned up the intake valves. They came out nicely.



The head is now all put back together and patiently waiting to be reunited with the block. Which brings me to the next part of the rebuild. As seen up above in this thread, the key on my timing gear gave way so the crank needed to come out.

Started tearing down the block


All the surfaces look fine, no scratches or marring on anything


Pistons all look to be in good shape and will be receiving new rings and bearings


With everything removed I was gave the block a nice coat of paint


Highlighted just incase I forget what I've got in there (even though it won't be seen on the back)


Parts are starting to pile up all over the garage




Also got my gauges in. I went with VDO in a Scirroco 1 center console. This matches really well with the interior of the Rabbit.




I've read mixed reviews about them but I'm hoping for the best. I've got a EGR probe from Aircraft Spruce waiting to be installed in the exhaust manifold.

Now I'm working on cleaning the mating surfaces for the head and block. It is taking forever but being sure to get everything clean and smooth for the best seal. Like I said I've been to a few shops to see about getting my crank nose done to accept the D shaped TDi timing gear but no luck yet. I'll see if I can get something like the ones linked above. I don't really want to drill and have studs put it. I feel like that would just as much work as having the nose made to accept the TDI gear; having to use a drill press to ensure everything to straight and true.
I've already got most of the parts I need to put the block back together so hopefully the end is near. My A4 is taking a major crap on me right now and needs the garage space so the Rabbit needs to be finished ASAP. Only hard piece left for me to find is a turbo diesel fuel filter mount, the one that goes on the firewall. No luck so far but figures crossed.

[745 turbogreasel]

I for one am digging the highlights.

[8v-of-fury]

I for one am digging the highlights.

Looks sharp. DIG IT.