AAZ rebuild for my '78 Rabbit

[8v-of-fury]

I did have to use the flywheel and clutch off the 1.6 on the AAZ to mate up to the starter.

All 1.5, 1.6, 1.7, 1.8, 1.9 (excluding the TDI) and even the mk3 2.0L ABA all use the same 8v flywheel and clutch. So unfortunately you didn't have to do anything with the clutch.. Unless the clutch was bad on the 1.9.

Seems everybody I ask says that an AAZ in a MK1 is great, and I'm no different!

The 1.9 is just better than the 1.6 in every way. Better air flow, more displacement, more power potential from stock components with free mods. lol

[shorttimer]

Other than twisting the IP screw/cool intake air & doing some porting to the head, what other 'free' mods can be done? I know big, stainless, mandrel bent exhaust is good too, but at a fairly steep price and usually has to be custom fabricated.

[libbydiesel]

I did have to use the flywheel and clutch off the 1.6 on the AAZ to mate up to the starter.

All 1.5, 1.6, 1.7, 1.8, 1.9 (excluding the TDI) and even the mk3 2.0L ABA all use the same 8v flywheel and clutch. So unfortunately you didn't have to do anything with the clutch.. Unless the clutch was bad on the 1.9.

Seems everybody I ask says that an AAZ in a MK1 is great, and I'm no different!

The 1.9 is just better than the 1.6 in every way. Better air flow, more displacement, more power potential from stock components with free mods. lol

Only the transverse installs use the same kind of clutch setup.  The longitudinal installs use a couple other versions. 

[8v-of-fury]

Oh, I was unaware of any longitudinal AAZ's in Canada that he may have got the donor engine from lol.

My bad. 

[R.O.R-2.0]

Regarding starting an engine sitting on the driveway, do you do it without coolant? How long can you run it w/o damage? 5 sec? 30 sec? 60 sec?

i run it cautiously, and keep feeling the block and head constantly..

ive run an engine for 2-3 minutes without coolant before.. diesels are STUPID efficient at idle.

when my diesel is cold, it will idle with roughly 200*f EGTs.. if your exhaust is only 200*, then the engine isnt gonna heat up very quick.

you can run a VW diesel for a LONG time without coolant.. longer than you could ever want to run one.

[RamcoNorris]

Seems everybody I ask says that an AAZ in a MK1 is great, and I'm no different!

The 1.9 is just better than the 1.6 in every way. Better air flow, more displacement, more power potential from stock components with free mods. lol

I'm really looking forward to this mostly so I can get up to speed on freeway on-ramps. The one I take often is a long uphill climb that takes a very long time before reaching 60mph with the 1.6

[RamcoNorris]

Regarding starting an engine sitting on the driveway, do you do it without coolant? How long can you run it w/o damage? 5 sec? 30 sec? 60 sec?

i run it cautiously, and keep feeling the block and head constantly..

ive run an engine for 2-3 minutes without coolant before.. diesels are STUPID efficient at idle.

when my diesel is cold, it will idle with roughly 200*f EGTs.. if your exhaust is only 200*, then the engine isnt gonna heat up very quick.

you can run a VW diesel for a LONG time without coolant.. longer than you could ever want to run one.

Do you secure the engine to anything while doing this? The more I think about running the engine on the ground the more it worries me. Just afraid to have it flopping around on the ground 

[745 turbogreasel]

It's not as bad as it seems for jumping around. 
I have a D24 on my stand right now, , and on the really cheap rickety stand it felt sketchy so I supported it form above. On the decent stand, no worries at all.
I looped the coolant hoses together, so I can get a 10-15 minute run time to operating temp, as monitored with an IR pyrometer.

[rallydiesel]

Nice Rabbit! Keep us updated.

[RamcoNorris]

Update Time

Started work on removing the head to see why the exhaust valve lifter on cylinder #1 wasn't returning to it's normal position.

Manifolds removed



Had a real problem trying to get the cam gear off. Ended up having to use some heat along with the puller.


Got the cam out, along with the lifters...


And this is what exhaust lifter #1 looks like  


Nice hole punched in it


Each cylinder has marks from meeting the valves.


Also came across this random, solid?, (right) lifter. Someone has been in here before me.


At least there is some nice cross hatching in each cylinder.


That's all for today. Tomorrow I will continue taking the head apart to see what else is broken. I'm guessing that either the timing belt broke at some point or someone may have messed up changing the belt. Either way, they messed up.

Have a good New Years and stay safe.

[TylerDurden]

Also came across this random, solid?, (right) lifter. Someone has been in here before me.

The one on the right is a hydraulic. The ones in my 91 TD are the same, the replacements I got are as well.

A solid should have the recess in the top for a puck (shim).

[RamcoNorris]

The one on the right is a hydraulic. The ones in my 91 TD are the same, the replacements I got are as well.

A solid should have the recess in the top for a puck (shim).

Thanks for clearing that up. Just thought it was weird to have one random on in the there. Oh well, they're all going to be replaced anyways.

[CrazyAndy]

That's all for today. Tomorrow I will continue taking the head apart to see what else is broken. I'm guessing that either the timing belt broke at some point or someone may have messed up changing the belt. Either way, they messed up.

Have a good New Years and stay safe.

I should say that you should also check out the nose of your crankshaft.  The AAZs do have one big flaw in that they use timing belt cogs that were cut with a keyway on their mating area as well as the crank nose, causing eventual wear and loosening of the cog, leading to cam timing concerns and piston to valve contact in bad cases.  You should get a timing cog from a 1Z/AHU TDI with a D shaped mating surface and get your crank nose machined for it.  This eliminates the loosening timing belt cog concern.

Also don't forget to check lifter bores and valve guides.

[RamcoNorris]

Also don't forget to check lifter bores and valve guides.

Is there a DIY way of checking the valve guides besides trying to wiggle the valves? Or, is there any reason not to just replaces the guides?

[CrazyAndy]

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.

They are easy to replace if you have a press.  I have heard of folks hammering them out, but I would not risk it.  And especially do NOT hammer them in! (Just saying for posterity)

As far as lifter bores, just check for smoothness or burring on the edges of the bores.  They aren't known for going bad unless something went wrong like a piston hitting a valve, but since you found funky lifters I suggested it so you can CYA.

Keep updating!