Which Head to Use ?

[ShoulderMan]

Hello all
 
Unfortuantally this will be the second time that I have to write this, since I took to long the first time, and it logged me out....

 Ive serched all over for inforamtion on the different type of heads that can be bolted on the the 1.6L block. But I cannot find the answers that I am looking for.
 
to shorten it up.,  I have a 1991 Jetta non turbo.  Dropped a valve,  and need a new head.  Bought a 84 or so 1.6l from a rabbit. tore it apart. decided i wanted a turbo engine.  Cant find one for a reasonable price (to me) so I Pulled the block from my jetta, tore it apart, and decided to turn it into a turbo diesel.  I Thought, if you can drill steem holes in your head and block, then i can drill oil squirter holes in the block where they would go if i had a TD.
 
 So, after reading everywhere on the internet, I have come to find out that i have a few choices on which heads I can use to bolt up to my block.
 
The OEM 1.6l the 1.9l AAZ  and possibly i read a 1.9TDI with Lupo pistons.
 
I am looking to get improved MPG out of the Jetta. Im told you can get up to 100mpg with the right mods,  id like to get about 80mpg @1800RPM
I do not know if this is feesable or not, but its what ive been told by some  diesel heads.

 I will be starting with a new bare head, and will build it up from there.
I will also be using a custom exhaust. 3" down and equal-length headers to a custom collector. I am undecided on what to do for the intake.

My questions are;

 Is there an advantage of running Hydraulic heads vs Mechanical Heads?
   Why use one over the other?    which is better in your opinion?        which offeres the best, bang for you buck?
which gives better mpg?

the difference between using the 1.6l and the 1.9l AAZ
 Why use one over the other?
Will the 1.9aaz lower my compression?
is there a big preformance difference? (mpg, hp, spool up time?)
I will also be using the stock injectors with a 155bar or higher rating.

is the 1.9TDI even worth looking into? or out of the question all togeather?
Ive read that the lupo uses the same piston dia. and shape needed to do this.

-Ron

[saurkraut]

I really think 100mpg with a 1.6 is out of the question.  You have to really drive like a granny to get over 50, and that will eventually carbon your ring lands to the point that the rings will be shot in 80K miles.

I wonder if you cold leave a cylinder out: no piston, rod, lifters, and take the appropriate plunger out in the pump.

You probably would have to gut the car to get the weight down too.  Then maybe you'd touch 60MPG

Which head?  It remains to be seen.  There is a remote chance that the 1.9 IDI head, which will lower the compression, will also yield better fuel milage due to lower cranking loss.  I'm building such a motor, but my endevor is more power, which means more boost and fuel.  So I don't think I'll be doing any hypermileing with it.

Lifters: I don't like the VAG hydro lifters.  I've never had a diesel with them.  But I have had many gassers with them.  And sometimes, for no appearent reason, they randomly fail to pump all the way up and make an annoying tapping sound.  You can take them all out, and putz and geuss which ones are bad.  Replace the 'offenders' and soon there after they'll be tapping again.

So I prefere mechanical lifters.  I have all the tools and shims to check and adjust.  So its no big task for me to adjust valve lash.

As far as the TDi option goes, its probably cheaper to buy a TDi, then trying to make an IDI into one.

[ShoulderMan]

Alright.
 Well Im not too much into the hypermilling. Id rather have a little more pep, Then a little more mpg. Before she died, I was getting 45-50mpg on the freeway.
 As long as I can keep it above 40mpg, I think Ill be happy enough.
 
 As far as the 1.9aaz goes,
 To me it would seem as if it is a better deal right out of the box, larger ports to boot. after a port and polish, I should flow overall better than the 1.6 ever could.    
  Am I correct on this?

 the other question on that head,  why do people split the valve stem size 50/50 on the intake and exhaust being 7-8mm?   Why not all 7 or all 8?

does anyone know who sorces sodium filled valves,?   and can I or should i consider coating the valves (ceramic or other)

Thanks
 -Ron

[saurkraut]

Appearently, the 7mm valves are more common.

The 1.9 IDI heads come with 8mm guides.  I just bought new valves for the head I have, and they're all 8mm.  So I really don't see a problem.

My 1.9 head build:
http://www.vwdiesel.net/forum/index.php?topic=15780.30

Anything other than the stock valves would mean custom made valves.  Nothing else is a direct fit.

[autoholic]

Dropped a valve huh? Is there anything to watch out for to avoid this (other then valve adjustment)?
Dropping precups and valves, that'll always be in the back of my mind now!
Do you have the 3 groove or 1 groove valves? Is it safe to assume the 3 groove are better?

Sorry to hear about the problem, I know how it is.

[ShoulderMan]

Yeah,
 But I bought the car for 500 with a Ticking... Drove the car for 3 days, on the thrid night 6 hours before I was going to fix it,  she dropped a valve on the freeway,  munched the valve in a few peices then drove it into the head, also bent the rod and opened up the piston a little.
 I havent tore down the head yet.  I was quoted 650 to reweld the head and fix it from there. I decided to buy another 1.6 for 800, then have extra rods/pistons.  But now have decided to spend more money than what its worth and build her from the ground up.

[autoholic]

Oh, it had a tick. Must have been quite a sound when that valve dropped at freeway speed, not alot of room in there for a valve to be smashing around!
Hope all goes well with the next motor.

[zukgod1]

Man I hope that's a sound I never hear..