Vako's AAZ rebuild

[vako]

long story short, recently i had some problems with my engine that has been in my car already for 25 000 kilometers. engine was bought used and was internals were not inspected in the begining

after 3 years of service 1 week ago car started twitching badly at low speeds/rpms, after few days it started overheating with no reason just pressing the accelerator pedal while driving was enough temp gauge to rise.  after inspection i found quite big amount of exhaust gasses were getting in the cooling system. cylinder head and the gaskets were the main suspects for the problem yesterday i pulled the head off the engine and found that there was old style non metallic head gasket installed, and exhaust gasses were getting in the cooling system from the edge of the firs cylinder. after visual inspection no sighns of damage were found on the cylinder heads. just small cracks between the valves (but the crack are very tiny and the are up to vw specs, which states that it should not be bigger than 0.5 milimeters).   i will have my head pressure checked anyway and check if the surface is flat up to the specs. if it isn't, i will have it rgounded a bit (i know that it isn't recomended by the manufacturer but from this forum i know that it often done to used heads prion to installing mettalic head gasket).


i will also have my crank checked and probably will change main and rod bearings  (with oversized ones). i will also fit tdy style crank spocket and modify flywheel end of the crank to fit apropriate bearing for suzuki vitara transmission input shaft (26X20 or 22X10 bearing).   

yesterday i found a little problem in my engine block. there is some scoring on n2 cylinder wall (( but i think that honing and new standard size rings will work just fine. because just pistonc cost much more than whole my rebuild and i do not need more than 100 000 km-s from this engine

pics coming soon

[vako]

these are my previous topics ))

http://www.vwdiesel.net/forum/index.php?topic=26361.0
http://www.vwdiesel.net/forum/index.php?topic=27377.0
http://www.vwdiesel.net/forum/index.php?topic=27328.0

[vako]

[vako]

[vako]

i had my cylinder head pressure checked and resurfaced today     it seems to be all right, but it was slightly wrapped (after overheating numerous times in my car ) and they had to take off 0.18 mm-s to make it perfectly flat.

i have to change valve seals and port the head. after that head will be ready for further use )) i will post pics tomorrow.  tomorrow i will also disasamble lower end and see what needs to be changed and machined there 

[vako]

some useful threads for me

http://www.vwdiesel.net/forum/index.php?topic=26175.0

http://www.vwdiesel.net/forum/index.php?topic=29810.0

[745 turbogreasel]

I usually find the exhaust  guides are pretty worn, and they are what  take the heat out of the valve....

[vako]

i'll check valve guide wear and change them if necessary  valve seals will be changed anyway.

my pressure tested and flat grounded (correct me if i've use the wrong term for that procedure) head )

[vako]

shafts itself isn't worn, but front bearing is worn a bit and it has some play. so both, back and front bearings, will be changed before engine assembly.

[vako]

[air-cooled or diesel]

isn't cam going to be out of alignment? heads no good.

[vako]

according to manual maximum non-flattness of the head when it does not need any resurfacing is 0.1 millimeters and it seems not to hurt camshaft.  it worked like this (deformed from years of service for more than 3 years and 25 000 kilometers) and camshaft (and camshaft bearing in the head) is still as good as new 

[libbydiesel]

Take a very close look at the precups and make sure there aren't any tiny cracks forming at the edge of the opening.  If there are, then replace the inserts. 

[vako]

there are veeery small and short cracks at the edge of precup hole itself. as long as there is almost no way of getting new them easily and cheap in georgia i will leave them alone. they were never taken out and sit very tight in their places, so IMHO there is almost no chance of them falling out   

[libbydiesel]

Those tiny cracks can grow very quickly and once split the precup will fall into the cylinder and cause a lot of pain.  The AAZ precups are available new through World Impex (Napa).