Some people just bore the hole for the barrel
right down to the bottom... with a sharp tool.
If it does not break through behind #3
it will most likely crack (from the sharp corner) at some point soon.
Some people do not "deck" the barrel face either.
My first step is to spot face the case savers
so they will not lift the barrel at all, when the head nuts are tensioned.
I spot face them about .010" below the proposed final deck.
I then "deck the case" ...usually about .070", to make sure that ALL four will clean up
and have a nice flat surface for the barrel to sit on.
All surfaces must be at the same height from the crankshaft centreline.
First step is for piston clearance,
and second step locates the barrel.
Before decking #3, I press in a sleeve
on top of the 'deep' top case saver,
to get a bit more support.
See the top stud hole closest to the FW.
By doing the bore and deck in one machine setting
you know that they are dead square.
You will note that the decking process is only removing just enough material for the barrel to sit on.
Also note that I have used a nice large radius in the corners. (3mm radius)
Going to a larger bore,
is a good way to remove he sharp corners that are there from the VW factory.
Sharp corners are a good place for cracks to start,
so it is good to get rid of them.
Doing the job properly takes twice as long as boring the hole straight to the bottom,
with no steps , radii, or decking.
But it will give your engine a good base for a better lifespan
Craig Torrens wrote:Good work Dave...........unfortunately there is plenty of workshops out there just boring a hole straight through, some using a drill press!!!
as a reference Stan Pobjoy charges $122 ($156 for an Aluminium case)for this work.....with the step bore, radius corners and the faces machined (and yes its perfect!)
If anyone is getting this type of work done, then make sure you use a trained machinist that knows what they are doing.(and yes Dave is trained!)
I think these prices may have changed now.
See the PDF attachment that Craig posted, for the latest prices.
This is nearly 4 years ago.
I have had my milling machine for a while now, so dont use the lathe any more.
Who ever people get to do their case machining,
ask them to use a radius tool (minimum 2 mm radii),
spot face the case savers just below the final deck,
and sleeve the #3 deep stud hole
to help support that thin web that is left when boring for 94's.
need to replace a broken head-stud 8mm ! recent Mexican case ..stud snapped on 1661 tp mtr
had a case saver in it ....hours to remove....anyone got larger savers ?
tried Micks just need 1 for ca 13mm dia saver and a 8 mm stud
happy to pay postage etc
0421286423
Bern...happy to come for a drive Sat?
want any vw bits old but like me, Made in Germany!!!
