Head removal.

[jadney@vwtype3.org (Melissa & Jim)]

>From: Jason Renville <Jason_Renville@ccm.al.intel.com>

>Someone asked why the nuts loosened.  I theorize that my new exhaust 
>which is bent enough that it touches the body solidly added enough 
>vibration to the head to loosen it up.  The muffler actually bent where 
>the body pushes on it. I am getting this fixed right now.  I have paper 
>work for the engine being rebuilt with a new case back in the late 80's. 
> I am not sure if they had ever been retorqued. 

I doubt if the muffler could have loosened the heads.  I usually see the 
body bend to make way.  The heads are VERY stiff compared to everything else 
here.
 
>        I tried to retorque the nuts with a mediocre Torque wrench.  It 
>helped but it still leaks a little.  The nuts seemed to hold the torque. 
> I think I used 27 ft/lbs?  Or Was it 36?  I cannot remember right now 
>cause I just did a head on the Datsun and I think that one was 36?  

I think it is 23, but I go a couple lb-ft higher if the case has inserts.  
If this case has 8mm head studs I think the number is different, but these 
should not have loosened.  The 8mm studs are better because they are 
actually more resilient and allow things to heat and cool without anything 
having to give.  OTOH, all mine have 10mm studs and I have had no trouble.  
15 years might just be reasonable.

>        I plan on removing the head and having it milled.  Should I use 
>any shims on the jugs to compensate for the increased compression 
>created by milling the head?  Can I double stack the little paper 
>gaskets at the base of the jug?  I am assuming that I won't need more 
>than .020 removed(big guess here).

If the cylinders have pounded into the metal of the head so that you can 
feel a depression there, then you will need to have the heads flycut.  The 
trick here is to make sure that both sides are cut to the same depth.  
Likewise the two support surfaces on the case must be coplanar.  The paper 
gaskets make poor shims; they will probably just extrude.  You can get 
custom shims from Berg or get the heads semi-hemi'd at the same time they 
are flycut.

I usually get my rods rebuilt at RIMCO at the same time.  Reworking the big 
ends shortens them very slightly, so I figure this helps make up for some of 
the length lost in refinishing the heads and case.  If your case doesn't 
have inserts, I recommend sending it to RIMCO to be align bored, have case 
savers installed, and the cylinder seating surfaces cleaned up.  If you do 
this, be sure to tell them what size your crank will be when it goes back 
together so they will send you the right bearings (included in the price of 
the align bore.)

Jim
   ---------------------------------------------------------------------
       Melissa Kepner                                    Jim Adney
       jadney@vwtype3.org              jadney@vwtype3.org
                             Laura Kepner-Adney
                             Madison, Wisconsin
   ---------------------------------------------------------------------