Any thoughts on using these heads for a stock rebuild. On the hunt for un-cracked heads I picked up a cheap pair of 1600 heads but notice they have had the barrel ledge cut down with spacers in to raise it up again. The spacer almost has a ledge within which it sits. I am not sure if this was a deliberate cut, ground in or the result of pounding? The ledge is about 1.5 mm with the spacer..
Yes, i have four heads with this spacer, two probably Remtec, the spacer was so gunged in I could not see it at first, two probably original 1978 VW, and the new Autolinea heads I have now are machined similarly but do not have the spacer.
The spacer is there to restore compression ratio after machining to the heads. I assume your old heads had the ledge? If yes you need the thickness of the spacers somewhere to maintain your CR, but better to fit equivalent thickness readily available spacer under the barrel where the extra sealing surface you are introducing is against oil splash rather than compression and explosion. In the same way you must determine if your case has been "decked". This is cleaning up (machining) the surface the barrels clamp against. This is also done with shims under the barrels. To find out, measure your deck height.
I believe VW put the "ledge" in - 2mm - to improve combustion. If heads are reworked, the ledge usually gets machined off, so spacers are added to restore it (and give the correct CR).
WHS ^^ but out of the box Autolinea have a sort of negative step where the machining changes from coarse to fine. The spacers are better at the bottom of the barrels as there is only one joint to leak with combustion pressure .. but it takes about 10 minutes more work to pull the barrel, and put in the spacer at the bottom. And of course the cylinder base is a similar width spacer but smaller diameter than the cylinder head one.
