[Vwdiesel] Head gaskets

[hwy9fergs at comcast.net]

Hi Andrew, Quantitively, we are splitting hairs here.  It really depends on how much material is taken off the head.  I've hand shaved heads on a flat granite machinists stone with sandpaper glued on top of it.  Dressed off about 4 thousanths around the perimeter of the head without really touching the combustion chamber areas much.  Worked like a charm. Brought the head back into spec without having to take any more than absolutely necessary.  In that case I stayed with the original thickness gasket. Most machine shops are probably not that careful.  When much more is taken off, wouldn't the valves and valve recesses be moved closer to the pistons than they were originally designed to be?  Why does the book state absolutely no shaving of the head is to be done (although we seem to get away with it)  I just don't know what sort of insidious problems might occur from going away from the original specs. Think in terms of keeping the valves the same distance away from the pistons and 
I'd say you're safer.  Doug 

-------------- Original message -------------- 
From: Libbybapa at wmconnect.com 
In a message dated 6/20/06 10:59:55 PM US Mountain Standard Time, hwy9fergs at comcast.net writes: 



If the head is stock, I agree you would want to go with the original method and figure it by measuring the piston protrusion. But if your head got "trimmed"  (WHICH THE MANUALS SAY IS A NO NO) wouldn't it make sense to go with the next thicker head gasket?  Especially if enough got trimmed off that they even took some off the precups.  I would say especially then, you want to go with the thicker gasket. Another thing to consider is that there are also the clearance issues in addition to the compression isssue IMHO.  It's mighty tight in there!! 



The head is flat including the combustion area of the main chamber.  If material is removed from that face, then there might be an extremely slight rise in compression from the fact that material is not removed from the valve areas and the precup openings.  But, if using a thicker gasket to compensate for the trimming of the head, then you will be dropping compression due to the fact that in all of the other areas of the combustion chamber (most of it) you would be replacing metal with space. 

Andrew