-
Tore the head down finally
by
silentdub
on 08 Aug, 2011 09:07
-
I got this 85 1.6d and man it is in very good condition.
No cracks anywhere and just one bent valve.
I was able to pull the glow plugs and injectors out with ease too, I have heard horror stories in the past.
I just picked up all new Brass Valve Guides, other than a cleaning and porting should I have anything else done to this little fella?
I have a 2 notch gasket, so I will have it surfaced enough to clean it up and may go to a thicker gasket to compensate.
-
#1
by
theman53
on 08 Aug, 2011 09:23
-
The valves are recessed so you do NOT need to go to a thicker gasket. The piston protrusion is the only determiner of the thickness you need.
I think you have it covered. Search dave vissard or viserd or some similar spelling. We had a thread on here on how to blend the bowl area better that would put you in the right mindset for porting.
-
#2
by
92EcoDiesel Jetta
on 08 Aug, 2011 10:51
-
Yes the valves are recessed into the head but if the head is cut, the valves are recessed less while the piston protrusion remain the same. Something has to change to compensate. Thicker head gasket? or cut piston? cut valves to seat deeper?
-
#3
by
Mark(The Miser)UK
on 08 Aug, 2011 12:23
-
Yes the valves are recessed into the head but if the head is cut, the valves are recessed less while the piston protrusion remain the same. Something has to change to compensate. Thicker head gasket? or cut piston? cut valves to seat deeper?
Just let the valves tap into the pistons a little. 
I find the exhaust valves will get kissed just before TDC, and miss at TDC on my car.
-
#4
by
silentdub
on 08 Aug, 2011 13:39
-
Yes the valves are recessed into the head but if the head is cut, the valves are recessed less while the piston protrusion remain the same. Something has to change to compensate. Thicker head gasket? or cut piston? cut valves to seat deeper?
Exactly my thinking.
This engine looks very clean too, I pulled the oil pan, nothing in it, no pieces of metal or anything, not even a build up of burnt oil, looks black, but free from any debris.
-
#5
by
theman53
on 08 Aug, 2011 17:37
-
If you are planning on cutting .100" then yes and the head is probably junk anyway. A couple thousands to clean it up aren't going to matter.
To do it correctly I have been told would be to heat the head up to plastic state and press it flat again. Just cutting the surface won't realign the cam journals. If the head is warped then that is probably what they should do.
I think running a thicker gasket is a bad idea IMHO.
-
#6
by
rallydiesel
on 08 Aug, 2011 17:52
-
If you have it just taken down a few thousandths than you shouldn't worry about valve/piston contact. If you are still worried, you could hand lap the seats. I would still measure piston protrusion before ordering the new headgasket to ensure the previous owner actually used the right size.
-
#7
by
DJPyro
on 09 Aug, 2011 04:36
-
-
#8
by
silentdub
on 09 Aug, 2011 09:17
-
-
#9
by
745 turbogreasel
on 09 Aug, 2011 12:15
-
the really proper way is to cut valve seats and precup cups to the proper depth
-
#10
by
silentdub
on 10 Aug, 2011 08:17
-
the really proper way is to cut valve seats and precup cups to the proper depth
It's not going to matter anyway, the head it perfect the way it is now. There are no cracks, cuts, burns. The surface is flat within spec, so I'll probably just have it cleaned up and surfaced.
In theory, if I had to cut it, I could cut it to make up the difference between the 2 and 3 notch gasket and be perfectly fine. The compression and clearance wouldn't change.
-
#11
by
theman53
on 10 Aug, 2011 14:04
-
That isn't the main problem. Quench is what will be messed with when playing with the different thicknesses of gasket.
VW didn't give different thickness gaskets to raise or lower compression, but to burn the fuel.
-
#12
by
745 turbogreasel
on 10 Aug, 2011 17:07
-
^ This, too fat HG you lose ~5 MPH for 0 gains(as measured on a ~50 MPH hill).