So, how do I actually get the oil and crap out of the LS4.9 cylinder heads?

Every single time I start welding on the internal side of the cylinder head, oil just starts bubbling up.  Welds look horrible,but penetrate decently (depending on when I get the rod to the puddle.)  Freshly ground gets good penetration, if I've been welding a while its... questionable.

Shove it in the oven?  Try to displace the oil somehow with a lighter-weight solvent (acetone?)  Other solutions?

Allegedly a simple ultrasonic cleaner tank will get oily aluminum weldable-clean.  I have my doubts but have heard enough good things to accept that it may be true.

At the machine shop we used a 180F solution of water and some stuff from Zep, in a machine that was like God's own dishwasher.

I wonder if boiling water would do it.  The water would displace the oil, which is lighter and will rise out.  The question is, how do you boil a cylinder head for a half hour or so   And then pull it out through a thin layer of oil...

In reply to Pete. (l33t FS) :

tin garbage bin on a propane burner stand. Dont pull the part out right away; add more water to overflow the oil out the top when you want to remove the part.

NOHOME said:

In reply to Pete. (l33t FS) :

tin garbage bin on a propane burner stand. Dont pull the part out right away; add more water to overflow the oil out the top when you want to remove the part.

You could drill a hole an inch or two down from the top edge to have a more controlled overflow that could allow the oil to be collected. 

I used to work for a company that did strain gage and other sensor installations on all sorts of components, some that came out of running engines.

We used to bake them to remove oil in the metal. Typically we would pick a temp that was 50F above the operating temp, so we wouldn't have any leach out under gages in testing, but that wouldn't work for welding. I'd pick the highest temp your comfortable with for the head and let them stay at temp for several hours before slowly cooling. 

You might be able to try a couple different temps using a scrap piece of the head and starting at 400F and then increasing by 50F if the test weld isn't clean. 

No Time said:

NOHOME said:

In reply to Pete. (l33t FS) :

tin garbage bin on a propane burner stand. Dont pull the part out right away; add more water to overflow the oil out the top when you want to remove the part.

You could drill a hole an inch or two down from the top edge to have a more controlled overflow that could allow the oil to be collected. 

...Or just soak up the oily film on top with paper towels.

Driven5 said:

...Or just soak up the oily film on top with paper towels.

Oil absorbing pads.  They'll soak up the oil, but they don't absorb water. 

In reply to rslifkin :

I drove brit cars for about 45 years, we are talking less than a thimble full of petroleum products on the ground here. Less than a day's work for anything that ever came out of the UK. Guessing the grass wont even notice.