Yanmar 3GM30 head - how to check condition

[dmksails]

Spent the last 2 hours trying to find someone who can check out the cylinder head from my 3GM30F. I had to remove it to deal with a precombustion chamber and would like to have it checked out before putting it back on. There is also one pre-chamber that refused to come out.

Looks like I'm going to have to tackle this myself. Any suggestion on what to look for in determining if the valve are ok or in need of grinding?

[Greatest Lakes]

Depress the valve so you can see the seat, look for pitting. Be very sure to retorque the head bolts in the correct order. It's very nice to find a place that does cylinder heads to have it redone and surfaces reground, but if that's not an option, don't try to do it yourself. You can clean surfaces with a scotch Brite pad without doing any damage.

[bil56]

it's easy to lap the valves with the lapping compound,
to check the tightness, cylinder head upwards, put a little diesel on the valve, it must stay in place without flowing underneath

[tkeithlu]

Messing with valves requires a few specialized tools and is generally a PITA. For that reason, heads commonly are sent to the shop, and come back beautifully bead blasted and lapped. It's a job you can do, but it's a job that is convenient to leave to the pros in a suitably equipped shop.