So Im in the middle of rebuilding my 2.3L after both exhaust valves on cylinder 4 burned up. Basically I had the head refurbished by Clearwater Cylinder Heads about four years and 70,000 miles ago. They did a sub par job on the head and used cheep valve stems seals (all the seals were petrified, broken, or not seated properly). So needless to say the motor was burning quite a bit of oil (1qt every 600~900 miles depending on driving situations).
I've showed the below photos to the engine re-builder who rebuilt my head this time (Very knowledgeable guy, years and years of experience) and he said that I shouldn't worry about it. He said it was probably staining caused by the excessive oil burning.
Before I put this paper weight back together I just wanted the Volvo community to take a look at this and give me their opinion.
1998 2.3L
207,000 miles
Compression Test results done when the motor was COLD (after the valves took a stuff).
CL1: 150psi
CL2: 150psi
CL3: 135psi
CL4: 0psi (burnt valves)
CL5: 150 psi
The motor ran great up until it ate the valves. It did have excessive oil consumption but no crankcase positive pressure (meaning I was not getting symptoms of a clogged PCV or blowby)
These marks are not deep, I can't feel them with my fingernails and they don't seem to be scratching off the cylinder's crosshatching. The marks are in every cylinder, at the same spot, and are the same size. They are located 1/2 down the cylinder wall only on the firewall side of the motor, about 1/2" wide and 1/4" tall.
The pistons and cylinders are soaked in WD40 to prevent rust, thats why they are so wet.
Cylinder 3:
Cylinder 2:
Cylinder 4:
Cylinder 5:
Here is the head damage for reference.
