Volvo AQ 260A lost compression, water in valve cover

[eggs712]

My 1985 Volvo Penta 260A with new risers was seemingly running well for a few hours after sitting for 10+ years. I was making about 4600 rpm WOT, cold started easily, but seemed to be vapor locking after warming up (140 thermostat). After a one hour hard run in a following sea, the motor fell flat, but I was able to idle it back. It started easily the next day, got on plane fast (1985 Bayliner 2750), and still made 4K+ RPMs, but fell flat again after 20 minutes and died for good.

Here are what the spark plugs look like: (2, 4, 6, 8):


(1, 3, 5, 7):


Oil looks fine to me:


Cold compression numbers:
1- 108
2- 91
3- 92 (100 with oil squirted in cylinder)
4- 80 (same with oil squirted in cylinder)
5- 92 (same with oil squirted in cylinder)
6- 67 (same with oil squirted in cylinder)
7- 101
8- 105

My started turned slower than it should even with the spark plugs removed.

Today I took off the valve covers and saw this on both sides:


To my untrained eye, something looks wrong with the valves on cylinders 2 & 6:



Any ideas on what damaged I caused? I can take the heads off tomorrow to get more pics.

 

[alldodge]

Don't see an issue with valves on 2 and 6, they appear to be opening

You most likely blew the head gasket and removing the head will verify

 

[Lou C]

Did you get water out of the cyls when doing your compression test?
Only other diagnostic you can do is a leak down test.

 

[eggs712]

Did you get water out of the cyls when doing your compression test?
Only other diagnostic you can do is a leak down test.

Nothing came out of the cylinders while checking compression

 

[eggs712]

I cleaned it up some before taking a pic, but there was milky oil under the intake manifold. The manifold itself doesn't have any cracks or holes that I see:




There was lots of carbon buildup by the middle cylinders of both sides.

Here is what it looked like under the heads
1, 3, 5, 7:


Cracks in two valves that I see:


2, 4, 6, 8:



Cracks in head around valves, worst of all on 6:

 

[eggs712]

Cylinders all looked like these two:

 

[Bondo]

I cleaned it up some before taking a pic, but there was milky oil under the intake manifold. The manifold itself doesn't have any cracks or holes that I see:

Ayuh,...... That little bit of milkiness there is just condensation,.....
No worries with that,....

 

[alldodge]

Hey @Bondo the first post shows a a bunch of milk under the valve covers and he had done some hard running with it.

Most the valves look steam cleaned, and plugs 2, 8, 1, 3, 5, 7 look steamed as well

Oil color looks ok because oil floats to the top

 

[eggs712]

@alldodge I did not see any milky oil right after the engine shut off, is it possible that little water made it into the crankcase? I'll drain and change the oil this afternoon to get a better look.

The cylinders and pistons made me hopeful that the block may be still good, but I'll defer to the experts here.

 

[alldodge]

This looks milky to me

 

[eggs712]

Good point, I'm just in denial I guess. This was saltwater, so I'm guessing the bearings/internals are likely toast by now?

 

[alldodge]

Good point, I'm just in denial I guess. This was saltwater, so I'm guessing the bearings/internals are likely toast by now?

Not necessarily water got in you need to get it out. Change the oil and use a drill to dun the oil pump to push oil thru the bearings. Some oil will also come oil the lifters but that's ok, rotate the crank a few times. Need to get the water out of the bottom of the pan so the oil pump doesn't pick it up.

Guys am I missing something?