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?

 

[eggs712]

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?

Sounds like a plan, and thanks for the advice. I ordered the oil pump primer tool, should be here tomorrow. This is my first time going past the valves in any engine, so sorry for any dumb questions.

So hypothetically, I'm trying to put together costs on fixing what I have versus getting a crate vortec motor. A reman head with valves installed is $350 each from MarineEngines4less (reputable?). Would it be worth it to find heads with hardened valve seats?

I'd also need new exhaust manifolds at $500 each plus all gaskets. New starter $300, and new electronic ignition $600 (the Thunderbolt IV module may have been acting up, or eventually will 30 miles offshore).

All that and I could have an unseen crack or other issues in this old block.

Opinions?

 

[Lou C]

I had a similar problem about 10 years ago, both head gaskets started leaking after an overheat that happened about 2 seasons earlier. Symptoms were water in the oil, rough running when cold, reluctance to start when cold. Compression testing was normal but I had some water in #2 and a tiny bit in #1. I pulled the boat and changed the oil like 4 times draining the block after each oil change to keep the water out. Then did what you did, removed the cyl heads and got some advice from mechanics. I cleaned up the block deck and took some high res pix, & took the cyl heads to a local hot rod and machine shop. They felt the pix of the block looked good, but the heads had cracks in valve seat areas on the middle cyls of the V6 head, no doubt due to the overheat.
I replaced the heads with reman heads and replaced the head bolts using ARP, and Fel Pro marine head gaskets. Installed new exhaust and it ran well for the next 8 seasons, been having some fuel system problems now but each year I have done a compression test at the end of each season and they have been good.
So if you want to save the engine try to get the oil changed several times, you might have to heat up the oil pan with a heat gun (carefully) to get it to pump out, the water makes it a lot thicker. So it is possible to save an engine with salt water in the oil but you have to act fast.
Compression test from 11/24 (reading on the tester is a bit lower because I just brushed against the valve core).

reman heads installed:

 

[Lou C]

This looks milky to me
View attachment 418854

milky oil shows up sooner under the valve covers than it does on the dipstick, it is thicker than just motor oil alone so it may not travel up the dipstick tube as quickly as it shows up under the valve covers.

 

[Lou C]

I find it interesting that your plugs are bleached white, but the pistons all seem to have a fair amount of carbon on them.
Looking closely it's hard to see where the HGs blew but it is often between the middle cyls beause that area runs hot seeing as how the exhaust valves are right next to each other on the 2 middle cyls. So that area can run hotter especially if the carb is running lean (yours might be) or the boat is over propped (don't think that's your problem though).
That's one of the few advantages of the Chevy V6 vs V8, none of the exhaust valves are adjacent to each other and the cylinder heads may run a bit cooler.
V6 reman cyl head:

 

[alldodge]

Check around your area for a auto or marine machine shop. Ask them what it would cost to overhaul your heads, most the time it's cheaper.

 

[Lou C]

Agreed, they can check for cracks as well and evaluate overall condition.

 

[Bondo]

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

My Bad, AD,.... I cruised through late, 'n obviously didn't pay attention,....