Mercruiser 3.0L Exhaust Valve Crack

[tupperj]

Greetings all!

Long time lurker, just about first time poster.

Recently picked up a 1986 Sea Ray Seville. Boat has been very well maintained, and the engine shows signs of perhaps a recent rebuild. Previous owner stated that boat had been losing power, and shop had done a compression test and found it low, probably a head gasket.

So, ordered parts, downloaded manuals, read a lot of posts, and started dismantling things.
Got the head off, and did not find a blown head gasket as expected/hoped for. Instead, I found what appears to be a cracked exhaust valve on #2. I need to acquired a tool to take the valve assembly out, but it certainly feels/looks like a crack.

As you can see from the pics, there has been water around the valves, and some intrusion into the cylinder.

My thinking is to have the head re-done. I might get away with replacing the one valve, but why not get everything freshened up while it's apart, other than cost and time.

Also, there is a rust stain on the outside of the block, under #2. Guessing excess pressure in the exhaust manifold pushing water out?

What say you all? Ideas and suggestions welcome!

Paul

 

[tupperj]

Re: Mercruiser 3.0L Exhaust Valve Crack

Bump - Anybody? Besides the crickets?

 

[Bondo]

Re: Mercruiser 3.0L Exhaust Valve Crack

Ayuh,... In picture #3, it appears the block is Cracked at the top of the rust stain....

The way the rust tracks on the valves, I'd guess in manifold might also be cracked...

 

[wire2]

Re: Mercruiser 3.0L Exhaust Valve Crack

Any signs of leakage from the the manifold, riser, or gasket?

 

[Big Boat Bay Buster]

Re: Mercruiser 3.0L Exhaust Valve Crack

You need to remove the valves. You need to see whats going on under them. Either go to sears and get a valve spring compressor or run it over to a machine shop for an inspection.
Lert us know the results.
Chris

 

[ENSIGN]

Re: Mercruiser 3.0L Exhaust Valve Crack

I think Bondo's right,At this point it would be a good idea to have the block,head and manifold pressure tested.

 

[mariner1900]

Re: Mercruiser 3.0L Exhaust Valve Crack

The valve is burnt and cracked, from heat probably caused by poor seating due to the rust from the water ingress. All valves and seats will need attention.

Block looks cracked. As mentioned you will need to check block, head and manifold for further signs of cracking.

 

[tupperj]

Re: Mercruiser 3.0L Exhaust Valve Crack

First, thanks to all who replied, I really appreciate the help.
As an update, pulled the valve in question, and it's definitely pooched. The valve seat is also missing. Also pooched. I'm thinking a new head is in order. Priced them out, and not too bad for the convenience and peace of mind.

To the replies:
Bond-o: Great catch on the block crack. I haven't been back to the shop to look closely, but that's on the agenda for tomorrow. Nothing apparent on the manifold, though I do have a pic I did not post that shows a rust "stain" from what could have been a puddle in the exhaust area of #2. There are now rust stains on the bottom of the manifold..

Wire-2: See above.

Bay Buster: Sears it was! Had to use a big c-clamp and socket to loosen things up, but then came apart well.

Ensign: I'm assuming checking the block will entail removing it from the boat? Who would do that sort of test?

So, current plan of action: Talking to a friend who is a car mechanic to see what he thinks about the head, and where to take it. If that turns out not to be cost effective, I've found a new one for approx $380 delivered to my door with all new valves, ready to go.
I'll hit the forum search to see if I can find out how/who will pressure check the block.

Thanks to all who responded, your time and effort is much appreciated. If any of you get down to Cherokee Lake in Tennessee, the first few drinks are on me!

Paul

 

[ENSIGN]

Re: Mercruiser 3.0L Exhaust Valve Crack

Our shop takes the blocks & manifolds to a local engine rebuilder,they do both pressure and vacuum testing also magnafluxing.