Water in 3.0 - Rebuilding/recondtioning cylinder head

[mark1905]

I'm about ready to yank off my cylinder head and inspect due to my wonderful water in the oil issue. We're leaning towards a blown/corroded head gasket or cracked/corroded cylinder head. With everyone's experience, how often is the head able to be reconditioned and re-installed? Wondering if I should be purchasing a cylinder head before I get it off to minimize my down time.

- Water in oil in an excessive amount and getting worse and worse
- Changed manifolds/exhaust elbow
- Engine has never overheated or froze
- Was a saltwater boat for 10 years before I had her.. freshwater only for the last 5
- Engine runs like a dream and doesn't miss a beat. Seriously purrs like a kitten at all RPMs.
- Good compression on all cylinders
- Zero blow-by/pressure out of the dipstick tube, but tons of blow-by out of the valve cover vent. Oil/water mix covering the engine and running into the bilge

 

[dollarten]

Re: Water in 3.0 - Rebuilding/recondtioning cylinder head

I hate to be the bearer of bad news but all the 120's that I worked on back then were getting water ingestion turned out to be a bad block We went through the same things too when the first engine arrived (120) with water in the oil . Further inspection revealed a rust trail inside the block near the main bearing journals and bottom of the water jacket .. It seems this area could be a area that could be porous when the block was made or, it could be a high stress area that finally gives way over time

I'm about ready to yank off my cylinder head and inspect due to my wonderful water in the oil issue. We're leaning towards a blown/corroded head gasket or cracked/corroded cylinder head. With everyone's experience, how often is the head able to be reconditioned and re-installed? Wondering if I should be purchasing a cylinder head before I get it off to minimize my down time.. This blow by that you are experiencing is just all the wind and turbulence created inside the engine . Not to be confused with piston ring leakage

- Water in oil in an excessive amount and getting worse and worse
- Changed manifolds/exhaust elbow
- Engine has never overheated or froze
- Was a saltwater boat for 10 years before I had her.. freshwater only for the last 5
- Engine runs like a dream and doesn't miss a beat. Seriously purrs like a kitten at all RPMs.
- Good compression on all cylinders
- Zero blow-by/pressure out of the dipstick tube, but tons of blow-by out of the valve cover vent. Oil/water mix covering the engine and running into the bilge

 

[mark1905]

Re: Water in 3.0 - Rebuilding/recondtioning cylinder head

:facepalm:

Ugh.. I'm trying to believe that it's anything but that. It's weird though.. the engine was fine one day.. and then one day.. after no overheating, nothing funny.. water just appeared in the oil and has steadily gotten worse and worse. I've always been under the understanding that if it's a cracked block, that:

- The engine would be running funny/poorly
- Usually comes after overheating or freezing
- It doesn't semi-rapidly get worse over a short period of time

 

[Don S]

Re: Water in 3.0 - Rebuilding/recondtioning cylinder head

I've always been under the understanding that if it's a cracked block, that:

- The engine would be running funny/poorly
Not necessarily, if only the water jacket has a hole in it, it doesn't affect the running. Like a an external cracked block. It leaks, but still runs fine.

- Usually comes after overheating or freezing
Metal fatigue, corrosion, thin spots during casting of the block. Some things break for no apparent reason.

 

[Bondo]

Re: Water in 3.0 - Rebuilding/recondtioning cylinder head

Ayuh,.... Have you drained the block, 'n air pressure tested it,..??

If not, Do it, 'n follow the sounds to the crack, or rot through...

Once ya pull the head, yer diagnostic time is over...

 

[mark1905]

Re: Water in 3.0 - Rebuilding/recondtioning cylinder head

I haven't pressure tested it, no. Care to list out/direct me to the proper steps?

I think I remember reading something on it here a while back..

 

[Bondo]

Re: Water in 3.0 - Rebuilding/recondtioning cylinder head

Ayuh,... Drain all the water outa the block,....

Block off all the block's water passages with whatever means ya got, 'n pressurize to 'bout 15psi, 'n Listen....

 

[mark1905]

Re: Water in 3.0 - Rebuilding/recondtioning cylinder head

lol.. there has to be a more cut and dry way..?

 

[dollarten]

Re: Water in 3.0 - Rebuilding/recondtioning cylinder head

That is about as cut and dry way there is , the way that Bond-o mentioned That is the way it's done . You can keep doubting the demise of the engine but, I' sure the party is over There is quite a few of these engines laying around that came out of rotten boats .

 

[Don S]

Re: Water in 3.0 - Rebuilding/recondtioning cylinder head

It would also be a good time to upgrade to a 140

The 140's are 3.0L engines 140 is just an old engine designation from the 80's when using engine crankshaft hp ratings instead of propshaft hp ratings they use now.

 

[Bondo]

Re: Water in 3.0 - Rebuilding/recondtioning cylinder head

The 140's are 3.0L engines 140 is just an old engine designation from the 80's when using engine crankshaft hp ratings instead of propshaft hp ratings they use now.

lol.. there has to be a more cut and dry way..?

Ayuh,.... Cut, 'n Dry,.... With a picture.....

 

[mark1905]

Re: Water in 3.0 - Rebuilding/recondtioning cylinder head

PERFECT.. that's what I was looking for. Hey.. I have to exhaust all avenues before I just start throwing money at it. Thanks for the helps as always, gentlemen.

 

[dollarten]

Re: Water in 3.0 - Rebuilding/recondtioning cylinder head

Had a brain fart for a minute and thought the topic was about a 120 oops!

 

[mark1905]

Re: Water in 3.0 - Rebuilding/recondtioning cylinder head

I hate to be the bearer of bad news but all the 120's that I worked on back then were getting water ingestion turned out to be a bad block We went through the same things too when the first engine arrived (120) with water in the oil . Further inspection revealed a rust trail inside the block near the main bearing journals and bottom of the water jacket .. It seems this area could be a area that could be porous when the block was made or, it could be a high stress area that finally gives way over time

I wanted to follow up that we did indeed yank the motor yesterday and this is EXACTLY what was up with it. I was firehosing raw water straight into my oil pan via a corroded out water jacket.

Just picked up a brand new 3.0 GM long block from Flagship Marine Engines for $1749 with no core charge (shop only price)... http://www.flagshipengine.com/catalogpages/23/page23.htm

New engine time! Huzzah!