Blown head scrap motor?

[StinkinRenken85]

after my trials and tribulations on my 181ci mercruiser 3.0 140 I have found out it has a blown head gasket. I ran it right after thanksgiving flushed it on muffs and noticed oil mixed with water pulled the head today and found the gasket blown with major water intrusion and a little rust on 2 of my lifter rods. My neighbor who is a mechanic tells me now is the time to finance an outboard. A local shop says they can rebuild the head for 175 give an extra 20-200 if it’s cracked. But my neighbor says that the bearings and other components in the block are submerged in water so even if I fix the head then the components in the block can go any minute...after hearing this I sprayed on blaster in it where the head once sat and walked away. Tomorrow’s I may pump the oil out and fill it with diesel a few times then with oil and maybe take the head to be rebuilt on Monday... do you all think my neighbor is right? The motor was running the other day for a few hours and ran fine at full throttle so could there still be damage in the block? What would y’all do. On top of this I work for the state outside the capital and there are rumors of shutting us down...being that I may be jobless soon maybe financing a new motor may have to wait a little while..any thoughts?

 

[StinkinRenken85]

Oh yeah it’s a 1985

 

[Bt Doctur]

do you all think my neighbor is right? Nope

 

[achris]

Yet to see a successful stern drive to outboard conversion.

It's expensive, and nobody is completely happy with the result. Yes, they say they are, but that's just confirmation bias.

Even pulling the current engine and stripping it down and doing a full rebuild will be less than 1/2 the cost of a pod and an outboard.

Water in the oil is unlikely to have damaged the bearings. That 350MPI I just did had exactly that, water in the oil. Bearings were all perfect. Replaced anyway, because you don't take it down that far without replacing them... Do your flush throughs with diesel, a new head gasket, and set the timing right this time and you should be good to go.

One last thing... Your neighbour is a car mechanic. Wrenching boats is a very different world.

Chris......

 

[StinkinRenken85]

Thanks for the replies. So I guess there is hope. Not sure if I was clear that this is salt water and the intrusion probably has been going on since before I bought the boat. It never seized and I have been running it a couple times a month for the year I’ve had it. Also the thermostat was rusted out and there was a piece of impeller stuck in a passage in the head. Should I replace the thermostat or leave it out all together? Thanks again!

 

[Lou C]

I repaired an engine that had a similar problem, my old '88 4.3 blew both head gaskets at the end of the '16 season. Probably was from a previous overheat in '13. The symptom was reluctant starting caused by water in a cyl. Not enough to hydrolock it but enough to cause very reluctant starting and rough running. It took me a few days to figure out that this was due to water in the #2 cyl, with a mist of water in #1. I fogged the engine multiple times after blowing out the water and draining the block and manifolds. I took it all apart and was amazed at the lack of corrosion inside. For one thing due to the salt water use I didn't think I'd be able to get the engine apart with out breaking head bolts but using my De Walt electric impact gun they all came out without breaking even one.

I took the heads to a machine shop and they said that the center cyls had cracks in the exhaust valve seat area and the cooling ports were getting eroded from salt water use. So I bought a set of reman marine 4.3 heads. The biggest part of the job was cleaning the cyl head bolt holes (carb cleaner, thread chaser and compressed air) and the block deck surface (must be flat to less than .003"). Put it back together with a set of Fel Pro marine gaskets and new ARP head bolts. Rebuilt the old Quadrajet and installed a center riser exhaust system to replace the NLA OMC batwings. First time I ever took a real engine apart (ie not a small engine like lawnmowers or 2 stroke yard engines).

 

[Lou C]

all back together with center riser Volvo style exhaust, fit the old OMC Y pipe perfectly...
if your block deck is in good shape, see if the head is not cracked and they can do a valve job and resurface on it. If not do what I did and buy a re-man marine head. On 4 cyl inline it is an easy job.

Forget about converting to an OB, that is a big job, risky and expensive. Repairing what you already have, is much much cheaper and that is about the simplest marine engine that ever was.....

 

[Scott Danforth]

My old 1984 3.0 blew the head gasket twice prior to my owning it. both times when dad owned it. first time, he paid $600 at the marina. a few years later, it went again. this time I did the work. took the head in to have surfaced ($75), used a piece of 1" cold drawn bar as a backer to sand the deck, used ARP bolts (a 2-bolt BBC main kit for $110) for the head bolts, a felpro head gasket set (about $75) and that was the end of head gasket issues.

as far as salt water in the block, depends on how long it was sitting whether you have an issue or not. most likely not.

as far as you head needing a rebuild, most likely no, however you wont know until you unbolt it

BTW, any 1990 or older 3.0 will bolt right in place if you dont want to sink that much money into it. you can find running motors for under $500. you can use the 1991 and later however you have a bit more stuff to get when you buy the motor

if you want a outboard, buying a boat set up for an outboard is cheaper than any conversion. not to mention the conversions are iffy.

 

[kenny nunez]

In addition to the advice be sure to replace the thermostat. When you restart the engine leave the oil filler cap off so that any moisture trapped in the block will steam out. It may take an hour or so at operating temperature. It might get a little messy, you will have to keep wiping the top of the valve cover off.
I have done it this way several times with boats that sunk and were under water for a few hours.

 

[Lou C]

Forgot to mention you may need to change the oil several times, I did 3 or 4 oil changes, during the rebuild process.