Water jacket blown on my 1985 OMC 3.8 Liter V6 - Need a engine block

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WagonHo

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Okay, dummy me put my boat in storage without anti-freeze and I am paying the price.
These OMC engines seem to be hard to find.
I am wondering, can I go to the auto junkyard and get a used engine out of a car and switch engines.
I could get new gaskets etc. and use all my other parts from my ruined engine to make it work.
I just don't know what engine to get at the junkyard.
I think it would be an Oldsmobile. If so what years are compatible?
Thank you!

I HAD A LATE EDIT: The title was 1987 and is corrected to 1985
 

Howard Sterndrive

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Re: Water jacket blown on my 1987 OMC 3.8 Liter V6 - Need a engine block

Re: Water jacket blown on my 1987 OMC 3.8 Liter V6 - Need a engine block

last year for the 3.8L OMC was 1985
so the first thing you need to do is verify that it's a 3.8 and not a 4.3
The 4.3 was introduced mid 1985 and replaced the 3.8
If it's a 3.8, then 1980-1984 Monte Carlo, El Camino, Malibu etc. used the 3.8L/229 cu inch 90 degree Chevrolet V6 same as OMC. except California got the 231 Buick based V6 so look for K as 5th VIN letter K=229

You can use a car block, but need to change the cam to marine (your old cam or use Edelbrock EDL2112), and replace the tin core plugs with brass ones, and change head gaskets to composite type (ebay item 130493787011 for example).

You also need exhaust manifolds if the boat was not winterized, those will be cracked. Budget $1300 for a conversion to center riser manifolds from OSCO, because the OMC 3.8 manifolds have been obsolete for years.
 

WagonHo

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Re: Water jacket blown on my 1987 OMC 3.8 Liter V6 - Need a engine block

Re: Water jacket blown on my 1987 OMC 3.8 Liter V6 - Need a engine block

Thank you Howard, I am not the mechanic but the one I have has found a chevy block but I don't think he will be changing the cam or changing anything except what gaskets will be needed to use my old parts and switch them over. He is concerned about manifolds being cracked and as of two nights ago he had the engines out of the car and boat and was just beginning to do the switching around.
I expect a call in the next few days to come and pick it up. He seems to be concerned about cracked manifolds but maybe they could be repaired with some sort of epoxy or metal bonding stuff?
This boat is not ugly junk but it's not worth sinking thousands into either.
All I really do is go to the swimming area and the few fishing spots on the river and thats about it.If his repair gives me more confidence I might get out on The St Lawrence or Ontario a few miles but I'll just be glad to get it back and running in the Susquehanna for the rest of this year.

I expect to get away with repairs for a lot less than $1300.00 at this time. I will update when I get it back in the water.
Tell ya this much, I'll never make this mistake again.
 

Howard Sterndrive

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Re: Water jacket blown on my 1987 OMC 3.8 Liter V6 - Need a engine block

Re: Water jacket blown on my 1987 OMC 3.8 Liter V6 - Need a engine block

the 3.8 229 car engine had such a smog-era cam - it was rated at 105hp vs. the 170HP marine rating. (185HP with 4 barrel)
Your boat might not even get on plane if you don't change the cam. it will struggle for sure
You also risk destroying the motor from reversion. Because of the water mixed in the exhaust, a marine cam has a special grind to make sure there is limited overlap of intake and exhaust valve opening.
He is concerned about manifolds being cracked
you need new ones

I wonder what the odds are that this mechanic understands the intricacies of the semi-even fire distributor in your engine and the trick to installing it correctly...
make sure the engine he's putting in is a 229, not a 200 or a 4.3

you'll know it's a 200 if he says there's one mounting boss for the alternator belt tensioner missing...and he has to improvise there. of course you haven't even correctly identified the motor or year of the boat so who knows....

a new engine and installed in your boat for less than $1300?
7_4_33.gif
 

doral1985

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Re: Water jacket blown on my 1987 OMC 3.8 Liter V6 - Need a engine block

Re: Water jacket blown on my 1987 OMC 3.8 Liter V6 - Need a engine block

Done the same with my 3.8l stringer, 84 Malibou engine, replaced cam to marine, works great, now to reseal my outdrive.
 

HT32BSX115

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Re: Water jacket blown on my 1987 OMC 3.8 Liter V6 - Need a engine block

Re: Water jacket blown on my 1987 OMC 3.8 Liter V6 - Need a engine block

Okay, dummy me put my boat in storage without anti-freeze and I am paying the price.
Everybody screws up so don't beat your self up too much about it..........bag the Antifreeze idea too.........OR, Don't do it unless you completely drain the block and manifolds FIRST!
 

WagonHo

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Re: Water jacket blown on my 1985 OMC 3.8 Liter V6 - Need a engine block

Got my engine swap over for $764.55 My boat is a Rinker 19 ft open bow mfg 1985.
OK so here I am with a 3.8 ( 1984 I believe ) Chevy engine block and all the parts from my old boat motor. The manifolds miraculously are not cracked.
I start this engine and it purrs like a kitten.
I got my boat up on plane with it the first hundred feet and travel at maybe 30 mph ( 3/4 throttle ) as I approached a no wake area and as I slowed down the boat stalls.
Worried, I put it in Neutral and it starts right up and I maneuver into anchor spot and take a nice swim.
To leave, I start out slow, no wake, and make it back to the launch at a bit slower speed and it doesn't stall. Idles nicely while I go fetch the trailer.
This was two days ago.
Tonight, I go out and it's a whole different story. As soon as it wants to get up on plane, stalls. I hear a bit of a rattle too, a little knock just before it stalls. 7 times I had to restart to make it to my river lot dock. The temperature has been getting up to 170 or 180 but no more. The manifolds are warm but I can hold them. They are almost hot.
A puff of smoke seems to be coming from the air filter after it stalls.
I get a squeal from my pulley ( probably the water circulator pulley ).
When I get it back in Neutral and start it, it sounds fine, no knocks or pings.
If it isn't something with the gas or carb. The gas could be a bit old and have some water in it? Then .....
I am thinking, yes, this Marine Cam might have been a must. Perhaps my mechanic doesn't know of this issue.
It might need the extra HP to pull off the job of pushing this heavy boat around. If it doesn't have the umph, maybe it is natural for it to stall. Just like me, if I try to do something and am tired, I am less able to do it because I don't have the energy?

So, if it is a cam issue, I imagine the engine will be torn down again and cams are probably quite expensive?
Is there a way I could just get this boat to run slow the way it is? I really only need to putter over to the swimming area and the travel on the river is only a maximum of 10 miles from one end to another.

I am going to try some Hi Octane and some dry gas and Sta-bil in the tank and see if it helps but I don't want to burn up another engine.
So I do appreciate these replies. I am not swearing by my mechanic and I am not saying he is right.

Help.

Here's my fixed engine. yeah, fixed alright. I will be calling him in the morning to see what he says about the stalling.

OMC2.jpg

OMC3.jpg
 

WagonHo

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Re: Water jacket blown on my 1985 OMC 3.8 Liter V6 - Need a engine block

Called my mechanic. He says it is water in my gas, recommends draining the old gas and putting in new and using gas stabilizer and some dry gas.
I have a gut feeling he is right and it will get me going good enough with whatever HP my engine will provide without the Marine Cam.
I would appreciate an opinion. I also thought, I should have kept my engine block, it already has a Marine Cam in it right? Just in case I have to absolutely make the changeover.
 

BCMAlIBU

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Feb 28, 2024
Messages
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Okay, dummy me put my boat in storage without anti-freeze and I am paying the price.
These OMC engines seem to be hard to find.
I am wondering, can I go to the auto junkyard and get a used engine out of a car and switch engines.
I could get new gaskets etc. and use all my other parts from my ruined engine to make it work.
I just don't know what engine to get at the junkyard.
I think it would be an Oldsmobile. If so what years are compatible?
Thank you!

I HAD A LATE EDIT: The title was 1987 and is corrected to 1985
Hello. I am late in the game but I have one of those rare OMC V6 engines that was mentioned in one of the posts. I bought a 1985 18' Malibu with a OMC V6 about 3 years ago with a plan to rebuild the floor and get the boat put back together and get it out on our lake property. I had the guy start it before I bought it, so I know it works. The floor was completely shot and I have tried rebuilding it, but I am no boat expert, so I have decided to sell it, to someone who 1) knows what they are doing and want to finish rebuilding it, or 2) want it for parts. There are many useful parts. The seats and other parts are in decent shape. The boat is on a trailer, that was made for it, so that goes with it as well. Anyway, I thought I would through that info out there to anyone who may be interested. If anyone is interested in the boat/boat parts, please email me at dmlogger@yahoo.com .
 
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