Bought a Junkyard Motor need advice

smiles16

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I have posted a couple topics as I have been tossing around different ideas, but took the plunge when I found an alpha one 140 mercruiser with good compression all all cyljnders. Only problem is the oil pan was all water, no oil. Also found water in the manifold when I pulled that drain plug. BUT, this motor sat in a boat next to a creek for at least 2 years. There are no obvious cracks and freeze plugs still intact.

Fired up first try. Ran great.

I am worried the block could be cracked, but was told these motors seldom crack ( not sure about that myself ). Everything looks great under the valve cover, ran my inspection camera down the cylinders with no evidence of corrosion, and all the drain plugs were loose (even though they were tight enough to hold water).

Any thoughts? Did I just by a junk motor, or am I being overly paranoid? Any thoughts guys?
 

Speak

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I have posted a couple topics as I have been tossing around different ideas, but took the plunge when I found an alpha one 140 mercruiser with good compression all all cyljnders. Only problem is the oil pan was all water, no oil. Also found water in the manifold when I pulled that drain plug. BUT, this motor sat in a boat next to a creek for at least 2 years. There are no obvious cracks and freeze plugs still intact.

Fired up first try. Ran great.

I am worried the block could be cracked, but was told these motors seldom crack ( not sure about that myself ). Everything looks great under the valve cover, ran my inspection camera down the cylinders with no evidence of corrosion, and all the drain plugs were loose (even though they were tight enough to hold water).

Any thoughts? Did I just by a junk motor, or am I being overly paranoid? Any thoughts guys?

My thoughts are this - being a new to you motor I would only do the bare minimum to make it run. Then I would work the pants off it. Basically run it like you stole it. If she holds up and doesn't throw a rod or some thing then I would invest into her. Do a pre and post run compression check. Make sure your oil isn't milky. Just my thoughts but hey who am to advise - good luck
 

Rick Stephens

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Easy to crack a 3.0L, all you need is water and a good freeze. However, if it is cracked it should be obvious when you run it. Doesn't take anything special to run it on blocks. https://www.youtube.com/watch?v=HMag9SbwpD4 It is usually pretty obvious when the block is cracked, most oftenthey leak water right under the intake manifold and exhaust.
 

flipbro

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If it fired up and ran great and oil isnt milky. What are you worried about. Is compression still good? Is oil preassure good? If yes your likley good to go.
 

smiles16

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Well I can't say based on milky oil. The engine had residual water in the oil pan with no oil in it when I bought it. I ran it for about 10 seconds with the outdrive off and no water hooked up after adding 4qts of some random 5w-30 I had lying around.

What's up he best way to flush all that crap out of the engine? Just multiple oil changes?
 
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Rick Stephens

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Well I can't say based on milky oil. The engine had residual water in the oil pan with no oil in it when I bought it. I ran it for about 10 seconds with the outdrive off and no water hooked up after adding 4qts of some random 5w-30 I had lying around.

What's up he best way to flush all that crap out of the engine? Just multiple oil changes?

That's what I would do, multiple oil changes until it runs clean. The alternative is to disassemble the motor and find what might have been rust damaged. Takes your pick. I probably wouldn't even install the outdrive. Just use a cutoff piece of garden hose and shove into the water port on the bellhousing while you do your checkup.
 

Grub54891

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Change the oil, then dump half a can of sea foam, with the new oil, run it till warmed up, change it again using the rest of the sea foam. I use the cheapest oil I can find for the process. After a few changes, put the real oil in and run it. See if it's worth dumping more dollars at.
 

smiles16

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Ok so I have an update. Just ran the engine as Rick suggested. Water poured like a waterfall from underneath the manifold as I turned on the water hose before I ever started the engine. Decided to go ahead and fire it up. Again ran great. Temp never even crossed 170 per the gauge. Thermostat was cold to touch as well.

Here's the kicker, as the engine ran and warmed up the leak went from a waterfall to a very light trickle. I am thinking manifold gasket ( I also found a mess of black rtv around the manifold from previous owner).

My thoughts are that a crack wouldn't act this way. Oil level did not change before or after running as of yet.
 

thumpar

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As the block warms it expands causing the crack to get smaller. Since you had water coming out with the engine not running you need a new impeller. Water doesn't pass the impeller unless it is turning.
 

Grub54891

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When I got my 140, all the core plugs were blown out, and the same crack under the manifold. I slapped in new core plugs, and dremmeled the crack, Jb welded it, stuffed the motor back in and ran it like I stole it. Never had any more leaks, clean oil every time I check/change it. Sometimes ya get lucky, I'm on 4 seasons now with no issues.
 

Rick Stephens

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As the block warms it expands causing the crack to get smaller. Since you had water coming out with the engine not running you need a new impeller. Water doesn't pass the impeller unless it is turning.

He didn't have the drive in, just stuck the hose in the water port on the bell housing.

If water is pouring from under the manifold there is 2 possiblities, and neither one would just dump water into your oil.

1) Block is cracked right where 3.0L blocks always crack, right under manifold. This will be a horizontal crack through the thin walls of the block to the water jacket around the cylinders. Since you ran the hose directly to the bell housing you pressurized the system more than it would be with just the impeller pumping water in. It is sometimes possible to clean up those cracks, drill the ends to prevent them cracking further, beveling them and using JB Weld to patch them. Boat cooling systems work under no pressure, so these repairs can last years.

2) Manifold is cracked. This CAN destroy a motor as it will put water into the cylinders.Fix is to replace the manifold.

Rick
 

achris

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......Here's the kicker, as the engine ran and warmed up the leak went from a waterfall to a very light trickle. I am thinking manifold gasket ......

It won't be the gasket. No water runs through it. But you should pull the manifold and check it for cracks. You said it was full of water too.

Chris......
 

smiles16

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So it sounds like either cracked block or manifold. I will pull the manifold and see what I find. But, no water through the gasket? If water passes through the exhaust, how could this not be a possibility?
 
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Rick Stephens

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So it sounds like either cracked block or manifold. I will pull the manifold and see what I find. But, no water through the gasket? If water passes through the exhaust, how could this not be a possibility?

Water passes through double walls in the manifold from a water hose at the end fed from the thermostat housing. There is no crossover whatsoever to the block for water, just exhaust gases which are dry there. The water inside the outer wall of the manifold then goes into the elbow still separated from the exhaust and doesn't mix with the exhaust until at the rubber connector hose to the lower exhaust pipe. If the internal manifold freeze cracks then it can dump water into the exhaust manifold and ultimately on the exhaust valves and into the cylinders.

Run the hose connected to the bell housing again and look under the manifold and see where the leak is.
 

smiles16

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i cannot identify the leak as it is so far up around the manifold to block connection that a mirror nor flashlight shows anything. There is a bunch of black rtv all around the manifold (guess somebody didnt want to buy a gasket?). So that's why I figured that was the culprit. I ran the engine with water connected and have yet to see any water enter the cylinders or oil.
 
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flipbro

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I bet if you get rid of all the rtv gasket maker you will see the crack. Sounds like someone tried to do a quik fix.
 

smiles16

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well boys, case closed. Motor is going back to where it came. Found a nice long crack in the block after removing the manifold. Going to go look for other motors. Thanks for all the help, I am sure this is not the last you'll hear from me. :very_drunk::censored::mad-new:
 
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