Break Out Another Thousand

Well,

I was a happy boat owner. Ran my 1984 Mercedes for about 4 hours before the #2 exhaust valve decided to bail and destroy the entire #2 cylinder (pics posted on an earlier thread). So I luck out (at least so I think) and find a rebuilt merc 120 on ebay. Here's the description:
This auction is for a Fresh 120 hp Mercruiser also know as a 153 Chevy 4 Cylinder engine
(0) Miles / Running Hours on it.



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This Motor was Completely Professionaly Rebuilt
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The entire motor has been hot tanked and maged for cracks
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The block has been Bored and fine honed to ..030 over
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New Speed Pro Pistons and Rings installed.
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The rods were reconditioned as needed and new cam bearings were installed.
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The Crankshaft has been turned and New Rod and Main bearings and seals and Brass Soft Plugs were installed.
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This motor has a New cam and matching lifters installed
along with a New timing chain set and a New melling oil pump.
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The Head has NEW Hardened Valve seats installed (for unleaded gas) with a 3 angle valve job and new valve seals were installed and it has been surfaced milled flat.
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The engine has all New Felpro gaskets installed.
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This motor is complete as you see it in the pictures, parts included in this auction are the crank adapter, oil pan and pick up tube, timing cover, Valve cover.
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This motor is ready to bolt in and is in 100% new remanufactured condition.

So I get the motor for a great deal, and line up a guy to do the repower for me. (I don't have the time to turn my own wrenches). My mechanic says I need a new exhaust manifold cuz the other one is rusted through, so he gets said manifold and puts it on. Motor fires up and while he's adjusting the timing, hears water sounds coming out of the exhaust area. According to him, my new block was a newer style merc 120 and that my older one (1984 sn6789332) has an ever so slightly different manifold(not sure of the sn of that one). So he swaps the manifolds and gets it running good. The night it gets home, I figure I'd check the oil. Milkshake city. So I call my mechanic and he says that it's prolly from running it earlier with the wrong manifold and that might be where the water is coming from. He says change the oil and run it and we'll go from there. So I change it and the filter add more oil, and run it. Still milky. So I call the mechanic up and he says he knows it aint the manifold. I trust him, so I'm waiting to hear back from the guy I bought the block from. He told me when I bought it that there would be a 1 year warranty on it. Anyhow, mostly venting. How hard is it to do a leakdown test? And if there was a little bit of water left, how much would make the new oil milky? (Hoping that it's just residual water and not new, but Hey I'm an optimist) [\endrant]

Re: Break Out Another Thousand

A leakdown or cylinder leakage test is similar to a compression test in that it tells you how well your engine's cylinders are sealing. But instead of measuring pressure, it measures pressure loss.

A leak down test requires the removal of all the spark plugs. The crankshaft is then turned so that each piston is at top dead center (both valves closed) when each cylinder is tested. Most people start with cylinder number one and follow the engine's firing order.

A threaded coupling attached to a leakage gauge is screwed into a spark plug hole. Compressed air (80 to 90 psi) is then fed into the cylinder.

An engine is great condition should generally show only 5 to 10% leakage. An engine that's still in pretty good condition may show up to 20% leakage. But more than 30% leakage indicates trouble.

The neat thing about a leakage test (as opposed to a compression test) is that it's faster and easier to figure out where the pressure is going. If you hear air coming out of the tailpipe, it indicates a leaky exhaust valve. Air coming out of the throttle body or carburetor would point to a leaky intake valve. Air coming out of the breather vent or PCV valve fitting would tell you the rings and/or cylinders are worn.

A leakage test can also be used in conjunction with a compression test to diagnose other kinds of problems.

A cylinder that has poor compression but minimal leakage usually has a valvetrain problem such as a worn cam lobe, broken valve spring, collapsed lifter, bent push rod, etc.

If all the cylinders have low compression but show minimal leakage, the most likely cause is incorrect valve timing. The timing belt or chain may be off a notch or two.

If compression is good and leakage is minimal, but a cylinder is misfiring or shows up weak in a power balance test, it indicates a fuel delivery (bad injector) or ignition problem (fouled spark plug or bad plug wire).

Re: Break Out Another Thousand

Nobody is going to guarentee an engine after you pumped a ton of water in the oil...(wrong manifold)

Re: Break Out Another Thousand

You are going to have to change the oil several times before you get the milky out of it. Usually half a dozen times.
I change the oil and filter the first time, second time I replace the filter, and substitute a couple of quarts of oil with diesel fuel. It helps break the water down and wash the milky thick stuff off a lot of the internal parts. Usually do this about 3 or 4 times. I also use the same filter with the oil/diesel mixture and just dump it out and wash it out with clean diesel. Run it for about 5 minutes between changes.
Then change the oil and the filter with all oil. Usually twice to make sure all the diesel is gone. Then take it out and run it good to make sure water doesn't get back in the engine. While under load it burns off the remaining moisture.......... eventually.

Re: Break Out Another Thousand

That what my mechanic did when water was in my engine--run diesel fuel through it. Worked great

Re: Break Out Another Thousand

Great info.

I've got someone who is going to do my leakdown test for me next week, but I got to reading on the boards here and actually had some time, so I pulled the spark plugs out. #1 and 2 were both wet, and 3 and 4 bone dry. Turning it over, sure enough, #1 looked like ol' faithful, #2 not as bad, and no moisture out of 3 and 4. So does that mean that water is leaking in strictly through the head, or could it also be the intake/exhaust manifold? Again, it's a mercruiser 120 on an alpha 1 outdrive (1984)