Water in oil from gas?
 

I just got done rebuilding a mercruiser 5.7 and it is now in the boat and running. Immediately a couple problems came up, the first being low oil pressure. It runs about 20 psi at idle and maybe climbed to 30 when I was at 3000 rpms. So I pulled the valve covers, ran it, and had a very slow stream of oil coming out the rockers. While running with the valve covers off all oil was staying in the heads (not shooting anywhere) This is where things really went south. While watching for oil to shoot out the rockers, I watched the oil start to turn milky....

I shut it off immediately and started inspecting. There was definitely water droplets in various spots down the throat of the carburetor and droplets were still falling from the jets down after the motor had been shutoff and throttle in nuetral. I tried to get some of the droplets on my finger but failed. Really did not smell like gas. I put about 4 gallons of fresh gas in before ever starting the motor but that gas was added to maybe 5 gallons that was already in the tank and I have no idea the condition of that gas.

Is it possible that there was moisture in the old gas that was already in the tank and that is what's making my motor oil milky?

No

Where is the water droplets in the carburetor I'm seeing coming from then?

I will also add that there was no sign of milky oil on the dipstick and the oil level did not raise at all. The only milky oil I saw was coming from the rockers with the valve covers off.

Are you running on the hose? What t-sta? Circ. Pump or cross over?

Yes running it on the hose. T Stat is a new stock replacement
not sure exactly what you mean on pump type

I just ran it from the hose again but this time pulling fuel from 5 gallon external tank I have and I did NOT change the oil. I only ran it for a minute or so but it ran significantly better than before. I had a bad hesitation throttling off idle that is gone and it starts with just a turn of the key where before I had to give it some throttle. Part of that I'm thinking is due to a sticking choke though. Still no water showing up on the dipstick and fluid level has not rose even a millimeter on the dipstick. Going to change the oil and filter now, continue running it from the external tank and see where were at.

If air temps are down it could of been condensation that you where seeing

Cold water being pushed by high city water main pressure could be making the intake sweat like a cold beer can. I have had it happen, especially with a crossover and thermostat bypass.

Since starting the motor we have seen 40 degree temps and 80 degree temps here in holland. Ran it one more time on the external tank with the valve over off and got a picture of the oil. Dipstick still is at the same level and oil on it looks like brand new.
https://cimg1.ibsrv.net/gimg/www.off...b2127a2ba3.jpg

I would pull the filter and dump it in a jar. I bet it has water in it.

We had a pair of manifolds that reverted and the oil in the heads looked just like yours. Best of luck.

that will drain to the pan eventually and all of it will become that color, you might have a small leak in the oil cooler ?

That’s not condensation. You have reversion or a leak.

If you have the bow of your boat pointed down the driveway sometimes that angle can cause reversion. It wouldn’t be the first time that’s happened here.

Thanks for the replies everybody. When I had the block at the machine I did not give them the manifolds to pressure check, I just visually inspected for rust trails so that is a possibility. I pulled all plugs last night though and none were wet. I also this morning went back through my gasket set and read through the instructions again, I did not put any thread sealant on the timing cover bolts or water pump bolts and my instructions are saying some of them should have it?

The cam in the motor is also not stock. I dont have the specs off the top of my head but when I get back to my shop I can get the specs. I believe it is the 383 ramjet cam.

shouldn't that engine make more than 30psi oil?
What is the spec?

The 350 in my power play makes 40 psi all day long. I believe spec is a minimum of 4 psi at idle and 30-60 psi 2000 rpm and more. I have read s rule of thumb of 10 psi per 100 rpm

Edit:
Oil pressure on this motor is definitely an issue that I'm working on addressing.

Here are the cam specs
https://cimg0.ibsrv.net/gimg/www.off...c4654abd81.jpg

I was reverting with a 110° lsa on my big block. I know there’s more to it than just the lsa but 109° is suspect in my shade tree mechanic eyes. The oil pressure is another issue so check with a mechanical gauge. It looks like a strong chance that it’s coming back out.

That cam is what comes in GM 96-2000 5.0/5.7 Vortec trucks.

Does it even have any overlap at .050 " ? Doubt it. 196*/206* duration at .050" is tiny. LSA has to be looked at with duration #'s to come up with enough overlap at .050" lobe lift to cause reversion.

Is this a sign of water in the combustion chamber? This is looking down the riser and the little speckles are rust spots.
https://cimg5.ibsrv.net/gimg/www.off...34f6744308.jpg

have you pressure checked the exhaust manifolds&risers?you may have something cracked.

No, but I wish I did when I had the block at the machine shop. There are no visual rust trails other than this riser, the other is just black from exhaust.

I also did a compression test and expected to see a little higher numbers on a new motor. Is it possible I tightened the valves to tight?
https://cimg1.ibsrv.net/gimg/www.off...6af6f3c6c4.jpg

Just for fun, had a few minutes, so I ran some #’s.

The above cam has -17* overlap at .050” .

A 209/213 at .050” with 114LSA cam has -17* overlap at .050” also.

Here are some popular performance cams :

A 218/224 at .050” with 112 LSA has -4* overlap at .050” .

A 226/232 at .050” with 112 LSA has +5* overlap at .050”. With 114LSA it has +1* overlap at .050”.

A 236 / 244 at .050 with 112 LSA has +*16 overlap at .050”. With a 114LSA it has +12*. overlap

So basically reversion is a non issue with my motor?

what preload are you using, I presume hydro roller ?

Yes hydraulic roller. I wiggled the push rod up and down while tightening until there was no movement left, then spun it with my fingers while tightening until I could not spin anymore. Once that was done I went a 1/2 turn more.
With #1 at TDC I tightened exhaust 1,3,4,8 and intake 1,2,5,7
With #6 at TDC I tightened exhaust 2,5,6,7 and intake 3,4,6,8

what lifters are you using, on mine, when I feel tension or drag on the push rod I then start the preload to 3/4 to 7/8 turn down, you could be collapsing the plunger if you tighten till you cant spin the push rod, and might be hanging a valve open

The original ones that came with the motor...

are they done bone or tie bar......or ?

Not tie bar, lifters are held in place by this:
https://www.jegs.com/i/JEGS+Performa...SABEgKX3_D_BwE

okay, thats referred to as dog bone

Ive never done it like this before, I always rotate the engine while setting the lash to make sure the lifter roller is on the base circle of the cam
With #1 at TDC I tightened exhaust 1,3,4,8 and intake 1,2,5,7
With #6 at TDC I tightened exhaust 2,5,6,7 and intake 3,4,6,8

I changed the oil and now am in the middle of replacing riser gaskets. Once I'm done with that I will probably adjust valves while its running

Fwiw, I’ve read about manifolds holding pressure but having a crack open up as they heat up while running so near impossible to find. I have no practical experience on the matter though.

From my experience, if you are getting water in through the exhaust then you could see it on the spark plugs. The cylinder getting the water will look brighter with less carbon buildup. Also the water has to get past the rings to get into the oil. If that is the case you have bad rings as well, for that much water to get in the oil. Check your oil cooler, my brother just had to pull his to get brazed back up.

Rings are brand new and the cylinders were just bored .030 over. I will check the oil cooler

No oil cooler on this boat. Just a power steering cooler

Other than exhaust, Head-bolts and intake gaskets are common. How did you seal them ? Which intake and what gaskets and how prepped ?