Puffing steam out vents

[a70eliminator]

First run of season, block and manifolds were drained for winter, ran all last year without incident, inoriced the steam at home in driveway on hose but disregarded it for moisture burning off.
Took on lake and vents spitting out droplets of water after running awhile, engine temp normal powers up 4800 rpm idles nice but now oil is copletely milky but level ok on dipstick.
Only thing that changed over winter was new riser gaskets, new thermostat.
Is it possible a riser gasket seeping could cause this?
I pulled the intake and heads, underside of v/c's and lifter valley all milkshake, head gaskets looked ok, im stumped.

 

[a70eliminator]

Pics

 

[Scott06]

Pics

Pressure test the cooling system see if it holds. of course better to do this before you tear it down. Did you see any cracks in lifter valley below heads, underside of thermostat is also a corrosion and crack area.

riser gaskets would have to leak water back into cylinders and in oil. Might take the plugs out and they usually look steam cleaned if water is getting in

you said you put a thermostat in did it get up to temp

 

[a70eliminator]

Yes it went to normal running temp.
Combustion chambers and piston tops all look uniform as did the spark plugs, the only thing that looks suspicious is see pics of intake runners 1 clean set on both banks, maybe from sucking steam in from vents at flame arrestor..

 

[Scott06]

Yes it went to normal running temp.
Combustion chambers and piston tops all look uniform as did the spark plugs, the only thing that looks suspicious is see pics of intake runners 1 clean set on both banks, maybe from sucking steam in from vents at flame arrestor..

Your best bet is to pressure test the cooling system.

Which isn’t hard to do and will confirm if you have a crack or other odd ball situation.
does you engine have an engine oil cooler by chance ?

 

[a70eliminator]

No oil cooler & its down ro the block, can I block off the deck with a sheet of rubber bolt on the heads & pressurize block with air?

 

[Lou C]

If you have an inspection camera I’d look inside the elbow and see if there sign of water leaking around the joint between the manifold & elbow. What about your intake gaskets? Any chance they were leaking?
Any overheats during the past few seasons? I had that problem and 3 seasons later had what you have there. Cause was leaking head gaskets. Also found small cracks in the exhaust valve seat area of the center cyl on each cyl head.
PS
You list a 5.8 Cobra in your sig but that’s def a Chevrolet! 5.8 I alway think of Ford.

 

[a70eliminator]

If you have an extra inspection camera I’d look inside the elbow and see if there sign of water leaking around the joint between the manifold & elbow. What about your intake gaskets? Any chance they were leaking?
Any overheats during the past few seasons? I had that problem and 3 seasons later had what you have there. Cause was leaking head gaskets. Also found small cracks in the exhaust valve seat area of the center cyl on each cyl head.
PS
You list a 5.8 Cobra in your sig but that’s def a Chevrolet! 5.8 I alway think of Ford.

Oh crap yea the 5.8 cobra was years ago, I now have a 5.7 chevy.
I cant help to think it has somethin to do with risers as thats all I messed with over winter, oh well Im learning going through the motions not necessarily needed uggh.

 

[a70eliminator]

Oh crap yea the 5.8 cobra was years ago, I now have a 5.7 chevy.
I cant help to think it has somethin to do with risers as thats all I messed with over winter, oh well Im learning going through the motions not necessarily needed uggh.

If you have an extra inspection camera I’d look inside the elbow and see if there sign of water leaking around the joint between the manifold & elbow. What about your intake gaskets? Any chance they were leaking?
Any overheats during the past few seasons? I had that problem and 3 seasons later had what you have there. Cause was leaking head gaskets. Also found small cracks in the exhaust valve seat area of the center cyl on each cyl head.
PS
You list a 5.8 Cobra in your sig but that’s def a Chevrolet! 5.8 I alway think of Ford.

Not aure what you mean by exhaust elbow, riser? The thing that bolts to the top of ex. manifold where water & exhaust mix?

 

[Lou C]

Yes the elbow is the part that bolts on top of the manifold, sometimes the gasket between them leaks and puts water in a few cyls.

I use an inspection camera to scope the inside of the elbow and manifold to make sure water isn't leaking in, it's nice to not have to take it all apart to find that out.

 

[Lou C]

Here's what I'm taking about, I removed the rubber exhaust hoses and the 90* exhaust pipes and fed an inspection camera wand into the exhaust opening and looked inside since they have been used in salt water for 5 seasons at this point. I plan on doing it at the end of each season to catch a problem before it gets bigger. Sometimes you'll see signs of condensation which will look like little beads of corrosion like a dot, that's because the exhaust in some engines may run cool enough at idle that it doesn't get burned off but a lot of rust in the bottom of the manifold, is a problem.

 

[Lou C]

Your engine pix don't look bad at first glance but look at the area between cyls 4&6 that looks a little suspicious for head gasket failure. I would like to see the block after cleaning off the old gasket and the cyl heads. If the block deck looks good, I'd probably get the heads magnafluxed and checked out and reinstall them.
That type of damage can happen even if the engine doesn't overheat, especially if the boat does not reach the specified wide open throttle max RPM. The combustion chambers can overheat especially on the center cylinders, they get the hottest because the exhaust valves are right next to each other on the small block Chevrolet.
What type of manifolds do you have, dry joint or wet joint? Volvo or Merc rigging?

 

[Scott06]

No oil cooler & its down ro the block, can I block off the deck with a sheet of rubber bolt on the heads & pressurize block with air?

Ideally you want to pressure test the heads too as often they crack at exhaust seat or jacket in salt wears through. If it were mine I’d put the o,d head gaskets back on torque the heads down and test.
why did you change riser gaskets ? Is this salt or fresh water

any chance water got down the carb during storage ?

 

[a70eliminator]

Your engine pix don't look bad at first glance but look at the area between cyls 4&6 that looks a little suspicious for head gasket failure. I would like to see the block after cleaning off the old gasket and the cyl heads. If the block deck looks good, I'd probably get the heads magnafluxed and checked out and reinstall them.
That type of damage can happen even if the engine doesn't overheat, especially if the boat does not reach the specified wide open throttle max RPM. The combustion chambers can overheat especially on the center cylinders, they get the hottest because the exhaust valves are right next to each other on the small block Chevrolet.
What type of manifolds do you have, dry joint or wet joint? Volvo or Merc rigging?

Oh jeez your right about the cyl 4-6 would this also take on water? The manifolds are freshwater cooled alpha gen 1, and I replaced riser gaskets due to visibile corrosion/leakage at external joint.

 

[Lou C]

It is possible but hard to say...
on mine what I found was that there was water in the 2 front cyls, #1 and #2, and I found a split in the fire ring of the head gaskets that were for those cyls, and the split was right near a water passage. So water got into the cyls (not enough to hydrolock but made the oil milky). I redid it with a pair of reman cyl heads new gaskets and new head bolts. Still running fine 8 years later. You're lucky you caught it early.

 

[a70eliminator]

UPDATE:
Torqed heads with new gaskets, set intake manifold with new gaskets, pressure tested to 20psi no hissing no leak down, so happy the block aint cracked, all valves are closed rockers loose if the even matters for this test.

 

[cyclops222]

I see several gasket areas at where the 2 cylinders are very close. Very uneven colors of surfaces there. The seals at those close spots can warp at high temperatures. Been there. Cold they seal up

 

[Lou C]

UPDATE:
Torqed heads with new gaskets, set intake manifold with new gaskets, pressure tested to 20psi no hissing no leak down, so happy the block aint cracked, all valves are closed rockers loose if the even matters for this test.

That’s great work! Fortunate outcome!
Just keep an eye on it during your first few runs. The Chevy small block is very forgiving because of simple design and good basic engineering.

 

[Scott06]

UPDATE:
Torqed heads with new gaskets, set intake manifold with new gaskets, pressure tested to 20psi no hissing no leak down, so happy the block aint cracked, all valves are closed rockers loose if the even matters for this test.

That’s good. Verify your exhaust is not leaking get it running do a couple oil changes to make sure it runs clear oil wise

exhaust manifolds can be tested by filling with acetone. It wicks into cracks easier than water

 

[a70eliminator]

Yes exhaust manifolds tomorrow...heres what it initially looked like if the video loads.