Chrysler M440 - water in oil

The swivel/risers on this should only help ingesting water from the exhaust, assuming it's coming from the pipes up to the engine. Now if it were leaking inside the riser itself, then the second you shut off the engine it would pool up in that rear cylinder. I would think that would just hydrolock it during cranking and you'd never get it started. Apparently this locks up while running for a minute or so.

Believe Joe mentioned the odd manifold config "could" be to keep water from backing up via exh, any chance that could be why no issue on hose but issue in water??

I'll just keep talking to myself here . Maybe some pictures will get some interest.



I took a few pictures last night of the intake and heads. I noticed that the intake had visible rust on the #8 runner (and its corresponding #5 on the other side). Naturally there was also signs of rust inside the head intake port as well. I don't know if this is the cause or the affect of hydolocking the cylinder.

Picture of #8 intake runner



Picture of #5 intake runner



Picture of #8 intake port on head

Ok folks. I ended up buying Adam's (pcjeeper) 73 SN with the Chrysler M440 this last weekend. Adam was looking for a boat that he could use right away and when this boat gave him some engine troubles, he decided to sell. With the 67 project still underway, I definitely didn't need another boat, but I have always loved that color combo on a 2nd gen, and with the rare big-block power, I just couldn't pass it up.

I need some help with the engine however. Adam successfully ran it on the hose but when he ran it at the boat ramp, it ended up hydrolocking on him 2 times. The 2nd of which broke an exhaust valve and bent a pushrod. The oil was also milky. I am definitely not a motorhead, so I need some guidance. What are the first steps to diagnosing this thing.

What we know:
-It ran on the hose (don't know if it started getting milky oil at this point)
-It started at the lake but locked up and died
-Pulled plugs and cranked over to remove water
-Refired engine but locked up again
-Locked up a 2nd time
-#8 exh. valve is broken, and associated pushrod is bent
-Oil was milky

So I figure the possibilities are:
-Bad exhaust manifold
-Bad ex. manifold/riser gasket
-Bad head gasket
-Cracked head
-Cracked block

The engine is still in the boat, but the Stb. head is removed.

Any thoughts?